Priority and emerging flame retardants in rivers: occurrence in water and sediment, Daphnia magna toxicity and risk assessment

Organophosphate ester in surface water of the Pearl River and South China Sea, China: Spatial variations and ecological risks

This study focused on investigating the concentrations, compositional profiles, partitioning behaviors and spatial variations of organophosphate esters (OPEs) in the Pearl River (PR), South China Sea (SCS) region, to evaluate their environmental risks. ∑OPEs concentrations in the surface water of the PR ranged from 117.5 to 854.8 ng/L in the dissolved phase and from 0.5 to 13.3 ng/L in the suspended particulate matter. In the surface seawaters of the northern and western parts of the SCS, ∑OPEs concentrations were 1.3-17.6 ng/L (mean: 6.7 ± 5.2) and 2.3-24.4 ng/L (mean: 7.6 ± 5.5), respectively. The percentage of chlorinated OPEs in surface water samples from the PR to the SCS was 79 ± 15%. Tripentyl phosphate (TPeP) (average: 28.3%) and triphenylphosphate (TPhP) (average: 9.6%) exhibited significant particulate fraction. A significant negative correlation (p < 0.05) between salt concentration and OPE congeners in seawater suggested that river runoff predominantly introduced OPEs into the coastal waters of the SCS. The findings also showed higher levels of OPEs in the PR and estuary than in offshore waters. The OPE loading from the PR into the SCS was estimated to be ∼119 t y-1. The presence of TCEP (RQmax = 2.1), TnBP (RQmax = 0.48) and TPhP (RQmax = 0.3) in PR water samples pose a high risk to aquatic organisms, whereas OPEs (RQ < 0.1) in SCS water samples do not pose a threat to aquatic organisms. This research emphasizes the environmental fate and impact of OPEs on surface waters of the PR and SCS.

The role of iron materials in the abiotic transformation and biotransformation of polybrominated diphenyl ethers (PBDEs): A review

Polybrominated diphenyl ethers (PBDEs), widely used as flame retardants, easily enter the environment, thus posing environmental and health risks. Iron materials play a key role during the migration and transformation of PBDEs. This article reviews the processes and mechanisms of adsorption, degradation, and biological uptake and transformation of PBDEs affected by iron materials in the environment. Iron materials can effectively adsorb PBDEs through hydrophobic interactions, π-π interactions, hydrogen/halogen bonds, electrostatic interactions, coordination interactions, and pore filling interactions. In addition, they are beneficial for the photodegradation, reduction debromination, and advanced oxidation degradation and debromination of PBDEs. The iron material-microorganism coupling technology affects the uptake and transformation of PBDEs. In addition, iron materials can reduce the uptake of PBDEs in plants, affecting their bioavailability. The species, concentration, and size of iron materials affect plant physiology. Overall, iron materials play a bidirectional role in the biological uptake and transformation of PBDEs. It is necessary to strengthen the positive role of iron materials in reducing the environmental and health risks caused by PBDEs. This article provides innovative ideas for the rational use of iron materials in controlling the migration and transformation of PBDEs in the environment.

Investigation of Urinary Metabolites of Organophosphate Esters in Hanoi, Vietnam: Assessment Exposure and Estimated Daily Intake

In recent years, organophosphate esters (OPEs) have become one of the most common additives in various consumer products worldwide, therefore the exposure and impact of OPEs on human health are drawing a lot of attention. In this study, three metabolites of OPEs including bis(1,3-dichloro-2-propyl) phosphate (BDCIPP), diphenyl phosphate (DPhP) and diethyl phosphate (DEP) were investigated in first-morning void urine samples taken from a population (age range: 3-76 years old) in Hanoi, Vietnam. The most dominant urinary OPE metabolite was DEP with the geometric mean of specific gravity adjust (SG-adjusted) concentration were 1960 ng mL-1 and detected frequency (DF) of 98%. Followed by DPhP (8.01 ng mL-1, DF: 100%) and BDCIPP (2.18 ng mL-1, DF: 51%). The results indicated that gender and age might have associations with the OPE metabolites variation in urine samples. The levels of OPE metabolites in urine samples from females were slightly higher than in males. An increase in age seems to have an association with a decrease in DPhP levels in urine. Exposure doses of parent OPEs were evaluated from the unadjusted urinary concentration of corresponding OPE metabolite. The estimated exposure doses of triethyl phosphate (TEP) (mean: 534,000 ng kg-1 d-1) were significantly higher than its corresponding reference dose, suggesting the high potential risk from the current exposure doses of TEP to human health. The results of this work provided the initial information on the occurrence of three OPE metabolites in urine from Hanoi, Vietnam and estimated exposure dose of corresponding parent OPEs.

Organophosphate esters in water and air: A minireview of their sources, occurrence, and air-water exchange

Organophosphate esters (OPEs) have received considerable attention in environmental research due to their extensive production, wide-ranging applications, prevalent presence, potential for bioaccumulation, and associated ecological and health concerns. Low efficiency of OPE removal results in the effluents of wastewater treatment plants emerging as a significant contributor to OPE contamination. Their notable solubility and mobility give OPEs the potential to be transported to coastal ecosystems via river discharge and atmospheric deposition. Previous research has indicated that OPEs have been widely detected in the atmosphere and water bodies. Atmospheric deposition across air-water exchange is the main input route for OPEs into the environment and ecosystems. The main processes that contribute to air-water exchange is air-water diffusion, dry deposition, wet deposition, and the air-water volatilization process. The present minireview links together the source, occurrence, and exchange of OPEs in water and air, integrates the occurrence and profile data, and summarizes their air-water exchange in the environment.

Temporal evolution of plastic additive contents over the last decades in two major European rivers (Rhone and Rhine) from sediment cores analyses

Although global plastic distribution is at the heart of 21st century environmental concerns, little information is available concerning how organic plastic additives contaminate freshwater sediments, which are often subject to strong anthropogenic pressure. Here, sediment core samples were collected in the Rhone and the Rhine watersheds (France), dated using 137Cs and 210Pbxs methods and analysed for nine phthalates (PAEs) and seven organophosphate esters (OPEs). The distribution of these organic contaminants was used to establish a chronological archive of plastic additive pollution from 1860 (Rhine) and 1930 (Rhone) until today. Sediment grain size and parameters related to organic matter (OM) were also measured as potential factors that may affect the temporal distribution of OPEs and PAEs in sediments. Our results show that OPE and PAE levels increased continuously in Rhone and Rhine sediments since the first records. In both rivers, ∑PAEs levels (from 9.1 ± 1.7 to 487.3 ± 27.0 ng g-1 dry weight (dw) ± standard deviation and from 4.6 ± 1.3 to 65.2 ± 11.2 ng g-1 dw, for the Rhine and the Rhone rivers, respectively) were higher than ∑OPEs levels (from 0.1 ± 0.1 to 79.1 ± 13.7 ng g-1 dw and from 0.6 ± 0.1 to 17.8 ± 2.3 ng g-1 dw, for Rhine and Rhone rivers, respectively). In both rivers, di(2-ethylhexyl) phthalate (DEHP) was the most abundant PAE, followed by diisobutyl phthalate (DiBP), while tris (2-chloroisopropyl) phosphate (TCPP) was the most abundant OPE. No relationship was found between granulometry and additives concentrations, while organic matter helps explain the vertical distribution of PAEs and OPEs in the sediment cores. This study thus establishes a temporal trajectory of PAEs and OPEs contents over the last decades, leading to a better understanding of historical pollution in these two Western European rivers.

Co-occurrence of organophosphate esters and phosphorus fractions in river sediments: Implications for pollution prediction and environment risk assessment

Organophosphate esters (OPEs) and phosphorus (P) are widespread pollutants in aquatic ecosystems, presenting potential ecological risks. However, there is still a lack of comprehensive understanding of their relationships in sediments. In this study, we investigated the co-occurrence and behaviors of the OPEs and P in urban river sediments. The results indicated serious OPE and P pollution in the study area, with substantial spatial variations in the contents and compositions. The OPE congeners and P fractions exhibited different correlations, particularly more significant linear relationships (R = 0.455 - 0.816, p < 0.05) were observed between the aryl-OPEs and P fractions, potentially due to the influence from sources, physicochemical properties, and total organic carbon. About 56 to 71% of variability in predicting the concentrations of aryl-OPE can be explained by the multiple linear regression model using the Fe/Al- and Ca-bound P contents. The study regions exhibited greater aryl-OPEs ecological risks were consistent with the regions with more serious Total P pollution levels. This study represents the first report demonstrating the potential of Fe/Al-P and Ca-P contents in predicting aryl-OPE contents in heavily polluted sediments, providing a useful reference to comprehensively assess the occurrence and environmental behaviors of aryl-OPEs in anthropogenic polluted sediments.

Influence of watershed characteristics and human activities on the occurrence of organophosphate esters related to dissolved organic matter in estuarine surface water

Organophosphate esters (OPEs) are widespread in aquatic environments and pose potential threats to ecosystem and human health. Here, we profiled OPEs in surface water samples of heavily urbanized estuaries in eastern China and investigated the influence of watershed characteristics and human activities on the spatial distribution of OPEs related to dissolved organic matter (DOM). The total OPE concentration ranged from 22.3 to 1201 ng/L, with a mean of 162.6 ± 179.8 ng/L. Chlorinated OPEs were the predominant contaminant group, accounting for 27.4-99.6 % of the total OPE concentration. Tris(2-chloroisopropyl) phosphate, tris(1,3-dichloro-2-propyl) phosphate, and tributyl phosphate were the dominant compounds, with mean concentrations of 111.2 ± 176.0 ng/L, 22.6 ± 21.5 ng/L, and 14.8 ± 14.9 ng/L, respectively. Variable OPE levels were observed in various functional areas, with significantly higher concentrations in industrial areas than in other areas. Potential source analysis revealed that sewage treatment plant effluents and industrial activities were the primary OPE sources. The total OPE concentrations were negatively correlated to the mean slope, plan curvature, and elevation, indicating that watershed characteristics play a role in the occurrence of OPEs. Individual OPEs (triisobutyl phosphate, tris(2-butoxyethyl) phosphate, tris(2-chloroethyl) phosphate, and tricresyl phosphate) and Σalkyl-OPEs were positively correlated to the night light index or population density, suggesting a significant contribution of human activity to OPE pollution. The co-occurrence of OPEs and DOM was also observed, and the fluorescence indices of DOM were found to be possible indicators for tracing OPEs. These findings can elucidate the potential OPE dynamics in response to DOM in urbanized estuarine water environments with intensive human activities.

Enantioselectivity in ecotoxicity of pharmaceuticals, illicit drugs, and industrial persistent pollutants in aquatic and terrestrial environments: A review

At present, there is a serious concern about the alarming number of recalcitrant contaminants that can negatively affect biodiversity threatening the ecological status of marine, estuarine, freshwater, and terrestrial ecosystems (e.g., agricultural soils and forests). Contaminants of emerging concern (CEC) such as pharmaceuticals (PHAR), illicit drugs (ID), industrial persistent pollutants, such as polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) and chiral ionic solvents are globally spread and potentially toxic to non-target organisms. More than half of these contaminants are chiral and have been measured at different enantiomeric proportions in diverse ecosystems. Enantiomers can exhibit different toxicodynamics and toxicokinetics, and thus, can cause different toxic effects. Therefore, the enantiomeric distribution in occurrence cannot be neglected as the toxicity and other adverse biological effects are expected to be enantioselective. Hence, this review aims to reinforce the recognition of the stereochemistry in environmental risk assessment (ERA) of chiral CEC and gather up-to-date information about the current knowledge regarding the enantioselectivity in ecotoxicity of PHAR, ID, persistent pollutants (PCBs and PBDEs) and chiral ionic solvents present in freshwater and agricultural soil ecosystems. We performed an online literature search to obtain state-of-the-art research about enantioselective studies available for assessing the impact of these classes of CEC. Ecotoxicity assays have been carried out using organisms belonging to different trophic levels such as microorganisms, plants, invertebrates, and vertebrates, and considering ecologically relevant aquatic and terrestrial species or models organisms recommended by regulatory entities. A battery of ecotoxicity assays was also reported encompassing standard acute toxicity to sub-chronic and chronic assays and different endpoints as biomarkers of toxicity (e.g., biochemical, morphological alterations, reproduction, behavior, etc.). Nevertheless, we call attention to the lack of knowledge about the potential enantioselective toxicity of many PHAR, ID, and several classes of industrial compounds. Additionally, several questions regarding key species, selection of most appropriate toxicological assays and ERA of chiral CEC are addressed and critically discussed.

Occurrence, distribution, potential sources, and risks of organophosphate esters in fresh snow on Urumqi Glacier No. 1, eastern Tien Shan, China

Organophosphate esters (OPEs), extensively used as flame retardants, are widely detected in various regions and environments. The potential toxicity of OPEs has caused great concern in recent years. Based on the global distillation model, the Tien Shan glaciers, such as Urumqi Glacier No. 1, could be as a potential "sink" for OPEs. However, little is known about the concentration, distribution, potential sources, and ecological risks of OPEs in Tien Shan glaciers. In this study, fresh snow samples were collected at various altitudes on the Urumqi Glacier No. 1, eastern Tien Shan, China. The total concentrations of ten OPEs (Σ10OPEs) ranged from 116 to 152 ng/L. The most abundant OPE was tris-(2-chloroisopropyl) phosphate (TCIPP), contributing to 74 % of the total OPEs. Σ10OPEs, tri-n-butyl phosphate (TnBP), and TCIPP concentrations showed positive correlations with altitude, indicating the effect of cold condensation on OPEs deposition. Based on air mass back-trajectory analysis and principal component analysis, we found that emissions from both traffic and household products in indoor environment were the important sources, and OPEs on the Urumqi Glacier No. 1 might mainly originate from Europe. Our assessment also showed triphenyl phosphate (TPhP) posed a low ecological risk in snow. This is the first systematic study of OPEs on the Tien Shan glaciers.

Bioaccumulation and thyroid endcrione disruption of 2-ethylhexyl diphenyl phosphate at environmental concentration in zebrafish larvae

2-ethylhexyl diphenyl phosphate (EHDPP) strongly binds to transthyretin (TTR) and affects the expression of genes involved in the thyroid hormone (TH) pathway in vitro. However, it is still unknown whether EHDPP induces endocrine disruption of THs in vivo. In this study, zebrafish (Danio rerio) embryos (< 2 h post-fertilization (hpf)) were exposed to environmentally relevant concentrations of EHDPP (0, 0.1, 1, 10, and 100 μg·L-1) for 120 h. EHDPP was detected in 120 hpf larvae at concentrations of 0.06, 0.15, 3.71, and 59.77 μg·g-1 dry weight in the 0.1, 1, 10, and 100 μg·L-1 exposure groups, respectively. Zebrafish development and growth were inhibited by EHDPP, as indicated by the increased malformation rate, decreased survival rate, and shortened body length. Exposure to lower concentrations of EHDPP (0.1 and 1 μg·L-1) significantly decreased the whole-body thyroxine (T4) and triiodothyronine (T3) levels and altered the expressions of genes and proteins involved in the hypothalamic-pituitary-thyroid axis. Downregulation of genes related to TH synthesis (nis and tg) and TH metabolism (dio1 and dio2) may be partially responsible for the decreased T4 and T3 levels, respectively. EHDPP exposure also significantly increased the transcription of genes involved in thyroid development (nkx2.1 and pax8), which may stimulate the growth of thyroid primordium to compensate for hypothyroidism. Moreover, EHDPP exposure significantly decreased the gene and protein expression of the transport protein transthyretin (TTR) in a concentration-dependent manner, suggesting a significant inhibitory effect of EHDPP on TTR. Molecular docking results showed that EHDPP and T4 partly share the same mode of action of binding to the TTR protein, which might result in decreased T4 transport due to the binding of EHDPP to the TTR protein. Taken together, our findings indicate that EHDPP can cause TH disruption in zebrafish and help elucidate the mechanisms underlying EHDPP toxicity.

Synthesis of EDTA-cysteine-β-cyclodextrin for the removal of organophosphate flame retardants (OPFR) from sediments and soil samples from the Buffalo River Estuary, Eastern Cape of South Africa

Due to the growing water and environmental pollution worldwide, it is important to develop new effective materials for the remediation of sediments, soil and water contaminated with organic pollutants including flame retardants. In this study, a new soluble and hydrophilic polymer material containing ethylenediaminetetraacetic acid (EDTA), cysteine and beta cyclodextrin (β-CD) depicted as EDTA-Cysteine-β-Cyclodextrin was prepared for the removal of organophosphate flame retardants (OPFRs) from simulated sediment and soil samples and those collected from the Buffalo River Estuary in East London, Eastern Cape Province of South Africa. The β-CD was modified using cysteine and EDTA. The EDTA-Cysteine-β-Cyclodextrin was characterized by Fourier transform infrared (FTIR), scanning electron microscope (SEM) and energy dispersive x-ray spectroscopy (EDX). The results show that a non-porous spherical and bubble shaped material was synthesized. For the adsorption study, different contaminants' concentrations, solution pH, adsorbent dose and contact time were varied to ascertain the optimum conditions for the removal of OPFRs from soil and sediment. The removal of OPFRs was highly dependent on pH, adsorbent dose, concentration and contact time of the adsorption process. The optimum pH, contact time, OPFRs concentration and adsorbent dose were 3, 120 min, 60 mM and 5 mL, respectively with average adsorption percentage of 97.13 ± 14.04 %. The results proved that this newly developed polymer can decontaminate sediments and soil. The EDTA-Cysteine-β-Cyclodextrin gave promising possibilities for practical application for the remediation of OPFRs from sediment and soil samples through adsorption process.

Proposal for priority emerging pollutants in the Nakdong river, Korea: Application of EU watch list mechanisms

The Nakdong River, the longest in Korea, has received numerous pollutants from heavily industrialized and densely populated areas while being used as a drinking water source. A number of research have reported occurrences of emerging pollutants (EPs) in the river. The results requested efficient monitoring and systematic management strategies such as EU watch list under Water Framework Directive. The aim of this study is to propose a watch list through preliminary monitoring of the river and risk-based prioritization approach. As candidates for monitoring target, 632 substances were selected based on literature and database searches. Among them, 175 substances were subjected to target screening method whereas 457 were evaluated via suspect screening. A risk-based prioritization was applied to substances quantified through target screening based on concentrations, and a scoring-based prioritization was applied to substances tentatively identified through suspect screening. Sampling campaigns (n = 12) were conducted from October 2020 to September 2021, at 8 sampling sites along the river. As a result, 130 target substances were quantified above the LOQ. Among the 21 substances whose priority score was assigned through risk-based prioritization, telmisartan and iprobenfos were identified with very high environmental risk while candesartan, TBEP, imidacloprid, azithromycin and clotrimazole were classified with high or intermediate risk. As result of the scoring system for 39 tentatively identified substances, 6 substances (benzophenone, caprolactam, metolachlor oxanilic acid, heptaethylene glycol, octaethylene glycol and pentaethylene glycol), which were then confirmed with reference standards, showed a potential environmental risk. Those substances prioritized through target and suspect screening followed by scoring systems can be a subset for the watch list and potential targets for nationwide water quality monitoring program in the future.

Spatial and temporal variability and risk assessment of organophosphate esters in seawater and sediments of the Yangtze River estuary

Organophosphate esters (OPEs) as substitutes for PBDEs have been widely detected in the marine environment, while little is known about the pollution characteristics and variation of OPEs in estuarine environments with complex hydrodynamic conditions and land-based input. Yangtze River Estuary (YRE) is a typical highly urbanized and industrialized estuary, with a complex hydrological environment and geochemical behavior. This study found that the concentrations of OPEs in both seawater and sediments in the YRE were higher in spring than in summer. Alkyl OPEs were the first contributor, with TnBP and TiBP as the main components, where the contribution of alkyl OPEs had exceeded 75 % in both seawater and sediments in spring, and 60 % in summer seawater, and even 80 % in sediments. In spring, OPEs peaked in the central to southern region near the YRE. In summer, OPEs were mainly concentrated in the southern branch waterway and southern nearshore area of the YRE and showed a decreasing trend to the northeast. The OPEs in the sediments were mainly concentrated in the Yangtze River Mud Area (YREMA) and the Zhe-Min Coastal Mud Area (ZMCMA). Based on the fugacity model and principal component analysis, sediments could be released into the aquatic environment as an endogenous source, and exogenous sources were mainly municipal and industrial sewage discharge sources, urban and marine traffic discharge sources, and atmospheric deposition sources. The ecological risk analysis showed that the Σ14OPEs had exhibited a low to moderate ecological risk in the southern branch waterway and the south-central region offshore.

An Initial Survey on Occurrence, Fate, and Environmental Risk Assessment of Organophosphate Flame Retardants in Romanian Waterways

Organophosphate ester flame retardants (OPFRs) are ubiquitous organic pollutants in the environment and present an important preoccupation due to their potential toxicity to humans and biota. They can be found in various sources, including consumer products, building materials, transportation industry, electronic devices, textiles and clothing, and recycling and waste management. This paper presents the first survey of its kind in Romania, investigating the composition, distribution, possible sources, and environmental risks of OPFRs in five wastewater treatment plants (WWTPs) and the rivers receiving their effluents. Samples from WWTPs and surface waters were collected and subjected to extraction processes to determine the OPFRs using liquid chromatography with mass spectrometric detection. All the target OPFRs were found in all the matrices, with the average concentrations ranging from 0.6 to 1422 ng/L in wastewater, 0.88 to 1851 ng/g dry weight (d.w.) in sewage sludge, and 0.73 to 1036 ng/L in surface waters. The dominant compound in all the cases was tri(2-chloroisopropyl) phosphate (TCPP). This study observed that the wastewater treatment process was inefficient, with removal efficiencies below 50% for all five WWTPs. The environmental risk assessment indicated that almost all the targeted OPFRs pose a low risk, while TDCPP, TCPP, and TMPP could pose a moderate risk to certain aquatic species. These findings provide valuable information for international pollution research and enable the development of pollution control strategies.

An effective method for the simultaneous extraction of 173 contaminants of emerging concern in freshwater invasive species and its application

A robust and efficient extraction method was developed to detect a broad range of pollutants of emerging interest in three freshwater invasive species: American red crab (Prokambarus clarkii), Asian clam (Corbicula fluminea), and pumpkinseed fish (Lepomis gibbosus). One native species, "petxinot" clam (Anodonta cygnea), was also evaluated. Invasive species are often more resistant to contamination and could be used in biomonitoring studies to assess the effect of contaminants of emerging concern on aquatic ecosystems while preserving potentially threatened native species. So far, most extraction methods developed for this purpose have focused on analyzing fish and generally focus on a limited number of compounds, especially analyzing compounds from the same family. In this sense, we set out to optimize a method that would allow the simultaneous extraction of 87 PhACs, 11 flame retardants, 21 per- and poly-fluoroalkyl substances, and 54 pesticides. The optimized method is based on ultrasound-assisted solvent extraction. Two tests were performed during method development, one to choose the extraction solvent with the best recovery efficiencies and one to select the best clean-up. The analysis was performed by high-performance liquid chromatography coupled to high-resolution mass spectrometry. The method obtained recoveries between 40 and 120% and relative standard deviations of less than 25% for 85% of the analytes in the four validated matrices. Limits of quantification between 0.01 ng g-1 and 22 ng g-1 were obtained. Application of the method on real samples from the Albufera Natural Park of Valencia (Spain) confirmed the presence of contaminants of emerging concern in all samples, such as acetaminophen, hydrochlorothiazide, tramadol, PFOS, carbendazim, and fenthion. PFAS were the group of compounds with the highest mean concentrations. C. fluminea was the species with the highest detection frequency, and P. clarkii had the highest average concentrations, so its use is prioritized for biomonitoring studies.

Targeted and non-targeted screening of flame retardants in rural and urban honey

Flame retardants (FRs) are often added to commercial products to achieve flammability resistance, but they are not chemically bonded to the materials, so, they can be easily released into the environment during the production and disposal processes. When honeybees travel to collect nectar during the pollination process, they are prone to be contaminated by chemicals in the air. Therefore, honey contamination has been proposed as an indicator of the pollution status in a particular region. To date, the occurrence of flame retardants in urban honey has yet to be explored. In this study, a direct injection method was used, coupled with LC-QTOF-MS, to analyze honey samples. This method was applied to urban (n = 100) and rural (n = 100) honey samples from the Quebec province (Canada), and the levels of flame retardants in urban and rural honey samples were not significantly different. In the targeted approach, two of the target FRs, tris(2-butoxyethyl) phosphate (TBOEP) and triphenyl phosphate (TPHP), were detected and confirmed at an average trace concentration (<1 ng mL-1). Additionally, a non-targeted screening workflow with an in-house-built library was developed and validated to screen for flame retardants in honey. Tris (2-chloropropyl) phosphate (TCIPP) was identified in honey using the non-targeted screening workflow and confirmed using a pure analytical standard, but there are other compounds detected in the non-targeted analysis that have yet to be validated. This study was the first to report FR compounds based on a direct injection method, coupled with a non-targeted screening workflow, at a trace level in a honey matrix. It also showed that a non-targeted workflow was effective to detect and identify unknown compounds present in the honey sample; hence, this provided a novel angle for the occurrence of FRs in air, with honey as a bio-indicator.

The plastic health map: A systematic evidence map of human health studies on plastic-associated chemicals

BACKGROUND

The global production and use of plastic materials has increased dramatically since the 1960s and there is increasing evidence of human health impacts related to exposure to plastic-associated chemicals. There is, however, no comprehensive, regulatory, post-market monitoring for human health effects of plastic-associated chemicals or particles and it is unclear how many of these have been investigated for effects in humans, and therefore what the knowledge gaps are.

OBJECTIVE

To create a systematic evidence map of peer-reviewed human studies investigating the potential effects of exposure to plastic-associated particles/chemicals on health to identify research gaps and provide recommendations for future research and regulation policy.

METHODS

Medline and Embase databases were used to identify peer-reviewed primary human studies published in English from Jan 1960 - Jan 2022 that investigated relationships between exposures to included plastic-associated particles/chemicals measured and detected in bio-samples and human health outcomes. Plastic-associated particles/chemicals included are: micro and nanoplastics, due to their widespread occurrence and potential for human exposure; polymers, the main building blocks of plastic; plasticizers and flame retardants, the two most common types of plastic additives with the highest concentration ranges in plastic materials; and bisphenols and per- or polyfluoroalkyl substances, two chemical classes of known health concern that are common in plastics. We extracted metadata on the population and study characteristics (country, intergenerational, sex, age, general/special exposure risk status, study design), exposure (plastic-associated particle/chemical, multiple exposures), and health outcome measures (biochemical, physiological, and/or clinical), from which we produced the interactive database 'Plastic Health Map' and a narrative summary.

RESULTS

We identified 100,949 unique articles, of which 3,587 met our inclusion criteria and were used to create a systematic evidence map. The Plastic Health Map with extracted metadata from included studies are freely available at https://osf.io/fhw7d/ and summary tables, plots and overall observations are included in this report.

CONCLUSIONS

We present the first evidence map compiling human health research on a wide range of plastic-associated chemicals from several different chemical classes, in order to provide stakeholders, including researchers, regulators, and concerned individuals, with an efficient way to access published literature on the matter and determine knowledge gaps. We also provide examples of data clusters to facilitate systematic reviews and research gaps to help direct future research efforts. Extensive gaps are identified in the breadth of populations, exposures and outcomes addressed in studies of potential human health effects of plastic-associated chemicals. No studies of the human health effects of micro and/or nanoplastics were found, and no studies were found for 26/1,202 additives included in our search that are of known hazard concern and confirmed to be in active production. Few studies have addressed recent "substitution" chemicals for restricted additives such as organophosphate flame retardants, phthalate substitutes, and bisphenol analogues. We call for a paradigm shift in chemical regulation whereby new plastic chemicals are rigorously tested for safety before being introduced in consumer products, with ongoing post-introduction biomonitoring of their levels in humans and health effects throughout individuals' life span, including in old age and across generations.

Organophosphate esters (OPEs) in a heavily polluted river in South China: Occurrence, spatiotemporal trends, sources, and phase distribution

In the past decade, organophosphate esters (OPEs) undergo rapid increase in production and use. Meanwhile, owing to their additive property, OPEs exhibit liability to escape from related products and therefore ubiquity in various environments. Moreover, numerous researches verify their bioavailability and negative effects on biota and human, hence their occurrence and associated risks have caught much concern, particularly those in aquatic systems. So far, however, OPEs in water are generally investigated as a whole, their phase distribution and behavior in waterbodies are incompletely characterized. We examined 25 OPEs in water (including dissolved and particulate phases), sediment, and sediment core samples from the Lian River, which flows through the Guiyu e-waste recycling zone and Shantou specific economic zone in South China. Compared to most global waterbodies, the Lian River showed high or ultrahigh OPE levels in both water and sediments, particularly in the reaches surrounded by e-waste recycling and plastic-related industries, which were the top two greatest OPE sources. Non-industrial and agriculture-related anthropogenic activities also contributed OPEs. Sediment core data suggested that OPEs have been present in waters in Guiyu since the 1960s and showed a temporal trend consistent with the local waste-recycling business. The phase distribution of OPEs in the Lian River was significantly correlated with their hydrophobicity and solubility. Owing to their wide range of physicochemical properties, OPE congeners showed significant percentage differences in the Lian River water and sediments. Generally, OPEs in water reflect their dynamic real-time inputs, while those in sediment signify their accumulative deposition, which is another cause of their phase distribution disparities in the Lian River. The physicochemical parameters of OPEs first imposed negative and then positive influences on their dissolved phase-sediment distribution, indicating the involvement of both the adsorption of dissolved OPEs and the deposition of particle-bound OPEs.

Sublethal effects of bio-plastic microparticles and their components on the behaviour of Daphnia magna

Bioplastics arise as an alternative to plastic production delinked from fossil resources. However, as their demand is increasing, there is a need to investigate their environmental fingerprint. Here we study the toxicity of microplastics (MPLs) of two widely used materials, the polylactic acid (PLA) and the polyhydroxybutyrate (PHB) on the environmental aquatic model species Daphnia magna. The study was focused on sublethal behavioural and feeding endpoints linked to antipredator scape responses and food intake. The study aimed to test that MPLs from single-use household comercial items and among them bioplastics should be more toxic than those obtained from standard plastic polymers and fossil plastic materials due to the greater amount of plastic additives, and that MPLs should be more toxic than plastic extracts due to the contribution of both particle and plastic additive toxicity. MPLs were obtained by cryogenic grinding and sea-sand erosion to obtain irregular particles. MPL included standard polymers and nine comercial items of PLA and PHB and one fossil-based material of high-density polyethylene (HDPE). The additive content in commercial items was characterised by liquid chromatography coupled with high-resolution mass spectrometry. D. magna juveniles were exposed for 24 h to particles and their plastic extracts. Results indicated that the toxicity of bioplastic particles was five times higher than the effects produced by exposure to the content of the additives alone, that bioplastic particles were more toxic than fossil ones and that particles obtained from commercial items were more toxic than those obtained from PLA, PHB or HDPE polymer standards. Predicted toxicity from the measured plastic additives in the studied commercially available household items, however, was poorly related with the observed behavioural and feeding effects. Further research on unknown chemical components together with physical factors is need it to fully understand the mechanisms of toxicity of bioplastic materials.

New brominated flame retardant decabromodiphenyl ethane (DBDPE) in water sediments: A review of contamination characteristics, exposure pathways, ecotoxicological effects and health risks

As an alternative to polybrominated diphenyl ethers (PBDEs), decabromodiphenyl ethane (DBDPE) has become one of the most important new brominated flame retardants (NBFRs). However, little is known about whether this emerging contaminant may has an environmental fate similar to PBDEs. Sediments are the main sink for DBDPE in the aqueous phase. Worldwide concentration data, since it was first found in sediments to date, have been collated, and the following conclusions have been drawn. (1) DBDPE concentrations in sediments have increased rapidly, often with a higher risk of contamination in source discharge areas. Compared with other countries, DBDPE contamination in China is more severe, especially in Guangdong Province, which is closely related to its being an e-waste dismantling area. (2) The amount of DBDPE in surface sediments has exceeded that of legacy brominated flame retardants (BFRs), and data recorded in sediment cores also corroborate that DBDPE is replacing decabromodiphenyl ether (BDE-209) as one of the most dominant NBFRs in the environment. (3) The exposure pathways of DBDPE include dietary intake, air or indoor dust intake, cutaneous absorption and endogenous exposure. For sediments, dietary exposure and endogenous exposure pathways need to be considered. Sediment DBDPE can enter the human body through bioenrichment such as contaminated seafood and the food chain. (4) DBDPE can exhibit neurotoxicity, thyrotoxicity, reproductive and developmental toxicity, hepatotoxicity and oxidative stress in organisms. Long-term DBDPE exposure may increase hyperthyroidism risk and inhibit normal cells activity. This review focuses on the distribution characteristics and exposure risks of DBDPE in global water sediments, providing a strong reference for environmental management and related legal policy formulation. The next steps are to focus on continuous source monitoring, process control and sediment clean-up of DBDPE. The development of sustainable water management options for waste microplastics (MPs) and e-waste spiked with DBDPE is a priority.

Fate of organophosphate flame retardants (OPFRs) in the "Cambi® TH + AAD" of sludge in a WWTP in Beijing, China

Organophosphate flame retardants (OPFRs) are emerging environmental pollutants that cause endocrine disruption, neurotoxicity, and reproductive toxicity. Sewage sludge is an important source of tri-OPFRs that are released into the environment. The occurrence, distribution, and ecological risk of OPFRs in the full-scale "Cambi® thermal hydrolysis (TH) + advanced anaerobic digestion (AAD) + plate-frame pressure filtration" sludge treatment process is closely related to the application of sewage sludge. We tested sludge samples from a wastewater treatment plant in Beijing, China. Nine tri-OPFRs were detected in the sludge samples collected at different treatment units during four seasons. The ΣOPFRs decreased from 1,742.65-2,579.68 ng/g to 971.48-1,702.22 ng/g. The mass flow of tri-OPFRs in treated sludge decreased by 61.4%, 48.9%, 42.4%, and 63.9% in spring, summer, autumn and winter, respectively, effectively reducing the corresponding ecological risk. The ecological risk of tri-OPFRs in sludge in forestland utilization mainly lies in chlorinated tri-OPFRs, especially TCPP and TCEP. No >42.20 t/hm2 of sludge could be used continuously for one year to prevent tri-OPFRs from exceeding the low ecological risk level, indicating that the current commonly applied proportion of sludge (1.6-30 t/hm2) will likely not raise the ecological risk of tri-OPFRs.

Ecological risk of galaxolide and its transformation product galaxolidone: evidence from the literature and a case study in Guangzhou waterways

Galaxolidone (HHCB-lac) is a major transformation product of the commonly used synthetic musk galaxolide (HHCB) and is ubiquitous in the environment along with the parent compound. Although many studies have shown the harmful effects of HHCB, little attention has been paid to the potential ecological risk of HHCB-lac. Herein, we reviewed the concentrations and ratios of HHCB and HHCB-lac (HHCB-lac : HHCB) in different media reported in the literature, derived the predicted no-effect concentrations (PNECs) for the two compounds using ECOSAR predictions and species sensitivity distribution (SSD) estimates, and assessed their ecological risks in the aquatic environment. The literature data indicated that HHCB-lac and HHCB were generally present in the environment at ratios of 0.01-10. Using the derived PNECs (2.14 and 18.4 μg L-1 for HHCB and HHCB-lac, respectively), HHCB in the aquatic environment was assessed to have medium to high risks, while HHCB-lac was assessed to have low risks. Furthermore, we carried out a case study on the occurrence and ecological risks of HHCB and HHCB-lac in Guangzhou waterways. The concentrations of the two compounds in Guangzhou waterways ranged from 20 to 2620 ng L-1 and 3 to 740 ng L-1, respectively, and the ratios were in the range of 0.15 to 0.64. The field study data also showed medium to high risks of HHCB and low risks of HHCB-lac. Additionally, the endocrine effects of HHCB and HHCB-lac were confirmed by Endocrine Disruptome, which calls for greater scrutiny of the potential effects of HHCB and HHCB-lac on human health.

International Comparison, Risk Assessment, and Prioritisation of 26 Endocrine Disrupting Compounds in Three European River Catchments in the UK, Ireland, and Spain

Endocrine-disrupting compounds (EDCs) constitute a wide variety of chemistries with diverse properties that may/can pose risks to both humans and the environment. Herein, a total of 26 compounds, including steroids, flame retardants, and plasticizers, were monitored in three major and heavily urbanized river catchments: the R. Liffey (Ireland), the R. Thames (UK), and the R. Ter (Spain), by using a single solid-phase extraction liquid chromatography-mass spectrometry (SPE-LC-MS/MS) method. Occurrence and frequency rates were investigated across all locations over a 10-week period, with the highest concentration obtained for the flame retardant tris(2-chloroethyl) phosphate (TCEP) at 4767 ng∙L-1 in the R. Thames in Central London. Geographical variations were observed between sites and were partially explained using principal component analysis (PCA) and hierarchical cluster analysis (HCA). In particular, discrimination between the R. Ter and the R. Thames was observed based on the presence and concentration of flame retardants, benzotriazole, and steroids. Environmental risk assessment (ERA) across sites showed that caffeine, a chemical marker, and bisphenol A (BPA), a plasticizer, were classified as high-risk for the R. Liffey and R. Thames, based on relative risk quotients (rRQs), and that caffeine was classified as high-risk for the R. Ter, based on RQs. The total risks at each location, namely ΣRQriver, and ΣrRQriver, were: 361, 455, and 723 for the rivers Liffey, Thames, and Ter, respectively. Caffeine, as expected, was ubiquitous in all 3 urban areas, though with the highest RQ observed in the R. Ter. High contributions of BPA were also observed across the three matrices. Therefore, these two compounds should be prioritized independently of location. This study represents a comprehensive EDC monitoring comparison between different European cities based on a single analytical method, which allowed for a geographically independent ERA prioritization to be performed.

Organophosphate esters in source, finished, and tap water in Wuhan, China

As important plasticizers and flame retardants, organophosphate esters (OPEs) have resulted in the contamination of various water bodies worldwide. However, their removal efficiency by different tap water treatment processes and seasonal variations in drinking water in China are not fully understood. In this study, source (n = 20), finished (n = 20), and tap (n = 165) water samples sourced from the Hanshui and the Yangtze River were collected in Wuhan, central China from July 2018 to April 2019 to measure selected OPE concentrations. The OPE concentrations in the source water samples ranged 10.5-113 ng/L (median: 64.6 ng/L). Most OPEs were not removed effectively by conventional tap water treatment, except for tris(2-chloroisopropyl) phosphate (TCIPP). Interestingly, trimethyl phosphate content was found to increase significantly during chlorination for water sourced from the Yangtze River. The OPEs could be removed more effectively by advanced processes with ozone and activated carbon (maximum removal efficiency of specific OPE was 91.0%). Similar cumulative OPE concentrations (ΣOPEs) values were found for the finished water and tap water in February rather than in July. The ΣOPEs (ng/L) in the tap water ranged 21.2-365 (median: 45.1). TCIPP and tris(2-chloroethyl) phosphate were the predominant OPEs in the studied water samples. Significant seasonal variations in the OPE residues in tap water were observed in this study. OPE exposure via tap water ingestion posed low health risks to human beings. This is the first study reporting the removal efficiencies of OPEs and the seasonal variations in tap water from central China. This is also the first study documenting the occurrence of cresyl diphenyl phosphate and 2,2-bis(chloromethyl)propane-1,3-diyltetrakis (2-chloroethyl) bisphosphate in tap water. Based on currently available data, the contamination of tap water by OPEs is in the order of Korea > eastern China > central China > New York State, the United States. Additionally, this study provides a method involving a trap column, to eliminate OPE contamination from the liquid chromatography system.

Organophosphate esters in the seawater of the Bohai Sea: Environmental occurrence, sources and ecological risks

Organophosphate esters (OPEs) are widely distributed in surface water systems, but limited information was available on the spatial occurrence and ecological risks of OPEs in the Bohai Sea. In this study, 89 water samples in the Bohai Sea and the five surrounding rivers were investigated for the determination of 15 OPEs. The concentration of ∑₁₅OPEs ranged from 373.20 to 2931.27 ng·L^-1 in the river water and 137.81 to 2641.30 ng·L^-1 in the seawater, with high levels of OPEs in Liaodong Bay. Tris(2-chloroethyl) phosphate (TCEP, 10- 92 %) and triethyl phosphate (TEP, 5- 64 %) were dominant for OPEs. The correlation analysis, principal component analysis and hierarchical cluster analysis suggested the conjunction of municipal wastewater via river input and maritime shipping was the main source of OPEs in the Bohai Sea. The ecological risk assessment indicated that the individual OPEs arise low ecological risks in the Bohai Sea, while medium ecological risks of ∑₁₅OPEs are in minority river samples.

Effects of 2-ethylhexyl diphenyl phosphate exposure on the glucolipid metabolism and cardiac developmental toxicity in larval zebrafish based on transcriptomic analysis

2-Ethylhexyl diphenyl phosphate (EHDPP) is an organophosphorus type of flame retardant. It is mainly used as a flame-retardant plasticizer in the production of flexible polyvinyl chloride. EHDPP is widely present in environment, particularly in aquatic environment. In this study, we reported that EHDPP exposure significantly affected glucose and lipid metabolism in zebrafish larvae, which was reflected by changes in the transcription of relevant genes and decreased levels of glucose, pyruvate, and triglycerides. In addition, the transcriptomic analysis revealed that the differentially expressed genes could enrich various endpoints in zebrafish larvae. Interestingly, EHDPP exposure could not only change the transcription of genes related to glucolipid metabolism but also cause cardiotoxicity by affecting the transcription of genes related to calcium signaling pathways in zebrafish larvae. To support these findings, we confirmed that these genes involved in cardiac morphology and development were significantly upregulated in zebrafish larvae after EHDPP exposure. More importantly, the distance and overlapping area of the atrium and ventricle were also changed in the EHDPP-exposed zebrafish larvae of transgenic Tg (myl7: EGFP). Overall, our study revealed that EHDPP exposure could affect various endpoints related to glucolipid metabolism and cardiac development in the early developmental stages of zebrafish.

Occurrence and ecological risk assessment of organophosphate esters in surface water from rivers and lakes in urban Hanoi, Vietnam

In this study, an investigation on the pollution status, distribution, and ecological risk to the aquatic organisms of six organophosphate tri-esters (tri-OPEs) and two organophosphate tri-esters (di-OPEs) in surface water in urban Hanoi, Vietnam were conducted. In 37 surveyed water samples (6 rivers and 17 lakes), all eight targeted OPEs were discovered with a detection frequency (DF) of 41-100% and the concentration varied largely from below the method detection limit (<MDL) to 6138 ng L^-1. The total concentrations of six tri-OPEs (Ʃ₆tri-OPEs) were 46-3644 ng L^-1 (average 1409 ng L^-1) and the total concentrations of two di-OPEs (Ʃ₂di-OPEs) ranged from 2.6 to 6138 ng L^-1 (average 351 ng L^-1). In general, the Ʃ₆tri-OPEs in water samples collected in rivers (average 2262 ng L^-1) were higher than those in lakes (average 1000 ng L^-1). The most dominant chemical was tris(2-chloro-1-methyl ethyl) phosphate (TCPP) with a DF of 100% and took up 75% (on average) of Ʃ₆tri-OPEs. Principal component analysis showed that most of the tri- and di-OPEs in lakes may come from similar emission sources. While, there were at least four different origins of organophosphate esters (OPEs) in rivers in urban Hanoi. The risk quotient (RQ) was estimated for the detected concentration of tri- and di-OPEs in water samples and the toxicological relevant concentration for three trophic groups of algae, crustaceans, and fish. The RQs and the total of RQs for each group were lower than 1, indicating that the effects of each OPE and their OPEs' combined effects on the aquatic environment in Hanoi were at low to medium levels.

Water pollution threats in important bird and biodiversity areas from Spain

Chemical pollution is still an underestimated threat to surface waters from natural areas. This study has analysed the presence and distribution of 59 organic micropollutants (OMPs) including pharmaceuticals, lifestyle compounds, pesticides, organophosphate esters (OPEs), benzophenone and perfluoroalkyl substances (PFASs) in 411 water samples from 140 Important Bird and Biodiversity Areas (IBAs) from Spain, to evaluate the impact of these pollutants in sites of environmental relevance. Lifestyle compounds, pharmaceuticals and OPEs were the most ubiquitous chemical families, while pesticides and PFASs showed a detection frequency below 25% of the samples. The mean concentrations detected ranged from 0.1 to 301 ng/L. According to spatial data, agricultural surface has been identified as the most important source of all OMPs in natural areas. Lifestyle compounds and PFASs have been related to the presence of artificial surface and wastewater treatment plants (WWTPs) discharges, which were also an important source of pharmaceuticals to surface waters. Fifteen out of 59 OMPs have been found at levels posing a high risk for the aquatic IBAs ecosystems, being the insecticide chlorpyrifos, the antidepressant venlafaxine and perfluorooctanesulfonic acid (PFOS) the most concerning compounds. This is the first study to quantify water pollution in IBAs and evidence that OMPs are an emerging threat to freshwater ecosystems that are essential for biodiversity conservation.

Presence and toxicity of drugs used to treat SARS-CoV-2 in Llobregat River, Catalonia, Spain

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a strain of coronavirus that causes COVID-19 (coronavirus disease 2019), the respiratory illness responsible for the on-going COVID-19 pandemic. In March 2020, it was declared global pandemic, causing millions of deaths. An evident tendency of global pharmaceutical consumption due to COVID-19 pandemic should be seen worldwide, and this increase might suppose an environmental threat. Pharmaceuticals administrated at home or in pharmacies are excreted by faeces and urine after consumption, and wastewater treatment plants (WWTPs) are not able to remove all pharmaceuticals residues that eventually will end up in the aquatic media (rivers and sea). For this reason, analytical techniques such as liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) have become prominent to identify and quantify pharmaceuticals residues in aquatic matrices. In view of the scarce data on the occurrence of pharmaceuticals used as COVID-19 treatment, the aim of the present study was to evaluate the presence of these class of pharmaceuticals in river water which were dexamethasone, prednisone, ciprofloxacin, levofloxacin, remdesivir, ritonavir, lopinavir, acetaminophen, hydroxychloroquine, chloroquine and cloperastine, their toxicity in the aquatic environment using D. magna and to perform an exhaustive risk assessment in seven points of the Llobregat river basin. Dexamethasone, cloperastine and acetaminophen were the pharmaceuticals with higher concentrations, showing mean levels between 313 and 859 ng L-1.

Polybrominated diphenyl ethers in water, suspended particulate matter, and sediment of reservoirs and their tributaries in Shenzhen, a mega city in South China

Urban reservoirs serve many purposes including recreation and drinking water, and larger bodies of water can alter the surrounding air temperatures, making urban areas cooler in summer and warmer in winter. However, reservoirs may also be sinks for contaminants. One such group of contaminants, the polybrominated diphenyl ethers (PBDEs), are persistent organic pollutants known to accumulate in sediments and suspended particulate matter (SPM). Few studies have been conducted on PBDEs in water, SPM, and sediment from reservoirs of Shenzhen which is a mega city in South China. To this end, 12 PBDEs were measured in water, SPM, and sediment samples during the dry season (DS) and wet season (WS), to explain the spatiotemporal distribution, congener profiles, sources, and risks of pollutants in four reservoirs (A-D) and their tributaries in the study region. The concentration of ∑₁₂PBDEs during the DS was found to be significantly higher than that during the WS. Source apportionment suggested that commercial penta-, octa-, and deca-BDEs are the major components of PBDEs, resulting mainly from atmospheric deposition, wastewater discharge, and external water-diversion projects. Further, attention should be paid to electronic equipment manufacturing factories in the study area. Risk assessment indicated risk of PBDEs (especially BDE-209) in sediment and SPM to be of concern. This study provides important data support for the control of PBDEs in natural drinking water sources.

Bioaccumulation and Trophic Transfer of Organophosphate Flame Retardants and Their Metabolites in the Estuarine Food Web of the Pearl River, China

The accumulation and trophodynamics of organophosphate flame retardants (OPFRs) and their metabolites were investigated in the estuarine food web of the Pearl River, China. The mean ∑OPFR concentration among the investigated species increased in the following order: fish [431 ± 346 ng/g lipid weight (lw)] < snail (1310 ± 621 ng/g lw) < shrimp (1581 ± 1134 ng/g lw) < crab (1744 ± 1397 ng/g lw). The di-alkyl phosphates (DAPs) of di-(n-butyl) phosphate (DNBP), bis(2-butoxyethyl) phosphate (BBOEP), and diphenyl phosphate (DPHP) were the most abundant metabolites, with concentrations same as or even higher than their corresponding parent compounds. The log bioaccumulation factors for most OPFRs were lower than 3.70, and significant biomagnification was only found for trisphenyl phosphate [TPHP, with the trophic magnification factors (TMFs) > 1]. The TMFs of OPFRs, except for TPHP and tributyl phosphate had a positive correlation with lipophilicity (log K_OW, p ≤ 0.05) and a negative correlation with the biotransformation rate (log K_M, p ≤ 0.05). The mean TMF > 1 was observed for all of the OPFR metabolites based on the bootstrap regression method. The "pseudo-biomagnification" of OPFR metabolites might be attributed to the biotransformation of OPFRs in organisms at high trophic levels.

Insights into the geographical distribution, bioaccumulation characteristics, and ecological risks of organophosphate esters

Organophosphate esters (OPEs), as flame retardants and plasticizers, have been numerously explored regarding the occurrence and ecotoxicology. Given their toxicity, persistency and bio-accumulative potential, however, they may pose negative effects on ecosystems, regarding which is a growing global concern. Accordingly, the present review systematically analyses the recent literature to (1) elucidate their worldwide distribution, bioaccumulation, and biomagnification potential, (2) determine their interim water quality criteria (i.e., effect thresholds), and (3) preliminarily assess the ecological risks for 32 OPEs in aquatic ecosystems. The results showed that the spatiotemporal distribution of OPEs was geographically specific and closely related to human activities (i.e., megacities), especially halogenated-OPEs. We also found that precipitation of airborne particulates could affect the concentrations of OPEs in soil, and there was a positive correlation between the bioaccumulation and hydrophobicity of OPEs. Tris(2-ethylhexyl) phosphate may exhibit high bioaccumulation in aquatic organisms. A substantial difference was found among interim water quality criteria for OPEs, partly attributable to the variation of their available toxicity data. Tris(phenyl) phosphate (TPHP) and tris(1,3-dichloroisopropyl) phosphate with the lowest predicted no-effect concentration showed the strongest toxicity of growth and reproduction. Through the application of the risk quotient and joint probability curve, TPHP and tris(chloroethyl) phosphate tended to pose moderate risks, which should receive more attention for risk management. Future research should focus on knowledge gaps in the mechanism of biomagnification, derivation of water quality criteria, and more precise assessment of ecological risks for OPEs.

Organophosphate esters in Chinese rice: Occurrence, distribution, and human exposure risks

Dietary intake is a crucial pathway of organophosphate esters (OPEs) exposure for human. However, information about the exposure risk of OPEs via rice consumption is still largely unknown. In the present study, a total of 234 rice samples from 25 provinces or city of China were collected and the concentrations of 24 OPEs were determined. Sixteen OPEs were detected in these rice samples and each rice sample was contaminated with at least 5 OPEs, indicating a ubiquitous occurrence of OPEs in Chinese rice. Moreover, the concentrations of Σ16 OPEs ranged from 1.46 to 552.65 μg/kg dry weight (dw), with a mean value of 64.74 μg/kg dw. For the composition profile of OPEs, three Cl-OPEs, including tris(2-chloroethyl) phosphate (TCEP), tri(2-chloroisopropyl) phosphate (TCIPP) and tris(1,3-dichloro-2-propyl) phosphate (TDCIPP), accounted for the highest proportion of Σ16 OPEs. For the spatial distribution of OPEs, although obvious spatial variations were observed among the 25 provinces or city, no obvious variations were found among the six rice-cultivating regions of China. Additionally, estimated dietary intakes (EDI) values of the 16 OPEs for adults and children were 1105.24 and 1399.13 ng/kg bw/day, respectively, under the high intake scenario. The hazard indexes of the 10 OPEs were 0.108 and 0.137 for adults and children, respectively. The risk assessment results indicated that Chinese adults and children did not suffer significant adverse effects from OPEs via rice intake.

Occurrence, bioaccumulation and trophic transfer of organophosphate esters in marine food webs: Evidence from three bays in Bohai Sea, China

Due to the widespread use of organophosphate esters (OPEs), the occurrence and trophic transfer of OPEs have attracted attentions in ecosystems. However, as the final sink for these chemicals, the bioaccumulations and trophodynamics of OPEs in marine ecosystems are still not clear. In this study, seawater, sediment and marine organisms collected from Bohai Bay (BHB), Laizhou Bay (LZB), and Liaodong Bay (LDB) in Bohai Sea (BS), China were analyzed to investigate the occurrence, bioaccumulation and trophic transfer of typical OPEs. Total concentration of OPEs (∑₉ OPEs) in surface water in LZB (255.8 ± 36.44 ng/L) and BHB (209.6 ± 35.61 ng/L) was higher than that in LDB (170.0 ± 63.73 ng/L). Marine organisms in LZB accumulated the highest concentrations of OPEs among the 3 bays (∑₁₀OPEs, 70.56 ± 61.36 ng/g ww). Average bioaccumulation factor (BAF) of OPEs in marine organism in BHB, LZB, and LDB was ranged from -2.48 to 0.16, from -2.96 to 1.78, and from -2.59 to 0.59. We also found that trophic magnification factors (TMF) are generally <1, which suggested trophic dilutions of OPEs in BS, China. Nevertheless, the relatively high OPEs levels in BS still may bring potential risks to ecosystem and human health.

Occurrence, spatiotemporal variation, and ecological risks of organophosphate esters in the water and sediment of the middle and lower streams of the Yellow River and its important tributaries

Research on the environmental occurrence and behavior of organophosphate esters (OPEs) is very imperative. In this study, 12 targeted OPEs in the water and sediment samples collected from the middle and lower streams of the Yellow River (YR) and its tributaries during the dry, normal, and wet season were analyzed, to reveal their concentration, spatiotemporal variations, and ecological risks. The results indicated that the total concentration of OPEs (ΣOPE) ranged from 97.66 to 2433.30 ng/L in water, and from 47.33 to 234.08 ng/g in sediment. Tris(2-chloroethyl) phosphate (TCEP), tris(2-chloroisopropyl)phosphate (TCIPP), and triethyl phosphate (TEP) were the most abundant OPEs in the surface water and sediment. The OPEs levels in river water were ranked as the order of dry &gt; normal &gt; wet season. The ΣOPE concentrations in water and sediment were relatively high in the central and lower sections of the YR. The resorcinol-bis(diphenyl)phosphate (RDP) effectively transferred from the overlying water to the sediment. TCEP and RDP posed relatively higher ecological risk than other OPEs. Municipal and chemical industrial discharge might be sources of OPEs in the middle and lower streams of the YR.

Occurrence, distribution, and ecological risk of organophosphorus flame retardants and their degradation products in water and upper sediment of two urban rivers in Shenzhen, China

Organophosphorus flame retardants (OPFRs) are widely used in various industrial manufacturing processes; thus, their environmental impact in agglomerated industrial areas is of great concern. In this study, seventeen kinds of OPFRs and five kinds of organophosphate diesters (Di-OPs) in water and upper sediment samples from two urban rivers in the agglomerated industrial area of Shenzhen city, China, were investigated. The results showed that the total concentrations of detectable OPFRs ranged from 3438.83 to 12,838.87 ng/L with an average of 6494.94 ng/L in water samples and from 47.16 to 524.46 ng/g (dry weight, dw) with an average of 181.48 ng/g dw in sediment. The values were higher than those in other rivers worldwide. Tris(2-chloroethyl) phosphate (TCEP) is the predominant OPFRs in water and upper sediment, up to 10,664.23 ng/L in water and 414.12 ng/g dw in sediment. The total concentration of OPFRs of sediment samples in the Maozhou River was around twice as high as in the Guanlan River. The results indicated that the level of OPFRs was associated with the industrial activity intensity. Di-OPs exhibited lower concentrations than their parent compounds, and can be attributed to the degradation/metabolism of their parent compounds in the river. The sediment-water partition of OPFRs is significantly correlated with their log Kow values. Risk assessment revealed moderate ecological risks posed by OPFRs in water to aquatic organisms. The present study revealed the pollution status of OPFRs in rivers from agglomerated industrial and residential areas.

Tetrabromobisphenol A and hexabromocyclododecanes from interior and surface dust of personal computers: implications for sources and human exposure

Tetrabromobisphenol A (TBBPA) and hexabromocyclododecane isomers (HBCDs) are widely detected in indoor environments, but the research on the accumulation, contamination, and human exposure of TBBPA and HBCDs in electronic products dust is still limited. It is unclear whether electronic products might pose human health risk via dust ingestion and dermal absorption. In this study, the levels and distributions of TBBPA and HBCDs were investigated in the personal computer (PC) interior dust and PC surface (upper and bottom) wipes. The median concentrations of TBBPA in PC interior dust, upper, and bottom surface wipes were 168.1 ng/g, 13.2 ng/m², and 15.2 ng/m², respectively. These levels were generally higher than those of HBCDs, which were 95.2 ng/g, 11.7 ng/m², and 12.3 ng/m², respectively. No significant correlations were found among the PC upper and bottom surface wipes, and interior dust, indicating different sources of TBBPA and HBCDs in PC interior and surface dust. The TBBPA and HBCDs in the PC interior dust were mainly released from inner PC materials, while the sources of target compounds on the surface wipes were likely from external environments. The exposure values of two occupational populations (including PC owners and PC repair workers) to TBBPA and HBCDs were measured by PC interior dust and upper surface wipes. The results imply dust ingestion (including hand-to-mouth uptake) is the main contributor of the exposure route to TBBPA and HBCDs for both PC owners and repair workers. Compared to PC owners, PC repair workers showed the greater risk in exposure assessment, which should be paid more attention.

Spatiotemporal transitions of organophosphate esters (OPEs) and brominated flame retardants (BFRs) in sediments from the Pearl River Delta, China

Recent regulations on the use of brominated flame retardants (BFRs, especially polybrominated diphenyl ethers, PBDEs) have led a sharp increase in the use of organophosphate esters (OPEs), which have become the subject of widespread environmental concern. To gain insights into their environmental transitions, we investigated the spatiotemporal trends and sources of 25 OPEs and 23 BFRs (21 PBDEs and two alternative BFRs) in sediments from the Pearl River Delta (PRD), the second economic/industrial region of China. Among them, PBDEs showed higher mean concentrations than OPEs and alt-BFRs in PRD sediments, a continual increase in most PRD areas, and positive correlations with most local socioeconomic parameters. The source analysis results indicated that all of these changes resulted from the substantial use/stock of PBDEs (especially deca-BDE) in this region, and BDE-209 displayed debromination in most sediments. OPEs demonstrated obvious increases in sediments from all major PRD rivers, especially those located in less-developed regions. This distribution might be related to the large-scale industry relocation from the central PRD area to its vicinities. Unexpectedly, decabromodiphenyl ethane (DBDPE), an important deca-BDE substitute, presented considerable declines in the PRD sediments while several novel OPEs showed considerably high proportions, especially aryl-substituted OPEs, which merit further screening analysis.

First Data on PAE Levels in Surface Water in Lakes of the Eastern Coast of Baikal

The increasing consumption of phthalates (PAEs), along with their high toxicity and high mobility, poses a threat to the environment. This study presents initial data on the contents of six priority PAEs in the water of lakes located on the eastern shore of Lake Baikal-Arangatui, Bormashevoe, Dukhovoe, Kotokel, and Shchuchye. The mean total concentrations of the six PAEs in lakes Arangatui and Bormashevoe (low anthropogenic load) were comparable to those in Kotokel (medium anthropogenic load, 17.34 µg/L) but were significantly higher (p < 0.05) than in Dukhovoe and Shchuchye (high anthropogenic load, 10.49 and 2.30 µg/L, respectively). DBP and DEHP were the main PAEs in all samples. The DEHP content in lakes Arangatui and Bormashevoe was quite high, and at some sampling sites it exceeded the MACs established by Russian, U.S. EPA, and WHO regulations. The assessment showed that there is no potential risk to humans associated with the presence of PAEs in drinking water. However, the levels of DEHP, DBP, and DnOP in the water pose a potential threat to sensitive aquatic organisms, as shown by the calculated risk quotients (RQs). It is assumed that the origin of the phthalates in the studied lakes is both anthropogenic and biogenic.

Accumulation of microplastics and Tcep pollutants in agricultural soil: Exploring the links between metabolites and gut microbiota in earthworm homeostasis

Agricultural soil contamination with plastic film has become a critical global environmental problem, requiring greater research on the possible occurrence and biological risk of microplastics (MPs) and their additives in soil ecosystems. The presence of MPs and tris (2-chloroethyl) phosphate (Tcep) in agricultural soil was investigated at nine sites in the present study. Polyethylene MPs (PE-MPs) and Tcep were found at all nine sites. To study co-exposure effects on soil microbiota and earthworms, and to mimic a realistic exposure scenario, 0.05 % (w/w) PE-MPs with three particle size ranges were combined with Tcep (1.0 mg/kg). After 28 days of exposure, there was no indication that added PE-MPs and/or Tcep significantly affected the soil microbial community structure. In earthworms, size-selective intake, digestion and egestion of PE-MPs may occur, with Tcep co-exposure affecting the residual Tcep concentration in earthworm intestines (3.52-9.31 μg/g dw). Long-term earthworm PE-MPs intake caused intestinal damage, and Tcep co-exposure increased oxidative stress, thereby influencing their feeding behavior and growth, resulting in weight loss (3.42 %-14.96 %), especially for the most common PE-MPs sizes (0-300 μm). High performance liquid chromatography-mass spectrometry (LC-MS) was used for metabolomic analysis, revealing the significant up-regulation of citrate (p < 0.001) and down-regulation of l-glutamate (p < 0.05) in co-exposure groups. Co-exposure resulted in the alteration of most metabolic pathways, thereby impairing nervous, digestive and excretory systems in the earthworm, with an associated decrease in amino acid metabolism and changes in tricarboxylic acid (TCA) cycle intermediates. Gut microbiota, such as Proteobacteria (Verminephrobacter and Bradyrhizobium) and Firmicutes (Bacillus), are critically important in maintaining earthworm metabolic homeostasis, particularly for the TCA cycle and amino acid metabolism. Overall, MPs and Tcep co-exposure in agricultural soil enhanced their toxicity to earthworms and may potentially endanger the development of agricultural sustainability.

Genotoxic and Toxic Effects of The Flame Retardant Tris(Chloropropyl) Phosphate (TCPP) in Human Lymphocytes, Microalgae and Bacteria

Tris(chloropropyl) phosphate (TCPP) is a characteristic and widely used organophosphorus flame retardant. TCPP is comprised of four isomers and the most abundant is tris(1-chloro-2-propyl) phosphate. TCPP can be released into the environment, with potential impacts on living organisms and humans due to its extensive industrial use. Aiming to assess the potential risks of TCPP on human health and the environment, its toxic and genotoxic effects-using organisms from different trophic levels, i.e., bacteria, green microalgae, and human cells-were investigated. TCPP exposure at nominal concentrations of 10, 20, 30 and 40 μg mL^-1 was studied to identify the potential risk of inducing genotoxic effects in cultured human lymphocytes. Treatment with 30 and 40 μg mL^-1 of TCPP induced marginally significant micronuclei (MN) frequencies as well as cytotoxic effects. Freshwater microalgae species treated with TCPP (0.5, 1, 10, 20 and 50 μg L^-1) showed different growth rates over time. All the tested microalgae species were adversely affected after exposure to TCPP during the first 24 h. However, differences among the microalgae species' sensitivities were observed. In the case of the freshwater species, the most sensitive was found to be Chlorococcum sp. The marine algal species Dunaliella tertiolecta and Tisochrysis lutea were significantly affected after exposure to TCPP. The effects of TCPP on Aliivibrio fischeri that were observed can classify this flame retardant as a "harmful" compound. Our results suggest a potential risk to aquatic organisms and humans from the wide utilization of TCPP and its consequent release into the environment. These results highlight that further research should be conducted to investigate the effects of TCPP individually and in combination with other organophosphorus flame retardants in various organisms. In addition, the concern induced by TCPP points out that measures to control the introduction of TCPP into the environment should be taken.

Organophosphate flame retardants in Hangzhou tap water system: Occurrence, distribution, and exposure risk assessment

The usage of Organophosphorus flame retardants (OPFRs) is gradually increased as the ban on brominated flame retardants (BFRs) worldwide. The frequent accessibility of OPFRs in aquatic environment poses potential risk to human. Previous studies have concerned on surface water, while studies on tap water are limited. In this research, we aim to evaluate the removal efficiency of the tap water treatment process and investigate the exposure risk of OPFRs in tap water. Herein, we collected 14 samples from water source, 10 samples from water treatment plants and 47 from tap to analyze the concentrations and removal efficiency of OPFRs in Hangzhou tap water supply system. The results showed the concentrations of ∑OPFRs ranged from 9.25 to 224.74 ng/L in all samples, with Tris(1-chloro-2-propyl) Phosphate (TCPP), Tris(2-chloroethyl) phosphate (TCEP), Triphenyl phosphate (TPHP), and Tributyl phosphate (TBP) being the predominant compounds. Levels of the OPFRs had a 10.0 % - 50.4 % declination when compared samples after treatment with that before. The maximum exposure doses of ∑OPFRs via tap water for both adults and children were much lower than the reference dose (RfD). As a result, the hazard index (HI) and the carcinogenic risk (CR) pinpointed a negligible non-carcinogenic and carcinogenic risk for the residents. Even so, given the pervasive usage of OPFRs, the residual levels and the potential risk of OPFRs in watershed should be continuously concerned.

Antibacterial and Antibiofilm Potential of Microbial Polysaccharide Overlaid Zinc Oxide Nanoparticles and Selenium Nanowire

Here, we report on the synthesis of zinc oxide nanoparticles (ZnO NPs) and selenium nanowires (Se NWs) using microbial exopolysaccharides (EPS) as a mediator and then examine their antibacterial and ecotoxicity effects in vitro and in vivo, respectively. At 100 µg/mL, EPS, EPS-ZnO NPs, and EPS-Se NWs all exhibited potent in vitro antibacterial properties, drastically inhibiting the development of aquatic Gram(-) pathogens. In addition, antibiofilm studies using a microscope revealed that EPS, EPS-ZnO NPs, and EPS-Se NWs at 75 µg/mL prevented biofilm development. Furthermore, the in vivo toxicity was carried out via Danio rerio embryos and Ceriodaphnia cornuta. Danio rerio embryos were determined at different time intervals (6 hpf, 12 hpf, 24 hpf and 48 hpf). The maximum survival rate (100%) was obtained in a control group. Correspondingly, EPS, EPS-ZnO NPs and EPS-Se NWs treated embryos showed a considerable survival rate with 93.3%, 86.7% and 77.2%, respectively, at 100 µg/mL for 48 hpf. The total mortality of C. cornuta was seen at 100 µg/mL, with 56.7% in EPS, 60.0% in EPS-ZnO NPs, and 70.0% in EPS-Se NWs. For C. cornuta, the LC50 values for EPS, EPS-ZnO NPs, and EPS-Se NWs were 90.32, 81.99, and 62.99 µg/mL, respectively. Under a microscope, morphological alterations in C. cornuta were analyzed. After 24 h, an amount of dark substance was seen in the guts of C. cornuta exposed to 100 µg/mL, but in the control group, all of the living C. cornuta were swimming as usual. Our results show that EPS and EPS-ZnO NPs were less harmful than EPS-Se NWs, and that they were successfully employed to shield freshwater crustaceans from the toxins in aquatic environments.

Heterogeneous Fenton-like removal of tri(2-chloroisopropyl) phosphate by ilmenite (FeTiO3): Kinetic, degradation mechanism and toxic assessment

Tri(2-chloroisopropyl) phosphate (TCPP), a common organophosphate flame retardant, was frequently detected in the environment and posed threats to human health. In this work, the main component of ilmenite FeTiO₃ was synthesized by the sol-gel method and employed as the catalyst for the degradation of TCPP by activating persulfate (PS) under UV irradiation. The degradation processes were fitted by the pseudo-first-order kinetic. The k_obs value in UV/FeTiO₃/PS system was up to 0.0056 min^-1 and much higher than that in UV/PS (0.0014 min^-1), UV/FeTiO₃ (0.0012 min^-1) and FeTiO₃/PS (0.0016 min^-1) systems, demonstrating a distinct synergistic effect in TCPP removal. The degradation efficiency of TCPP increased with the increase of UV intensity, PS concentration and catalyst dosage, and with the decrease of pH. By quenching experiment and EPR analysis, ·OH was confirmed to be the dominant radical in the reaction of the UV/FeTiO₃/PS system. The possible degradation pathways of TCPP were dechlorination, dealkylation, and further oxidation of alkyl groups based on the theoretical calculation of frontier molecular orbits. The toxicity of degradation intermediates evaluated by luminescence inhibition rate of photoluminescence was higher than TCPP. Thus, TCPP can be degraded in the UV/FeTiO₃/PS system effectively at the premise of introducing controlling measures to reduce the toxicity of degradation intermediates.

Occurrence, distribution and risk assessment of organophosphate esters (OPEs) in water sources from Northeast to Southeast China

With the wide utilization of organophosphate esters (OPEs) in recent years, OPEs have been detected more frequently in the aquatic environment. However, the distribution of OPEs in drinking source water has rarely been investigated across a large region. In this study, the occurrence and distribution of 13 OPEs were investigated in 23 source water sites from Northeast to Southeast (spacing greater than 3320 km) with a direct injection ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method. Total OPEs ranged from 218.8 to 636.6 ng/L, with a mean of 380.8 ng/L. The average detected concentration of OPEs in southern cities was higher than that in northern cities. Chlorinated OPEs accounted for 64.74% of the total concentration. Triethyl phosphate (TEP), tri (2-chloroethyl) phosphate (TCEP), and tri (chloropropyl) phosphate (TCPP) were detected in all water samples. Rainfall is a significant factor that affects the OPE concentration (less rainfall, higher concentration). China's OPE concentrations have rapidly reached a median level when compared to those of other countries. Ecological risk assessment showed that most OPEs have no or low risk to organisms (fish, crustacea, algae), except tricresyl phosphate (TCP), which is medium risk. The risk of OPEs in less-rain regions needs to be of greater concern, especially TCP.

Organophosphate esters in the mariculture ecosystem: Environmental occurrence and risk assessments

Most investigations on organophosphate esters (OPEs) are conducted predominantly in a separate biological or abiotic medium, and few joint analyses have been performed in the mariculture ecosystem based on yearly sampling. Herein, we investigated the occurrence, load estimation, phase distribution, source diagnostics, and risks of 20 OPEs in seawater, sediment, and aquaculture organisms from a typical mariculture area in China. The total of these OPEs (∑_OPEs) ranged within 3.97-1068 ng/L, 0.39-65.5 ng/g (dw), and 4.09-16.3 ng/g (ww) in seawater, sediment and organisms, respectively. Chlorinated OPEs were the predominant congeners detected in seawater, whereas alkyl-OPEs were the leading contributors in sediment and biological samples. Seasonal variations of ∑_OPEs in seawater were more distinct than those in sedimentary environments. Load estimation indicated that approximately 70% of the OPEs in the study area existed in the water bodies. Source identification performed using the U.S. EPA positive matrix factorization indicated that polyurethane foam/plastics and hydraulic oil made the greatest contributions in seawater, whereas chemical production was the predominant source in sediment. Indices of ecological and health risks of OPEs were lower than their risk threshold, indicating that the OPEs detected in this study posed a low risk to the aquatic environment and human health.

Occurrence, distribution, source identification, and risk assessment of organophosphate esters in the coastal waters of Beibu Gulf, South China Sea: Impacts of riverine discharge and fishery

As emerging pollutants, the environmental geochemistry of organophosphate esters (OPEs) in the coastal zone with multiple functional areas are still less recognized. This study investigated spatiotemporal distribution, sources and risks of 11 widely used OPEs in surface waters from seagoing rivers and multiple coastal functional areas of the Beibu Gulf. The results indicated that significantly higher ∑₁₁OPEs (total concentrations of 11 OPEs, ng/L) occurred in summer (34.2-1227) than in winter (20.6-840), as a result of the high emission caused by climate reasons. In general, higher ∑₁₁OPEs occurred in rivers (41.2-1227) than in the coast (34.2-809) in summer, especially in the urban rivers, while in winter, higher ∑₁₁OPEs occurred in the coast (23.4-840 vs 20.6-319 in rivers) because of obviously higher ∑₁₁OPEs in marine fishery areas (99-840). Source identification revealed that fishery activity, especially fishing vessels, and urban rivers were the main sources of OPEs in the Beibu Gulf. For the individual OPE, only tri-n-butyl phosphate (TNBP) may have ecological risks to aquatic organisms in a few sites, but if considering the additive effects, the OPEs mixtures would pose a high risk to algae and low to medium threats to crustaceans and fish.

Distribution, partitioning, and health risk assessment of organophosphate esters in a major tributary of middle Yangtze River using Monte Carlo simulation

Globally, organophosphate esters (OPEs) have attracted substantial attention because of their ubiquity in the environment, toxicity, and potential ecological and health risks. This study comprehensively investigated the occurrence, partitioning, and spatial distribution of nine ordinary monomeric OPEs (m-OPEs) and three emerging oligomeric OPEs (o-OPEs) in a major tributary of the middle Yangtze River, which is the Zijiang River (ZR), and their associated potential health risks. Total OPE concentrations ranged from 18.8 to 439 ng L^-1, 1.40 to 19.1 ng L^-1, and 3.71 to 77.3 ng g^-1 dw in the surface water, suspended particulate matter (SPM), and sediment, respectively. Tris (2-chloroisopropyl) phosphate (TCPP) dominated the water (61.3%) and sediment (60.1%) samples, whereas tris (2-butoxyethyl) phosphate (TBOEP) was present in the SPM (59.0%) samples. The proportion of o-OPEs was low in all three media, ranging from 0.60% to 1.90%. Field-based log K_oc values of the frequently detected OPEs were higher than those predicted by EPI Suite and were negatively correlated with temperature. The spatial distribution of OPEs in the water and hierarchical cluster analysis suggested that sewage treatment plant effluents and the mining industry were the main sources of OPEs in the ZR. The total noncarcinogenic and carcinogenic risks of OPEs in the water were low at the detected concentrations, even in the high-exposure scenario.

IPPD-induced growth inhibition and its mechanism in zebrafish

N-isopropyl-N-phenyl-1,4-phenylenediamine (IPPD) is used as a ubiquitous antioxidant worldwide, it is an additive in tire rubber easily discharged into the surrounding environment. At present, there is no study concerning the subacute toxicity of IPPD on fish. We used zebrafish embryos (2 h post-fertilization) exposed to IPPD for 5 days at concentrations of 0, 0.0012, 0.0120 and 0.1200 mg/L to investigate its toxic effects of embryonic development, disruption of growth hormone/insulin-like growth factor (GH/IGF) and hypothalamic-pituitary-thyroid (HPT) axis. The results showed that IPPD exposure decreased hatchability, weakened movement ability, reduced body length, and caused multiple types of deformities in zebrafish embryos. The expression of genes involved to GH/IGF and HPT axis were altered after exposure to IPPD in zebrafish larvae. Meanwhile, exposure to IPPD significantly decreased thyroxine (T4) and 3,5,3'-triiodothyronine (T3) contents in larvae, which indicated that HPT axis was in a disturbed state. Moreover, treatment of IPPD decreased the enzymatic activities of superoxide dismutase (SOD) and catalase (CAT) as well as levels of glutathione (GSH). While the contents of malondialdehyde (MDA) were elevated after exposure to IPPD. The present study thus demonstrated that IPPD induced oxidative stress, caused developmental toxicity and disrupted the GH/IGF and HPT axis of zebrafish, which could be responsible for developmental impairment and growth inhibition.

A new and systematic review on the efficiency and mechanism of different techniques for OPFRs removal from aqueous environments

Organic phosphorus flame retardants (OPFRs), as a new type of emerging contaminant, have drawn great attention over the last few years, due to their wide distribution in aquatic environments and potential toxicities to humans and living beings. Various treatment methods have been reported to remove OPFRs from water or wastewater. In this review, the performances and mechanisms for OPFRs removal with different methods including adsorption, oxidation, reduction and biological techniques are overviewed and discussed. Each technique possesses its advantage and limitation, which is compared in the paper. The degradation pathways of typical OPFRs pollutants, such as Cl-OPFRs, alkyl OPFRs and aryl OPFRs, are also reviewed and compared. The degradation of those OPFRs depends heavily upon their structures and properties. Furthermore, the implications and future perspectives in such area are discussed. The review may help identify the research priorities for OPFRs remediation and understand the fate of OPFRs during the treatment processes.