Simultaneous effervescence-assisted microextraction and magnetic adsorbent generation for rapid and cost-effective organochlorine pesticides analysis.

This study introduced an innovative magnetic effervescence-assisted microextraction method, streamlining the preparation of effervescent tablets through a one-pot method that blends a CO2 donor (Na2CO3) and an H+ donor (NaH2PO4) with bare magnetic particles (Fe3O4) and an adsorbent (hydroxylated multi-walled carbon nanotubes), followed by pressing. During the extraction process, the bare magnetic particles and adsorbent undergo in-situ self-assembly to create a magnetic adsorbent. The effervescence generates bubbles that enhance effective extraction and magnetism facilitates the easy separation of the magnetic adsorbent from the sample solution, completing the process within 4 min. Applied to organochlorine pesticide analysis in fruit juices and herbal extracts, the method exhibits excellent linearity (R2 > 0.993), sensitivity (detection limits: 0.010-0.125 ng/mL), accuracy (recoveries: 85.8-99.9%), and precision (RSDs < 9.7%) with GC-ECD. Overall, this approach stands out for its simplicity, cost-effectiveness, and suitability for on-site analysis, owing to its operational ease and independence from specialized equipment.

Analysis of Organochlorine Pesticide Residues in Various Vegetable Oils Collected in Chinese Markets.

Organochlorine pesticides (OCPs), chemicals frequently used in agriculture, are a group of highly toxic and persistent organic pollutants. This study assesses the distribution and congener profiles of residual OCPs in 11 types of vegetable oils collected from Chinese markets. All samples were extracted using the modified QuEChERS method prior to analysis by gas chromatography-triple quadrupole mass spectrometry. The sesame oil samples had the highest concentration of OCPs, within the range of 15.30-59.38 ng/g, whereas the peanut oil samples had the lowest OCP concentrations, within the range of 10.83-35.65 ng/g. The possible effect of the processing technology on the pesticide residues in these vegetable oils was also evaluated. It was found that the pressing method leaves more OCPs in vegetable oils than the aqueous extraction and cold-pressing, but the result for leaching was not obvious. In light of the obtained results, it was estimated that the average daily intake of different pesticides is between 0.01 and 2.20 ng/kg bw/day for urban and rural households. Hence, it can be affirmed that, given the amount of the concentration of OCPs detected in the vegetable oils collected from Chinese markets, there are no obvious health risks for urban and rural households by intake.

Assessment of Organochlorine Pesticides in Phreatic Aquifer of Pampean Region, Argentina.

This work evaluates the factors affecting the presence of organochlorine pesticides in Pampeano aquifer in the Quequén Grande River watershed, Buenos Aires Province, Argentina. Eighteen sampling sites were selected in order to have representatives of different type of wells and types of soil. Among the analyzed compounds, endosulfan showed the highest concentrations (4.75 ng l- 1 mean), which could be related to use in the recent past. Others important pesticides groups detected were HCHs (1.1 ng l- 1 mean) and heptachlors (2.17 ng l- 1mean). The analysis of the results show that the thickness of the unsaturated zone is the main factor related to the concentrations of pesticides and there were no differences according to wells or soil types. Although agricultural use of most OCPs has been banned in Argentina from more than 30 years ago, their residues are still detected in groundwater of the region, indicating their high persistence.

Environmentally friendly polychlorinated naphthalenes (PCNs) derivatives designed using 3D-QSAR and screened using molecular docking, density functional theory and health-based risk assessment.

A complete design and screening system for environmental-friendly polychlorinated naphthalene (PCN) derivatives was established through three-dimensional quantitative structure-activity relationship (3D-QSAR), molecular docking, density functional theory (DFT) methods and health-based risk assessment based on dynamic multimedia fugacity model. Two types of 3D-QSAR models were established for PCNs using the experimental biological toxicity (logEC50) of 14 PCNs to carry out a modification to lower the logEC50 of CN-70. Consequently, 67 new monosubstituted and disubstituted derivatives with a lower biological toxicity than CN-70 were designed. Furthermore, 21 new CN-70 derivatives were selected through the evaluation of their persistent organic pollutant properties (biological toxicity, bio-concentration, long-range transport potential, biodegradability) and practicability (stability, insulativity, flame retardancy) using 3D-QSAR, molecular docking and DFT methods. Finally, the non-carcinogenic and carcinogenic risks of 19 new CN-70 derivatives in different exposure pathways were reduced, and 5 derivatives with a significant decrease both in biological toxicity (amplitude reduction: 12.73%-32.51%) and risk (amplitude reduction: 32.18%-59.19%) were selected as environmental-friendly PCN derivatives, which had been screened using the health-based risk assessment system associated with dynamic multimedia fugacity model. This study provides a theoretical basis for the design of environmental-friendly flame retardants and insulating materials.

Assessment of pesticide contamination in Akkar groundwater, northern Lebanon.

According to its high production and value, Akkar is considered as the second agricultural region in Lebanon. Groundwater constitutes the principal source of water in Akkar including drinking water of local inhabitants in Akkar. As such, the contamination of groundwater by organic pollutants can impact directly the population health. In this study, we evaluated the contamination status of groundwater in this region. Three classes of pesticides including 19 organochlorine (OC) pesticides, 8 organophosphorus (OP) pesticides, and 6 organonitrogen (ON) pesticides were monitored in 15 groundwater samples collected from different villages on the Akkar plain. Samples were extracted by using solid phase extraction (SPE) and analyzed by gas chromatography coupled with mass spectrometry (GC-MS). The results showed high contamination of Akkar groundwater by OCs with levels that can reach 58.9 µg/L. They were detected in the majority of the sample and represent 95-100% of ∑pesticides. Our results showed the recent use of these molecules with an average level of 0.3 and 0.39 µg/L for ∑HCHs and DDTs, respectively. Their concentrations were higher than those observed in the same region in 2014 and other regions elsewhere. OPs were also detected at high levels and among them, methylparathion was the predominant OP detected (44.6 µg/L). For ONs, lower levels were measured in all samples with a mean value of 5.6 µg/L. As a conclusion of this work, groundwater on the plain of Akkar was remarkably contaminated by the studied pesticides; indefinitely, more efforts should be taken to manage the pesticide use in this region, assess, and reduce their effects on human health. In the future, the application of organic farming can be a great solution to the groundwater contamination problem.

Chemical contamination assessment in mangrove-lined Caribbean coastal systems using the oyster Crassostrea rhizophorae as biomonitor species.

This paper aims to contribute to the use of mangrove cupped oyster, Crassostrea rhizophorae, as a biomonitor species for chemical contamination assessment in mangrove-lined Caribbean coastal systems. Sampling was carried out in eight localities (three in Nicaragua and five in Colombia) with different types and levels of contamination. Oysters were collected during the rainy and dry seasons of 2012-2013 and the tissue concentrations of metals, polycyclic aromatic hydrocarbons (PAHs), and persistent organic pollutants (POPs) were determined. Low tissue concentrations of metals (except Hg) and PAHs; moderate-to-high tissue concentrations of Hg, hexachlorocyclohexanes (HCHs), and dichlorodiphenyl-trichloroethanes (DDTs); detectable levels of chlorpyrifos, polychlorinated biphenyls (PCBs) (mainly CB28, CB118, CB138 and CB 153) and brominated diphenyl ethers 85 (BDE85); and negligible levels of musks were recorded in Nicaraguan oysters. A distinct profile of POPs was identified in Colombia, where the tissue concentrations of PCBs and synthetic musk fragrances were low to moderate, and Ag, As, Cd, Pb, and PAHs ranged from moderate to extremely high. Overall, the values recorded for HCHs, DDTs and PCBs in Nicaraguan mangrove cupped oysters greatly exceeded the reference values in tissues of C. rhizophorae from the Wider Caribbean Region, whereas only the levels of PCBs were occasionally surpassed in Colombia. Different contaminant profiles were distinguished between oysters from Nicaragua and Colombia in radar plots constructed using the main groups of contaminants (metals, PAHs, musks, PCBs, and organochlorine pesticides (OCPs)). Likewise, integrated pollution indices revealed differences in the levels of contaminants. Moreover, the profiles and levels in oyster tissues also varied with season. Thus, principal component analysis clearly discriminated Nicaraguan and Colombian localities and, especially in Colombia, seasonal trends in chemical contamination and differences amongst localities were evidenced. The geographical and environmental disparity of the studied scenarios may represent to a large extent the diversity of mangrove-lined Caribbean coastal systems and therefore the present results support the use of C. rhizophorae as suitable biomonitor species at Caribbean regional scale, where seasonal variability is a major factor controlling pollutant mobility and bioavailability.

Plant-Pesticide Interactions and the Global Chloromethane Budget.

Ecological, signaling, metabolic, and chemical processes in plant-microorganism systems and in plant-derived material may link the use of chlorinated pesticides in the environment with plant chloromethane emission. This neglected factor should be taken into account to assess global planetary budgets of chloromethane and impacts on atmospheric ozone depletion.

Effects of terrestrial and marine organic matters on deposition of dechlorane plus (DP) in marine sediments from the Southern Yellow Sea, China: Evidence from multiple biomarkers.

As an emerging halogenated organic contaminant, Dechlorane Plus (DP) was scarcely reported in marine environments, especially in China. In this work, 35 surface sediments and a sediment core were collected across the Southern Yellow Sea (SYS) to comprehensively explore the spatio-temporal distribution and possible migration pathway of DP. DP concentrations ranged from 14.3 to 245.5 pg/g dry weight in the surface sediments, displaying a seaward increasing trend with the high levels in the central mud zone. This spatial distribution pattern was ascribed to that fine particles with the elevated DP levels were preferentially transported to the central mud zone under hydrodynamic forcing and/or via long-range atmospheric transportation and deposition. DP concentrations in sediment core gradually increased from the mid-1950s to present, which corresponded well with the historical production and usage of DP, as well as the economic development in China. Significantly positive correlation between DP and total organic carbon (TOC) in both surface sediments and sediment core indicated TOC-dependent natural deposition of DP in the SYS. We used multiple biomarkers, for the first time, to explore the potential effects of terrestrial and marine organic matters (TOM and MOM) on DP deposition. The results showed that competition may occur between TOM and MOM for DP adsorption, and MOM was the predominant contributor in controlling DP deposition in the marine sediments from the SYS.

Assessment of seasonal variations in persistent organic pollutants across the region of Tuscany using passive air samplers.

Concentrations of persistent organic pollutants (POPs) were measured for an entire year in the region of Tuscany, Italy. Passive air samplers consisting of polyurethane foam (PUF) disks were deployed over four sampling periods of 3-5 months from April 2008 to July 2009 in urban (n = 6) and rural (n = 4) sites. The aim of the study was to characterize the spatial and seasonal variations in selected POPs. The POP concentrations (pg m-3) in the air were dominated by dichlorodiphenyltrichloroethane and metabolites (DDTs) and polychlorinated biphenyls (∑7PCBs). DDTs, and ∑7PCBs showed a clear decreasing urban > rural gradient. The concentrations of DDTs and PCBs were up to 10 and 6 times higher, respectively, in urban sites than in rural sites. ∑7PCBs showed a significant correlation with the urbanized areas located <5 km around the sampling sites. For hexachlorocyclohexanes (HCHs), α-HCH concentrations were similar at both sampling sites and were found to be quite uniform during the four sampling periods. Seasonal fluctuations were observed for DDTs, and ∑7PCBs, with the highest concentrations observed during period 4 (summer-spring); this is most likely due to a temperature-driven re-emission from local sources. These findings were also supported by an air back trajectory analysis in the study area. This study contributes new information about POP levels in the Italian atmosphere and demonstrates the feasibility of using PUF disks to simultaneously assess seasonal concentrations at different sampling sites.

Short-chain chlorinated paraffins in soil, paddy seeds (Oryza sativa) and snails (Ampullariidae) in an e-waste dismantling area in China: Homologue group pattern, spatial distribution and risk assessment.

Short-chain chlorinated paraffins (SCCPs) in multi-environmental matrices are studied in Taizhou, Zhejiang Province, China, which is a notorious e-waste dismantling area. The investigated matrices consist of paddy field soil, paddy seeds (Oryza sativa, separated into hulls and rice unpolished) and apple snails (Ampullariidae, inhabiting the paddy fields). The sampling area covered a 65-km radius around the contamination center. C10 and C11 are the two predominant homologue groups in the area, accounting for about 35.7% and 33.0% of total SCCPs, respectively. SCCPs in snails and hulls are generally higher than in soil samples (30.4-530 ng/g dw), and SCCPs in hulls are approximate five times higher than in corresponding rice samples (4.90-55.1 ng/g dw). Homologue pattern analysis indicates that paddy seeds (both hull and rice) tend to accumulate relatively high volatile SCCP homologues, especially the ones with shorter carbon chain length, while snails tend to accumulate relatively high lipophilic homologues, especially the ones with more substituted chlorines. SCCPs in both paddy seeds and snails are linearly related to those in the soil. The e-waste dismantling area, which covers a radius of approximate 20 km, shows higher pollution levels for SCCPs according to their spatial distribution in four matrices. The preliminary assessment indicates that SCCP levels in local soils pose no significant ecological risk for soil dwelling organisms, but higher risks from dietary exposure of SCCPs are suspected for people living in e-waste dismantling area.

Occurrences, sources and risk assessment of short- and medium-chain chlorinated paraffins in sediments from the middle reaches of the Yellow River, China.

Chlorinated paraffins (CPs), one class of hydrophobic and toxic compounds, are easily adsorbed into sediments and then pose potential risks to the ecosystem and human health. However, few researches on short- and medium-chain CPs (SCCPs and MCCPs) in sediments have been performed. In order to comprehensively investigate the spatial distributions, sources, and ecological risks of CPs, sediments collected from the middle reaches of the Yellow River were analyzed by two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GC × GC-TOFMS). The concentrations of SCCPs and MCCPs ranged from 11.6 to 9.76 × 103 ng/g dry weight (dw) and from 8.33 to 168 ng/g dw, respectively. No significant correlation was found between total organic carbon (TOC) and CP concentrations (P > 0.05). The spatial distributions showed that contamination levels of CPs were relevant to human activities. In addition, two types of sediment samples were classified by hierarchical cluster analysis (HCA) and results indicated the predominant congener groups were C10Cl6-7 for SCCPs and C14Cl7-8 for MCCPs. Principal component analysis (PCA) revealed that SCCPs and MCCPs in the sediments may have different sources, and SCCPs are likely to come from the production and use of CP-42 and CP-52. Moreover, complex environmental processes, including long-range transportation via the atmosphere and/or river, deposition and degradation of CPs, resulted in increased abundances of short chain and low chlorinated congeners in sediment samples compared with commercial mixtures, and different homolog patterns among samples. The significant negative correlation between SCCP concentrations and MCCP/SCCP ratios could be related to long-range transport of CPs. A preliminary risk assessment indicated that CPs at current levels posed no significant ecological risk.

Risk Assessment of Organochlorines in Mollusk from the Mediterranean and Red Sea Coasts of Egypt.

Organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) residues were studied in different mollusk species from the Egyptian Mediterranean and Red Sea coasts. The average levels of OCPs in mollusks comprised chlordanes, dieldrins, total endrin, endosulfan compounds, and methoxychlor (DECEM), dichlorodiphenyltrichloroethanes (DDTs), and, hexachlorocyclohexanes (HCHs). The averages of HCHs, DDTs, and polychlorinated biphenyls (PCBs) in mollusks from the Mediterranean Sea were 1.13±1.21, 1.30±1.27, and 1.40±0.93 ng/g, respectively; from the Red Sea, they were 0.62±0.90, 1.77±1.82, and 6.44±5.05 ng/g, respectively. The analysis of HCHs, DDTs, and PCBs in mollusks indicates a new usage of lindane, PCB congeners, and the input of technical HCH and aged DDT. The data showed that the Red Sea Coast was more affected by PCBs congeners than the Mediterranean Sea Coast, which may be attributed to the different activities along the two coastal areas. Mollusks in the Mediterranean Sea had higher dieldrins, total endrin, endosulfan compounds, and methoxychlor contents than those in the Red Sea. Interestingly, HCHs, DDTs, and PCBs levels were lower than those recommended for Swedish Food Regulation and U.S. Food and Drug Administration, which means that mollusks from these two coastal areas are safe as food.

Persistent organic pesticide residues in sediments of Vasai Creek near Mumbai: Assessment of sources and potential ecological risk.

Thirteen persistent organic pesticides were investigated in the sediments of Vasai Creek near Mumbai to evaluate their pollution levels and potential risks. It was observed that ΣOCPs level was in the range of 597-1538ng/g dw, with an average value of 1115.25ng/g dw. The level of ΣOPPs was in the range of 492-1034ng/g dw, with an average value of 798.15ng/g dw. The values o,p'-DDT/p,p'-DDT ratio gives an indication of use of technical DDT as the prime source of DDT, while the α/γ-BHC ratio indicate that BHCs in study area might have been received from fresh lindane. The results of an ecological risk assessment showed that sediment bound organic pesticides are of more ecotoxicological concern as they might create adverse ecological risk to the marine breeding habitats. These pesticides residues may get remobilize and released to overlying waters creating adverse effects on terrestrial and aquatic organisms.

Safety Assessment of Pentaerythrityl Tetraesters as Used in Cosmetics.

The Cosmetic Ingredient Review (CIR) Expert Panel (Panel) reviewed the safety of 16 pentaerythrityl tetraester compounds as used in cosmetics. These ingredients mostly function as hair-conditioning agents, skin-conditioning agents-miscellaneous and binders, skin-conditioning agents-occlusive, viscosity-increasing agents-nonaqueous, and skin-conditioning agents-emollient. The Panel reviewed the available animal and human data related to these ingredients and previous safety assessments of the fatty acid moieties. The Panel concluded that pentaerythrityl tetraisostearate and the other pentaerythrityl tetraester compounds were safe in the practices of use and concentration as given in this safety assessment.

Occurrence and sources of selected organochlorine pesticides in the soil of seven major Indian cities: Assessment of air-soil exchange.

India is an agricultural country and organochlorine pesticides (OCPs) accounts for nearly three fourth of the annual pesticide consumption. Selected OCPs were therefore quantified in 81 soil samples along urban-suburban-rural transect from New Delhi and Agra in the north, Kolkata in the east, Mumbai and Goa in the west and Chennai and Bangalore in the southern part of India. ΣOCPs ranges from 2 to 410 ng/g dry weight (Mean, 35) with dominance of endosulfan sulfate in the rural sites. Urban centers and suburbs reflects OCP usage for vector control. Lower winter temperature in New Delhi favored site-specific deposition of most OCPs in soil. Volatilization of OCPs from soil occurred in the Indian cities having higher ambient temperature. Due to the compounded impact of past and ongoing usage of selected OCPs like DDT, a sporadic cycle of emission and re-emission from Indian soil is expected to continue for many more years to come.

Sustainable in-well vapor stripping: A design, analytical model, and pilot study for groundwater remediation.

A sustainable in-well vapor stripping system is designed as a cost-effective alternative for remediation of shallow chlorinated solvent groundwater plumes. A solar-powered air compressor is used to inject air bubbles into a monitoring well to strip volatile organic compounds from a liquid to vapor phase while simultaneously inducing groundwater circulation around the well screen. An analytical model of the remediation process is developed to estimate contaminant mass flow and removal rates. The model was calibrated based on a one-day pilot study conducted in an existing monitoring well at a former dry cleaning site. According to the model, induced groundwater circulation at the study site increased the contaminant mass flow rate into the well by approximately two orders of magnitude relative to ambient conditions. Modeled estimates for 5h of pulsed air injection per day at the pilot study site indicated that the average effluent concentrations of dissolved tetrachloroethylene and trichloroethylene can be reduced by over 90% relative to the ambient concentrations. The results indicate that the system could be used cost-effectively as either a single- or multi-well point technology to substantially reduce the mass of dissolved chlorinated solvents in groundwater.

Health risk assessment of pesticides residue in maize and cowpea from Ejura, Ghana.

Low productivity in agriculture due to damage cause by pests has led to the application of pesticides to control pest infestation. Residues of pesticides applied on crops are often found in the food which can cause chronic effect on the health of humans who consume such products. The aim of this study is to measure pesticides residues in maize and cowpea and compare the values with stablished safety limits. A total of 37 pesticides comprising 15 organochlorines, 13 organophosphorus and 9 pyrethroids pesticides were identified in maize and cowpea samples obtained from farms in Ejura. Analytical methods included solvent extraction of the pesticide residues and their subsequent quantification using gas chromatograph equipped with Electron Capture Detector and Pulse Flame Photometric Detector after clean-up on alumina/activated charcoal column. The results showed that the mean concentration of pesticides in maize ranged from 0.001 to 0.103 mg kg(-1) for organochlorine pesticides, 0.002-0.019 mg kg(-1) for organophosphorus pesticides and 0.002-0.028 mg kg(-1) for pyrethroids pesticides. In cowpea the mean concentration ranged from 0.001 to 0.108 mg kg(-1) for organochlorine pesticides, 0.002-0.015 mg kg(-1) for organophosphorus pesticides and 0.001-0.039 mg kg(-1) for pyrethroids pesticides. Maximum Residue Limits for ß-HCH, ß-endosulfan, p,p'-DDE and p,p'-DDD were exceeded in both maize and cowpea samples. Health risk estimation revealed that residues of heptachlor, dieldrin, endrin, ß-endosulfna, γ-chlordane and chlorfenvinphos found in maize exceeded the Acceptable Daily Intake. Similarly the levels of heptachlor and p,p'-DDD found in cowpea also exceeded the Acceptable Daily Intake. This suggests a great potential for chronic toxicity to consumers of these food items.

Musks and organochlorine pesticides in breast milk from Shanghai, China: levels, temporal trends and exposure assessment.

The concentrations of musks (polycyclic musks and nitro musks) and traditional organochlorine pesticides (OCPs), including dichlorodiphenyltrichloroethane and its metabolites (DDT, DDE, DDD, and total DDTs), hexachlorobenzene (HCB), and hexachlorocyclohexanes (HCHs) in breast milk collected in Shanghai, China during the period 2006-2010, were determined. The total concentrations ranged from 4.7 to 276.2 (median: 58.4) ng/glipid weight (lw) for musks and from 88.3 to 2532.9 (median: 1003.8) ng/glw for OCPs. 4,4'-DDE (median: 655.4 ng/glw) was the predominant OCP, followed by ß-HCH (median: 172.5 ng/g lw), and HHCB (1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta[γ]-2-benzopyran) (median: 17.7 ng/g lw) was the dominant musk. There was no statistical correlation between total musk concentrations, and HCB, HCHs, DDTs or total OCP concentrations, indicating their different exposure routes and metabolism in humans (p=0.182-0.325). Clear reductions in temporal trends in the levels of DDTs and HCB, especially HCHs (p<0.01) were observed during the sampling period, and the high DDE/DDT ratios in the samples indicated past exposure to DDTs. The relatively high median concentrations of HHCB and HHCB-lactone in 2010 suggested a probably increasing tendency. There were statistically significant influences regarding maternal age and parity on OCP accumulation (p=0.001-0.002), but no significant effect on musks was found (p=0.542-0.919). Musk exposure in neonates via breast milk was 2-3 orders of magnitude lower than suggested provisional tolerable daily intakes (PTDI). The estimated daily intakes for HCB and DDTs were below the PTDI in Canada, however, 56% of those for HCHs exceeded the Canadian PTDI. OCP contamination of breast milk requires further attention.

Effects of hydrodynamics on the distribution of trace persistent organic pollutants and macrobenthic communities in Bohai Bay.

In recent years, the rapid economic development along Bohai Bay, has brought out continuous increasing of the pollution loads in the Bohai Sea, especially by the large coastal reclamation project, Tianjin Binhai New Area. In the period of 2007-2009, we collected the sediments of the main rivers, estuaries, intertidal zone, and near-shore area of Bohai Bay, and Macrobenthos associated with the marine sediments to assess the influence of hydrodynamics in the coastal environment on the pattern of trace contaminants and the macrobenthic community. Based on data derived from these samples, the levels of polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) in sediments followed the order PAHs>OCPs>PCBs>PBDEs. The higher concentrations of PCBs, OCPs, PAHs and PBDEs were found in the estuarine and near-shore environment of the Dagu Drainage River. The spatial distribution of OCPs was different to that of PCBs due to the direction of the velocity field of Bohai Bay in its old and new topography, and the higher water-solubility of OCPs than that of PCBs. The results of the Pearson correlation and the PCA indicate that the medium diameter (MD) of sediments was the predominant factor influencing the distribution of PCBs and OCPs, most sampling sites were characterized mainly by TOC of sediments and biomass of macrobenthos. The results indicate that the distribution of trace contaminants and macrobenthic community in Bohai Bay are mainly affected by the hydrodynamic conditions.

Higher-tier assessment of the potential for groundwater issues due to the use of 1,3-D soil fumigant; evaluation of the active ingredient, metabolites and potentially related chlorinated compounds.

BACKGROUND: 1,3-Dichloropropene (1,3-D, CAS No. 542-75-6) is a broad-spectrum soil fumigant used to control numerous species of soilborne plant-parasitic nematodes. 1,3-D consists of two isomers, (Z)- and (E)-1,3-D. There are a number of low-level chlorinated compounds that could potentially be produced as a part of the 1,3-D manufacturing process. 1,3-D and its metabolites, as well as potentially related chlorinated compounds, represent potential groundwater contaminants. RESULTS: This study has investigated the hydrolytic stability, under biotic and abiotic conditions in the laboratory, of an extensive representative list of 1,3-D and potentially related chlorinated compounds in order to predict their environmental fate. All of these compounds showed intrinsic hydrolytic instability under both abiotic and biotic test conditions. Furthermore, a monitoring programme was carried out. Twenty-five wells were monitored in five Italian regions characterised by historical and existing use of 1,3-D. The parent compound, its two major metabolites and potentially related chlorinated compounds were not detected in the well water at > 0.1 µg L(-1) at any sampling location. CONCLUSION: The soil fumigant (E,Z)-1,3-D, its metabolites and potentially related chlorinated compounds constitute a low risk to groundwater.