Persistent organochlorine pesticide and PCB residues in surface sediments of Lake Qarun,a protected area of Egypt

Organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) were determined in sediment samples collected from 34 locations in Lake Qarun, Egypt to elucidate their concentrations, distribution, possible sources and potential ecological risk. A total of 25 OCPs and 29 PCBs were identified and quantified. OCPs and PCBs were found to be ubiquitous pollutants in the aquatic environment of Lake Qarun, particular near urban areas reflecting the local usage and input of these pollutants. Total concentrations of OCPs and PCBs in sediments ranged from 1.01 to 164.8 ng g^?1 and 1.48 to 137.2 ng g^?1, respectively. Among OCPs, γ-HCH, heptachlor, aldrin, endrin, p,p′-DDE, oxy-chlordane and endosulfan I and II were the most abundant compounds. The composition of PCB congeners was dominated by the tri-, tetra-, penta- and hexa-chlorinated biphenyls. The ratios of certain metabolites (isomers) to their parent compounds (mixtures) indicated there are still new inputs of lindane, endrin, heptachlor and technical endosulfan to Qarun Lake, while the ratios of (p,p′-DDE + p,p′-DDD)/∑p,p′-DDTs indicate earlier usage of DDT. Contamination levels of PCBs and HCHs can be categorized as moderate to high compared to other urbanized regions worldwide. According to established sediment quality guidelines, γ-HCH, endrin and chlordanes would be more concerned OCP species for the ecotoxicological risk in Lake Qarun.     

Distribution and ecological risk of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in surface sediments from the Bizerte lagoon,Tunisia

Polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) were determined in 18 surface sediment samples collected from Bizerte lagoon, Tunisia. The total concentrations of ten PCBs (∑PCBs) and of four OCPs (∑OCPs) in the sediments from this area ranged from 0.8 to 14.6 ng g^?1 dw (average value, 3.9 ng g^?1 dw) and from 1.1 to 14.0 ng g^?1 dw (average value, 3.3 ng g^?1 dw), respectively. Among the OCPs, the range of concentrations of dichlorodiphenyltrichloroethane and its metabolites (DDTs) and hexachlorobenzene (HCB) were 0.3–11.5 ng g^?1 dw (1.9 ng g^?1 dw) and 0.6–2.5 ng g^?1 dw (1.4 ng g^?1 dw), respectively. Compositional analyses of the POPs indicated that PCB 153, 138 and 180 were the predominant congeners accounting for 60 % of the total PCBs. In addition, p,p′-DDT was found to be the dominant DDTs, demonstrating recent inputs in the environment. Compared with some other regions of the world, the Bizerte lagoon exhibited low levels of PCBs and moderate levels of HCB and DDTs. The high ratios ΣPCBs/ΣDDTs indicated predominant industrial versus agricultural activities in this area. According to the established guidelines for sediment quality, the risk of adverse biological effects from such levels of OCPs and PCBs, as recorded at most of the study sites, was insignificant. However, the higher concentrations in stations S1 and S3 could cause biological damage.     

Levels of Organochlorine Pesticide Residues in Marine-, Surface-, Ground- and Drinking Waters from the Eastern Cape Province of South Africa

Abstract

Persistent organochlorine pesticides (OCPs) such as DDT and its metabolites (DDDs and DDEs), chlordane, hexachlorobenzene (HCB), heptachlor and endosulfan were determined in drinking-, ground-, surface- and marine waters from the Eastern Cape Province of South Africa. Percentage recoveries of the OCPs from spiked river water ranged from 71.03 ± 8.15% (dieldrin) to 101.25 ± 2.17% (α-BHC). The levels of OCPs ranged from 5.5 ng/L (2,4-DDD) to 160 ng/L (HCB) in the water samples. Some endocrine disrupting OCPs such as DDT, DDE, heptachlor, endosulfan and chlordane were detected.     

Persistence,variance and toxic levels of organochlorine pesticides in fluvial sediments and the role of black carbon in their retention

The present study assesses the persistence and variation of organochlorine pesticides (OCPs) and their regulation by total organic carbon (TOC) and black carbon (BC) in freshwater sediment. Sediment samples from the Yamuna River, a major tributary of the Ganges (one of the most populated and intensively used rivers in Asia), had high levels of Σ₂₀OCPs (21.41 to 139.95 ng g^?1). β-Hexachlorocyclohexane (β-HCH) was the most predominant component. ΣHCH and Σdichloro-diphenyl-trichloroethane (DDT) constituted ~86 % of Σ₂₀OCPs. Isomer ratios indicated fresh usage of lindane, DDT and technical-grade HCH. Toxicological comparison with freshwater sediment quality guidelines showed γ-HCH and DDT at high levels of concern. β-HCH, α-HCH, endrin, heptachlor epoxide, dichloro-diphenyl-dichloroethane (DDD), dichloro-diphenyl-dichloroethylene and chlordane were above some of the guideline levels. TOC and BC had mean concentrations of 1.37?±?0.51 % and 0.46?±?0.23 mg g^?1, respectively. BC constituted 1.25 to 10.56 % of TOC. We observed low to moderate correlations of BC with isomers of HCH, p,p′-DDT and methoxychlor while of TOC with Σ₂₀OCPs, γ-HCH, endosulfan sulfate and methoxychlor. Principal component analysis enabled correlating and clustering of various OCPs, BC and TOC. OCP distribution was related with pH, electrical conductivity, soil moisture and finer fractions of sediment. OCPs with similarity in properties that determine their interactions with carbonaceous components of sediment clustered together. A number of factors may, thus, be involved in the regulation of interactive forces between BC and OCPs. BC in this study may be more important than TOC in the retention of some OCPs into fluvial sediments, thereby reducing their bioavailability. The finding is probably the first of its kind to report and emphasises the role of BC in the persistence of OCPs in fluvial sediments.     

Concentrations,distributions, sources,and risk assessment of organochlorine pesticides in surface water of the East Lake,China

East Lake resides in the urban area of Wuhan City and is the largest urban lake in China. The concentrations of 16 organochlorine pesticides (OCPs) were analyzed in 108 surface water samples collected from the East Lake. The total concentrations of OCPs ranged from not detected to 120 ng L^?1 with predominance of δ-HCH, heptachlor, and α-HCH. The mean values of HCHs and DDTs were 7.40 and 5.70 ng L^?1, respectively, accounting for 40 and 31 % of the total OCPs. For the five lakelets in East Lake, Houhu Lake exhibited the highest concentrations of HCHs, DDTs, and total OCPs, which has been used actively for fisheries and surrounded by suburban rural areas and farmlands. Historical lindane or technical HCH input was probably the source of HCH, while technical DDTs might be the source of DDT in the East Lake. The ratio between heptachlor and its metabolic products indicated recent input of heptachlor. Although the combining ecological risks for all aquatic species in the East Lake calculated by species sensitivity distribution reached approximately 10^?5, the OCPs in the East Lake had slight effects on aquatic organisms. The carcinogenic risks and non-carcinogenic hazard indices of DDTs and HCHs indicated that water in the East Lake was not suitable as water sources for human. However, the results indicated the water quality was safe for people to swim in the urban lake.     

The estimation of consumer health risk associated with organochlorine xenobiotics in hard smoked cheese in Poland

The aim of this study was to estimate the health risks associated with consumption of smoked cheeses, which are popular in Poland. The analysis covered polychlorinated biphenyl (PCB) indicator congeners (ndl-PCBs: PCB 28, PCB 52, PCB 101, PCB 138, PCB 153, PCB 180), dioxin-like PCBs (dl-PCBs): non-ortho (PCB 77, PCB 81, PCB 126, PCB 169) and mono-ortho (PCB 105, PCB 114, PCB 118, PCB 156, PCB 157), as well as organochlorine pesticides (OCPs: αHCH, βHCH, γHCH, heptachlor, aldrin, heptachlor epoxid isomer B, dieldrin, pp'DDE op′DDD, pp′DDT, pp′DDD, op′DDT, endrin). The pesticide residues detected in the examined cheese were below the maximum residues levels. The estimated daily intake [lifetime average daily dose (LADD)] referring to the sum of the compounds varied within 4.21·10^?7–3.92·10^?6 mg·kg^?1·day^?1 and was significantly lower than the tolerable daily intake/acceptable daily intake (TDI/ADI) for individual compounds. The health hazard quotient, being the exact measure of the magnitude of exposure potential or a quantifiable potential for developing non-carcinogenic health effects after an averaged exposure period, was also very low, ranging from 2.87·10^?6 to 5.32·10^?5. The obtained results confirmed that the intake of rennet cheese does not pose any consumer health risk in Poland.     

Distribution characteristics of organochlorine pesticides in surface and vertical sediments from the Zha Long Wetland, China

Introduction

The Zha Long Wetland, the first water bird conservation area in China, lies on the northern bank of the Song Nen Plain with an area of 2,100 km². In many areas of the Zha Long Wetland, water pollution has led to a decrease in the wetland??s ecological function, vegetation degradation, a decrease in the number of bird species, and the depletion of fish resources.

Materials and methods

The sediments used in this study were collected from the surface sediment of seven sites and from different depths in three types of marshes in the Zha Long Wetland in northeast China in late October 2006. The levels and distribution patterns of 17 organochlorine pesticides (OCPs; ??-HCH, ??-HCH, ??-HCH, ??-HCH, p,p??-DDE, p,p??-DDD, p,p??-DDT, endosulfan I, endosulfan II, endosulfan sulfate, heptachlor, heptachlor epoxide, aldrin, dieldrin, endrin, endrin aldehyde, and methoxychlor) in surface sediments as well as hexachlorocyclohexane (HCH) and 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane (DDT) in vertical sediments were investigated.

Results and discussion

The concentrations of HCHs, DDTs, endosulfans, heptachlors, aldrin, and methoxychlor in surface sediments ranged from 10.44 to 41.97 ng/g, nd (undetectable levels) to 211.88 ng/g, nd to 69.89 ng/g, nd to 28.10 ng/g, 9.81 to 623.83 ng/g, and from nd to 3.99 ng/g, respectively. The highest levels of OCPs were detected in Tangtugangzi at a total concentration of 727.72 ng/g, where the dominant compound was endrin at a concentration of 483.04 ng/g. In the vertical sediments, the HCHs and DDTs were in the ranges of nd?C136.00 and nd?C214.06 ng/g, respectively.

Conclusions

Different distributions of HCHs, DDTs, and other OCPs indicated that they originated from different contamination sources. Composition analyses in surface sediments indicated recent OCP usage or discharge at some sample sites in the Zha Long Wetland.     

Sources of polycyclic hydrocarbons and pesticides in soluble fraction of deposition samples in Kocaeli,Turkey

A wet–dry deposition sampler was located at The Scientific and Technological Research Council of Turkey-National Metrology Institute (TUBITAK-UME) station, and a bulk deposition sampler was placed at the Kad?ll? village to determine the atmospheric deposition flux of polycyclic aromatic hydrocarbons (PAHs) and pesticides (organochlorine and organophosphorus) in soluble fraction of samples in Kocaeli, Turkey. The 28 samples for each wet, dry, and total deposition were collected weekly from March 2006 to March 2007. Gas chromatography-tandem mass spectrometry was used to analyze the samples which were prepared by using solid-phase extraction (SPE) method. The sum of volume weighted mean of deposition fluxes was obtained as 7.43 μg m^?2 day^?1 for wet deposition, 0.28 μg m^?2 day^?1 for dry deposition and 0.54 μg m^?2 day^?1 for bulk deposition samples for PAHs and 9.88 μg m^?2 day^?1 for wet deposition, 4.49 μg m^?2 day^?1 for dry deposition, and 3.29 μg m^?2 day^?1 for bulk deposition samples for pesticides. While benzo(a)anthracene had the highest fluxes among PAH compounds for all types of depositions, guthion and phosphamidon had the highest deposition flux compared with the other pesticides. Benzo(ghi)perylene, dibenz(a,h)anthracene, indeno(1,2,3-c,d)pyrene, benzo(a)pyrene, and acenaphthene were not detected in any of the samples. Beta-HCH, gamma-HCH, and endrin aldehyde were the only compounds among 18 organochlorine pesticides to be detected in all deposition samples. The main sources of pesticides were the high number of greenhouses around the sampling stations. However, all of the organophosphorus pesticides were detected in all deposition samples. The pollution sources were identified as coal and natural gas combustion, petrogenic sources, and traffic for TUBITAK-UME station whereas coal and natural gas combustion and traffic were the main sources for Kad?ll? station by considering the results of factor analysis, ratios, and wind sector analysis.     

Distribution and ecological risk assessment of organochlorine pesticides in surface sediments from the East Lake,China

Organochlorine pesticides (OCPs) are ubiquitous pollutants, and their presence in urban lakes is a concern for human and ecological health. Surface sediments in the East Lake, China, were collected in winter 2012 and summer 2013 to investigate concentrations, distribution patterns, possible sources, and potential ecological risks of OCPs in this area. The total concentrations of 14 OCPs ranged from 6.3 to 400 ng g^?1 dry weight (dw) with an average concentration of 79 ng g^?1 dw. The mean values of hexachlorocyclohexanes (HCHs) (α-, β-, γ-, and δ-HCH) and dichlorodiphenyltrichloroethanes (DDTs) (p,p’-DDE, p,p’-DDD, and p,p’-DDT) were 36 and 7.6 ng g^?1 dw, accounting for 45 and 10 % of the total OCPs, respectively. The concentrations of OCPs in sediment samples collected in winter were significantly higher than those in summer, especially the HCHs, of which in winter were two times greater than summer. Composition analyses indicated that DDTs and endosulfan were mainly from historical contribution. Historical use of technical HCH and new input of lindane were probably the source of HCHs in the East Lake. Most sampling sites of HCHs and DDTs were found to have the potential ecological risk based on levels specified in the sediment quality standards.     

Analysis of pesticide residues using the Quick Easy Cheap Effective Rugged and Safe (QuEChERS) pesticide multiresidue method in traditional Chinese medicine by gas chromatography with electron capture detection

The Quick Easy Cheap Effective Rugged and Safe multiresidue method (QuEChERS) has been validated for the extraction of 15 organochlorine pesticides (OCPs) in completely different matrices of traditional Chinese medicine (TCM). The method employed a rapid, simple and cost-effective procedure. The spiking levels for the recovery experiments were 0.1, 0.5 and 2.0 mg kg⁻¹. Mean recoveries mostly ranged between 76.0% and 114.0% (96.0% on average), and relative standard deviations (RSD) were generally below 10% (4.72% on average). Based on these results, the methodology has been proven to be highly efficient and robust and thus suitable for monitoring the MRL compliance of a wide range of commodity. The contamination status of 15 OCPs on 80 different TCMs marketed in China, and a total of 400 samples were also performed using a previously validated method. 15 OCPs were benzene hexachloride (BHC, including α-BHC, β-BHC, γ-BHC, δ-BHC), hexachlorobenzene, heptachlor, heptachlor epoxide, aldrin, p, p′-DDE, p, p′-DDD, o, p′-DDT, p, p′-DDT, mirex, endrin, dieldrin. This study indicates that the proposed method is useful for analyzing OCPs in TCM.     

Evaluation of toxic metal (Hg, Cd, Pb), polychlorinated biphenyl (PCBs), and pesticide (DDTs) levels in aromatic herbs collected in selected areas of Southern Italy

This study provides, for the first time, data regarding levels of toxic metals (Hg, Cd, and Pb) and organochlorine compounds (PCBs and DDTs) in various aromatic herbs as rosemary (Rosmarinus officinalis), sage (Salvia officinalis), laurel (Laurus nobilis), oregano (Origanum vulgare), and spearmint (Mentha viridis) collected in some towns of the Southern Italy with different anthropogenic and population pressure. Metal and organochlorine compound concentrations were determined using atomic absorption spectrophotometer and gas-chromatography mass spectrometer (GC/MS), respectively. Pb emerged as the most abundant element, followed by Cd and Hg, while between organochlorine compounds, PCB concentrations were higher than those of DDTs. The pollutant concentrations were found to vary depending on the different herbs. The highest Pb levels were observed in rosemary (1.66 μg g^?1 dry weight) and sage (1.41 μg g^?1 dry weight), this latter showing also the highest Cd concentrations (0.75 μg g^?1 dry weight). For PCBs, the major concentrations were found in rosemary (2.75 ng g^?1 dry weight) and oregano (2.39 ng g^?1 dry weight). The principal component analysis applied in order to evaluate possible similarities and/or differences in the contamination levels among sampling sites indicated differences area-specific contamination.     

Persistent organic pollutants (POPs) in populations of the clam Chione californiensis in coastal lagoons of the Gulf of California

This study examines the potential public health risk due to the massive use of organochlorine pesticides (OCs) in agriculture in the Gulf of California. Specimens of the clam Chione californiensis were collected from three coastal lagoons (Yavaros, Altata and Reforma). Sites were classified as polluted/nonpolluted based on the presence/absence of OCs as an indicator of the persistence of these pollutants; in polluted sites, the time elapsed since pesticide application (past or recent) was estimated. Screening values (SV) for protecting human health as per the U.S. Environmental Protection Agency (EPA) were used for risk assessment. OCs detected were ranked according to frequency of occurrence as follows: γ-chlordane (75%) > endrin (54%) > aldrin (48%) > heptachlor, and dichlorodiphenyl-trichloroethane (DDE) (37%) > β-heptachlor epoxide (30%) > lindane (α-BHC, δ-BHC) and endosulphan I (≤ 6%). Specifically, OCs detected at the highest concentration were heptachlor in Yavaros (0.0168 µgg^?1) and Altata (0.0046 µgg^?1), and aldrin in Reforma (0.0019 µgg^?1). β-Heptachlor epoxide in Altata and Reforma was the only OC with a concentration exceeding the EPA Screening Value. From our results and based on the monthly consumption limit set forth by EPA, the maximum safe consumption of clams to avoid a carcinogenic risk derived from β-heptachlor epoxide in the fishing villages of Yavaros and Altata is 4 servings per month (1 serving = 0.227 kg) by a 70-kg person. These findings suggest that concentrations of OCs and their isomers in C. californiensis populations reflect environmental persistence as well as recent inputs of OCs into coastal lagoons in the Gulf of California.     

Residues levels of organochlorine pesticide in cow's milk from industrial farms in Hidalgo,Mexico

A survey was carried out from 2008 to 2010 to determine the concentrations of 16 organochlorine pesticide residues (OPRs) from Tizayuca, Hidalgo, Mexico. Organochlorine residue determinations were made from milk fat, using chromatographic cleanup and analysis by gas chromatography with an electron capture detector. The OPR concentrations found were from below the detection limit (DL) to 0.91 ng g^?1 in 2008, DL to 0.38 ng g^?1 in 2009 and DL to 0.59 ng g^?1 in 2010. In general concentrations of organochlorine pesticides were higher in the wet season (3.37 ng g^?1 and 4.79 ng g^?1) than the dry season (1.92 ng g^?1 and 2.71 ng g^?1) for 2009 and 2010, due to control of pests in the pasture and sheds. According to Codex Alimentarius regulations, individual pesticides did not exceed the permissible limits, which for example were 10 μg kg^?1 for alpha hexachlorocyclohexane (HCH) and endosulfan I, 20 μg kg^?1 for p,p’-DDT, and 6 μg kg^?1 for dieldrin, endrin and heptachlor. A reduction of organochlorine pesticide concentrations in cow's milk was noted, indicating that the Mexican government has achieved reduction or elimination of some organochlorine pesticides in response to global agreements on persistent organic pollutants.     

Dietary arsenic consumption and urine arsenic in an endemic population: response to improvement of drinking water quality in a 2-year consecutive study

We assessed the association between arsenic intake through water and diet, and arsenic levels in first morning-void urine under variable conditions of water contamination. This was done in a 2-year consecutive study in an endemic population. Exposure of arsenic through water and diet was assessed for participants using arsenic-contaminated water (≥50 μg L^?1) in a first year (group I) and for participants using water lower in arsenic (<50 μg L^?1) in the next year (group II). Participants with and without arsenical skin lesions were considered in the statistical analysis. Median dose of arsenic intake through drinking water in groups I and II males was 7.44 and 0.85 μg kg body wt.^?1 day^?1 (p <0.0001). In females, it was 5.3 and 0.63 μg kg body wt.^?1 day^?1 (p <0.0001) for groups I and II, respectively. Arsenic dose through diet was 3.3 and 2.6 μg kg body wt.^?1 day^?1 (p?=?0.088) in males and 2.6 and 1.9 μg kg body wt.^?1 day^?1 (p?=?0.0081) in females. Median arsenic levels in urine of groups I and II males were 124 and 61 μg L^?1 (p?=?0.052) and in females 130 and 52 μg L^?1 (p?=?0.0001), respectively. When arsenic levels in the water were reduced to below 50 μg L^?1 (Indian permissible limit), total arsenic intake and arsenic intake through the water significantly decreased, but arsenic uptake through the diet was found to be not significantly affected. Moreover, it was found that drinking water mainly contributed to variations in urine arsenic concentrations. However, differences between male and female participants also indicate that not only arsenic uptake, but also many physiological factors affect arsenic behavior in the body and its excretion. As total median arsenic exposure still often exceeded 3.0 μg kg body wt.^?1 day^?1 (the permissible lower limit established by the Joint Expert Committee on Food Additives) after installation of the drinking water filters, it can be concluded that supplying the filtered water only may not be sufficient to minimize arsenic availability for an already endemic population.     

Risk assessment of inhalation exposure to polycyclic aromatic hydrocarbons in school children

Polycyclic aromatic hydrocarbons (PAHs) associated with the inhalable fraction of particulate matter were determined for 1 year (2009–2010) at a school site located in proximity of industrial and heavy traffic roads in Delhi, India. PM₁₀ (aerodynamic diameter ≤10 μm) levels were ～11.6 times the World Health Organization standard. Vehicular (59.5 %) and coal combustion (40.5 %) sources accounted for the high levels of PAHs (range 38.1–217.3 ng m^?3) with four- and five-ring PAHs having ～80 % contribution. Total PAHs were dominated by carcinogenic species (～75 %) and B[a]P equivalent concentrations indicated highest exposure risks during winter. Extremely high daily inhalation exposure of PAHs was observed during winter (439.43 ng day^?1) followed by monsoon (232.59 ng day^?1) and summer (171.08 ng day^?1). Daily inhalation exposure of PAHs to school children during a day exhibited the trend school hours?>?commuting to school?>?resting period in all the seasons. Vehicular source contributions to daily PAH levels were significantly correlated (r?=?0.94, p?<?0.001) with the daily inhalation exposure level of school children. A conservative estimate of ～11 excess cancer cases in children during childhood due to inhalation exposure of PAHs has been made for Delhi.     

Concentrations of organochlorine pesticides and polychlorinated biphenyls in human serum and their relation with age,gender, and BMI for the general population of Bizerte,Tunisia

Human serum samples (n?=?113) from Bizerte, northern Tunisia, collected between 2011 and 2012 were analyzed for 8 organochlorine pesticides (OCPs) including p,p′-dichlorodiphenyltrichloroethane (DDT) and its metabolites, hexachlorobenzene (HCB), hexachlorocyclohexane isomers, dieldrin, and heptachlor and 12 polychlorinated biphenyls (PCBs) congeners. Concentrations of these residues in serum were determined by gas chromatography with electron capture detector and total cholesterol (CHOL) and triglycerides (TG) levels were evaluated by enzymatic colorimetric method. HCB, p,p′-DDE, PCB-138, PCB-153, and PCB-180, were the most abundant organochlorine compounds (OCs) detected in >95 % of the study subjects. The mean levels of p,p′-DDE and HCB in serum were 168.8 and 49.1 ng?g^?1 lipid, respectively. The sum PCBs concentrations ranged from 37.5 to 284.6 ng?g^?1 lipid in the samples, with mean and median value of 136.1 and 123.2 ng?g^?1 lipid, respectively. The PCB profile consisted of persistent congeners, such as PCB-138, PCB-153, and PCB-180 which contributed for approximately 82.7 % to the ∑PCBs. Statistical analysis showed that most OCs correlated significantly with age, considering all samples together or with gender differentiation. The present study shows that the levels of p,p′-DDE and ∑DDTs were significantly higher in females than in males (p?<?0.05), while PCBs levels were significantly higher in male (p?<?0.05) than in females. No statistically significant association was found between body mass index and concentration of any organochlorine pesticide or PCB congeners 153, 138, 180, or ∑PCBs.     

Assessing spatial distribution,sources, and human health risk of organochlorine pesticide residues in the soils of arid and semiarid areas of northwest China

Thirty-two topsoil samples were collected to analyze the residue levels of organochlorine pesticides (OCPs) in topsoil of arid and semiarid areas of northwest China in 2011. Results showed that DDTs were the dominant contaminants with a mean concentration of 12.52 ng/g. The spatial distribution characteristics indicated that α-hexachlorocyclohexanes (HCHs) were mainly used in rural sites, whereas hexachlorobenzene (HCB) and endosulfan were detected mostly in urban areas. DDTs, heptachlor, and chlordane were found almost equally in both urban and rural areas. Source identification revealed that the current levels of HCHs in soils were attributable to the residues from their historical use and fresh usage of lindane (γ-HCH). DDTs were mainly from historical use and fresh usage of dicofol, and HCB was emitted from the chemical industry. It was also found that the current soil levels of heptachlor were mainly from its historical usage, endosulfan from fresh input, and chlordane from long-range atmospheric transport, respectively. The noncarcinogenic health risk assessment with a model was also conducted using USEPA standards for adults and children. Results indicated that health risk under nondietary exposure to OCPs decreased in the sequence of ΣDDT?>?ΣHCH?>?HCB?>?Σheptachlor?>?Σendosulfan?>?Σchlordane. According to the reference dose from the USEPA, the health risk under nondietary exposure to OCPs in the soil samples was at a relatively safe level.     

Persistent organic pollutants in the atmosphere from urban and industrial environments in the Rhine Valley: PCBs, PCDD/Fs

Polychlorinated biphenyls (PCBs) and polychlorinated dibenzodioxin and furan (PCDD/F) concentrations in the atmosphere were analysed using passive air samplers (PAS) close to the Rhine River between France and Germany. Collectors were placed in industrial, urban, rural and remote areas (Vosges Mountains) between March 2009 and August 2010, and the mean PCB concentrations (sum of 22 congeners) were 3.3, 3.9, 4.1 and 1.4 ng?PAS^?1?day^?1, respectively. Two events during the sampling period were observed in April 2009 and February–March 2010 with the highest PCB concentrations found in the industrial area (19.6 ng?PAS^?1?day^?1). PCDD/F level were measured during these periods, and the maximum concentration observed was from 37.5 fg?WHO?PAS^?1?day^?1     

Development of a new polyclonal antibody for the determination of polychlorinated biphenyls in indoor air by ic-ELISA

A new polyclonal antibody (pAb) was prepared and used for the determination of polychlorinated biphenyls (PCBs) in air samples to promote the application of immunoassay technology in the determination of PCBs. Three PCB congeners immunogen mixture was used to stimulate immune responses in rabbits. The specific pAb to PCBs was obtained and used to develop an indirect competitive enzyme-linked immunosorbent assay (ic-ELISA). A standard curve for Aroclor 1248 was prepared using concentrations ranging from 0.1 to 100 μg L^?1. The average IC₅₀ value was 16.21 μg L^?1 and the limit of detection at 10 % inhibition (IC₉₀) was 0.069 μg L^?1. The entire procedure was then evaluated using spiked air samples. The recoveries of Aroclor 1248 at various spiking levels in the air samples ranged from 84 to 113 %, with relative standard deviations of 3 to 6 %. Under optimum conditions, the cross-reactivity profiles of the assays were obtained using three selected congeners, four Aroclor products, and other structurally related compounds of PCBs. The assays were found to be highly specific for PCB congeners and Aroclors 1248 and 1242. The air samples were then analyzed using gas chromatography coupled with high-resolution mass spectrometry to confirm the ic-ELISA results. The attained results demonstrated that the proposed method was an effective and inexpensive technique for the PCBs determination in air samples.     

Evaluating the degradation of the herbicides picloram and 2,4-D in a compartmentalized reactive biobarrier with internal liquid recirculation

Tordon is a widely used herbicide formulation of 2,4-dichlorophenoxyacetic acid (2,4-D) and 4-amino-3,5,6-trichloropicolinic acid (picloram), and it is considered a toxic herbicide. The purposes of this work were to assess the feasibility of a microbial consortium inoculated in a lab-scale compartmentalized biobarrier, to remove these herbicides, and isolate, identify, and evaluate their predominant microbial constituents. Volumetric loading rates of herbicides ranging from 31.2 to 143.9 g m^?3 day^?1, for 2,4-D, and 12.8 to 59.3 g m^?3 day^?1 for picloram were probed; however, the top operational limit of the biobarrier, detected by a decay in the removal efficiency, was not reached. At the highest loading rates probed, high average removal efficiencies of 2,4-D, 99.56?±?0.44; picloram, 94.58?±?2.62; and chemical oxygen demand (COD), 89.42?±?3.68, were obtained. It was found that the lab-scale biofilm reactor efficiently removed both herbicides at dilution rates ranging from 0.92 to 4.23 day^?1, corresponding to hydraulic retention times from 1.087 to 0.236 days. On the other hand, few microbial strains able to degrade picloram are reported in the literature. In this work, three of the nine bacterial strains isolated cometabolically degrade picloram. They were identified as Hydrocarboniphaga sp., Tsukamurella sp., and Cupriavidus sp.