Occurrence of phthalate esters in river sediments in areas with different land use patterns

Assessing the fate, toxicity, and ecological risk of mixtures of di(2-ethylhexyl)phthalate and di-n-butylphthalate using aquatic and terrestrial microcosms

Di(2-ethylhexyl)phthalate (DEHP) and di-n-butylphthalate (DBP) frequently coexist in different environmental compartments. Thus, in this study, model aquatic and terrestrial microcosms were prepared to analyze the combined effect of DEHP and DBP on their fate, toxicity, and ecological risk. In the aquatic microcosms, with the addition of the same amount of DEHP and DBP, a higher total amount of DEHP was detected in water, suspended particles, and sediment than DBP due to the higher Kow and half-life of DEHP than DBP. Sediment was the major sink of both phthalates, as the highest percentages of DEHP (90.0 % ∼ 95.6 %) and DBP (68.7 % ∼ 78.1 %) were found in the sediment. The results of the whole sediment toxicity test showed that DBP (LC50/LC10: 6.75/1.171 μg/g dw) was more toxic than DEHP (LC50/LC10: 158.75/27.25 μg/g dw) to the tubificid oligochaete Monopylephorus limosus, with a synergistic toxic effect of the mixture of DEHP and DBP (LC50/LC10: 100.3/4.6 μg/g dw). The mobility of DEHP and DBP in soil was low during irrigation, with the release of 0.054 % ∼ 2.29 % DEHP and 0.097 % ∼ 1.86 % DBP. The bioconcentration factors/biota-sediment accumulation factors for DEHP (70.8-145 L/kg/0.093-0.359) in the muscle of the fish Carassius auratus were lower than those for DBP (82.2-300 L/kg/0.514-1.625). The bioaccumulation factors of DEHP and DBP for earthworms were 0.373 and 0.682, respectively. The levels of DEHP and DBP in the water and sediment of aquatic systems and in the soil of terrestrial systems might pose high ecological risks to some fish species, M. limosus and earthworms, according to the risk quotient values. These data provide valuable insights for the development of government control strategies to minimize the ecological risks of DEHP and DBP.

Levels, sources, and health risk assessment of phthalate acid esters in indoor dust of various microenvironments in university

Phthalate acid esters (PAEs), as a common group of plasticizers, are widely present in indoor environments and pose a risk to human health. Indoor dust samples collected from dormitory, classroom, laboratory, and office in several universities in China, were analyzed for seven types of PAEs. The total concentrations of seven PAEs (Σ7PAEs) ranged from 4.87 to 360 μg/g, with a median concentration of 51 μg/g, which is lower than that reported by other studies. Using the median concentration of Σ7PAEs as a metric, we assessed the levels of contamination in different microenvironments, resulting in the following ranking: dormitory > classroom > laboratory > office. There are significant differences in the levels of individual PAEs in different microenvironments. Radiation from sunlight, ventilation rates, cleaning frequency, and sprays were influential factors for the concentrations of individual PAEs in indoor dust. The indoor environmental conditions and consumption patterns profoundly affect PAEs levels. The sources of PAEs in classroom and office were more complex than in dormitory and laboratory. Daily intakes of PAEs were used to calculate carcinogenic and non-carcinogenic human risk for males and females, indicating a low health risk to humans. This is the first study to assess the risk of PAEs in university microenvironments and provides a valuable reference for further research.

Phthalate acid esters: A review of aquatic environmental occurrence and their interactions with plants

The increasing use of phthalate acid esters (PAEs) in various applications has inevitably led to their widespread presence in the aquatic environment. This presents a considerable threat to plants. However, the interactions between PAEs and plants in the aquatic environment have not yet been comprehensively reviewed. In this review, the properties, occurrence, uptake, transformation, and toxic effects of PAEs on plants in the aquatic environment are summarized. PAEs have been prevalently detected in the aquatic environment, including surface water, groundwater, seawater, and sediment, with concentrations ranging from the ng/L or ng/kg to the mg/L or mg/kg range. PAEs in the aquatic environment can be uptake, translocated, and metabolized by plants. Exposure to PAEs induces multiple adverse effects in aquatic plants, including growth perturbation, structural damage, disruption of photosynthesis, oxidative damage, and potential genotoxicity. High-throughput omics techniques further reveal the underlying toxicity molecular mechanisms of how PAEs disrupt plants on the transcription, protein, and metabolism levels. Finally, this review proposes that future studies should evaluate the interactions between plants and PAEs with a focus on long-term exposure to environmental PAE concentrations, the effects of PAE alternatives, and human health risks via the intake of plant-based foods.

Occurrence, source apportionment and ecological risk of bisphenol analogues in river sediments in areas with different land use patterns

Bisphenol analogues (BPs) have gained increasing attention in recent years due to their ubiquitousness and potential endocrine disrupting properties in environments. However, little information is available on their spatiotemporal distribution, source apportionment and ecological risk in river sediments, especially the case in river basins with a high population density and those typical regions with agricultural-urban gradient, where land use patterns and intensity of human activity are varying. In this study, field investigations of BPs in the sediment of the entire Qinhuai River Basin, a typical agricultural-suburban agricultural-urban gradient area, were conducted before and after the flood period. Thirty-two sites were sampled for six types of BPs, resulted in no significant difference in the concentration of ΣBPs between the two periods, with ΣBPs ranging from 3.92 to 151 ng/g and 2.16-59.0 ng/g, respectively. Bisphenol A (BPA) was the main contributor. Whereas a multivariate analysis of variance (MANOVA) suggested that the composition structure of BPs had been influenced by water periods. The land use patterns had an impact on the distribution of ΣBPs in river sediments, which was more significant in after the flood period, with ΣBPs in urban rivers was 1.85 times, 3.44 times, and 3.08 times higher than the suburban rivers, agricultural rivers, and reservoirs, respectively. Yet land use types did not significantly alter the composition structure of BPs. The correlation analysis between BPs and the physicochemical properties of sediments showed a significant positive correlation between BPA and total organic carbon (TOC). The positive matrix factorization model (PMF) suggested that BPs in sediments of the basin might be influenced by industrial coatings, textiles, electronics and biopharmaceuticals, as well as urban wastewater or solid waste generated from daily life. The ecological risk assessment posed by BPA, based on the risk quotient, indicated that the ecological risk of BPA in sediments was low for three indicator benthic organisms: crustaceans, worms, and mollusks. However, the risk of BPA in river sediments varied among different land use patterns, with the risk ranking as follows: reservoirs < agricultural rivers < suburban rivers < urban rivers.

Di (2-ethylhexyl) phthalate induced lipophagy-related renal ferroptosis in quail (Coturnix japonica)

Di(2-ethylhexyl) phthalate (DEHP) is a synthetic chemical applied as a plasticizer. As an environmental toxicant, DEHP poses a serious health threat. Many studies have revealed that DEHP can cause lead to various degrees of damage to the kidney. However, the evidence of DEHP-induced renal ferroptosis has not been reported. The purpose of this work was to probe the specific role of lipophagy in DEHP-induced renal injury and to investigate the relationship between lipophagy and ferroptosis. Quail were treated with DEHP (250 mg/kg BW/day, 500 mg/kg BW/day and 750 mg/kg BW/day) for 45 days. Microstructural and ultrastructural observations showed that DEHP caused damage to glomerular and tubular cells, and autophagy with multilayer structures were observed, suggesting that DEHP can induce lipophagy. The results indicated that the iron homeostasis was abnormal and the lipid peroxidation was increased. SLC7A11 and SLC3A2 were down-regulated. PTGS2, ACSL4 and LPCAT3 were elevated. In conclusion, DEHP could induce lipid peroxidation, lead to ferroptosis, and damage renal cells. Therefore, the relationship between lipophagy and ferroptosis was elucidated, which provided a new basis for intervention and prevention of DEHP increased diseases.

Distribution and ecological risk assessment of priority water pollutants in surface river sediments with emphasis on industrially affected areas

Priority water pollutants comprising six plasticizers, 18 volatile organic compounds (VOCs), total petroleum hydrocarbon (TPH), 1,4-dioxane, epichlorohydrin, formaldehyde, acrylamide, and cyanides were determined in surface river sediments to assess their distribution patterns and ecological risks. Among these, di (2-ethylhexyl) phthalate (DEHP), toluene, TPH, and acrylamide were frequently found in sediments. The industrial sites had higher concentrations of ∑plasticizers (median 628 ng/g dry weight (dw)), ∑VOCs (median 3.35 ng/g dw), acrylamide (median 0.966 ng/g dw), and TPH (median 152 μg/g dw) in sediments than the mixed and non-industrial areas. The other pollutants did not show the significant differences in levels according to site types because of their relatively low detection frequencies. Volatile and soluble substances as well as hydrophobic pollutants were predominantly detected in surface sediments from industrial areas. Sediment contamination patterns were affected by the size and composition of the industrial zones around the sampling sites. The ecological risks determined using the sediment quality guidelines (DEHP, VOCs, and TPH) and the mean probable effect level quotients (DEHP) were mostly acceptable. However, the two most representative industrial regions (the largest industrial area and the first industrial city) showed risks of concern for DEHP and TPH.

Emerging and legacy plasticisers in coastal and estuarine environments: A review

The occurrence of plastic waste in the environment is an emerging and ongoing concern. In addition to the physical impacts of macroplastics and microplastics on organisms, the chemical effects of plastic additives such as plasticisers have also received increasing attention. Research concerning plasticiser pollution in estuaries and coastal environments has been a particular focus, as these environments are the primary entry point for anthropogenic contaminants into the wider marine environment. Additionally, the conditions in estuarine environments favour the sedimentation of suspended particulate matter, with which plasticisers are strongly associated. Hence, estuary systems may be where some of the highest concentrations of these pollutants are seen in freshwater and marine environments. Recent studies have confirmed emerging plasticisers and phthalates as pollutants in estuaries, with the relative abundance of these compounds controlled primarily by patterns of use, source intensity, and fate. Plasticiser profiles are typically dominated by mid-high molecular weight compounds such as DnBP, DiBP, and DEHP. Plasticisers may be taken up by estuarine and marine organisms, and some phthalates can cause negative impacts in marine organisms, although further research is required to assess the impacts of emerging plasticisers. This review provides an overview of the processes controlling the release and partitioning of emerging and legacy plasticisers in aqueous environments, in addition to the sources of plasticisers in estuarine and coastal environments. This is followed by a quantitative analysis and discussion of literature concerning the (co-)occurrence and concentrations of emerging plasticisers and phthalates in these environments. We end this review with a discussion the fate (degradation and uptake by biota) of these compounds, in addition to identification of knowledge gaps and recommendations for future research.

Accumulation, sources, and health risks of phthalic acid esters (PAEs) in road dust from heavily industrialized, urban and rural areas in southern Iran

In this research, a total of 51 road dust samples were collected from three districts (Asaluyeh, Bushehr, and Goshoui) in the south of Iran from April to June 2022 and analyzed for the concentration of 7 phthalic acid esters (PAEs) compounds. Asaluyeh was considered as an industrial area (near gas and petrochemical industries), Bushehr as an urban area, and Goshoui as a rural area (far from pollution sources). The PAEs concentration of the street dust samples was determined using a mass detection gas chromatography (GC/MS). The mean ± SD levels of ƩPAEs in samples from industrial, urban, and rural sources were 56.9 ± 11.5, 18.3 ± 9.64, and 5.68 ± 1.85 μg/g, respectively. The mean concentration levels of ƩPAEs was significantly (P < 0.05) higher in samples from the industrial area than urban and rural areas. The mean levels of di(2-Ethylhexyl) phthalate (DEHP) in industrial, urban, and rural areas were 20.3 ± 8.76, 4.59 ± 1.71, and 2.35 ± 0.98 μg/g, respectively. The results of the PCA analysis indicate that the likely major sources of PAEs in the road dust in the studied areas are the application of various plasticizers in industry, solvents, chemical fertilizers, waste disposal, wastewater (e.g., agricultural, domestic, and industrial), and the use of plastic films and plastic-based irrigation pipes in greenhouses. As well as, it was found that the non-cancer risk of exposure to dust-bound PAEs was higher for children than for adults. These values were <1 for both age groups (children and adults) and the exposure of inhabitants to PAEs in road dust did not pose a notable non-cancer risk. The cancer risk from exposure to DEHP in road dust was below the standard range of 10-6 in all three areas. Further studies that consider different routes of exposure to these contaminants are needed for an accurate risk assessment. Moreover, since higher PAEs level was found in industrial area, decision-makers should adopt strict strategies to control the discharging of pollution from industries to the environment and human societies.

Biodegradation of di-2-ethylhexyl phthalate by Bacillus firmus MP04 strain: parametric optimization using full factorial design

Di-2-ethylhexyl phthalate (DEHP) is used as a plasticizer in making plastics and released from landfills. This study attempted to degrade DEHP using microbial isolates. Isolates of Bacillus spp. were tested for their efficacy in degrading DEHP. Degradation was assessed using liquid chromatography-mass spectrometry (LC-MS). The most efficient DEHP degradation was achieved by Bacillus firmus MP04, which has been identified as Bacillus firmus MP04. This strain was found to use DEHP as the sole source of carbon without carbon source supplementation. Full factorial design was used to optimize the conditions for DEHP degradation which revealed the suitability of pH 7, 5% salt concentration, 20 to 37 °C temperature, and yeast extract as a nitrogen source. LC-MS elucidated the possible degradation mechanism via benzoic acid formation. However, prolonged incubation formed a typical compound denatonium benzoate due to reactions with other compounds. As maximum degradation was achieved in 4 days, prolonged incubation is not suggested. It can be concluded that new strain Bacillus firmus MP04 is the most efficient strain among all the tested strains for DEHP degradation.

Phthalate esters delivery to the largest European lagoon: Sources, partitioning and seasonal variations

Phthalate esters (PAEs) due to their ability to leach from plastics, widely used in our daily life, are intensely accumulating in wastewater water treatment plants (WWTP) and rivers, before being exported to downstream situated estuarine systems. This study aimed to investigate the external sources of eight plasticizers to the largest European lagoon (the Curonian Lagoon, south-east Baltic Sea), focusing on their seasonal variation and transport behaviour through the partitioning between dissolved and particulate phases. The obtained results were later combined with hydrological inputs at the inlet and outlet of the lagoon to estimate system role in regulating the transport of pollutants to the sea. Plasticizers were detected during all sampling events with a total concentration ranging from 0.01 to 6.17 μg L-1. Di(2-ethylhexyl) phthalate (DEHP) was the most abundant PAEs and was mainly found attached to particulate matter, highlighting the importance of this matrix in the transport of such contaminant. Dibutyl phthalate (DnBP) and diisobutyl phthalate (DiBP) were the other two dominant PAEs found in the area, mainly detected in dissolved phase. Meteorological conditions appeared to be an important factor regulating the distribution of PAEs in environment. During the river ice-covered season, PAEs concentration showed the highest value suggesting the importance of ice in the retention of PAEs. While heavy rainfall impacts the amount of water delivered to WWTP, there is an increase of PAEs concentration supporting the hypothesis of their transport via soil leaching and infiltration into wastewater networks. Rainfall could also be a direct source of PAEs to the lagoon resulting in net surplus export of PAEs to the Baltic Sea.

Contaminant occurrence, distribution and ecological risk assessment of phthalate esters in the Persian Gulf

Due to the increasing population of the world, the presence of harmful compounds, especially phthalate esters (PAEs), are one of the important problems of environmental pollution. These compounds are known as carcinogenic compounds and Endocrine-disrupting chemicals (EDCs) for humans. In this study, the occurrence of PAEs and the evaluation of its ecological risks were carried out in the Persian Gulf. Water samples were collected from two industrial sites, a rural site and an urban site. Samples were analyzed using magnetic solid phase extraction (MSPE) and gas chromatography-mass spectrometry (GC/MS) technique to measure seven PAEs including Di(2-ethylhexyl) phthalate (DEHP), butyl benzyl phthalate (BBP), diethyl phthalate (DEP), dibutyl phthalate (DBP), Dimethyl phthalate (DMP), di-n-octyl phthalate (DNOP), and Di-iso-butyl phthalate (DIBP). The BBP was not detected in any of the samples. The total concentration of six PAEs (Σ6PAEs) ranged from 7.23 to 23.7 μg/L, with a mean concentration of 13.7μg/L. The potential ecological risk of each target PAEs was evaluated by using the risk quotient (RQ) method in seawater samples, and the relative results declined in the sequence of DEHP >DIBP > DBP > DEP > DMP in examined water samples. DEHP had a high risk to algae, crustaceans and fish at all sites. While DMP and DEP showed lower risk for all mentioned trophic levels. The results of this study will be helpful for the implementation of effective control measures and remedial strategies for PAEs pollution in the Persian Gulf.

Occurrence and health risk assessment of phthalate esters in tobacco and soils in tobacco-producing areas of Guizhou province, southwest China

Flue-cured tobacco is one of the important sources of national economy in China. However, Phthalic acid esters (PAEs) are ubiquitous contaminants in the cultivation and growth management of flue-cured tobacco, and attracting more and more attention. Here, six priority PAEs were detected in tobacco and soils and their residue characteristics, pollution sources were analyzed, and their exposure risks to the health of farmers were assessed. The concentration of six total PAEs ranged from 0.78 to 4.79 mg/kg in tobacco with the average of 1.75 mg/kg, and 0.84-25.68 mg/kg in soils with the average of 5.40 mg/kg. Di-(2-ethylhexyl) phthalate (DEHP) and di-n-butyl phthalate (DBP) had the highest detection frequency (DF = 100%) both in soil and tobacco samples. DEHP was the most abundant of the total PAEs in soil and tobacco samples, with the mean contribution values of 71.0% and 58.8%, respectively. Principal component analysis (PCA) indicates that the major sources of PAEs in the tobacco-soil system were plastic films, fertilizers and pesticides. Health risk assessment suggests that the non-cancer hazard indexes (NCHI) of dimethyl phthalate (DMP), diethyl phthalate (DEP), DBP and di-n-octyl phthalate (DnOP) in all samples for farmers were at acceptable levels (NCHI < 1), and the average carcinogenic hazard indexes (CHI) of butyl benzyl phthalate (BBP) and DEHP for farmers were 3.79 × 10-13 and 8.54 × 10-11 in soils, respectively, 8.23 × 10-13 and 1.95 × 10-11 in tobacco, respectively, which were considered to be very low level (CHI < 10-6). This study provides data on PAEs in tobacco and soils and their health risks which may provide valuable information to aid the management of tobacco cultivation and risk avoidance.

Combining eDNA and morphological approaches to reveal the impacts of long-term discharges of shale gas wastewaters on receiving waters

The potential threats of shale gas wastewater discharges to receiving waters is of great concern. In this study, chemical analyses and biomonitoring were performed three times in a small river that received treated wastewater over a two-year period. The results of chemical analyses showed that the concentrations of chloride, conductivity, barium, and strontium increased at the discharge site, but their concentrations decreased considerably farther downstream (≥500 m). The concentrations of toxic organic compounds (16 US EPA priority polycyclic aromatic hydrocarbons and 6 priority phthalates), trace metals (strontium, arsenic, zinc, copper, chromium, lead, cadmium, nickel, and neodymium), and natural radionuclides (⁴⁰K, ²³⁸U, ²²⁶Ra, and ²³²Th) were comparable to the corresponding background values or did not exhibit obvious accumulation in sediments with continued discharge. Morphological and environmental DNA approaches were used to reveal the potential effects of wastewater discharges on aquatic ecosystems. The results showed that the community structure of benthic invertebrates was not altered by the long-term discharges of shale gas wastewaters. However, the biodiversity indices (richness and Shannon) from the two approaches showed inconsistencies, which were caused by multiple reasons, and that substrates had a strong influence on the morphological biodiversity indices. A multimetric index was proposed to further analyze morphological and environmental DNA data, and the results showed no significant difference between the upstream and downstream sites. Generally, the chemical and biological results both demonstrated that the discharges of shale gas wastewaters had limited impacts on river ecosystems within two years.

Distribution and ecological risk assessment of phthalic acid esters in surface sediments of three rivers in Northern Vietnam

Pollution status and distribution characteristics of ten typical phthalic acid esters (PAEs) were investigated in 36 sediment samples collected from three rivers in Northern Vietnam from June to October 2020. The total concentrations of PAEs in sediment samples collected from the To Lich River (n = 9), the Nhue River (n = 12), and the Day River (n = 15) were in ranges of 11,000-125,000 ng/g-dwt (mean/median: 50,000/42,200 ng/g-dwt), 2140-89,900 ng/g-dwt (mean/median: 29,300/20,700 ng/g-dwt), and 1140-43,100 ng/g-dwt (mean/median: 13,800/10,400 ng/g-dwt), respectively. Among ten PAEs studied, di-(2-ethylhexyl) phthalate (DEHP) was found at the highest levels in all samples meanwhile dimethyl phthalate (DMP), diethyl phthalate (DEP), and dipropyl phthalate (DPP) were detected at low frequency and concentration. Significant correlations have existed between the median-chain (C₄-C₇) PAE pairs in sediment samples. Due to the high accumulation in the sediments, the median-chain PAEs had a higher ecological risk than the short-chain (C₁-C₃) PAEs. These contaminants may present a longstanding influence on organisms and ecosystems.

Phthalate esters in seawater and sediment of the northern South China Sea: Occurrence, distribution, and ecological risks

In this study, the occurrence and distribution of 15 phthalate esters (PAEs) in seawater and sediment from the northern South China Sea (NSCS) were investigated for the first time to improve understanding on the contamination status of PAEs in this region. The concentrations of total PAEs (∑₁₅ PAEs) were found to range from 68.8 to 1500 ng/L, 46.0 to 7800 ng/L, and 49.2 to 440 ng/g dry weight in surface seawater, bottom seawater, and sediment, respectively. Among the 15 PAEs, dibutyl phthalate (DBP) and bis(2-ethylhexyl) phthalate (DEHP) were the predominant PAE congeners, with mean contributions of 44.7% and 24.0% in surface water, and 42.7% and 25.8% in bottom water, respectively. Moreover, diisobutyl phthalate (DiBP) constituted the majority of ∑15 PAEs in the sediment (61.3%). Comparatively high concentrations of Σ15 PAEs were observed in seawater at the sites within the western NSCS, whereas relatively higher concentrations of Σ15 PAEs were detected in sediments at the eastern NSCS. River input and atmospheric deposition could be the main sources of PAEs in the NSCS. Preliminary risk assessment implied that DBP, DiBP, and DEHP posed low to high potential risks for marine organisms at different trophic levels. These results would be valuable for implementing effective control measures and remediation strategies for PAEs contamination in the region.

Contamination of typical phthalate acid esters in surface water and sediment of the Pearl River, South China: Occurrence, distribution, and health risk assessment

The occurrence and distribution of six phthalate acid esters (PAEs) in surface water and sediment of the Pearl River were investigated, including Xijiang River (XR), Beijiang River (BR), Lingdingyang Estuary (LE), and Guangzhou River (GR) in South China. Six target PAEs were identified in surface water and sediment at almost all sites in the Pearl River, with di(2-ethyl-ethyl) phthalate (DEHP) and dibutyl phthalate (DBP) as dominant PAEs. Total 6 PAEs (ΣPAEs) in surface water and sediment ranged from 1,797.5 to 4,968.5 ng L^-1 and 95.24 to 3,677.26 ng g^-1 dw, respectively. In addition, the contamination levels of PAEs in the Pearl River are in the following order: XR > BR > GR > LE for surface water and BR > XR > GR for sediment. Local agricultural activities, industrial production, water confluence, and seawater intrusion are the probable sources of PAEs in the Pearl River. Based on correlation analysis, the possible collocation patterns of different PAEs were revealed. The risk assessment indicates that residual PAEs in the Pearl River pose a serious threat to the ecological environment. According to risk characterization of fish living in the Pearl River, the decreasing order of health risks was: GR > LE > XR > BR.

Occurrence, spatial distribution and ecological risk assessment of phthalate esters in water, soil and sediment from Yangtze River Delta, China

A total of 96 water, soil, and sediment samples, collected from 32 sampling sites in the Yangtze River Delta (YRD) region, were analyzed for 9 phthalate esters (PAEs). The sum concentrations of 9 PAEs (∑₉PAEs) in the water, soil, and sediment samples were 2.23-6.30 μg L^-1 (mean: 4.11 μg L^-1), 155-1410 μg kg^-1 (408 μg kg^-1), and 30.1-16,000 μg kg^-1 (1200 μg kg^-1), respectively. Among the 9 PAEs, di-n-butyl phthalate (DBP), bis(2-ethylhexyl) phthalate (DEHP), and di-isobutyl phthalate (DIBP) are the predominant congeners in the YRD region. DBP was the dominant PAE congener in water, accounting for 50.6% of the Σ₉PAEs, while DEHP was the predominant one in soil and sediment (accounting for 69.6% and 83.1% of the Σ₉PAEs, respectively). Soil and sediment samples collected from Wuxi city manifested relatively higher PAE concentrations. The partitioning of PAEs between water and sediment was attributed to the fact that low molecular weight PAEs (e.g., dimethyl phthalate (DMP) and diethyl phthalate (DEP)) were dominant in water, medium molecular weight PAEs (e.g., BzBP) were close to the equilibrium between sediment-water, and high molecular weight PAEs (e.g., DEHP) were more prevalent in sediment. The ecological risk assessment of PAEs in the surface water showed that the potential environmental risks followed the order of DEHP > DIBP > DBP > DMP > DEP. Comparatively, DEHP posed high ecological risk to sensitive algae, crustaceans and fish, while DMP and DEP exhibited low risk. In the sediment, DIBP exhibited a high risk to the sensitive fish, whereas DMP, DEP, DBP and DEHP displayed no risk.

Distributions, temporal trends and ecological risks of polyethylene terephthalate (PET) and di-(2-ethylhexyl) phthalate (DEHP) in sediments of Jiaozhou Bay, China

Spatiotemporal distribution and ecological risk of the polyethylene terephthalate (PET) plastic polymer and plasticizer di-(2-ethylhexyl) phthalate (DEHP) were investigated using both surface and core sediments in Jiaozhou Bay, China. The concentrations of PET and DEHP ranged 210.6-1929.7 μg/kg and 0-591.2 μg/kg, respectively. The depth profiles of PET and DEHP in the sediment cores indicated that PET and DEHP pollution increased since the 1970s, which is in accord with the regional PET and DEHP consumption history. The levels of PET in Jiaozhou Bay was found to represent low ecological risk based on the assessment models for Potential Ecological Risk factor and Potential Ecological Risk. The amounts of DEHP also posed a low risk to the aquatic organisms in the sediment phase as indicated by the Risk Quotient method.

Pollution characteristics of phthalate acid esters in agricultural soil of Yinchuan, northwest China, and health risk assessment

Eighty-nine agricultural surface soil samples from different types of land of Yinchuan were collected and detected for sixteen phthalate acid ester (PAE) compounds; the pollution characteristics and pollution distribution were analyzed. In addition, the potential health risk exposures to local resident of six priority control phthalates by the US EPA were assessed. All soil samples were contaminated with PAEs, the total concentrations of Σ₁₆PAEs were between 0.391 and 11.924 mg kg^-1, and the mean concentrations were 4.427 mg kg^-1 in soil. Among the sixteen PAE congeners, DMP was the most abundant component, which accounted for average 44.64% of the total PAEs, then DnBP and DEHP, which accounted for the average contribution rate, were 21.25% and 23.34%, respectively, and DpHP was not detected in all soil samples. Risk assessment indicated that the risk of non-carcinogenesis in this study was within the acceptable range; however, the carcinogenic risk of DEHP through intake dietary significantly exceeded the carcinogenic level recommended by the US EPA (1 × 10^-6) and therefore presented a potential carcinogenic risk. More considerable attention should be given to the PAEs contamination status in soils and potential effects on local resident health.

Distribution, partitioning behavior, and ecological risk assessment of phthalate esters in sediment particle-pore water systems from the main stream of the Haihe River, Northern China

The distribution, partitioning behavior and risk assessment of phthalate esters (PAEs) in the surface sediment-pore water system of the Haihe River were investigated. The total cumulative concentrations of 21 PAE species (Σ₂₁PAEs) in the surface sediment ranged from 45.9 to 1474.1 ng·g^-1 dry weight (dw) and were from 17.9 to 2628.8 ng·mL^-1 in the pore water. Di (2-ethylhexyl) phthalate (DEHP), dibutyl phthalate (DBP), and diisobutyl phthalate (DIBP) were the dominant components, and their sum accounted, on average, for 88.4% and 72.0% of Σ₂₁PAEs in the surface sediment and pore water, respectively. The spatial distributions of Σ₂₁PAEs in the surface sediment and pore water indicated that large amounts of the consumed products contained plasticizers in the urban and nearshore areas and increased the discharge of PAEs into the Haihe River. The river dam also affected PAEs distributions. The organic carbon normalized partitioning coefficient (logK_OC) followed a sequence as dry season (2.47 ± 0.35 mL·g^-1) > wet season (2.02 ± 0.45 mL·g^-1) > normal season (1.98 ± 0.42 mL·g^-1). The risk quotient (RQ) method was employed to assess the potential ecological risk from specific species. High ecological risks of DEHP to the sensitive algae, crustacean, and fish species along with high ecological risks of DIBP to sensitive fish species were found in the surface sediment and pore water for all sampling seasons. In addition, DBP in the surface sediment and pore water exhibited moderate and high ecological risks to sensitive aquatic species. The highest RQ values for PAEs were found in the surface sediment and pore water in suburban and urban areas, respectively, and indicated that anthropogenic activities may cause severe river pollution and high risk to the local aquatic ecosystem. CAPSULE: High levels and ecological risks from PAEs were found in the urban river, and the partitioning behaviors of PAEs between the surface sediment and pore water were not significantly affected by their hydrophobicity, especially for species with low K_OW.

Deterministic Assessment of the Risk of Phthalate Esters in Sediments of U-Tapao Canal, Southern Thailand

This baseline study evaluated the ecological risk associated with the concentration of six common Phthalate esters (PAEs) in sediment samples collected from the U-Tapao canal in Southern Thailand. Deterministic approaches consisting of standard sediment quality guidelines (SQGs) and Risk quotient (RQ) were used to evaluate the potential ecological risk of individuals and a mixture of Phthalate esters (PAEs) detected in sediment samples. Of the 6 PAEs measured, only three, including di-n-butyl phthalate (DBP), di-2-ethyl hexyl phthalate (DEHP) and di-isononyl phthalate (DiNP), were identified and quantified. The total concentration of the 3 PAEs congeners found in the sediment samples ranged from 190 to 2010 ng/g dw. The results from the SQGs and RQ were not consistent with each other. The SQGs results for individual PAEs showed that DEHP and DBP found in sediment was estimated to cause moderate risk on benthic organisms, DiNP was not estimated due to lack of SQGs data. However, the RQ method indicated a low risk of DEHP and DBP on algae, crustacean and fish, whereas DiNP poses no risk on crustacean. Furthermore, based on the result obtained in this study, the consensus SQGs for mixture effects prove to be a more protective tool than the RQ concentration addition approach in predicting mixture effects. Despite inevitable uncertainties, the integration of several screening approaches of ecological risk assessment (ERA) can help get a more inclusive and credible result of the first tier of individuals and a mixture of these pollutants.

Pollution characteristics, spatial variation, and potential risks of phthalate esters in the water-sediment system of the Yangtze River estuary and its adjacent East China Sea

Spatiotemporal variability in seawater, spatial variation in sediment, pollution characteristics, and risks related to 16 phthalate esters (PAEs) were investigated in the Yangtze River estuary and its adjacent East China Sea. The total concentrations of ΣPAEs in surface water were 0.588-17.7 μg L^-1 in summer, 2.63-22.9 μg L^-1 in winter, and 1.93-20.7 μg L^-1 in spring, with average values of 2.05, 10.2, and 4.89 μg L^-1, respectively. PAE concentrations exhibited notable seasonal variations with the highest value in winter and the lowest value in summer. The seasonal variation in PAE concentrations may be influenced by runoff and diluted water from the Yangtze River. The chemical composition of PAEs showed that di-n-butyl phthalate (DnBP), diisobutyl phthalate (DiBP), and di(2-ethylhexyl) phthalate (DEHP) had significantly higher (p < 0.05) concentrations than the other congeners and were the most abundant PAE species in sediment and seawater in all three seasons. In addition, DnBP and DiBP were the two main congeners in seawater, and DEHP concentrations were higher in sediment than in seawater. DEHP had higher potential risks to sensitive organisms in water environment than DnBP and DiBP, and DiBP and DnBP which presented high levels of risk in sedimentary environment. DMP and DEP in watery and sedimentary environments and DEHP in sedimentary environment showed no or low risks to sensitive organisms.

Plastic-derived contaminants in Aleutian Archipelago seabirds with varied foraging strategies

Phthalates, plastic-derived contaminants, are of increasing global concern. This study quantified phthalates in seabirds collected across >1700 km of the Aleutian Islands, Alaska, and contributes to a body of knowledge on plastic contaminants in marine wildlife. We measured six phthalate congeners in seabirds representing ten species and four feeding guilds. Phthalates were detected in 100% of specimens (n = 115), but varied among individuals (3.64-539.64 ng/g). DEHP and DBP occurred at an order of magnitude higher than other congeners. Total phthalates did not vary geographically, but differed among feeding guilds, with significantly higher concentrations in diving plankton-feeders compared to others. Plastic particles were detected in 36.5% of randomly subsampled seabird stomachs (n = 74), suggesting plastic ingestion as a potential route of phthalate exposure. Our findings suggest feeding behavior could influence exposure risk for seabirds and lend further evidence to the ubiquity of plastic pollutants in marine ecosystems.

Plasticizers and bisphenol A in Adyar and Cooum riverine sediments, India: occurrences, sources and risk assessment

Adyar and Cooum, the two rivers intersecting Chennai city, are exposed to serious pollution due to the release of large quantities of dumped waste, untreated wastewater and sewage. Sediments can act as repository for emerging organic contaminants. Hence, we have monitored the occurrence and risk associated with plasticizers [six phthalic acid esters (PAEs), bis(2-ethyl hexyl adipate) (DEHA)] and bisphenol A (BPA) in surface riverine sediments of Adyar and Cooum rivers from residential/commercial, industrial and electronic waste recycling sites. Σ₇plasticizers (PAEs + DEHA) in the Adyar riverine sediment (ARS) and Cooum riverine sediment (CRS) varied between 51.82-1796 and 28.13-856 ng/g, respectively. More than three-fourth of Σ₇plasticizers came from bis(2-ethylhexyl) phthalate (DEHP), in accordance with the high production and usage of this compound. BPA varied between 10.70-2026 and 7.58-1398 ng/g in ARS and CRS, respectively. Average concentrations of plasticizers and BPA were four times higher in electronic waste (e-waste) recycling sites when compared with industrial and residential/commercial sites. BPA and DEHP showed a strong and significant correlation (R² = 0.7; p < 0.01) in the e-waste sites thereby indicating common source types. Sites present at close proximity to raw sewage pumping stations contributed to 70% of the total BPA observed in this study. For the derived pore water concentration of plasticizers and BPA, the ecotoxicological risk has been found to be higher in ARS over CRS. However, sediment concentrations in all the sites of ARS and CRS were much below the recommended serious risk concentration for human (SRC_human) and serious risk concentration for ecotoxicological (SRC_eco).

Occurrence, Ecological and Health Risk Assessment of Phthalate Esters in Surface Water of U-Tapao Canal, Southern, Thailand

Phthalate esters (PAEs) are well known for their environmental contamination and endocrine-disrupting effects on wildlife and humans. In this study, the occurrence of PAEs and ecotoxicological risk assessments were performed in one of the significant canals in southern Thailand, named U-Tapao. Water samples were collected and analyzed for the six most common PAEs by using a gas chromatograph-mass spectrometer (GC-MS). Of the 6 PAEs analyzed, only three PAEs, including di-n-butyl phthalate (DBP), di (2-Ethylhexyl) phthalate (DEHP), and diisononyl phthalate (DiNP) were detected in water samples. The total concentration of PAEs ranged from 1.44 to 12.08 µg/L, with a mean level of 4.76 µg/L. The total average concentration of PAEs found in the canal was higher than the criteria of 3 µg/L for PAEs recommended for the protection of fish and other aquatic organisms by the United States Environmental Protection Agency (USEPA). The results of the potential ecological risk assessment of the risk quotient (RQ) method revealed that DEHP and DiNP posed a high risk to algae and crustacean and crustacean and fish, respectively, whereas DBP posed a medium risk to the different aquatic species. However, current levels of noncarcinogenic and carcinogenic risks via ingestion and dermal exposure in children and adults are within acceptable limits. The baseline data of PAEs in this canal will be beneficial to the strategic and future pollutant control along the canal network.

Uptake and toxicity of di-(2-ethylhexyl) phthalate in Brassica chinensis L

This work focuses on the bioaccumulation and toxic effects of di-(2-ethylhexyl) phthalate (DEHP) in the leafy vegetable Shanghaiqing (SHQ) (Brassica chinensis L.). The accumulated DEHP amount in the edible part and roots of SHQ increased as the DEHP concentration in the soil increased. DEHP accumulation was higher in the roots than in the edible part of the plant. The root concentration factors and bioaccumulation factors for DEHP in SHQ were 0.13-2.49 and 0.03-2.00, respectively. The DEHP translocation factors were below 1.0, indicating that DEHP preferentially accumulated in plant roots. The DEHP risk index in the edible part of SHQ in relation to the human body and in terms of dietary exposure risk assessment was also below 1.0, indicating a low health risk. High DEHP concentrations caused 1) inhibition of SHQ growth, 2) an increase in SHQ chlorophyll and malondialdehyde contents and 3) a decrease in soluble sugar and vitamin contents. Low DEHP concentrations stimulated total superoxide dismutase, peroxidase and catalase activities, while high DEHP levels showed an inhibitory effect. DEHP presence in soil affected not only SHQ growth but also quality. Our results provide the data needed for the proper assessment of food safety and the ecological impact of DEHP contamination in agricultural soils.

Trends for plasticizers in German freshwater environments - Evidence for the substitution of DEHP with emerging phthalate and non-phthalate alternatives

Plasticizers are marketed in high volumes and Di(2-ethylhexyl) phthalate (DEHP) is frequently detected in the environment and human populations. Industry had largely relied on DEHP until regulation started to restrict its marketing in 1999 due to environmental and human health concerns. The aim of this study was to obtain spatial-temporal trends for DEHP and its substitutes in German rivers. We have investigated suspended particulate matter (SPM) samples from the German Environmental Specimen Bank (ESB) for the presence of 23 plasticizers, i.e. 17 phthalates and 6 non-phthalates. The samples were collected in the last 10 years at 13 sites in large river basins in Germany such as the Rhine, Elbe and Danube. A decrease in DEHP concentrations was observed at all sampling sites between the mid-2000s and 2017. The maximum concentration for DEHP was determined in 2006 in samples from Rehlingen/Saar (6720 ng/g dry weight (dw)). By 2017, the DEHP concentration in Rehlingen had dropped to 2080 ng/g dw. Currently, Diisononyl phthalate (DINP) is the plasticizer with the highest levels in the SPM samples (maximum value 4150 ng/g dw in Rehlingen/Saar). Our results show that novel plasticizers such as Diisononylcyclohexane-1,2-dicarboxylate (DINCH) spread rapidly in surface waters after their market introduction. We have found several plasticizers of emerging concern in the environmental samples, the further use of which is currently under review under the EU chemicals regulation (REACH, registration, evaluation, authorisation and restriction of chemicals). In particular for Di(2-propylheptyl) phthalate (DPHP) a significant increase in concentration was observed at almost all sites between the mid-2000s and 2017, for example in Prossen/Elbe from 24 ng/g dw (2005) to 1380 ng/g dw (2017).

Impacts of anthropogenic activities on spatial variations of phthalate esters in water and suspended particulate matter from China's lakes

In the largest developing country, China, plastic has become a serious environmental issue because of its overuse and non-treatment. In fact, plasticizers, such as phthalate esters (PAEs), are more toxic than plastic, and their global awareness is rising. To determine the response of sensitive PAE congeners to the anthropogenic activities in a typical lake ecosystem of China, in the present study, 12 PAEs in the water and the suspended particulate matter (SPM) phases of 46 lakes in China were measured. The concentrations of all the Σ₁₂ PAEs in water and SPM phases ranged from 3.647 to 65.618 μg/L and 0.175 to 10.921 μg/L, respectively. Di-n-butyl phthalate (DnBP) was the predominant PAEs in the water phase, whereas diisobutyl phthalate (DIBP), DnBP, and bis(2-ethylhexyl) phthalate (DEHP) were the dominating PAEs in the SPM phase. Forty-six lakes were divided into four groups based on the anthropogenic activity intensities. The PAEs in both the water and SPM phases had increasing tendency along the human activity gradient. DIBP appears to be a sensitive PAE indicator that could distinguish the lake regions with different human industrial and agricultural activities. Dimethyl phthalate (DMP) and diethyl phthalate (DEP) are intensely affected by industrial development. DnBP and DEHP were positively correlated with agricultural activities, including the use of films and pesticides. It is suggested to control the addition and usage of PAEs in agricultural activities and improve their removal rates in industrial wastewater to reduce the PAE pollution in the water bodies in the environment management of China.

Occurrence of phthalic acid esters in sediment samples from East China Sea

Phthalic acid esters (PAEs) are widely used as plasticizers in many industrial and household products. The widespread distribution of PAEs in marine environment has attracted great concerns, due to their adverse health effects on marine organisms. However, the data on the occurrence of PAEs in sediment from East China Sea is still scarce. In this study, 16 PAEs were analyzed in 67 sediment samples collected from the Hangzhou Bay, Taizhou Bay, and Wenzhou Bay. Eight PAEs were detected in collected sediment samples, and the total concentrations of detected PAEs (∑PAEs) were in the range of 654-2603 ng/g. The di(2-ethylhexyl) phthalate (DEHP) was the predominant PAE (mean 663 ng/g; accounted for mean 52% of ∑PAEs), followed by di-isobutyl phthalate (DiBP; 284 ng/g; 22%), di-n-butyl phthalate (DBP; 184 ng/g; 15%), and dimethyl phthalate (63 ng/g; 5.0%). The mean sediment concentration of ∑PAEs in the Hangzhou Bay (1623 ng/g) was higher than that in the Taizhou Bay (1282 ng/g) and Wenzhou Bay (1185 ng/g). Concentrations of diethyl phthalate, DiBP, and DBP were significantly and positively correlated with one another in sediment from Taizhou Bay and Wenzhou Bay. The estimated inventories of ∑PAEs in sediment from Hangzhou Bay, Taizhou Bay, and Wenzhou Bay were 82 tons, 28 tons, and 26 tons, respectively. Overall, this study provides the first data on the occurrence of PAEs in sediment from the East China Sea, which is necessary to conduct the PAE exposure risk assessment for the marine benthos.

Occurrence of phthalic acid esters in marine organisms from Hangzhou Bay, China: Implications for human exposure

Owing to the wide application of phthalic acid esters (PAEs) in the manufacturing of plastic products, they are ubiquitous in the marine environment. However, the occurrence of various PAEs in marine organisms from China has not been well characterized. In this study, 341 marine organism samples (including fish, shrimp, crab, and shellfish) were collected from Hangzhou Bay, China and analyzed for 16 PAEs. Further, the human PAE exposure risks raised from the consumption of marine organisms were evaluated for adults and children. In total, eight PAEs were detected in collected organism samples, with the concentration of total PAEs (∑PAEs) ranging from 64 to 2840 ng/g (mean 238 ng/g). Crab (mean 811 ng/g) samples had the highest mean concentration of ∑PAEs, followed by fish (465 ng/g), shrimp (293 ng/g), and shellfish (261 ng/g) samples. Among detected PAEs, di-isobutyl phthalate (DiBP), di-n-butyl phthalate (DBP), and di-ethylhexyl phthalate (DEHP) were the predominant PAEs, and they collectively accounted for 84-97% of the ∑PAEs concentrations in all samples. The estimated daily intakes of DiBP, DBP, and DEHP were more than one order of magnitude higher than remaining PAEs. Calculated hazard quotient values of PAEs were all <0.1, suggesting non-cancer risks for the general population through the consumption of marine organisms. Overall, for the first time, this study systematically examined the occurrence of multiple PAEs in four types of marine organisms from Hangzhou Bay, China.

Study on biodegradation kinetics of di-2-ethylhexyl phthalate by newly isolated halotolerant Ochrobactrum anthropi strain L1-W

Objective

Di-2-ethylhexyl phthalate (DEHP) pollution is one of the major environmental concerns all over the world. This research aimed at studying the biodegradation kinetics of DEHP by a newly isolated bacterial strain. Water and sediment samples were collected from Wuhan South Lake and potent bacterial isolates were screened for DEHP degradation, characterized by biochemical, physiological, morphological and 16S rDNA gene sequencing, and optimized under suitable pH, temperature, NaCl and DEHP concentrations. DEHP and its metabolites were quantified by High Performance Liquid Chromatography and their degradation kinetics were studied.

Results

The newly isolated bacterium was identified as Ochrobactrum anthropi strain L1-W with 99.63% similarity to Ochrobactrum anthropi ATCC 49188. It was capable of utilizing DEHP as the carbon source. The optimum growth temperature, pH, DEHP and NaCl concentration for the strain L1-W were 30 °C, 6, 400 mg/L and 10 g/L respectively. Strain L1-W was capable of degrading almost all (98.7%) of DEHP when the initial concentration was 200 mg/L within a period of 72 h. Besides, it was also found capable of degrading five other phthalates, thus making it a possible candidate for bioremediation of phthalates in the environmental settings.

Anthropogenic Occurrence of Phthalate Esters in Beach Seawater in the Southeast Coast Region, South Korea

In modern times, humans have contributed to the occurrence of phthalate esters (PEs) in various environmental matrices by consuming plastics that generally contain PEs, which are essential synthetic organic chemicals for fabrication of various consumer products. Five beaches in Ulsan and Busan, South Korea, were investigated for the anthropogenic occurrence of four PEs (dimethyl phthalate (DMP), diethyl phthalate (DEP), di-n-butyl phthalate (DnBP), and bis(2-ethylhexyl) phthalate (DEHP)) in beach seawater. Using stir-bar sorptive extraction-thermal desorption-gas chromatography/mass spectrometry, DnBP and DEHP were determined as generally dominant. At Ilsan Beach, both the northern and southern ends showed higher DnBP and DEHP concentrations than the middle of the beach, while DMP and DEP showed similar concentrations at all points. The differences in the DnBP and DEHP concentrations may be related to the fishery industry and domestic sewage inflow to the beach. In addition, a comparison among Ilsan, Imnang, and Songjeong beaches suggested the effects of neighboring industrial areas on the DnBP and DEHP ratio. This study provides information on the effects of seasons, weather events, the proximity of rivers, industrial behavior, and domestic sewage to PE concentrations in beach seawater.

Biodegradation of di-(2-ethylhexyl) phthalate by a newly isolated Gordonia sp. and its application in the remediation of contaminated soils

A bacterial strain (Gordonia sp. Lff) capable of efficiently degrading di-(2-ethylhexyl) phthalate (DEHP) was isolated from river sludge. The optimal pH and temperature for the degradation of DEHP by Lff were 7.0 and 35 °C, respectively. Lff could degrade high concentrations of DEHP (100-2000 mg/L) with a degradation efficiency of over 91.43%. The DEHP degradation curves fit well with first-order kinetics, with a half-life ranging from 0.598 to 0.746 d. Substrate inhibition analyses showed that the maximum specific degradation rate, half-saturation constant and inhibition constant were 0.8 d^-1, 45.8 mg/L and 462.18 mg/L, respectively. A detailed biodegradation pathway of DEHP was proposed based on GC-MS analysis. Furthermore, Lff could also efficiently degrade DEHP in soils. DEHP or DEHP plus Lff changed the bacterial community in soils, and Lff accelerated the shaping of the bacterial community. To the best of our knowledge, this study is the first to perform a detailed investigation into the biodegradation of DEHP in soil by Gordonia sp. and its effect on the soil bacterial community. These results suggest that Lff is an ideal candidate for the bioremediation of DEHP-contaminated environments.

Phthalate esters (PAEs) in atmospheric particles around a large shallow natural lake (Lake Chaohu, China)

The pollution of phthalate esters (PAEs) remains an important issue in the world. Current studies mainly focused on atmospheric PAEs in urban area with strong anthropogenic activities, but there were no studies on PAEs in the ambient air around large natural lake. This paper focused on two sites around Lake Chaohu to investigate the monthly occurrence, composition and source of PAEs in the atmospheric particles around large shallow natural lake. New insights into atmospheric PAEs in large shallow natural lake and the overall fate of PAEs in lake ecosystem were given. The concentrations of the Σ₁₃PAEs in atmospheric particles were at a significantly low level ranging from 2740 to 11,890 pg·m^-3 and 2622 to 15,331 pg·m^-3 in ZM (the lakeshore site) and HB (the downtown site), respectively. There were no statistically significant differences of PAEs between ZM and HB. The highest atmospheric PAE concentrations in August were likely related to the long-range transport from Guangdong Province. Di(2-ethylhexyl) phthalate (DEHP), diisobutyl phthalate (DIBP) and dibutyl phthalate (DBP) were the main PAE congeners. Temporally, DIBP and DBP had the highest fractions in winter and the lowest fractions in summer. It might be justified by the condensation of DIBP and DBP from gas phase to particulate phase at low temperature. Multimedia comparison of PAE profiles in Lake Choahu revealed that low molecular weight (LMW) congeners were transported mainly through water while high molecular weight (HMW) congeners were transported mainly through atmosphere.

Occurrence of phthalate esters in the eastern coast of Thailand

In this work, we investigated possible contamination of phthalates in seawater and sediment around the eastern coast of Thailand in the area of Chonburi, Rayong, and Chanthaburi. The main focus was on Pradu Bay east of Map Ta Phut, a well-known industrial and economic hub in Thailand. Among six selected phthalates of interest, diethyl phthalate (DEP), and benzyl butyl phthalate (BBP) were not found in any sample, while the concentrations of dimethyl phthalate (DMP) and dioctyl phthalate (DnOP) were very low or undetectable in most samples. In December 2014, the concentration of dibutyl phthalate (DBP) and diethylhexyl phthalate (DEHP) in Pradu Bay were 0.23-0.77 and 0.31-0.91 μg L^-1 in seawater, respectively and non-detected (ND)-0.80 and ND-1.65 μg g^-1 for 11 out of 20 sediment samples. DBP and DEHP were considered as the predominant congeners. A surface mapping system provided us an overview concentration distribution of DBP and DEHP congeners in seawater and sediment in Pradu Bay, showing a correlation between water and sediment and allowing a prediction of a possible point source. A comparison with the EU standard concentration limit in surface water confirmed that the phthalate concentration in this area was acceptable. However, continuous monitoring of phthalate congeners in the matrices should be done to detect a possible increase in their concentrations. To the best of our knowledge, this is the first study to determine concentrations of phthalates in seawater and sediment along the east coast of Thailand.

Biodegradability and biodegradation pathway of di-(2-ethylhexyl) phthalate by Burkholderia pyrrocinia B1213

This study was conducted to investigate the biodegradation of di-(2-ethylhexyl) phthalate (DEHP) by Burkholderia pyrrocinia B1213. The results showed that DEHP at concentration of 500 mg/L in a mineral salt medium containing 1.0% yeast extract can be almost completely degraded (98.05%) by strain B1213. The optimal condition for DEHP degradation was pH 7.0, temperature 30 °C. Moreover, B1213 shows better degradation effect on long-chain PAEs, such as DEHP, which provides a great potential for its use in bioremediation of soils contaminated with PAEs. The kinetic studies showed that DEHP depletion curves fit well to the modified Gompertz model. The mono(2-ethylhexyl) phthalate (MEHP), mono-dibutyl phthalate (MBP), phthalic acid (PA) and 4-oxo-hexanoic acid were identified as the metabolites of DEHP by HPLC-ESI-QTOFMS. The detection of MBP and 4-oxo-hexanoic acid as intermediates prompted us to propose a novel and more complete DEHP biodegradation pathway compared to the classic pathway: DEHP is first degraded to MEHP by esterases, which is then converted to MBP through β-oxidation. Then MBP is degraded to PA by esterases, which is then converted to protocatechuate (PCA) under aerobic conditions rapidly. PCA is ultimately cleaved to generate CO₂ and H₂O via 4-oxo-hexanoic acid.

The occurrence, composition and partitioning of phthalate esters (PAEs) in the water-suspended particulate matter (SPM) system of Lake Chaohu, China

The occurrence, composition, and partitioning of six phthalate esters (PAEs) (dimethyl phthalate (DMP), diethyl phthalate (DEP), diisobutyl phthalate (DIBP), dibutyl phthalate (DBP), butyl benzyl phthalate (BBP) and di(2-ethylhexyl) phthalate (DEHP)) in the water-suspended particulate matter (SPM) system of Lake Chaohu were investigated in this study. Our results showed that PAEs were ubiquitous contaminants in Lake Chaohu. The concentration of the Σ₆ PAEs in dissolved and particulate phases ranged from 0.370 to 13.2 μg·L^-1 and from 14.4 to 7129 μg·L^-1, respectively. The Σ₆ PAEs in water and SPM phases exhibited different seasonal trends. PAEs with different degrees of hydrophobicity demonstrated different temporal distributions in the dissolved phase. In particulate phase, all PAEs exhibited the same temporal distribution. Regarding the occurrence of PAEs, significant spatial differences exist between lake and estuary. However, there were no specific differences in PAEs across lake zones and river types of Lake Chaohu. River input should be considered an important source of PAEs in Lake Chaohu. DIBP and DBP were the most abundant PAEs in Lake Chaohu, and DIBP should attract more attention in the future. The organic carbon normalized partitioning coefficient (logKoc) ranged from an average of 2.38 ± 0.86 L·g^-1 for BBP to 3.98 ± 0.66 L·g^-1 for DEHP, and approximately 2 to 3 unit variations of logKoc existed for the individual PAEs. It was difficult to ascertain whether the partitioning of PAEs was in, near or far from the equilibrium. No linear relationship was found between logKoc and the octanol-water partitioning coefficient (logKow) for PAEs. Koc might not be suitable for describing the partitioning of PAEs in the water-SPM system. The hydrophobicity of PAEs may have little impact on their partitioning in the complex environmental system, and the Kow model may be inappropriate to predict the partitioning of PAEs in natural large lakes.

Phthalate pollution driven by the industrial plastics market: a case study of the plastic market in Yuyao City, China

In attempts to evaluate the environmental risk produced by plastic markets, the levels and congener profiles of phthalate esters (PAEs) in soil, vegetable, and sediment samples collected from the plastic market in China, where numerous plastic products are exchanged every year, were investigated. The concentrations of ∑₂₂PAEs ranged from 2131 to 27,805 ng g^-1 in agricultural soils, from 8023 to 37,556 ng g^-1 in vegetables and from 9031 to 87,329 ng g^-1 in sediments. The predominant PAE pollutants were di-(2-ethylhexyl) phthalate (DEHP), di-n-butyl phthalate (DnBP), di-isobutyl phthalate (DiBP), and dibenzyl phthalate (DBzP). The mean percentages of the predominant PAEs in the soil, vegetable, and sediment samples accounted for 98.4%, 97.3%, and 99.5% of the total PAEs, respectively. The concentrations of PAEs at the sites around the plastic market were significantly higher than those at other pollution sites, such as sites contaminated by agricultural plastic film, electronic waste (e-waste) recycling sites, and industrial parks, indicating that the plastic market was an important pollution source. The DEHP concentrations in the soils, vegetables, and sediments and the DnBP concentrations in the vegetables all exceeded the environmental risk levels (ERL) or the environmental allowable levels (EAL), indicating that the plastic market posed potential environmental risks.

Phthalate acid esters (PAEs) accumulation in coastal sediments from regions with different land use configuration along the Persian Gulf

Phthalate acid esters (PAEs) are widely used as plasticizers in various plastic products and have aroused considerable concern over their ubiquitous presence and potentially hazardous effects on the environment. This research provides the first data on PAEs distribution in the sediments of northern part of the Persian Gulf. To determine the concentration of 16 PAEs, 26 samples of sediments were collected from industrial stations (IS), urban stations (US), agricultural stations (AGS), and natural field stations (NS) from Asalouyeh Harbor coasts from Nov 2016 to Jan 2017. The mean values of Ʃ16PAEs in the samples taken from IS, AGS, US, and NS were 78.08, 11.69, 46.56, and 5.180 µg/g, respectively. The results indicated that the mean concentrations of Ʃ16PAEs in the samples taken from IS and AGS areas were significantly higher (p < 0.05) than the ones taken from US and NS areas. The order of PAEs concentrations in sediment samples were as di(2-ethylhexyl) phthalate (DEHP), di-n-butyl phthalate (DnBP), butylbenzyl phthalate (BBP), and di-n-octyl phthalate (DnOP), respectively. DEHP was detected in all collected samples and the mean ± SD of its concentration in the IS, US, AGS, and NS regions were as 28.15 ± 4.9, 4.040 ± 0.53, 11.58 ± 1.2, and 1.780 ± 0.78 µg/g, respectively. The major sources of PAEs in the sediments collected from the study region were associated with the industrial and agricultural activities. The findings of this study indicated that the sediments of the Asalouyeh coasts are heavily contaminated with PAEs. They have shown potential ecotoxicological effects on the aquatic organisms and benthic. Therefore, more attention should be paid to prediction of the marine ecosystem in this region by the authorities.

Occurrence and spatial distribution of phthalate esters in sediments of the Bohai and Yellow seas

Phthalate esters (PEs) are a class of synthetic chemicals that have been widely used as plasticizers in industrial products and households. The occurrence of PEs in the marine environment has been a concern for many years because of their adverse impacts on marine organisms and human health. In this study, six major PEs, i.e. diethyl phthalate (DEP), di‑isobutyl phthalate (DiBP), di‑n‑butyl phthalate (DnBP), benzylbutyl phthalate (BBP), dicyclohexyl phthalate (DCHP) and di‑(2‑ethylhexyl) phthalate (DEHP), were analyzed in sediment samples collected in the Bohai and Yellow seas. The sum concentrations of the six PEs ranged from 1.4 to 24.6 ng/g and the average was 9.1 ng/g. The highest concentrations of PEs in the sediment samples were those of DEHP with a median concentration of 3.77 ng/g, followed by DiBP (median, 1.60 ng/g), DnBP (0.91 ng/g), DEP (0.32 ng/g), BBP (0.03 ng/g) and DCHP (0.01 ng/g). Generally, concentrations of PEs in the Bohai Sea are higher than those in the Yellow Sea. The varying spatial distributions of the individual PEs can be the result of discharge sources, regional ocean circulation patterns, and mud areas in the Bohai and Yellow seas. Significant positive correlations were found between total organic carbon content and the concentrations of DiBP, DnBP, and DEHP. It is estimated that the inventories of the ∑6PEs were 20.73 tons in the Bohai Sea and 65.87 tons in the Yellow Sea. Both riverine discharge and atmospheric deposition are major input sources for the PE sedimentation, while massive plastic litter and microplastics sinking to the ocean floor can directly release PEs into sediment. This study provides an appropriate data set for the assessment of the risk of PEs to the marine ecosystem.

Distribution, Toxic Potential, and Influence of Land Use on Conventional and Emerging Contaminants in Urban Stormwater Pond Sediments

This study examined the distribution and toxic potential of conventional and emerging contaminants in composite sediment samples from 15 stormwater ponds in the Minneapolis-St. Paul, MN metropolitan area. Previously, coal tar-based sealants were shown to be a major source of polycyclic aromatic hydrocarbons to these ponds, and concentrations of carcinogenic benzo[a]pyrene (B[a]P) equivalents were influencing management options about pond maintenance. For the second component of this study, a complex mixture of 13 metal(loid)s, 4-nonylphenols, 8 brominated diphenyl ethers (BDEs), and total polybrominated diphenyl ethers (PBDEs) were detected in all surficial samples. Contaminants with detection frequencies ≥ 20% included: silver (46.7%), beryllium (20.0%), chloride (60.0%), bis(2-ethylhexyl)phthalate (60.0%), 10 per- and polyfluoroalkyl substances (PFASs; 26.7-80.0%), 4-nonylphenol monoethoxylate (66.7%), 4-nonylphenol diethoxylate (40.0%), bifenthrin (20.0%), total permethrins (33.3%), and 24 other BDE congener groups (20.0-93.3%). Five stormwater ponds had contaminants exceeding benchmarks likely to be associated with harmful effects to benthic organisms. Ponds with watersheds dominated by either commercial and/or industrial land uses had significantly higher (p < 0.05) concentrations of zinc, 4-nonylphenol, six BDEs (28 + 33, 47, 99, 100, 154, and 209), and total PBDEs than those dominated by residential land uses. Multivariate statistical analyses verified that updated B[a]P equivalents were an effective chemical proxy for making management decisions about excavated pond sediment. Jurisdictions that do not test their stormwater pond sediments prior to maintenance dredging should consider the environmental ramifications of applying this potentially contaminated material to land.

Occurrence and distribution of phthalate esters in freshwater aquaculture fish ponds in Pearl River Delta, China

The concentrations, congener profiles and spatial distribution of 13 phthalate esters (PAEs) in the freshwater fish ponds in the Pearl River Delta (PRD) region were investigated in water and sediment samples collect from 22 sites during Jul. 2016-Sept. 2017. The di-2-ethylhexyl phthalate (DEHP) was the predominant compounds in both water and sediment samples, accounting for 70.1% and 66.1% of ∑PAEs, respectively. The DEHP concentrations in the water samples collected from the sites of Zhongshan (35.7 μg/L), Jingmen (17.3 μg/L) and Nanhai (14.2 μg/L) were higher than that collected from other sampling sites (p <0.05), and exceed the Chinese environmental quality standards for surface water (DEHP, 8.00 μg/L). The concentrations of ΣPAEs (mean and median were 11.8 mg/kg dw and 7.95 mg/kg dw) in sediment was higher than that in sediment of river and estuary in the PRD region (p <0.05). The median concentrations of DEHP and di-n-butyl phthalate (DBP) exceeded recommend environmental risk limit (ERL) that posed a potential risk to the aquaculture fish pond environment in the PRD.

Intercropping wheat and maize increases the uptake of phthalic acid esters by plant roots from soils

Whether crop intercropping can affect the uptake of phthalic acid esters (PAEs) by plant roots from soils is unclear. In this study, we compare the PAE uptake by plant roots between the wheat/maize intercropping and the wheat and maize monocropping in a field work. We show that the PAE bioconcentration factors of wheat and maize roots are remarkably higher under wheat/maize intercropping than under monocropping, indicating that intercropping may significantly increase the biouptake of PAEs as compared to monocropping. The wheat/maize intercropping can increase the electron transfer capacity (ETC) of water-extractable organic matter (WEOM) in soils by increasing the abundance of redox-active functional groups in WEOM. The ETC-enhanced WEOM may be an important reason for facilitating the reduction of ferric iron [Fe(III)] minerals to soluble ferrous iron [Fe(II)] by acting as electron shuttle, thus leading to the release of the PAEs originally occluded in Fe(III) minerals into soil pore water. The increased bioavailable PAEs distributed in the soil pore water under wheat/maize intercropping eventually result in the increase in the uptake of PAEs by plant roots from soils. The results can provide insights into the link between the uptake of PAEs by crops and the cropping practices in agricultural ecosystems.

Photosynthetic and antioxidant response of wheat to di(2-ethylhexyl) phthalate (DEHP) contamination in the soil

Di(2-ethylhexyl) phthalate (DEHP) is a commonly used, artificially-synthesized, industrial chemical that can be released into the soil. However, to date, there is no comprehensive study on the effects of DEHP on photosynthesis, induction of reactive oxygen species, and response of the antioxidant defense system in wheat plants growing in DEHP contaminated soil. This study was conducted to address this gap in knowledge. Our results showed that after application of 10, 20, and 40 mg/kg DEHP, photosynthetic parameters, fluorescence parameters, and chlorophyll content of wheat leaves at seedling, jointing, and booting stages decreased, while the intercellular carbon dioxide concentration increased. This indicates that the observed decrease in net photosynthetic rate in wheat leaves was due to a non-stomatal limitation, wherein DEHP seems to have hindered the photoelectron transfer process. Both superoxide anion (O₂^-) and hydrogen peroxide (H₂O₂) content increased in the roots, stems, and leaves in plant under DEHP treatment compared with those in the control plants. Antioxidant enzyme activity increased with increasing DEHP stress, except under the 40 mg/kg treatment at the seedling stage. The antioxidant system had a certain protective effect on wheat, but DEHP still caused peroxidation of cell membrane lipids. The extent of DEHP damage to the roots, stems, and leaves was concentration dependent. Furthermore, enzymatic activity tolerance increased with metabolism, and long-term effects of DEHP gradually decreased with plant growth. Finally, the toxic effects of DEHP on root tissues were more serious at the seedling and jointing stages.

Distribution and ecotoxicological state of phthalate esters in the sea-surface microlayer, seawater and sediment of the Bohai Sea and the Yellow Sea

The spatial distribution, chemical composition and ecological risk of 16 phthalate esters (PAEs) were investigated in the sea-surface microlayer (SML), seawater and sediment samples of the Bohai Sea (BS) and the Yellow Sea (YS). The concentration levels of the ΣPAEs spanned a range of 449-13441 ng L^-1 in the SML, 453-5108 ng L^-1 in seawater, and 1.24-15.8 mg kg^-1 in the sediment samples, respectively, with diisobutyl phthalate (DiBP), di-n-butyl phthalate (DBP) and di-ethylhexyl phthalate (DEHP) as the dominant PAEs in both the water and sediment samples. The concentrations of ΣPAEs in the BS were higher than those in the YS. The vertical distribution of ΣPAEs in the water column showed that the concentrations were higher in the surface waters, but decreased slightly with depth, and started to increase at the bottom. Additionally, PAEs were significantly enriched in the SML, with an average enrichment factor of 1.46. The ecological risk of the PAEs was evaluated by the risk quotient (RQ) method, which indicated that DEHP posed a high risk to aquatic organisms in the whole water-phase, while the RQ values of DBP and DiBP reached a high risk levels in sedimentary environment.

Phthalate esters distribution in coastal mariculture of Hong Kong, China

The aim of the study is to evaluate the impact of mariculture on phthalate esters speciation and distribution in sediments and cultured fish in the Hong Kong regions and near mainland China. Concentrations of ∑phthalate esters in mariculture surface sediments (0 to 5 cm) ranged from 0.20 to 54.3 mg/kg dw (mean 10.3 mg/kg dw), with the highest recorded at M2 (20.4 mg/kg dw). Concentrations of phthalate esters were not significantly (p > 0.05) enriched in surface and sediment cores at mariculture sites relative to the reference sediments, 1 to 2 km away in areas without mariculture activities. Among different congeners, only butyl benzyl phthalate (BBP) concentrations demonstrated a significant correlation (R² = 0.40, p < 0.05) with TOC values of sediments. The median concentrations of di-2-ethylhexyl phthalate (DEHP) and di-n-butyl phthalate (DBP) in the sediments were 1.57 and 6.96 times higher than the environmental risk levels (ERL), which may pose environmental risks. Results of health risk assessments revealed that the cultured fish (snubnose pompano, orange-spotted grouper, and red snapper) were safe for consumption, in terms of phthalate esters. This is the first study to assess the differences of phthalate esters contamination between mariculture and natural coastal sediments.

Occurrence, distribution, and ecological risks of phthalate esters in the seawater and sediment of Changjiang River Estuary and its adjacent area

A total of 133 seawater samples and 17 sediment samples were collected from 81 sampling sites in the Changjiang River Estuary and its adjacent area and were analyzed for 16 phthalate esters (PAEs). The Σ₁₆ PAE concentrations in the seawater and sediment samples ranged from 180.3ng·L^-1 to 3421ng·L^-1 and from 0.48μg·g^-1 to 29.94μg·g^-1dry weight (dw), respectively, with mean values of 943.6ng·L^-1 and 12.88μg·g^-1. The distribution of ∑₁₆PAE concentrations in the water column showed that PAE concentrations in the bottom samples were higher than those in the surface samples (except the transect C located inside the Changjiang River Estuary), with the maxima appearing in the bottom layer at the offshore stations. Among the 16 PAEs, di (2-ethylhexyl) phthalate (DEHP), diisobutyl phthalate (DiBP), and dibutyl phthalate (DnBP) dominated the PAEs, with 25.1%, 21.1%, and 18.9% of the Σ₁₆PAEs in seawater, respectively. The comparison of ∑₁₆PAEs and salinities in transects C and A6 suggested that the Changjiang River runoff was an important driving factor influencing the distribution of PAEs. DEHP concentrations in water samples and DEHP and DnBP concentrations in sediment samples exceeded the environmental risk levels (ERL), indicating their potential hazard to the ocean environment.

Micro-pollutants in sediment samples in the middle Danube region, Serbia: occurrence and risk assessment

This is the first comprehensive study on the occurrence of 940 semi-volatile organic compounds including sterols, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), pesticides, plasticizers, and other emerging compounds in 10 river and canal sediments collected in northern Serbia. For quantification of investigated compounds GC-MS-MS (selected reaction monitoring) and GC-MS (using both selected ion monitoring and total ion monitoring) methods were used. The number of detected compounds was in the range of 85-117, while the sum of the concentrations varied from 959 μg/kg dry-wt to 84,445 μg/kg dry-wt. Sterols were quantified with high frequency in nearly 100% of investigated samples suggesting that the studied rivers and canals have been contaminated by sewage. Regarding persistent organic compounds, p,p'-DDE, p,p'-DDD, and o,p'-DDT were the dominant members of organochlorine pesticides (OCPs). The concentration range of 11 quantified pesticides of 452 analyzed was from 0.564 to 61.6 μg/kg dry-wt, while the concentration range of 47 quantified PCBs of 90 analyzed was from 0.928 to 32.1 μg/kg dry-wt. OCPs (DDE, DDD, and γ-HCH) and several PAHs (fluoranthene, pyrene, phenanthrene, chrysene, benzo(a)anthracene, benzo(a)pyrene) exceeded the maximum values of the sediment quality guidelines. Contents of domestic compounds comprise a large proportion of the total contaminant concentration. Overall, the study reveals that river sediments in Vojvodina Province were moderately polluted mainly by domestic wastewater. The toxic equivalent quantity (TEQ) relative to benzo(a)pyrene and 2,3,7,8-tetrachlorodibenzodioxin for seven carcinogenic PAHs and six quantified dioxin-like PCBs ranged from 3.59 to 103 μg TEQ/kg and from 0.001 × 10^-3 to 2.10 × 10^-3 μg TEQ/kg, respectively, and were in the range or lower than the literature published data.

Spatial distribution and ecological risk assessment of phthalic acid esters and phenols in surface sediment from urban rivers in Northeast China

Concentration and spatial distribution of six phthalic acid esters (PAEs) and eight phenols in sediments of urban rivers, namely the Xi River (XR) and Pu River (PR) in Shenyang city, Northeast China were investigated and the ecological risk of these target pollutants was assessed based on the risk quotient (RQ) approach. Target PAEs and phenols were detected in most of sediment samples collected from the XR and PR. The concentrations of total PAEs in sediments varied from 22.4 to 369 μg/g dw in the XR and 3.71-46.9 μg/g dw in the PR. The levels of phenols ranged from 2.72 to 106 μg/g dw in the XR and 0.811-25.0 μg/g dw in the PR, respectively. The dominant pollutants in both XR and PR were DEHP, phenol and 4-methylphnol. The sampling locations XR1-3 in the XR suffered severe contamination from PAEs and phenols. The sites PR1 and PR6 were heavily polluted by phenols and PAEs, respectively. Almost all target PAEs and phenolic compounds in sediment of the XR exhibited medium or high ecological risk to organisms and the ecological risk in the PR mainly originated from PEAs, phenol and 4-methylphenol. These results would provide guidance for individual pollutant control and indicate that it is imperative to take some effective measures to reduce the pollution of those contaminants.