Environmental occurrence of phthalate and organophosphate esters in sediments across the Gulf of Lion (NW Mediterranean Sea)

Organophosphate esters (OPEs) pollution characteristics, bioaccumulation and human consumption implication in wild marine organisms from the Yellow River Estuary, China

As the substitutes of polybrominated diphenyl ethers, organophosphate esters (OPEs) with high concentrations have accumulated in the estuaries, bays, and harbors. However, limited information is available about the OPEs in the estuary organism categories, especially under the multiple industrial pressure. This study investigated the occurrence, bioaccumulation and human consumption implication in wild marine organisms from the Yellow River Estuary, where located many petroleum and chemical manufacturing industries. This study found that concentrations of Σ13OPEs ranged from 547 ng/L to 1164 ng/L in seawater (median: 802 ng/L), from 384 to 1366 ng/g dw in the sediment (median: 601 ng/g dw), and from 419 to 959 ng/g dw (median: 560 ng/g dw) in the marine organisms. The congener compositions in the organisms were dominated by alkyl-OPEs (80.7 %), followed by halogenated-OPEs (18.8 %) and aryl-OPEs (0.5 %). Based on the principal component analysis, petrochemical pollution, and industrial wastewater discharge were distinguished as the main plausible sources of OPEs to the YRE ecosystem. Most OPEs had potential or strong bioaccumulation capacity on the organisms, with a positive correlation between log BAF (Bioaccumulation Factor) and log Kow of OPEs. The highest estimated daily intake value of OPEs was tri-n-propyl phosphate, exceeding 300 ng/kg·bw/day via consuming fish. The highest hazard quotients from OPEs ranged from 0.001 to 0.1, indicating a low risk to human health by consuming marine organisms in the YRE. As the consumption of OPEs increases year by year, the risks of OPEs still cannot be ignored.

Occurrence, spatial distribution and ecological risk assessment of Organophosphate Esters in surface water and sediments from the Ravi River and its tributaries

Organophosphate esters (OPEs) are widely used as substitutes for brominated flame retardants and characterized as emerging contaminants. Due to their toxicity and persistent nature, OPEs are becoming a matter of greater concern worldwide. However, information about the pollution profile of OPEs and associated ecological risks is still scarce in environmental matrices of the South Asian region, particularly Pakistan. Hence, the current study was conducted to investigate the occurrence, spatial distribution patterns, ecological risks and riverine flux of 10 organophosphate esters in surface water and sediments of Ravi River and its four tributaries. The concentrations of ∑10OPEs were in the range of 19.2 - 105 ng/L, with the dominance of chlorinated-OPEs (51 %) in surface water, whereas in case of sediments, the ∑10OPEs concentrations ranged from 20.7 to 149 ng/g dw, with high abundance of non - chlorinated alkyl-OPEs, which contributed about 56 % to total OPE concentration. The correlation analysis signified a strong positive relation of OPEs with TOC (p < 0.05, R = 0.76) in sediments; and in addition to this, field-based LogKoc values were estimated to be higher than predicted LogKoc. Moreover, a significantly positive correlation (p < 0.05, R = 0.88) was observed between LogKoc and LogKow, implying that hydrophobicity plays a significant role in OPE distribution in different environmental matrices. The global comparison revealed that contamination status of OPEs in the present study was comparatively lower than other regional findings, furthermore, principal component analysis suggested vehicular emissions, industrial discharges, household supplies and atmospheric deposition as main sources of OPEs occurrence in current study region. Furthermore, the riverine flux of ∑10OPEs was estimated to be 0.68 tons/yr and the ecological risk assessment indicated that all OPEs, except EHDPP and TCrP, showed negligible or insignificant ecological risks for aquatic organisms.

Contamination levels and ecological risk assessment of phthalate esters (PAEs) in the aquatic environment of Chaohu Lake

Phthalate esters (PAEs), widely recognized as synthetic organic compounds with extensive production and utilization, are known to disrupt physiological processes in both animals and humans, even at low environmental concentrations. This study investigated the occurrence, distribution, and potential ecological risk of five representative PAEs (DMP, Dimethyl phthalate; DEP, Diethyl phthalate; DBP, Dibutyl phthalate; DiBP, Diisobutyl phthalate; DEHP, Bis(2-ethylhexyl) phthalate) in a typical lake (Chaohu Lake, China). It was found that PAEs were detected in both the aqueous (1.09-6.402 µg/L) and solid phases (0.827-6.602 µg/g) of Chaohu Lake. Notably, DiBP and DBP were the predominant PAEs in the water, and DiBP and DEHP were the most prevalent in the sediments. The concentrations of PAEs exhibited significant seasonal variations in the aqueous phases, with total PAEs in summer being nearly twice those in winter. Toxicity assessments revealed that DEHP, DBP, and DiBP posed high risks to the survival of three indicator organisms (algae, Daphnia, and fish) in the aqueous phase. In the solid phase, the exceeding rate of DiBP was as high as 92.9%. On the other hand, DBP and DEHP generally presenting moderate risk, although some sites were identified as high-risk. This study's analysis of PAEs concentrations in Chaohu Lake reveals a discernible increasing trend when compared with historical data. These findings underscore the urgent need for interventions to mitigate the ecological threats posed by PAEs in Chaohu Lake.

Phthalic acid esters: Are they a big concern for rivers flowing into reservoir with ecological facilities?

The city-river-reservoir system is an important system for safeguarding drinking water. Phthalic acid esters (PAEs) are emerging contaminants in drinking water sources that are gaining attention, and they could pose risks to human health and aquatic organisms. In this study, field studies that lasted four years were conducted to analyze the concentrations, spatial-temporal distribution, and removal effects of six PAEs. The total concentrations of the Σ6PAEs in the water and sediment samples were 0.2-7.4 μg L-1 (mean: 1.3 μg L-1) and 9.2-9594.1 ng g-1 (mean: 847.5 ng g-1), respectively. Di-n-butyl phthalate (DBP) and, bis(2-ethylhexyl) phthalate (DEHP) were the predominant congeners, accounting for 57.2 % in the water samples and 94.1 % in the sediment samples. The urban area contributed 72 % of the PAEs in the system. A significant removal effect of PAEs was observed in the wetland, with a removal rate of 40.2 %. The partitioning of PAEs between the water and sediment was attributed to the removal of dimethyl phthalate and diethyl phthalate that occurred during the water phase, while the removal of DBP and DEHP primarily occurred during the sediment phase. The ecological risk calculation based on the sensitivity distribution model indicated that DBP (HQwater = 0.19, HQsediment = 0.46) and DEHP (HQwater = 0.20, HQsediment = 0.13) possessed moderate risks according to some water and sediment samples. The ecological projects were verified to be effective engineering strategies to reduce ecological risk in the drinking water source.

Temporal trends of plastic additive contents in sediment cores of three French rivers (Loire, Meuse and Moselle) over the last decades

Sediment cores from three major French watersheds (Loire, Meuse and Moselle) have been dated by 137Cs and 210Pbxs from 1910 (Loire), 1947 (Meuse) and 1930 (Moselle) until the present in order to reconstruct trajectories of plastic additive contaminants including nine phthalate esters (PAEs) and seven organophosphate esters (OPEs), measured by gas chromatography-mass spectrometer (GC-MS-MS). Historical levels of ∑PAEs were higher than those of ∑OPEs in the Loire and the Moselle sediments, while ∑PAEs and ∑OPEs contents were of the same order of magnitude in the Meuse sediments. Although increases in concentrations do not evolve linearly, our results clearly indicate an increase in OPEs and PAEs concentrations from the 1950-1970 period onwards, compared with the first half of the 20th century. Our results show that, ∑OPE contents increase gradually over time in the Loire and Meuse rivers but evolve more randomly in the Moselle River. Trajectories of ∑PAEs depend on the river and no generality can be established, suggesting sedimentary reworking and/or local contamination. Data from this study allowed comparisons of contents of ∑OPEs and ∑PAEs between rivers, with ∑OPE concentrations in the Moselle River > Meuse River > Loire River, and concentrations of ∑PAEs in the Loire River > Moselle River > Meuse River. Among all PAEs, di(2-ethylhexyl) phthalate (DEHP) was the most abundant in all sediment samples, followed by diisobutyl phthalate (DiBP). Tris (2-chloroisopropyl) phosphate (TCPP) was the most abundant OPE in sediments of the three rivers. In addition, strong positive Pearson correlations were observed between organic matter (OM) parameters and OPE concentrations, and to a lesser extent, between OM parameters and PAE concentrations. This is particularly true for the Moselle River and for the Loire River, but less so for the Meuse River.

Basin scale monitoring of microplastics and phthalates in sediments from the Persian Gulf and the Gulf of Makran using GIS-based algorithms: Insights towards spatial variation and potential risk assessment

Information on sedimentary microplastics and phthalates has been restricted to the coastal regions of the Persian Gulf and the Gulf of Makran. Our basin-wide study monitored their levels, spatial behaviors, and potential risks using GIS-based techniques. Microplastics and phthalates ranged from 5 to 75 particles/kg d.w and 0.004-1.219 μg g-1 d.w, respectively. Microplastics were in the size category of 100 μm to 3 mm, and black microfibers (< 1 mm) and high-density polymers were dominant. The total number of microplastics was between 356.333 × 1012 and 469.075 × 1012 particles in the surface sediments of the studied regions (confidence interval = 99 %). Diethylhexyl phthalate (DEHP) and Di-isobutyl phthalate contributed 88 % of detected phthalates. Significant correlations among microplastic abundance, total phthalates, and DEHP were distinguished (p < 0.05). Overall, the findings reiterated the widespread presence of microplastics and a potential link between phthalates and microplastics. Semi-variogram, cluster Voronoi polygons, and Trend analysis identified spatial outliers and major deposition sites of microplastics and phthalates and consequently outlined the localities where upcoming studies should be concentrated. A hotspot of potential risks was marked using Fuzzy logic and GIS-based algorithms in the Sea of Makran, covering an area equal to 342. 99 km2.

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.

Assessment of the impact of microplastic ingestion in striped red mullets from an Eastern Mediterranean coastal area (Zakynthos Island, Ionian Sea)

Monitoring microplastics (MPs) in the marine environment is an ongoing process, and our understanding of their impact on marine organisms is limited. The present study evaluates the effects of ingested MPs on the marine MP pollution bioindicator fish species Mullus surmuletus. The study follows a three-fold approach to assess the impact of MPs on marine organisms by investigating: 1) the ingestion of MPs, 2) the bioaccumulation of phthalate compounds as plastic additives, and 3) the evaluation of toxicological biochemical and cellular biomarkers. Striped red mullets were sampled in the marine protected area (MPA) of the National Marine Park of Zakynthos and coastal sites with high touristic pressure in Zakynthos Island in the Ionian Sea, Greece. Fewer ingested MPs and lower phthalate concentrations were found in fish inside the MPA compared to those sampled outside the marine park. However, no relationship was found between either phthalate concentrations or biomarker levels with the ingested MPs in the red striped mullets. Biomarker levels were influenced by season and site, but no effect could be attributed to the ingested MPs. The lack of association of biomarker responses and plasticizer bioaccumulation to MP ingestion can be explained by the low number of ingested MPs in the fish from Zakynthos coastal area as MP abundance ranged from 0.15 to 0.55 items per individual fish.

Organophosphate ester additives and microplastics in benthic compartments from the Loire estuary (French Atlantic coast)

We report the first empirical confirmation of the co-occurrence of organophosphate esters (OPEs) additives and microplastics (MPs) in benthic compartments from the Loire estuary. Higher median concentrations of MPs (3387 items/kg dw), ∑13tri-OPEs (12.0 ng/g dw) and ∑4di-OPEs (0.7 ng/g dw) were measured in intertidal sediments with predominance of fine particles, and under higher anthropogenic pressures, with a general lack of seasonality. Contrarily, Scrobicularia plana showed up to 4-fold higher ∑tri-OPE concentrations in summer (reaching 37.0 ng/g dw), and similar spatial distribution. Polyethylene predominated in both compartments. Tris(2-ethylhexyl) phosphate (TEHP), its degradation metabolite (BEHP) and tris-(2-chloro, 1-methylethyl) phosphate (TCIPP) were the most abundant OPEs in sediments, while TCIPP predominated in S. plana. The biota-sediment accumulation factors suggest bioaccumulation potential for chlorinated-OPEs, with higher exposure in summer. No significant correlations were generally found between OPEs and MPs in sediments suggesting a limited role of MPs as in-situ source of OPEs.

Pollution characteristics and affecting factors of phthalate esters in agricultural soils in mainland China

Phthalate esters (PAEs), the most commonly produced and used plasticizers, are widely used in plastic products and agroecosystems, posing risks to agricultural products and human health. However, current research on PAE pollution characteristics in agricultural soils in China is not comprehensive; affecting factors and relationships with microplastics and plasticizer organophosphate esters have not been sufficiently considered. In this study, farmland soil samples were collected with field questionnaires on a national scale across mainland China. The results showed that the detection rate of PAEs was 100% and the Σ16PAEs concentrations were 23.5 - 903 μg/kg. The level of PAEs was highest in the greenhouse, and significantly higher than that in mulched farmland (p < 0.05). The PAE concentration in northwestern China was the lowest among different physical geographic zones. PAEs in farmlands posed a low cancer risk to Chinese people. PAE pollution in farmlands was significantly (p < 0.05) affected by agronomic measures (such as disposal method), environmental factors, and socioeconomic factors. Overall, PAEs were significantly and positively correlated (p < 0.05) with organophosphate esters but not with microplastics. This study aims to provide scientific data for relevant prevention and control policies, as well as actionable recommendations for pollution reduction.

Comparison of phthalate esters (PAEs) in freshwater and marine food webs: Occurrence, bioaccumulation, and trophodynamics

Phthalate esters (PAEs) have received widespread attentions due to their ubiquity in various kinds of matrices and potential biotoxicity. This study systematically compared the concentrations, bioaccumulation, trophodynamics and health risk of PAEs in 25 species (n = 225) collected from a marine (Bohai Bay, BHB) and freshwater environment (Songhua River, SHR), China. Results showed that di-(2-ethylhexyl) phthalate and di-n-butyl phthalate were the predominant PAEs in the organisms from the two aquatic environments. The total concentrations of 6 PAEs in algae and fish from SHR were significantly higher than those from BHB. Two food webs were constructed in BHB and SHR based on the abundance of 15N in the organisms. All the PAEs except dimethyl phthalate exhibited trophic dilution with the trophic magnification factors less than 1. Moreover, an obvious biodilution of PAEs was observed in marine food web compared to freshwater food web. A low health risk of PAEs was found in organisms from both BHB and SHR. However, di-(2-ethylhexyl) phthalate exhibited a potential carcinogenic risk by consumption of some benthos in BHB and fish in SHR. This study provides a valuable perspective for understanding the trophodynamics and health risk of PAEs in marine and freshwater environments.

Tracing Organophosphate Ester Pollutants in Hadal Trenches─Distribution, Possible Origins, and Transport Mechanisms

Unraveling the mysterious pathways of pollutants to the deepest oceanic realms holds critical importance for assessing the integrity of remote marine ecosystems. This study tracks the transport of pollutants into the depths of the oceans, a key step in protecting the sanctity of these least explored ecosystems. By analyzing hadal trench samples from the Mariana, Mussau, and New Britain trenches, we found the widespread distribution of organophosphate ester (OPE) flame retardants but a complex transport pattern for the OPE in these regions. In the Mariana Trench seawater column, OPE concentrations range between 17.4 and 102 ng L-1, with peaks at depths of 500 and 4000 m, which may be linked to Equatorial Undercurrent and topographic Rossby waves, respectively. Sediments, particularly in Mariana (422 ng g-1 dw), showed high OPE affinity, likely due to organic matter serving as a transport medium, influenced by "solvent switching", "solvent depletion", and "filtering processes". Amphipods in the three trenches had consistent OPE levels (29.1-215 ng g-1 lipid weight), independent of the sediment pollution patterns. The OPEs in these amphipods appeared more linked to surface-dwelling organisms, suggesting the influence of "solvent depletion". This study highlights the need for an improved understanding of deep-sea pollutant sources and transport, urging the establishment of protective measures for these remote marine habitats.

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.

Phthalates contamination in sediments: A review of sources, influencing factors, benthic toxicity, and removal strategies

Sediments provide habitat and food for benthos, and phthalates (PAEs) have been detected in numerous river and marine sediments as a widely used plastic additive. PAEs in sediments is not only toxic to benthos, but also poses a threat to pelagic fish and human health through the food chain, so it is essential to comprehensively assess the contamination of sediments with PAEs. This paper presents a critical evaluation of PAEs in sediments, which is embodied in the analysis of the sources of PAEs in sediments from multiple perspectives. Biological production is indispensable, while artificial synthesis is the most dominant, thus the focus was on analyzing the industrial and commercial sources of synthetic PAEs. In addition, since the content of PAEs in sediments varies, some factors affecting the content of PAEs in sediments are summarized, such as the properties of PAEs, the properties of plastics, and environmental factors (sediments properties and hydrodynamic conditions). As endocrine disruptors, PAEs can produce toxicity to its direct contacts. Therefore, the effects of PAEs on benthos immunity, endocrinology, reproduction, development, and metabolism were comprehensively analyzed. In addition, we found that reciprocal inhibition and activation of the systems lead to genotoxicity and apoptosis. Finally, the paper discusses the feasible measures to control PAEs in wastewater and leachate from the perspective of source control, and summarizes the in-situ treatment measures for PAEs contamination in sediments. This paper provides a comprehensive review of PAEs contamination in sediments, toxic effects and removal strategies, and provides an important reference for reducing the contamination and toxicity of PAEs to benthos.

Occurrence of phthalic acid esters (PAEs) and active pharmaceutical ingredients (APIs) in key species of anthozoans in Mediterranean Sea

The Mediterranean Sea's biodiversity is declining due to climate change and human activities, with plastics and emerging contaminants (ECs) posing significant threats. This study assessed phthalic acid esters (PAEs) and active pharmaceutical ingredients (APIs) occurrence in four anthozoan species (Cladocora caespitosa, Eunicella cavolini, Madracis pharensis, Parazoanthus axinellae) using solid phase microextraction (SPME) and liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). All specimens were contaminated with at least one contaminant, reaching maximum values of 57.3 ng/g for the ∑PAEs and 64.2 ng/g (wet weight) for ∑APIs, with dibutyl phthalate and Ketoprofen being the most abundant. P. axinellae was the most contaminated species, indicating higher susceptibility to bioaccumulation, while the other three species showed two-fold lower concentrations. Moreover, the potential adverse effects of these contaminants on anthozoans have been discussed. Investigating the impact of PAEs and APIs on these species is crucial, given their key role in the Mediterranean benthic communities.

Occurrence, source apportionment, and ecological risk assessment of organophosphate esters in surface sediment from the Ogun and Osun Rivers, Southwest Nigeria

Organophosphate esters (OPEs) are synthetic chemicals widely used as e.g., flame retardants and plasticisers in various consumer products. Due to the toxicity of OPEs in aquatic ecosystems, exposure of fauna and flora to these compounds is of potential concern. In this study, the concentrations, profiles, sources, and ecological risk of eight OPEs were investigated in the sediments from the two major rivers in southwest Nigeria. Concentrations of ∑OPEs in surface sediments were in the range 13.1 - 2110 ng/g dry weight (dw) (median: 378 ng/g dw) in the Ogun River and 24.7-589 ng/g dw (median: 174 ng/g dw) in the Osun River. These concentrations are broadly within the range of those reported in surface sediment in previous studies conducted in other locations around the world. Tris (2-butoxyethyl) phosphate (TBOEP) was the dominant OPE in the sediment samples with a median concentration of 337 and 126 ng/g dw for the Ogun and Osun Rivers respectively, while tri-n-butyl phosphate (TnBP) was not detected in any sample. Excluding TBOEP, the chlorinated organophosphate esters: tris(2-chloroethyl) phosphate (TCEP), tris(2-chloro-propyl) phosphate (TCIPP), and tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) were the dominant OPEs in the Osun River, while the aryl-OPEs: triphenyl phosphate (TPHP), 2-ethylhexyl diphenyl phosphate (EHDPP), and tri-m-tolyl phosphate (TMTP) were dominant in the Ogun River. Under a median exposure scenario, moderate ecological risk was predicted from exposure to TCIPP in the Osun River. In contrast, under a high exposure scenario, concentrations of TDCIPP (risk quotient, RQ = 5.33-5.37) constituted a high ecological risk in both rivers, with moderate risks observed for TBOEP (RQ = 0.022-0.18) and TCIPP (RQ = 0.097 - 0.16). Therefore, the risk to aquatic organisms from concomitant exposure to mixtures of OPEs in freshwater ecosystems requires further investigation.

Phthalate esters in the Largest River of Asia: An exploration as indicators of microplastics

Phthalate esters (PAEs) are the most ubiquitous and highly used plasticizers in plastic products globally, yet studies on the spatial variation, risks, and their correlation with microplastics (MPs) are limited, particularly throughout the Yangtze River (the largest river in China/Asia). Therefore, this study investigated for the first time the PAEs pollution characteristics throughout the Yangtze River sediments, studied the environmental factors linked to the distribution of PAEs, and explored their potential as chemical indicators for interpreting pollution patterns of MPs. Totally 14 out of 16 PAEs were detected in sediments, with total concentrations ranging from 84.67 ng/g to 274.0 ng/g (mean: 163.5 ng/g), dominated by Bis(2-ethylhexyl) phthalate (DEHP), Di-n-butyl phthalate (DBP), and Di-isobutyl phthalate (DIBP), with contributions of 38.9 %, 31.8 %, and 20.8 %, respectively. Spatial distribution of PAEs did not indicate significant differences, which may be related to anthropogenic activities (i.e., emission intensity), runoff, and sediment physicochemical properties (i.e., TOC and TN), with TOC and TN being potential predictors of PAEs. The quantitative relationships (p < 0.001) between DEHP/∑16PAEs ratio and MPs (both individual and total MPs) were found in sediments, which suggested that DEHP could be potentially used as an indicator for MPs. DEHP, DIBP, and DBP posed high risks, accounting for 100 %, 68.4 %, and 10.5 % of the monitoring sites, respectively. Further work is necessary to better understand the relationship between DEHP/∑16PAEs and MPs in the environment and to take corresponding management and control measures for these pollutants.

Assessment of phthalic acid esters plasticizers in sediments of coastal Alabama, USA: Occurrence, source, and ecological risk

Considering the ubiquitous occurrences and ecotoxicity of phthalates (PAEs), it is essential to understand their sources, distribution, and associated ecological risks of PAEs in sediments to assess the environmental health of estuaries and support effective management practices. This study provides the first comprehensive dataset on the occurrence, spatial variation, inventory, and potential ecological risk assessment of PAEs in surface sediments of commercially and ecologically significant estuaries in the southeastern United States, Mobile Bay and adjoining eastern Mississippi Sound. Fifteen PAEs were widely detected in the sediments of the study region, with total concentrations varying between 0.02 and 3.37 μg/g. The dominance of low-molecular-weight (LMW) PAEs (DEP, DBP and DiBP) relative to high-molecular-weight (HMW) PAEs (DEHP, DOP, DNP) indicates that residential activities have stronger impacts than industrial activities on PAE distributions. The total PAE concentrations displayed an overall decreasing trend with increasing bottom water salinity, with the maximum concentrations occurring near river mouths. These observations suggest that river inputs were an important pathway by which PAEs were transported to the estuary. Linear regression models identified sediment adsorption (measured by total organic carbon and median grain size) and riverine inputs (measured by bottom water salinity) as significant predictors for the concentrations of LMW and HMW PAEs. Estimated 5-year total inventories of sedimentary PAEs in Mobile Bay and the eastern Mississippi Sound were 13.82 tons and 1.16 tons, respectively. Risk assessment calculations suggest that LMW PAEs posed a medium-to-high risk to sensitive aquatic organisms, and DEHP posed a low or negligible risk to the aquatic organisms. The results of this study provide important information needed for establishing and implementing effective practices for monitoring and regulating plasticizer pollutants in estuaries.

Investigating the presence of organophosphate esters in sediments from a typical fishing port agglomeration in Dalian, North China

The presence of 14 organophosphate esters (OPEs) in surface sediments from a typical fishing port agglomeration in Dalian, North China was investigated for the first time. Tris(2-ethylhexyl) phosphate (TEHP), triphenylphosphine oxide (TPPO), and tris(2-chloroethyl) phosphate (TCEP) dominated 12 detectable OPEs (∑OPEs), with concentrations ranging widely from 0.56 to 352 ng/g (dry weight basis). The ∑OPE levels in sediments varied significantly across fishing harbors of various grades, and within the same grade, highlighting uneven distribution of OPE sources and inputs to harbors. The first- and second-class fishing harbors had higher geometric mean of ∑OPE contents compared to center and natural harbors, reflecting higher OPE pollution in these areas. Although there were significant correlations among the OPE congeners with high detection frequencies, the composition patterns of sediment OPEs varied considerably among fishing ports. The sediments in the center and first-class harbors had higher abundance of non-chlorinated OPEs (non-Cl-OPEs), suggesting heterogeneity in source strength and pollution characteristics of Cl- and non-Cl-OPEs in fishing ports. The distribution of OPEs in sediments was weakly associated with sediment organic carbon, but not socioeconomic variables, indicating complex controlling factors of their distributions in port sediments. The ecological risks of sediment OPEs were evaluated, and while OPE accumulations ranged broadly (7-684 ng/cm2), exposure hazards were negligible. The sediments in first- and second-class fishing harbors, which had greater OPE accumulation, were identified as reservoirs of OPEs in port aquatic environments.

Concentrations of bisphenols and phthalate esters in the muscle of Mediterranean striped dolphins (Stenella coeruleoalba)

Bisphenols (BPs) and phthalate esters (PAEs) are important compounds for the plastics industry, also called "everywhere chemicals" due to their ubiquity in daily use products. Both chemical groups are well-known environmental contaminants, whose presence has been reported in all environmental compartments, and whose effects, mainly associated to endocrine disruption, are detrimental to living organisms. Cetaceans, due to their long life-span, low reproduction rate and high position in the trophic web, are especially vulnerable to the effects of contaminants. However, little is known about BP and PAE concentrations in cetacean tissues, their potential relation to individual biological variables, or their trends over time. Here, the concentration of 10 BPs and 13 PAEs was assessed in the muscle of 30 striped dolphins (Stenella coeruleoalba) stranded along the Spanish Catalan coast (NW Mediterranean) between 1990 and 2018. Six BP and 6 PAE compounds were detected, of which only 4,4'-(cyclohexane-1,1-diyl)diphenol (BPZ) was detected in all the samples, at the highest concentration (mean 16.06 μg g-1 lipid weight). Sex or reproductive condition were largely uninfluential on concentrations: only dimethylphthalate (DMP) concentrations were significantly higher in immature individuals than in adults, and the overall PAE concentrations were significantly higher in males than in females. Temporal variations were only detected in bis(4-hydroxyphenyl)ethane (BPE), diethylphthalate (DEP) and dimethylphthalate (DMP), whose concentrations were lower, and 9,9-Bis(4-hydroxyphenyl)fluorene (BPFL), which were higher, respectively, in samples taken between 2014 and 2018, probably reflecting shifts in the production and use of these chemicals. These results provide the first assessment of concentrations of several BP and PAE compounds in the muscle of an odontocete cetacean.

Air-Sea Exchange and Atmospheric Deposition of Phthalate Esters in the South China Sea

Phthalate esters (PAEs) have been investigated in paired air and seawater samples collected onboard the research vessel SONNE in the South China Sea in the summer of 2019. The concentrations of ∑₇PAEs ranged from 2.84 to 24.3 ng/m³ with a mean of 9.67 ± 5.86 ng/m³ in air and from 0.96 to 8.35 ng/L with a mean of 3.05 ng/L in seawater. Net air-to-seawater deposition dominated air-sea exchange fluxes of DiBP, DnBP, DMP, and DEP, while strong water-to-air volatilization was estimated for bis(2-ethylhexyl) phthalate (DEHP). The estimated net atmospheric depositions were 3740 t/y for the sum of DMP, DEP, DiBP, and DnBP, but DEHP volatilized from seawater to air with an average of 900 t/y. The seasonally changing monsoon circulation, currents, and cyclones occurring in the Pacific can significantly influence the concentration of PAEs, and alter the direction and magnitude of air-sea exchange and particle deposition fluxes. Consequently, the dynamic air-sea exchange process may drive the transport of PAEs from marginal seas and estuaries toward remote marine environments, which can play an important role in the environmental transport and cycling of PAEs in the global ocean.

Trends of legacy and emerging organic contaminants in a sediment core from Cienfuegos Bay, Cuba, from 1990 to 2015

Legacy and emerging organic pollutants pose an ever-expanding challenge for the marine environment. This study analysed a dated sediment core from Cienfuegos Bay, Cuba, to assess the occurrence of polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), polybrominated diphenyl ethers (PBDEs), alternative halogenated flame retardants (aHFRs), organophosphate esters (OPEs), and phthalates (PAEs) from 1990 to 2015. The results evidence the continuing presence of historical regulated contaminants (PCBs, OCPs, and PBDEs) in the southern basin of Cienfuegos Bay. PCB contamination declined since 2007, likely in response to the gradual global phasing out of PCB containing materials. There have been relatively consistent low accumulation rates for OCPs and PBDEs at this location (in 2015 approximately 1.9 and 0.26ng/cm²/year, respectively, with 2.8ng/cm²/year for Σ₆PCBs), with indications of recent local DDT use in response to public health emergencies. In contrast, sharp increases are observed between 2012 and 2015 for the contaminants of emerging concern (PAEs, OPEs, and aHFRs), and in the case of two PAEs (DEHP and DnBP) the concentrations were above the established environmental effect limits for sediment dwelling organisms. These increasing trends reflect the growing global usage of both alternative flame retardants and plasticizer additives. Local drivers for these trends include nearby industrial sources such as a plastic recycling plant, multiple urban waste outfalls, and a cement factory. The limited capacity for solid waste management may also contribute to the high concentrations of emerging contaminants, especially plastic additives. For the most recent year (2015), the accumulation rates for Σ₁₇aHFRs, Σ₁₉PAEs, and Σ₁₇OPEs into sediment at this location were estimated to be 10, 46 000, and 750ng/cm²/year, respectively. This data provides an initial survey of emerging organic contaminants within this understudied region of the world. The increasing temporal trends observed for aHFRs, OPEs, and PAEs highlights the need for further research concerning the rapid influx of these emerging contaminants.

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.

Aryl-, halogenated- and alkyl- organophosphate esters induced oxidative stress, endoplasmic reticulum stress and NLRP3 inflammasome activation in HepG2 cells

Organophosphate esters (OPEs) are a group of extensively used man-made chemicals with diverse substituents that are ubiquitously detected in human-related samples including serum, breastmilk, food and house dust. The understanding of their toxicological effects and potential mechanisms on hepatocytes is still limited. In this study, nine most frequently detected OPEs were selected and divided into three subgroups (aryl-, halogenated- and alkyl-OPEs) based on their substituents. The cytotoxicity, apoptosis, oxidative stress, endoplasmic reticulum (ER) stress and NLRP3 inflammasome activation induced by OPEs were evaluated in human hepatocellular carcinomas HepG2 cells. All OPEs induced apoptosis likely through a caspase-dependent apoptotic pathway. The activities of anti-oxidative enzyme SOD and CAT exhibited sensitive responses after OPEs treatment for 6 h. The OPEs induced ROS overproduction, DNA damage, endoplasmic reticulum (ER) stress and NLRP3 inflammasome activation varied among aryl-, halogenated- and alkyl-OPEs. Halogenated- and alkyl- OPEs induced overproduction of ROS and DNA damage, and elevated ER stress and NLRP3 inflammasome activation are observed aryl-OPEs induced cytotoxicity.

Effective degradation of organophosphate ester flame retardants and plasticizers in coastal sediments under high urban pressure

Empirical evidence of the effective degradation at environmentally relevant conditions of organophosphate esters (OPEs) flame retardants and plasticizers in coastal sediments from an impacted area in the NW Mediterranean Sea is provided. Half-lives varied from 23.3 to 77.0 (abiotic conditions) and from 16.8 to 46.8 days (biotic conditions), depending on the compound, highlighting the relevant role of microbial assemblages enhancing OPE degradation. After an immediate significant reduction of the bacterial abundance due to OPE addition to the sediment at the very beginning of the experiment, the observed biodegradation was associated to a general stimulation of the growth of the bacterial community during a first period, but without a marked change of the structure of the community. However, OPE contamination induced a decrease on the diversity of the bacterial community in the coastal sediment, noticeable after 14 days of incubation. It is likely that on one side the contamination had favoured the growth of some bacterial groups maybe involved in the biodegradation of these compounds but, on the other side, had also impacted some sensitive bacteria. The estimated half-lives fill a data gap concerning OPE degradation rates in marine sediments and will be valuable data for the refinement of OPE chemical risk assessment in marine environments, particularly on impacted sites.

Assessing microplastic ingestion and occurrence of bisphenols and phthalates in bivalves, fish and holothurians from a Mediterranean marine protected area

Microplastic (MP) ingestion, along with accumulated plasticizers such as bisphenol A (BPA), bisphenol F (BPF), and bisphenol S (BPS), and phthalates represented by diethyl phthalate (DEP), dibutyl phthalate (DBP) and bis (2-ethylhexyl) phthalate (DEHP), were quantified in bivalves, fish, and holothurians collected from a coastal pristine area at the western Mediterranean Sea. MP ingestion in sediment-feeders holothurians (mean value 12.67 ± 7.31 MPs/individual) was statistically higher than ingestion in bivalves and fish (mean 4.83 ± 5.35 and 3 ± 4.44 MPs/individual, respectively). The main ingested polymers were polyethylene, polypropylene, and polystyrene. The levels of BPS, BPF, and DEHP were highest in bivalves' soft tissue; BPA and DBP had the highest levels in the holothurians' muscle. In addition, the levels of all plasticizers assessed were lowest in fish muscle; only BPA levels in fish were higher than in bivalves, with intermediate values between those of bivalves and holothurians. This study provides data on exposure to MPs and plasticizers of different species inhabiting Cabrera Marine Protected Area (MPA) and highlights the differences in MP ingestion and levels of plasticizers between species with different ecological characteristics and feeding strategies.

Determination and environmental risk assessment of organophosphorus flame retardants in sediments of the South China Sea

As ubiquitous contaminants in the environment, organophosphorus flame retardants (OPFRs) would eventually settle in marine sediment. In this study, concentrations, spatial distributions, and ecological risks of seven OPFRs in sediment samples of the South China Sea (SCS) were investigated for the first time. Total concentration of all OPFRs ranged from 2.5 to 32.3 ng/g dry weight (dw), in which the abundance of tri-cresyl phosphates (TCPs) was the highest. OPFRs in the SCS were at a medium level compared with those from other parts of the world. The nearshore ocean current, ship transportation, and riverine inputs might influence the spatial distributions of OPFRs. The total inventory of six OPFRs in sediment was estimated to be 202.8 tons (16.7×10⁴ km²). The hazard quotient (HQ) of OPFRs ranged from 0 to 3.2E-02, indicating the ignorable ecological risk of OPFRs in sediments of the SCS. This study provides insight into the occurrence of current-use OPFRs in the SCS which deserved long-term concern in the future due to their continuous terrigenous inputs.

Sources, behaviors, transformations, and environmental risks of organophosphate esters in the coastal environment: A review

The rapid growth in the global production of organophosphate esters (OPEs) has resulted in their high environmental concentrations. The low removal rate of OPEs makes the effluents of wastewater treatment plants be one of the major sources of OPEs. Due to relatively high solubility and mobility, OPEs can be carried to the coastal environment through river discharge and atmospheric deposition. Therefore, the coastal environment can be an important OPE sink. Previous studies have shown that OPEs were widely detected in coastal atmospheres, water, sediments, and even aquatic organisms. OPEs can undergo various environmental processes in the coastal environment, including adsorption/desorption, air-water exchange, and degradation. In addition, bioaccumulation of OPEs was observed in coastal biota but current concentrations would not cause significant ecological risks. More efforts are required to understand the environmental behaviors of OPEs and address resultant environmental and health risks, especially in the complicated environment.

Source and Distribution of Emerging and Legacy Persistent Organic Pollutants in the Basins of the Eastern Indian Ocean

Persistent organic pollutants (POPs) have received significant and ongoing attention. To establish favorable regulatory policies, it is vital to investigate the occurrence, source, and budgets of POPs worldwide. POPs including phthalic acid esters (PAEs), organophosphate esters (OPEs), brominated flame retardants (BFRs), and highly chlorinated flame retardants (HFRs) have not yet been examined in the Eastern Indian Ocean (EIO). In this study, the distribution of POPs has been investigated from surface sediments with the depth of 4369-5742 m in the Central Indian Ocean Basin (CIOB) and Wharton Basin (WB) of EIO. The average (±SD) concentrations of ∑₁₁PAEs, ∑₁₁OPEs, ∑₄ BFRs, and ∑₅HFRs were 1202.0 ± 274.36 ng g^-1 dw, 15.3 ± 7.23 ng g^-1 dw, 327.6 ± 211.74 pg g^-1 dw, and 7.9 ± 7.45 pg g^-1 dw, respectively. The high abundance of low-molecular-weight (LMW) PAEs, chlorinated OPEs, LMW BDEs, and anti-Dechlorane Plus indicated the pollution characteristics in the EIO. Correlation analysis demonstrated that LMW compounds may be derived from the high-molecular-weight compounds. The monsoon circulation, currents, and Antarctic Bottom Water may be the main drivers. POP accumulation rate, depositional flux, and mass inventory in the Indian Ocean were also estimated.

Organophosphate esters in surface waters of Shandong Peninsula in eastern China: Levels, profile, source, spatial distribution, and partitioning

Organophosphate ester (OPE) levels, profiles, sources, spatial distribution, and partitioning were firstly studied in the rivers of the Shandong Peninsula. A total of 53 water samples and 45 sediment samples were collected from the rivers and the sewage treatment plant in the peninsula to quantitate levels of 13 targeted OPEs. Total OPE concentrations ranged from 263 to 6676 ng L^-1 in the water, and 39.3-360 ng g^-1 in the sediment. TEP, TCPP, and TCEP together contributed more than 90% of total OPE content. TCEP and TCPP concentrations in the Xiaoqing River sediment were increased by approximately two and seven times from 2014 to 2019, respectively. Total OPE concentrations generally increased from upstream regions to the estuaries. The main OPE sources were municipal effluent in the Jiaozhou Bay (JZB) watershed and chemical industrial wastewater in the Laizhou Bay (LZB) watershed. TCPP, TEP, and TCEP were generally approaching equilibrium between sediment and overlying water, while TNBP, TIBP, and TBOEP effectively transferred from the overlying water to the sediment. The riverine OPE flux was 0.66 ton/year to JZB and 3.58 ton/year to the LZB. TCPP and TCEP in municipal effluent, and TEP in chemical industrial wastewater should be regulated to protect Shandong Peninsula waters.

Occurrence, potential sources and risks of organophosphate esters in the high-elevation region, Tibet, China

Organophosphate esters (OPEs) are widely used flame retardants that are frequently released into the environment, causing potential harm to humans and ecosystems. Tibet is located on the Tibetan Plateau, known as the "roof of the world", but the occurrence of OPEs in Tibet remains unclear. This is the first report of the occurrence, potential sources and risks of 12 OPEs in water, soil, sediment and snow from Xainza, a typical town at high-elevation in Tibet (average elevation = 4700 m). Ten OPEs were observed, with ∑OPE concentrations of 46.45-1744.73 ng/L in surface water, 29.74-73.85 ng/g in soil, and 13.30-32.23 ng/g in sediment. Moreover, the mean ∑OPE concentration in snow was 413.90 ng/L. Tris (2-chloroethyl) phosphate (TCEP) and tris (2-chloroisopropyl) phosphate (TCPP) were the main OPEs in surface water and snow, while 2-ethylhexyl diphenyl phosphate (EHDPP) was dominant in soil and sediment. Local human activities and long-distance atmospheric transport may be the main sources of OPEs in Xainza. The assessment of ecological risk indicated that EHDPP in soil poses potential risk. The occurrence of OPEs in Xainza showed that more attention should be paid to persistent organic pollutants in high-elevation regions.

Phthalates in the environment: characteristics, fate and transport, and advanced wastewater treatment technologies

Phthalates are well-known emerging contaminants that harm human health and the environment. Therefore, this review aims to discuss about the occurrence, fate, and phthalates concentration in the various environmental matrices (e.g., aquatic, sediment, soil, and sewage sludge). Hence, it is necessary to treat sources containing phthalates before discharging them to aqueous environment. Various advanced wastewater treatments including adsorption process (e.g., biochar, activated carbon), advanced oxidation processes (e.g., photo-fenton, ozonation, photocatalysis), and biological treatment (membrane bioreactor) have been successfully to address this issue with high removal efficiencies (70-95%). Also, the degradation mechanism was discussed to provide a comprehensive understanding of the phthalate removal for the reader. Additionally, key factors that influenced the phthalates removal efficiency of these technologies were identified and summarized with a view towards pilot-scale and industrial applications.