γ-HCH Isomers Research Articles

Co-metabolic growth and microbial diversity: Keys for the depletion of the α, δ, β and γ-HCH isomers

The objective of this study was the isolation and enrichment of microbiomes capable of degrading the main hexachlorocyclohexane isomers quantified in environmental matrices, e.g.: the α, δ, β and γ-HCH isomers. Four microbiomes were isolated and enriched from an HCH-contaminated dumpsite in Italy, both in the presence of HCH isomers (1:1:1:1) as the sole carbon sources and under co-metabolic growth conditions in presence of glucose (0.1 % v/v). The microbiomes were assessed for their relevant metabolic capabilities. A quantitative metabarcoding approach was employed to analyze the compositional evolution of the four microbiomes during the enrichment phase and the phase of testing of the HCH isomers degradation kinetics. The use of a co-metabolic substrate during enrichment process was essential for selecting microbiomes with higher biodiversity. All microbiomes efficiently degraded the α, δ, and γ-HCH isomers. The highest efficiency in the β-HCH degradation capacity was positively correlated to the highest biodiversity of the microbiome, and the involvement of Chryseobacterium and Asinibacterium sps. have been proposed for a recorded increment in bacterial load during the HCH degradation process.

Enhancing hexachlorocyclohexane solubility with surfactants and ionic liquids

Surfactant-enhanced remediation of soil can increase the solubility of hydrophobic organic contaminants in water and improve their removal. In this study, the effect of 24 traditional surfactants and surface-active ionic liquids (SAILs) on the solubility of hexachlorocyclohexane isomers (α-, β-, γ-, δ-HCH) was evaluated in batch-type experiments. The combination of two different proportions of a cationic SAIL and an anionic surfactant was also assessed. The solubilisation capacity of the surfactant varied depending on its concentration and structure, but also the HCH isomer considered. In general, the anionic surfactants yielded the best results, increasing solubilisation of HCH up to 2.4 times compared to the control (pure water). α-HCH and γ-HCH isomers were more easily solubilised than β-HCH and δ-HCH regardless of the surfactant’s type. The main advantage of ionic liquids being their tunability, some clues are given for formulating surfactants to enhance the solubilisation of HCH. The combination of a traditional surfactant and a SAIL influenced the critical micelle concentration, but not the solubilisation of the contaminant. Further studies on the use of blends for this application are required. The increase of solubility achieved with the studied surfactants encourages their application in washing HCH-contaminated soils through solubility enhancement.

Pesticides in the hydrogeo-environment: a review of contaminant prevalence, source and mobilisation in India.

Chemical pesticides in the hydrogeological system are a global concern as they pose a severe threat to humans and other organisms. In agriculture, around 4.12 million tonnes of pesticides were used globally in 2018, which is 50% more than in the 1990s. Various pesticides detected in the hydrogeological system of India since the 1990s have been documented and reviewed to understand the prevalence, source, history and degradation pathways. This review contributes to a better understanding of existing pesticide pollution and the state of hydrogeological resource deterioration. Small to excess levels of pesticide residues were detected in groundwater, surface water, soil, and sediments. Pesticides that were most commonly and predominantly found in the hydrogeological system were HCHs, DDTs, endosulfan, heptachlor, drins (aldrin, dieldrin, endrin), chlordane etc. β and γ-HCH isomers among HCHs, whereas p,p'-DDT and p,p'-DDE among the DDTs were detected most prevalently. In many regions, pesticide residue levels in water have exceeded the maximum residue limits of WHO and BIS, while those in soils and sediments have exceeded the threshold effect level and probable effect level. Higher pesticide residues were detected in the water resources of rural agricultural areas compared to peri-urban or urban areas. A positive correlation of pesticide residues between water resources and soil has been observed in some regions, suggesting a similar contamination source. Diagnostic ratios of pesticides reveal their source, history and degradation pathways. Diagnostic ratios observed in various studies conducted in India suggest historical as well as recent use of banned pesticides. Strengthening current policies and regulations, monitoring pesticide use, changes in pesticide application practices, awareness among farmers, and the use of prominent removal techniques are necessary to tackle pesticide contamination in India.

Health risk assessment of organochlorine pesticide residues in edible tissue of seafood.

Fish is one of the most valuable foods with high-quality animal protein. However, aquaculture, or ingesting contaminated food, allows organochlorine pesticides (OCPs) to enter the fish's body, and therefore, it negatively impacted public health. One-hundred and twenty random samples of Clupea harengus (C. harengus), Mugil cephalus (M. cephalus), Sardinella aurita (S. aurita), Oreochromis niloticus (O. niloticus), Neptunus pelagicus (N. pelagicus) and Sepia savigngi (S. savigngi) (n = 20 each) were collected from local markets in Mansoura city, Egypt. Samples were checked to see whether any residues of OCPs with the application of risk assessment due to their consumption by Mansoura citizens. The findings indicated that summation hexachlorocyclohexane (∑HCH) in examined seafood samples ranged from 0.27 ± 0.13 in N. pelagicus to 61.61 ± 52.03 μg.kg-1 in S. aurita. Also, the γ-HCH isomer was considered the more prominent among isomers. Hexachlorobenzene (HCB) was found in five different species, with mean values of 2.03 ± 1.85, 1.5.7 ± 1.17, 0.94 ± 0.87, 0.35 ± 0.06, and 0.18 ± 0.06 μg.kg-1 in C. harengus, S. aurita, M. cephlaus, O. niloticus, and S. savigngi. Moreover, summation of Heptachlors (∑HPTs) was 10.19 ± 7.63, 1.27 ± 0.26, 2.58 ± 0.11, 0.95 ± 0.12, 0.21 ± 0.11 and 0.32 ± 0.03 μg.kg-1 of wet weight in examined C. harengus, M. cephlaus, S. aurita, O. niloticus, N. pelagicus, and S. savigngi. Aldrin and dieldrin residues were 3.75 ± 1.31 and 4.86 ± 1.33 μg.kg-1 in C. harengu, meanwhile they were 1.61 ± 0.77 and 0.78 ± 0.04 μg.kg-1in M. cephalus. Dichlorodiphenyldichloroethylene (pp-DDE) was dominant in all examined species within different concentrations 5.08 ± 4.12, 0.98 ± 0.10, 3.07 ± 0.91, 0.93 ± 0.27, 0.08 ± 0.01 and 0.35 ± 0.02 μg.kg-1 in C. harengus, M. cephlaus, S. aurita, O. niloticus, N. pelagicus and S. savigngi, respectively. We concluded that all examined seafood samples were lower than the recommended maximum residue limit. Also, the estimated daily intake was less than the permitted daily intake. Non-carcinogenic indices of target hazard quotient and hazard index for OCPs in all examined species were less than 1.

Effect of plant root exudates on the desorption of hexachlorocyclohexane isomers from contaminated soils

Plants and their associated microbiota can have a significant impact on the behaviour of soil contaminants. Particularly, root exudation is one of the most important plant-associated processes in this respect, as it may have a substantial effect on the bioavailability of soil contaminants, specially of hydrophobic contaminants strongly sorbed by soil. The aim of the present study was to evaluate the effect of root exudates (natural and artificial) on the desorption of α-, β-, δ- and γ-isomers of hexachlorocyclohexane (HCH) from contaminated soil, using batch experiments. Natural root exudates were obtained from Holcus lanatus plants growing in the same (contaminated) area. Fifteen compounds (mainly organic acids and phenolic compounds) usually found in root exudates were also tested, individually or as mixtures (1 and 10 mM). Both natural and artificial exudates favoured the mobilization of sorbed HCH in soil. The effect was highly significant for α-, β- and γ-HCH isomers, for which the desorption rates increased by 23.0, 26.8 and 15.5% in the presence of natural root exudates and by 40.1, 25.9 and 25.6% in the presence of the artificial mixture (at 10 mM). The δ-HCH desorption rates increased by less than 10%. The effect of individual exudate components was very variable, but increased with the carbon content, reflecting the significance of hydrophobic interactions between the exudates and HCH molecules in the desorption of these last from soil. These findings indicate that plants may significantly influence the bioavailability of persistent contaminants, with major implications for improving phyto- and bioremediation procedures.

Partitioning of chlorinated organic compounds from dense non-aqueous phase liquids and contaminated soils from lindane production wastes to the aqueous phase

Hexachlorocyclohexane (HCH) and mainly the γ-HCH isomer, namely lindane, were extensively produced and used as pesticides. Huge amounts of wastes, solids and liquids, were disposed of in the surroundings of the production sites. The liquid residuum was a complex mixture of chlorinated organic compounds, COCs, from chlorobenzene to heptachlorocyclohexane. This Dense Non-Aqueous Phase Liquid, DNAPL, migrated by density through the subsurface to greater depths, being trapped or adsorbed into the soil in this movement posing a significant risk to the groundwater. Knowledge of the partitioning in water of COCs in DNAPL is a key issue to determine its fate in the environment. However, there are no data in literature for the partitioning and/or solubility of many of the COCs in this DNAPL, such as pentachlorocyclohexene, hexachlorocyclohexene and heptachlorocyclohexane despite them constitute about 13–30% of the mole fraction of the DNAPLs. In this work, the partitioning to water of COCs in free and those adsorbed onto soil has been studied. In addition, measured and predicted aqueous concentrations of each COC in the DNAPL mixture have been compared. To do this, the solubility of a compound that is a solid crystal when pure at P = 298 K and P = 1 atm has been evaluated considering the approach of sub-cooled liquid state of solid organochlorines. Samples were obtained at Sabiñanigo landfills and soils used had several grain sizes. Transformation in alkaline media of COCs had a positive environmental impact.

Anaerobic biotransformation of hexachlorocyclohexane isomers by Dehalococcoides species and an enrichment culture.

The biotransformation of hexachlorocyclohexane isomers (HCH) by two Dehalococcoides mccartyi strains (195 and BTF08) and an enrichment culture was investigated and compared to conversion by the obligate anaerobic strain Clostridium pasteurianum strain DSMZ 525. The D. mccartyi strains preferentially transformed γ-HCH over α-HCH and δ-HCH isomers while β-HCH biotransformation was not significant. In case of the enrichment culture, γ-HCH was preferentially transformed over the δ-HCH, β-HCH and α-HCH isomers. Major observed metabolites in both cases were tetrachlorocyclohexene and as end products monochlorobenzene (MCB) and benzene. Dechlorination of the γ-HCH isomer was linked to an increase in cell numbers for strain 195. γ-HCH transformation was linked to considerable carbon stable isotope fractionation with the enrichment factor εc = - 5.5 ± 0.8‰ for D. mccartyi strain 195, εc = - 3.1 ± 0.4‰ for the enrichment culture and εc = - 4.1 ± 0.6‰ for co-metabolic transformation by C. pasteurianum.

Passive air sampling of persistent organic pollutants (POPs) and emerging compounds in Kolkata megacity and rural mangrove wetland Sundarban in India: An approach to regional monitoring

Polyurethane foam (PUF) disk passive air samplers were deployed concurrently at five sites across Kolkata megacity and the rural mangrove wetland of Sundarban (UNESCO World Heritage Site) between January–March in 2014. Samples were analyzed for hexachlorocyclohexanes (HCHs), dichlorodiphenyltricholoroethanes (DDTs), polychlorinated biphenyls (PCBs) and, polybrominated diphenyl ethers (PBDEs) using gas chromatography and mass spectrometry (GC-MS). Derived air concentrations (pg/m3) for Kolkata ranged: for ∑α- and γ-HCH between 70 and 207 (114 ± 62), ∑6DDTs: 127–216 (161 ± 36), ∑7PCBs: 53–213 (141 ± 64), and ∑10PBDEs: 0.30–23 (11 ± 9). Low values for all the studied POPs were recorded in the remote area of the Sundarban site (with the exception of DDTs: o,p’-DDT and p,p’-DDT), where ∑4DDTs was 161 ± 36. In particular, the site of Ballygunge, located in the southern part of Kolkata, showed the highest level of all the metabolites/congeners of POPs, suggesting a potential hot spot of usage and emissions. From HCHs, α-/γ-HCH isomers ratio was low (0.67–1.96) indicating a possible sporadic source of lindane. γ-HCH dominated the HCH signal (at 3 sites) reflecting wide spread use of lindane both in Kolkata and the Sundarban region; however, isomeric composition in Kolkata also suggests potential technical HCHs use. Among DDT metabolites, both o,p’-DDT and p,p’-DDT shared the dominant percentages accounting for ∼26–46% of total DDTs followed by p,p’-DDE (∼12–19%). The PCB congener profile was dominated by tri- and tetra-Cl at the southern and eastern part of Kolkata. These results are one of the few contributions that reports air concentrations of POPs, concurrently, at urban and remote villages in India. These data are useful to assess atmospheric pollution levels and to motivate local and regional authorities to better understand the potential human exposure risk associated to urban areas in India.

Concentrations and sources of pesticides and PCBs in surficial sediments of the Red Sea coast, Egypt

Sixteen surface sediments from the Egyptian coast of the Red Sea were collected and studied for organochlorine contamination. This research was endeavored to study sources, concentrations and risk factors of pesticides and PCBs in the surficial sediments collected from the studied locations. The sediments in the studied areas are predominantly sand. The most abundant PCB congeners detected in the investigated sediment samples of the Red Sea proper were a total of PCB 52 and a total of PCB 138 (225 and 465ngkg−1drywt., respectively). Meanwhile, in the Aqaba Gulf the most abundant PCB congener was a total of PCB 138 (226ngkg−1drywt.). At the Suez Gulf, the most abundant PCB congeners were a total of PCB 180 and 153 (127 and 103ngkg−1drywt., respectively). The input of direct industrial and domestic discharge in most of the contaminated zones of the studied area resulted in a larger concentration of total PCB 52, 138, 153 and 180. The results obtained showed fairly low levels of pesticide residues. The most dominant pollutants were the HCHs and DDTs, high proportions of α-HCH over γ-HCH isomer indicated less recent input of lindane. The α-HCH/γ-HCH ratios in most of the studied locations are slightly less than those in technical-grade HCH mixture (66.5% α isomer, 11.4% β isomer, 15.2% γ isomer (lindane), 6.4% δ isomer, and 0.5% other isomers) indicating that there was less input of lindane in the past several years. This study clearly indicates that PCB concentrations, DDTs, cyclodienes, HCHs were much lower than those recorded by the international organization.

Distribution and health risk assessment of organochlorine pesticides (OCPs) residue in edible cattle tissues from northeastern part of Egypt: High accumulation level of OCPs in tongue.

Food consumption is an important route of human exposure to organochlorine pesticides (OCPs). In order to assess the potential human health risks associated with OCPs, edible cattle tissues (liver, kidney and tongue) were collected from three slaughter houses in Mansoura, Zagazig and Ismailia cities, Egypt. Levels of 22 OCPs such as hexachlorocyclohexanes (HCHs), dichlorodiphenyltrichloroethanes (DDTs), aldrin, dieldrin and endrin (Drins), chlordanes (CHLs), heptachlors (HPTs) and hexachlorobenzene (HCB) residues were investigated. Among the investigated OCPs, HCHs represented the most dominant group with high proportions of γ-HCH isomer (53-91% of total HCHs). Mansoura city had the highest OCPs contamination load ranged from 0.1 to 2827 ng g(-1) lw (lipid weight). Surprisingly, tongue samples collected from Mansoura showed the highest concentration of HCHs (448 ng g(-1) lw) in comparison to liver (152 ng g(-1) lw) and kidney (266 ng g(-1) lw). Generally, contamination pattern of OCPs was in the order of HCHs > Drins > CHLs > DDTs ≅ HCB and HPTs. Estimated daily intakes (EDIs) through dietary consumption of cattle tissues were lower than the recommended acceptable daily intakes (ADIs) established by FAO/WHO. However, the hazard ratios (HRs) based on cancer risk were greater than 1.0 for HCHs based on the average and 95th centile concentrations, indicating carcinogenic effects to consumers through cattle tissues consumption.

Residue of Select Organochlorine Pesticides (OCPs) in Sediment from Vietnam’s CauBay River and Their Impact on Agricultural Soil and Human Health

An evaluation of OCP residue (OCPs = α, β, δ, γ-HCH isomers, p,p’-DDE, p,p’-DDD, p,p’-DDT) from the CauBay River and the KieuKy area in Vietnam was carried out. The CauBay has played an important role in irrigated water supply for agriculture activities in KieuKy downstream. The OCP concentrations of sediment and soil samples were analyzed and results indicated the wide extent of contamination of OCPs in the CauBay (DDTs: 68.35±13.57 ng·g -1 dw; HCHs: 7.82±2.36 ng·g -1 dw) and KieuKy (DDTs: 85.24±15.43 ng·g -1 dw; HCHs: 6.94±1.49 ng·g -1 dw). This clearly reflected the effects of OCP residue from the CauBay on quality of KieuKy agricultural soil. The OCP composition analyses in the samples reflect their long-time release. The total cancer risk of OCPs in KieuKy soil fell into a very low range, suggesting low risk. However, since OCPs were the species of POPs with more concern in this area, ecological risk assessment should be further investigated.

Fingerprint of persistent organic pollutants in tissues of Antarctic notothenioid fish

In the present work, persistent organic pollutants (POPs), such as polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane (DDT) and metabolites, polybrominated diphenyl ethers (PBDEs), and hexachlorocyclohexane (HCH) were analyzed in three Antarctic notothenioids fish species: Trematomus newnesi (TRN), Notothenia coriiceps (NOC) and Notothenia rossii (NOR). The contribution of each POP-family to the total load was as follows: ΣPCB (40%)>ΣDDT (27%)>ΣPBDEs (23%)>ΣHCH (10%). Among the 23 PCB congeners analyzed, penta-CBs homologues were the prevalent group, followed by hexa-CBs and hepta-CBs. DDT and its metabolites presented the following trend: p,p′-DDT>p,p′-DDE~p,p′-DDD. PBDE profile was dominated by BDE-47 and BDE-99 congeners, followed by BDE-100>BDE-28>BDE-154, BDE-153. Among HCHs, the γ-HCH isomer was detected in all samples, constituting 69% total HCH load, while α-HCH and β-HCH contributions were 15% and 16%, respectively.The levels of POPs reported here suggest that NOR and NOC are more susceptible to accumulate the analyzed contaminants than TRN, a species not previously analyzed for POPs.Distribution of POPs among different tissues of the three species (muscle, liver, gonads, and gills) was also investigated. Considering lipid weight, the general pattern of POPs distribution in tissues indicated that while gonads showed higher levels of PCBs, DDTs and HCH, the most significant PBDE concentrations were recorded in gills. Also, a comparative analysis of POPs concentration in fish samples from Antarctic area was included.

Distribution and ecological risk assessment of organochlorine pesticides in sediments from four lakes of Heilongjiang Province, China

There is growing concern for the lake environment because polluted sediments may cause ecotoxicological effects. In the current study, persistent organochlorine compounds (OCPs), including hexachlorocyclohexanes (HCHs), dichlorodiphenyltrichloroethanes (DDTs) and cyclodienes, were analyzed in core sediments taken from Huoshaohei Lake, Xihulu Lake, Wanghua Lake and Keqin Lake, Heilongjiang Province, China. The total OCPs concentrations ranged from 0.92 to 7.09, 0.15 to 9.95, 0.19 to 1.84 and 0.06 to 3.52ng/g, respectively. The most dominant pollutants were the HCHs, high proportions of γ-HCH isomer indicating the recent input of lindane. The ratios of α-HCH/γ-HCH of four lakes are all lower than that in technical HCH mixtures indicating that there was input of lindane in the past several years, and the mean ratios of (DDE+DDD)/DDTs are all <0.5, suggesting recent release of DDT compounds. Compared with the corresponding ecological environmental quality guidelines from Ingersoll and base on the model of risk based corrective action environmental health risk assessment, the sediments from the four lakes poses a lower potential hazard to human health and the environment but still should be taken into account.

Persistent organic pollutants (POPs) in the marine food web: herrings from the southern Baltic Sea (Clupea harengus) — penguins from the zoo (Spheniscus demersus)

Abstract The aim of this project was to study the fate of chemically persistent organochlorine xenobiotics in the marine link of the food web, between penguins and herrings (Clupea harengus), which are the only food for Spheniscus demersus from the Gdańsk Zoo. Concentrations of hexachlorobenzene (HCBz), pentachlorobenzene (PCBz), trichlorobenzene (TCBz) and the γ-HCH isomer were determined in Baltic herrings, in muscles, fat and liver of penguins, unhatched eggs, contour feathers and guano. The highest concentrations of fungicides were observed for HCBz. Fungicides were not detected in the liver of penguins and herrings. The bioaccumulation factor (BAF) for fungicides reached the highest values in the penguin brain. The highest biomagnification factor (BMF) for PCBz was determined in the muscle tissue and for lindane — in liver. It was confirmed that detoxification of penguins occurred through deposition of fungicides and lindane in guano and through epithelial tissue and eggs.

Organochlorine Residues in Vegetables

Vegetables are important components of the human diet, and even low levels of pesticides in vegetables may have adverse effects for consumers. A study was carried out to assess residue levels of dichlorodiphenyltrichloroethane (DDT), hexachloro-cyclohexane (HCH), and endosulfan in vegetables. The total concentration of organochlorine pesticides (OCPs) ranged from 0.29 to 106.65 μg.kg−1 (wet weight). All vegetable samples had some levels of one or more organochlorine pesticide in them. Mean concentrations of ∑DDT, ∑HCH, and ∑endosulfan in vegetables were 4.20 ± 1.68, 3.12 ± 0.66, and 0.97 ± 0.21 μg.kg−1 (wet weight), respectively. The greatest OCP accumulation was in root vegetables, followed by fruit and flower and leaf vegetables. The ratio of α-HCH to γ-HCH isomers (α/γ HCH ratio) ranged from 0.03 to 3.77, which reflects the use of lindane as well as technical formulations of HCH. The ratio of (DDE + DDD)/∑DDT, and DDT/DDE were 0.55 and 1.30, respectively, indicating biotransformation and input of DDT to the environment. Vegetables had residue levels of OCPs much below recommended maximum residue limits set by the European Commission and Indian government, indicating minimal risk to the consumers.

Organochlorine contaminants in the hair of Iranian pregnant women

In the present study, the hair of pregnant women was sampled between November 2007 and January 2008 in Ahvaz and Noushahr cities and the countryside of Noushahr, Iran. They were analyzed for organochlorine pesticides (OCPs), such as dichlorodiphenyltrichloroethane (DDT) and its metabolites, hexachlorobenzene (HCB), α-, β-, and γ-hexachlorocyclohexane (HCH) isomers and seven polychlorinated (PCBs) congeners (IUPAC Nos. 28, 52, 101, 118, 138, 153 and 180). Significant differences between the concentrations of investigated pollutants were found between the locations ( p < 0.05). For HCHs, the γ-HCH isomer was measured at higher mean concentrations (6 ng g −1 hair) compared to the β-HCH isomer (0.03 ng g −1), which generally is the most prevalent HCH in biological matrices. Very high mean concentrations of p, p′-DDT in countryside of Noushahr (24 ng g −1) combined with lower values (0.6) of ratio p, p′-DDE/ p, p′-DDT in the hair samples suggest recent exposure to “fresh” DDT in this region. Significant differences in OCPs and PCBs were found between primiparous and multiparous mothers ( p < 0.05). There was no correlation between levels of OCPs and PCBs in the hair of Iranian pregnant women and their age. There was a significant difference ( p < 0.05) in the organochlorine levels, including HCHs, between mothers who have eaten fish once a week and those who consumed fish more than once per week in Noushahr.

Evaluation of risk associated with organchlorine pesticide contaminated sediment of the Lake Lianhuan watershed

Characteristics and risk evaluation of organchlorine pesticides (OCPs) in the sediments of four lakes located in the Lake Lianhuan area were conducted to observe the risks on ecological system and identify the sources of pollutants. Measurement of eleven OCPs, four hexachlorocyclohexane (HCH) isomers (α-HCH, β-HCH, γ-HCH, δ-HCH), three dichlorodiphenyltrichloroethane (DDT) homologues (p,p'-DDT, p,p'-DDD, p,p'-DDE), and four cyclodienes (Aldrin, Dieldrin, Endrin and Heptachlor), indicated that concentrations of OCPs, HCHs and DDTs ranged from 0.04 to 9.95, 0 to 7.40 and 0 to 2.44 ng/g, respectively. The most dominant pollutants were the HCHs, high proportions of γ-HCH isomer indicating the recent input of lindane. The ratios of α-HCH/γ-HCH of four lakes are all lower than that in technical HCH mixtures indicated that there was input of lindane in the past several years, or that significant α-HCH evaporation into the atmosphere occurred. The ratios of (p,p'-DDE + p,p'-DDD)/p,p'-DDT in four sediments are all <1, and the mean ratios of (DDE + DDD)/∑DDT are all <0.5, suggesting recent DDT compounds input. The risk assessment was based on ERL and ERM values obtained by the approach used for assessment of ocean risk. The results suggest that OCPs in sediments of the Lake Lianhuan system poses a potential hazard to human health and environment.

Analysis of composition, distribution and origin of hexachlorocyclohexane residues in agricultural soils from NW Spain

Concentrations of the isomers of the organochlorine pesticide hexachlorocyclohexane (HCH) were determined in 252 surface soil samples collected within a sampling network covering agricultural areas in Galicia (NW Spain). The concentration of total HCH (sum of α + β + γ + δ) ranged between 4 and 2305 ng g −¹ (dry weight), with the α-HCH and γ-HCH isomers predominating (< 1–1404 ng g −¹ and < 1–569 ng g −¹, respectively). The distribution of the pesticide residues was very heterogeneous, with the largest concentrations present in one of the studied areas (the province of A Coruña). The distribution of HCH was not found to be related to any soil property (organic matter, pH, clays, and metals). Multivariate statistical analysis of the data revealed that three populations of samples with a defined composition of HCH, can be related to the source of HCH: technical HCH (α/γ > 3), lindane (99% γ-HCH), or both. The existence of a third population consisting almost exclusively of α-HCH suggests that background contamination of anthropogenic origin dates from several decades ago. The detailed analysis of these populations enabled the possible temporal scale of the application of these pesticides to be deduced.

Screening of white rot fungal species for their capacity to degrade lindane and other isomers of hexachlorocyclohexane (HCH)

J.C. Quintero, M.T. Moreira, G. Feijoo, and J.M. Lema. 2008. Screening of white rot fungal species for their capacity to degrade lindane and other isomers of hexachlorocyclohexane (HCH). Cien. Inv. Agr. 35(2):159-167. White-rot fungi have demonstrated a high capacity to degrade organic pollutants, including the insecticide lindane (γ-HCH). The purpose of this study γ was to evaluate the degradative capacities of several white rot fungi species, Bjerkandera adusta, Irpex lacteus, Lentinus tigrinus, Phanerochaete chrysosporium, Phanerochaete sordida, Phlebia radiata, Pleurotus eryngii, Poliporus cialatus, and Stereum hirsutum. Fungal tolerance to various concentrations of α-, β-, γ- and γ δ isomers of hexachlorocyclohexane (HCH) was studied in both liquid and soil media samples. δ- and γ-HCH isomers showed the highest inhibition of fungal γ growth of all HCH isomers. P. chrysosporium and B. adusta exhibited a high tolerance to HCH pollution. The δ- and γ-HCH isomers were degraded between 15.1 and 70.8% by six of the nine γ fungal species, B. adusta, P. ciliatus, L. tigrinu, S. hirsutum, P. eryngii, and I. lacteus; β-HCH was 56.6, 26.5 and 23.9% degraded by B. adusta, P. ciliatus and P. er yngii, respectively. In nonsterile soil, all the HCH isomers were degraded between 8.2 and 17.5% by B. adusta immobilized on corncobs or woodchips. In nonsterile soil, other soil microfl ora showed an antagonistic effect on white-rot fungi catalyzed degradation of HCH isomers.

Organochlorine contaminants in hair of adolescents from Iassy, Romania

Human hair samples (n=42) from Iassy county (Eastern Romania) collected in 2002-2003 from adolescents were analyzed for hexachlorocyclohexane (HCH) isomers, p,p'-DDT and its metabolites, hexachlorobenzene (HCB), chlordane and metabolites and 5 polychlorinated biphenyl (PCB) congeners. Very low levels were found for HCB and oxychlordane (0.8 and 2.5 ng g(-1)) indicating a low usage of these pesticide formulations in the studied area. In case of HCHs, gamma-HCH isomer was measured at higher median concentrations (79 ng g(-1) hair) compared to the beta-HCH isomer (55 ng g(-1)), which generally is the most prevalent from HCHs. The DDTs profile consisted in p,p'-DDE and p,p'-DDT which levels correspond to 81% of sum DDTs. Very high median concentrations measured for p,p'-DDT (192 ng g(-1)) combined with lower values for p,p'-DDE/p,p'-DDT of 0.4 (from 0.20 to 2.0) in all hair samples suggest recent exposure to "fresh" DDT. When gender was considered, significantly higher concentrations for most of the investigated contaminants were found in girls hair compared to boys. Very high levels were found in the present study for HCHs and DDTs compared to samples from Greece, Western Europe and China. In case of PCBs, the levels found in Romanian samples were found to be in the same range compared to other previously published data.