Concentrations Of Phthalate Esters Research Articles

Bacterial enzyme based spectrophotometric determination of phthalate esters in drinking water stored in PET bottles

Phthalate esters (PEs) are major water pollutants raising concern of endocrine disruption on daily uptake even at nano-gram level. Among PEs, di-(2-ethylhexyl) phthalate (DEHP) is a high molecular weight PE predominently found in most of the plastic and PVC products. In the present study, daily consumption of PET bottle stored drinking water was taken into account; where leaching PEs occurs easily from its supporting matrix. Determination of PEs in water and other environmental samples by conventional methods involves solvent extraction and sophisticated instruments. To overcome such scenario, in the present study enzyme based spectrophotometric determination of PEs is been proposed. Purified bacterial esterase of 38 kDa is used in the study with optimised pH, temperature and T50 as 7.0, 40 °C and 65 °C. The Km and Vmax values of the purified esterase were derived to be 138.88 µM for DEHP as substrate and 3.15 µmol of phthalic acid liberated min−1 mL−1. Inhibitory effect of metals, minerals and salts that are commonly present in water was assessed at two varied concentrations: 10 and 30 ppm. Magnesium, sodium and mercury exhibited maximum inhibition of 41–47% when compared to other inhibitors. In spectrophotometric determination, upon enzymatic reaction of purified esterase with condensed PET bottle stored drinking water, PE concentration was quantified to be 0.01–0.54 µg L−1. LoD and LoQ based on method validation were calculated to be 0.4 and 1.18 µg L−1. Thus, this study would serve to overcome tedious solvent based extraction process and sophisticated instruments in the detection and quantification of PEs.

Pollution Characteristics and Ecological Risk Assessment of Phthalate Esters (PAEs) in the Surface Water of Jiaozhou Bay

In order to better understand phthalate esters (PAEs) pollution in Jiaozhou Bay, surface water samples were collected for content analysis in August and November 2015 and January 2016. Fifteen kinds of PAEs were detected by stir bar sorptive extraction and gas chromatography-mass spectrometry. The content, composition, spatial distribution, seasonal variation, and ecological risk assessment of the PAEs in the surface waters were examined and analyzed. The results showed that:① The total concentrations of PAEs in the surface seawater in August and November 2015 and January 2016 were 3.63-21.20 μg·L-1, 2.24-12.60 μg·L-1, and 0.01-4.15 μg·L-1, respectively, and the average concentrations were 11.10 μg·L-1, 5.26 μg·L-1, and 0.80 μg·L-1, respectively. ② Influenced by runoff and ocean currents, the concentration of PAEs in the surface water of Jiaozhou Bay is higher near the shore and lower in the middle, and the total concentration of the east coast is higher than that of the west coast. Compared with surveys of other rivers and oceans, the PAEs content in the surface water of Jiaozhou Bay is moderate, but it is heavily polluted compared with other oceans. ③ Considering the rainfall and other factors, the distribution of PAEs in the three seasons followed the order summer > autumn > winter. The main PAEs detected were DBP, BBP, and DEHP. ④ The results of the ecological risk assessment showed that the risk quotient (RQ) of DBP at each station in Jiaozhou Bay was greater than 1; that is, the ecological risk was relatively large, while the risk of the other PAEs (RQ<1) was small. PAEs have become a potentially threatening organic pollutant in Jiaozhou Bay. Their behavior and the ecological hazards that they present to the environment still require further study.

Occurrence and seasonal distribution of microplastics and phthalates in sediments from the urban channel of the Ria and coast of Campeche, Mexico

Microplastics (MPs) are part of a global problem affecting all countries including those with smaller populations. Coastal sediments are a reservoir of pollutants generated in basins. Phthalate esters (PAEs) are used as additives to make plastics stronger and more flexible. Urban ecosystems are the most susceptible to receive and transport pollutants. In this study, we determined the presence of MPs and PAEs in coastal sediments and in an urban and natural drainage system, known as the “Ria” in San Francisco de Campeche city. Plastics were detected in all samples taken from both regions, with plastics ranging in size from 0.3 to 5 mm in diameter. This indicates that they are particles of plastics, paints, and fibers, which may come from boats and nylon nets or synthetic products. The greatest abundance of MPs was detected on the coast with quantities of 1392 items/m2 (dry weight), which is double than that seen in the urban channel. As for PAEs, the highest concentrations were determined in two sites: M7A with 18.292 μg g−1 dw and PE with 21.702 μg g−1 dw, with the Ría channel being the area with the highest concentration of PAEs totaling 49.315 μg g−1 dw. The amounts of MPs detected in the sediments of the coast and the Ria vary significantly among the sites (p = 0.001) and seasons (p = 0.001), with the rainy season being the season where the greatest amount of MPs were detected. Likewise, the concentrations of ∑PAEs varied significantly among seasons (p = 0.0002) and sampling sites (p = 0.0001), with the west sub-basin being the site where the greatest concentration of PAEs was detected. A strong correlation was found between the ∑PAEs and MPs, which indicates that the conditions of the system favor the release and extended presence of PAEs on the coast.

An integrative assessment to determine the sediment toxicity of Kaohsiung Harbor in Taiwan: combining chemical analysis and cytotoxicity assay.

To evaluate the toxicity of sediments collected from the mouths of four rivers and entrances of Kaohsiung Harbor, Taiwan, a combination of in vitro cytotoxicity assays (Clone 9 cells) and chemical analysis that quantified 16 polycyclic aromatic hydrocarbons (PAHs), 10 phthalate esters (PAEs), and 2 alkylphenols (APs) was employed. Results showed that the total concentrations of PAHs, PAEs, and APs ranged between 77.9 and 24,363 ng/g dw, between 268 and 118,010 ng/g dw, and between 32.6 and 84,438 ng/g dw in sediments, respectively. The highest concentrations of PAHs, PAEs, and APs were found in the mouths of the Salt River (SR), Love River (LR), and Jen-Gen River (JR), respectively. Mean reference sediment quotient (m-RSQ) values were calculated using the chemical concentrations measured in the sediment of entrance I (EI) as the benchmark, and the order was SR > LR > JR > CR (Canon River mouth) > EII (entrance II) > EI. Results of the cytotoxicity assay showed that the 50% inhibitory concentration (IC50) of Clone 9 cells was in the order of LR < SR < JR < CR < EII < EI. Results on DNA content, apoptotic and autophagy protein biomarkers, and acridine orange staining indicated that the cause of death of Clone 9 cells after treatment with sediment extracts of the LR site was mainly through apoptosis. There was a significant correlation between m-RSQ values and IC50 of Clone 9 cells. The correlation analysis between cytotoxicity and chemical analytical data indicated that certain unknown chemicals may exist in LR sediment. Overall, this study demonstrated that the combination of chemical and biological analyses can provide a more comprehensive and realistic assessment of sediment toxicity to aquatic organisms compared to traditional chemistry-based-only analytical approaches.

Plastic film mulching increased the accumulation and human health risks of phthalate esters in wheat grains

Plastic film mulching is a common practice to increase crop yield in dryland, while the wide use of plastic film has resulted in ubiquitous phthalate esters (PAEs) releasing into the soil. PAEs in soil could be taken up and accumulated by dietary intake of food crops such as wheat, thus imposing health risks to residents. In the present study, samples from a long-term location-fixed field experiment were examined to clarify the accumulation of PAEs in soil and wheat, and to assess the human health risks from PAEs via dietary intake of wheat grain under plastic film mulching cultivation in dryland. Results showed that concentrations of PAEs in grains from mulching plots ranged from 4.1 to 12.6 mg kg−1, which were significantly higher than those in the control group. There was a positive correlation for the PAE concentrations between wheat grains and field soils. Concentrations of PAEs in the soil were in the range of 1.8–3.5 mg kg−1 for the mulching treatment, and 0.9–2.7 mg kg−1 for the control group. Di-n-butyl phthalate (DBP) and di-(2-ethylhexyl) phthalate (DEHP) were detected in all soil and grain samples, and DEHP was found to be the dominant PAE compound in grains. Based on DEHP concentrations in wheat grains, the values of carcinogenic risk for adults were higher than the recommended value 10−4. Results indicated that wheat grains from film mulching plots posed a considerable non-carcinogenic risk to residents, with children being the most sensitive resident group. Findings of this work call the attention to the potential pollution of grain crops growing in the plastic film mulching crop production systems.

Distribution of phthalate esters in air, water, sediments, and fish in the Asan Lake of Korea

Phthalate esters (PEs) are the most commonly used plasticizers and one of the endocrine disrupting chemicals (EDCs) which are extensively present in various environment. Therefore, it is important to examine the levels and distribution of phthalates in multimedia environment. This study investigated the seasonal and spatial variation of 14 PEs in air, water, sediments, and fish in the Asan Lake. Asan Lake is one of the largest artificial lakes in Korea, and is surrounded by industrial complex and farmlands. The PEs were found to be present throughout the study area. The mean concentration of total PEs (∑14 PEs) was 3.92–33.09 ng/m3 in air, not detected (n.d.)-2.29 μg/L in water, 3.6–8973 μg/kg dry weight (dw) in sediment, and n.d.-1081 μg/kg dw in fish, respectively. The most frequently detected phthalate in the samples was di(2-ethylhexyl) phthalate (DEHP), and followed by di-n-butyl phthalate (DBP). The concentrations of PEs in water and sediment samples tended to decrease moving downstream of Asan Lake. Bioaccumulation of PEs showed that benthic feeding fish such as crucian carp or skygager contained higher levels of DEHP. Partitioning of DEHP and DBP between water and sediment was calculated using paired sediment/water samples and fugacity fraction (ff). High ff value (ff = 0.89 ± 0.1) of DBP and low ff value of DEHP (ff = 0.24 ± 0.1) confirmed that DEHP is the most abundant PEs in the sediment, and DBP is the second most abundant PEs except DEHP in water. Our results can provide important information of the distribution and behavior of PEs in the lake environment.

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 27,805ngg-1 in agricultural soils, from 8023 to 37,556ngg-1 in vegetables and from 9031 to 87,329ngg-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.

Assessment of phthalate ester residues and distribution patterns in Baijiu raw materials and Baijiu

Phthalate esters (PAEs) are harmful to human health and have been repeatedly identified in Baijiu samples. In our study, the distribution and degradation characteristics of 14 PAEs in Baijiu raw materials (BRMs) and Baijiu during distillation were detected using QuEChERS or vortex-assisted surfactant-enhanced-emulsification liquid–liquid micro-extraction (VSLLME) methods coupled with gas chromatography-mass spectrometry. The same five PAEs were detected in all tested samples, values ranged from 0.003 to 0.292 mg/kg; however, higher concentrations existed in BRMs compared to Baijiu samples. Using multivariate statistical analysis, detailed distinctions between different varieties of Baijiu and BRMs and separation-related PAE markers were revealed. PAEs concentration during Baijiu distillation showed a decreasing trend. The highest concentrations detected in distillate heads, were 1.6-, 2.3-, and 8.1-fold higher than those in heart1, heart2, and tail distillates, respectively. These findings revealed that PAEs may migrate from BRMs; moreover, that PAEs content can be regulated by distillation.

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.

Environmental distribution and ecotoxicological concerns of phthalic acid esters in creek ecosystem

The long-term ecological risk of synthetic organic contaminants, exclusively endocrine disrupting chemicals (EDCs) such as phthalates has threatened reclaimed seawater quality in marine environment. In this study, environmental distributions of 14 phthalic acid esters (PAEs) in seawater, and biota (fish and crab) across Thane Creek, Mumbai India is reported. Identification and quantifications of phthalates in environmental matrices was carried out using GC-MS technique. Abundance of phthalates in each matrix was discussed and compared with literature value. Total phthalate esters concentrations in seawaters, fish and crab samples were found to be 104.8 ± 37.8 μg L−1, 113 ± 36.4 μg g−1 and 155 ± 38 μg g−1 (dry weight) respectively. Di-n-butylphthalate (DBP) was most abundant compound among analyzed PAEs in all tested aquatic media. In situ bio-concentration factors (BCFs) were calculated for all monitored phthalates in fish and crabs and compared with log Kow values. Risk quotient and estradiol equivalent concentration were also calculated to evaluate ecological risk and estrogenic potential of seawater in terms of DBP and di (2-ethylhexyl) phthalate. The average values of total PAEs daily intake were calculated as 58.1 ± 13.6 and 79.6 ± 19.6 (µg kg–1-bw/day) for fish and crab respectively in an adult population.

Toxicity of phthalate esters to lettuce (Lactuca sativa) and the soil microbial community under different soil conditions.

Phthalate esters (PAEs) are globally used plasticizers and typical endocrine disruptors that can readily accumulate in agricultural products and represent a substantial risk to human health via the food chain. The range of soil properties has an important influence on the expression of PAE toxicity, and the mechanisms by which soil physical and chemical properties affect the expression of toxicity of target PAEs to plants and microorganisms requires further investigation. Important soil factors affecting the eco-toxicological effects of two typical PAEs, di-n-butyl phthalate (DnBP) and bis (2-ethylhexyl) phthalate (DEHP), on lettuce (Lactuca sativa) in a spiked soil were investigated in the present study. Soil at various pH values was spiked with three PAE concentrations (1, 5 and 20 mg DnBP or DEHP kg-1 soil), organic matter contents and water holding contents to simulate the greenhouse soil environment for 30 days. Their influence on the biomass, photosynthetic pigment contents, various physiological changes and soil microbial communities was determined as endpoints. The toxicity to lettuce of DnBP was higher than that of DEHP in the soil and soil pH was the most important factor affecting their single toxicity, followed by soil organic matter content and soil moisture content in agreement with the Biolog test results. Under different soil conditions total protein, total soluble sugar and free amino acid contents were positively correlated with concentrations of the target PAEs, but leaf area, biomass, •O2- activity, vitamin C content and soil microbial diversity indices showed the opposite trend. Chlorophyll a and carotenoid contents were more inhibited by DnBP together with impacts on indices of soil microbial diversity. The results suggest that soil conditions in greenhouses directly explain the patterns of pollutant toxicity displayed and impact the quantity, quality and food safety of vegetables produced using highly intensive production systems.

Derivation of aquatic life criteria for four phthalate esters and their ecological risk assessment in Liao River

As a critical family of endocrine disruptors, phthalate esters (PAEs) attracted considerable attentions due to increasingly detected worldwide. Aquatic life criteria (ALC) for PAEs are crucial for their accurate ecological risk assessment (ERA) and have seldom been derived before. Given this concern, the purpose of the present study is to optimize the ALCs of four priority PAEs to estimate their ecological risks in Liao River. Reproductive endpoint was found to be more sensitive than other endpoints. Thus, reproduction related toxicity data were screened to derive ALCs applying species sensitivity distribution (SSD) method. ALCs of DEHP, DBP, BBP and DEP were calculated to be 0.04, 0.62, 4.71 and 41.9 μg L-1, which indicated decreased toxicity in sequence. Then, the derived ALCs of the four PAEs were applied to estimate their ecological risks in Liao River. A total of 27 sampling sites were selected to detect and analyze the exposure concentrations of PAEs. ERA using the hazard quotient (HQ) method was conducted. The results demonstrated that DEHP exhibited higher risks at 92.6% of sampling sites, and risks posed by DBP were moderate at 63.0% sampling sites. However, risks posed by BBP were low at 70.4% of sampling sites, and there were no risks posed by DEP at 96.3% of sampling sites. The results of probabilistic ecological risk assessment (PERA) indicated that probabilities of exceeding effects thresholds on 5% of species were 60.41%, 0%, 0.12%, 14.28% for DEHP, DEP, BBP and DBP, respectively. The work provides useful information to protect aquatic species in Liao River.

Degradation kinetic of phthalate esters and the formation of brominated byproducts in heat-activated persulfate system

The degradation kinetics of two phthalate esters (PAEs) (i.e., diethyl phthalate (DEP) and dibutyl phthalate (DBP)) in heat-activated persulfate (PS) system were studied and followed pseudo-first-order kinetics. Results demonstrated that both sulfate radical (SO4-·) and hydroxyl radical (HO) were responsible for degrading DEP and DBP. The pseudo-first-order rate constant (kobs) enhanced remarkably as reaction temperature and PS dosages increased, while it decreased as the initial PAEs concentrations increased. Lower pH values promoted the degradation over the pH range chosen here (5.0–8.0). Natural organic matter (NOM) and HCO3- showed inhibitory effects on PAEs degradation by quenching SO4-· and HO. At any pH value studied here, Cl− enhanced PAEs degradation at lower concentrations while it suppressed degradation as Cl− concentration further increased. The coexisting Br− hindered the degradation of PAEs mainly by suppressing SO4-·. Significant formation of dibromoacetonitrile (DBAN) and bromoform (TBM) was verified with Br− and NOM in the degradation system, while only TBM was detected without NOM. Bromate was also detected in the Br− containing degradation system. Generally, NOM facilitated the formation of brominated disinfection byproducts (Br-DBPs), while it suppressed the generation of bromate. Additionally, it is noteworthy that the degradation efficiency of DBP was higher than that of DEP probably owing to the longer alkyl side chain of DBP. The DBP degradation system was observed to form slightly more Br-DBPs than DEP, while bromate had an opposite trend. Besides, the potential initial degradation pathways of DEP and DBP were discussed by the computational analysis.

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.

Application of catastrophe theory in comprehensive ecological security assessment of plastic greenhouse soil contaminated by phthalate esters.

Large amount of phthalate esters (PAEs) used as plasticizers in polyvinyl chloride (PVC) products has caused ubiquitous contamination to the environment and potential ecology security risk all around the world, especially in places plastic films were indispensably utilized due to the widely proposing of facility agriculture in China. A case of PAEs contamination in four suburb areas of Nanjing was analyzed and discussed in this study. A new frame work has been put forward based on multi-criteria evaluation model and mathematical method of catastrophe theory, using farming work, laboratory determination and relevant environmental standards to measure the ecology security risk of PAEs in study areas. The factors were selected based on the availability of the data and the local conditions. The assessment model involves the contamination status of PAEs in soil and vegetables, the contamination effects of PAEs to human and soil organisms and the contamination source of PAEs from plastic films and other products in the four study facility agriculture areas. An evaluation system of the model was composed of thirteen mesosphere indicators and twenty-five underlying indicators including total PAEs concentration in soils, single PAE concentration in soils, total PAEs concentrations in roots, leafy, solanaceous and stem vegetables, PAE human risks, soil microbial counts, microorganism diversity indices, atmospheric deposition of PAEs, whether sewage wastewater irrigation, planting mode of the facility agriculture areas and climate condition of study areas. The modified evaluation system was used in the assessment of ecology security of the same place based on the data of 2012, and the results suggested that the ecology security indicators were reliable and were agree well with the practical situation of the study areas. The results could provide guidance for the application of health risk assessment of soil environment for the strong objectivity of catastrophe theory compared with other evaluation methods.

Comparison of greenhouse and open field cultivations across China: Soil characteristics, contamination and microbial diversity

A national scale survey was conducted to determine an array of inorganic and organic contaminants in agricultural soils from two cultivation modes (greenhouse vs. open field) in 20 provinces across China. The investigated contaminants include organochlorine pesticides (OCPs), phthalate esters (PAEs), polycyclic aromatic hydrocarbons (PAHs), lead (Pb), zinc (Zn), copper (Cu) and cadmium (Cd). The large amounts of agrochemicals used and special cultivation mode in greenhouse caused substantial soil pollution and deterioration of soil quality. Mean concentrations of both OCPs and PAEs in greenhouse soil were approximately 100% higher than those in open field. The pH values were 6.85 ± 1.04 and 7.34 ± 0.84 for greenhouse and open field, respectively (p > 0.05). The soil microbial community was predicted to be affected by pollution in greenhouse through the PICRUSt analysis of 16s rRNA sequences. The 12 variables including various chemicals and soil properties together explained 15% of the observed variation in the community composition. In the studied variables, PAEs and lead were the primary factors affecting microbial diversity in greenhouse soils, while pH had the greatest impact on the microbial community in open field soils. These findings enhanced our understanding of the environmental impact and contamination management of greenhouses worldwide.

Measurements of 50 Non-polar Organic Compounds Including Polycyclic Aromatic Hydrocarbons, n-Alkanes and Phthalate Esters in Fine Particulate Matter (PM2.5) in an Industrial Area of Chiba Prefecture, Japan

Quantitative data of 50 non-polar organic compounds constituting PM2.5 were continuously collected and analyzed from June 2016 to October 2017 (approximately 17 months) at Ichihara, one of the largest industrial areas in Japan. Target non-polar organic compounds including 21 species of polycyclic aromatic hydrocarbons (PAHs), 24 species of n-alkanes and 5 species of phthalate esters (PAEs) were simultaneously measured by gas chromatography/mass spectrometry. Basically, the average concentrations of the total PAHs, n-alkanes and PAEs in each season remained nearly level, and seasonal variations were little throughout the study period. These results suggest that the emission sources, which are not influenced by the seasons, are the dominant inputs for the target organic compounds. Diagnostic ratios of PAHs, assessment of n-alkane homologue distributions, carbon preference index, and the contribution of wax n-alkanes from plants were used to estimate source apportionments. These results indicate that anthropogenic sources were the main contributor for most PAHs and n-alkanes throughout the study period. The concentrations of PAEs selected in this study were low because emission amounts of these chemicals were little within the source areas of the sampling site. To our knowledge, this study is the first attempt to simultaneously measure a high number of non-polar organic compounds in PM2.5 collected from the ambient air of Japan, and the resultant data will provide valuable data and information for environmental researchers.

Long-Term Plastic Greenhouse Cultivation Changes Soil Microbial Community Structures: A Case Study.

Plastic greenhouse vegetable cultivation (PGVC) has been widely developed around the world and has resulted in great changes in soil properties and potential contamination by phthalate esters (PAEs). Using high-throughput sequencing, this study investigated the succession and potential factors impacting soil microbial community structures over 20 years of PGVC. The results showed that the pH of soils under PGVC were significantly lower, while the nutrient contents of soils were higher, relative to those of open field soil. The residue concentrations of PAEs in soil under PGVC increased with increasing periods of PGVC. The fungal community diversity, rather than the bacterial community diversity, was significantly reduced in soils under PGVC. However, both the soil bacterial and fungal community structures were changed by long-term PGVC. Among the tested soil physicochemical properties, soil pH and clay were the top two factors affecting the soil bacterial community, while pH and phosphorus (P) mainly affected the soil fungal community structures. No relationship between the changes of microbial communities and PAE residues in soil was observed. This study indicates that the soil acidification and nutrient accumulation under PGVC mainly shifted the changes of soil microbial community structures, which could occur after only 5 years of PGVC.

Contamination Levels and Ecological Risk Assessment of Phthalate Esters (PAEs) in the Aquatic Environment of Key Areas of Taihu Lake

To better understand phthalate esters (PAEs) pollution in key areas of Taihu Lake, water and sediment samples were collected for content analysis. The concentrations of ∑PAEs in water samples from wet, dry, and normal seasons ranged 1.6-11.2 μg·L-1 (mean:3.68 μg·L-1), nd-6.21 μg·L-1 (mean:1.3 μg·L-1), and nd-1.72 μg·L-1 (mean:0.48 μg·L-1), respectively. No differences were found between upstream and downstream samples. DEHP was the predominant component in water samples, whereas DBP exceeded the national surface water environmental quality standards. The total PAE concentration in the sediment ranged between 0.74 and 6.90 μg·g-1 (mean:2.64 μg·g-1), with DBP and DEHP the predominant PAEs. The risk quotient (RQ) results showed that DBP and DEHP contributed the most potentially adverse effects to the aquatic environment in the key areas. The contents of PAEs in sediment were all less than the ERLs, thus posing no significant threat to aquatic organisms. The overall level of PAEs in the study area was moderate compared to those in other areas, including rivers, lakes, and estuaries from cities worldwide. Industrial pollution and urban activities are the major sources of PAEs in the aquatic environment of key areas of Taihu Lake.

Occurrence and Distribution of Phthalate Esters in Urban Soils of Chongqing City

In total, 66 soil samples were collected from five different urban functional areas in Chongqing, and the concentration levels of phthalate esters (PAEs) were analyzed using ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS). Meanwhile, the composition and characteristics of PAEs were discussed, along with their possible sources, through correlation analysis and principal component analysis. The results showed that the concentrations of ∑PAEs ranged from 93.1-312 ng·g-1 dry weight, which is at the low end of the worldwide figure. DEHP, DBP, and DIBP were the dominant compounds, contributing 87.4%-92.9% of the total ∑PAEs. DEHP was the most abundant PAE congener, responsible for 52.4% of the total ∑PAEs. Through correlation analysis, it was noted that PAEs with similar molecular weight were more likely to show a significant relationship with each other, which suggested that these PAEs may share a similar source. According to the principal component analysis, DBP, DIBP, and DEHP had a similar source, while BBP and DnOP strongly correlated with each other. Compared to other studies, relatively low PAE concentrations were apparently observed in this study, but the potential human risk via exposure to these compounds should also been considered.