Residues of hexachlorocyclohexane isomers in soil and water samples from Delhi and adjoining areas (original) (raw)
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Chemosphere, 2008
Con cen tra tions of hex a chlo ro cy clo hex ane iso mers (a-HCH, b-HCH, c-HCH, and d-HCH) were stud ied in soils sam ples col lected from a small scale indus trial unit of Luc know asso ci ated with lin dane pro duc tion. All four iso mers were detected from ten sites and the total HCH iso mers in the ana lyzed sam ples varied from 53 to 99 mg kg ¡1. Clus ter anal y sis was per formed to group the soil sites in terms of their HCH con tam i na tion level. Low a/c HCH ratios were found and they indi cate recent input of HCH. There is an urgent need for the on-site reme di a tion of these con tam i nated sites in order to pre vent the long-term envi ron men tal pol lu tion.
Though the use of Organochlorine pesticides significantly develops the economic status of many developing countries by increasing the crop yield and preventing the vector-borne diseases, but it becomes a serious threat to our environment increasing serious health problems. The persistence of Organochlorine pesticide, Hexachlorocyclohexane (HCH) and its isomers are toxic and cause hepatotoxic, immune-toxic, reproductive, and developmental effects. These become persistent in the soil and environment for a longer period due to their recalcitrant properties and their slow bioconversion into inorganic compounds. Hence, these are biomagnified into the tropic level and cause acute and chronic health problems. Though the use of HCH is banned in developed countries still several developing countries are using lindane (HCH) in domestic and agriculture purposes including India. Different abiotic factors like moisture, pH and Eh, temperature, organic matters affect the persistence of HCH.
European Journal of Experimental Biology, 2011
HCH and DDT, the organochlorine pesticides (OCPs) were measured in soils from northern Uttar Pradesh, India. The average concentration of HCHs and DDTs was 7.58±1.54 ng g-1 and 0.61±0.21 ng g-1 (dry wt.). Compositional analysis of HCH and DDT isomers was carried out to identify the possible contamination sources. The α/γ ratio of HCH (<0.01 - 8.83) reflects the use of technical as well as lindane formulation. The ratio of p,p’-DDT/p,p’-DDE (0.73) and p,p’- DDT/ΣDDT (0.42) indicates the combined effects of past and ongoing usage of DDT. o,p’- DDT/p,p’-DDT (<0.01) ratio suggest the contamination of soils from technical DDT and not from Dicofol type DDT.
Environmental Monitoring and Assessment, 2013
Eighty-two surface soil samples were collected from forest, grassland, tea estate, wildlife sanctuary, wetland, and roadside areas from the northeastern states of India, viz., Tripura, Manipur, and Assam. Thirteen different organochlorine pesticides (OCPs) were detected from background soils using gas chromatography electron capture detector. Manipur soils were found to be with higher concentration of dichlorodiphenyltrichloroethanes (DDTs), hexachlorocyclohexanes (HCHs), and endosulfan followed by Tripura and Assam. The spearman correlation coefficient shows significant correlation between HCHs, DDTs, and endosulfan isomers (r 2 >0.5 and p<0.05). Additionally, α-HCH, δ-HCH, o,p′-DDE, and endosulfansulfate shows good correlation with total organic carbon in soil (r 2 =0.5, p=0.05), indicating that the soil organic matter could enhance adsorption of these compounds, also demonstrating that the present OCPs in the background soil were from similar source. Further principal component analysis evaluates that most of the higher volatile compounds where clustered together in soil. However, after comparing with different states of Indian soil samples, the concentrations of OCPs in the present study areas are much lower and comparable with background soil across the globe.
2021
Pakistan is an agro-economy country where hexachlorocyclohexane (HCH) pesticides are being used to improve crop productivity, as a result the risk of contamination of soil and sediment has been increased. HCH exhibits all the characteristics of persistent organic pollutants (POP), and was therefore added to the list of 'new POPs' in 2009. This review report revealed that the major rivers of Pakistan such as the Indus Basin, River Ravi, River Chenab and their tributaries all are contaminated with HCH and the highest residual concentration (4,090 ng/g) was detected in a pesticide burial ground in Hyderabad city. Major sources of HCH contamination were identified as agricultural runoff, discharge of untreated industrial effluents and surface runoff. In order to manage HCH pollution, various ex-situ and in-situ remediation techniques along with their merits and demerits are thoroughly reviewed. Among these, microbial bioremediation is a low cost, environment friendly, effective ...
Biodegradation of hexachlorocyclohexane-isomers in contaminated soils
Soil Biology & Biochemistry, 2006
Several sites that are contaminated with isomers of the chlorinated insecticide hexachlorocyclohexane (HCH) are present across the globe and cause toxicity. For their bioremediation, we studied the degradation of HCH-isomers in contaminated soils by an isolate Pseudomonas aeruginosa ITRC-5. The degradation is optimal at 2 mg technical-HCH (t-HCH)/g soil, 15% water content, pH 8.0, temperature 28 1C and inoculum density 10 6 colony forming unit/g soil. Under these conditions, from 5 kg soil, 498% aand g-HCH, 17% b-HCH and 76% d-HCH are degraded after 15 days of incubation, which is accompanied with the release of 600 mg chloride/mg t-HCH. Concomitant to the degradation, a four-fold reduction in the toxicity of HCH-isomers to earthworm, Eisenia foetida, is also observed. Addition of ITRC-5 enhanced the degradation of soil-applied HCH-isomers in 'open field' conditions as well, and 97%, 43%, 94% and 77% of a-, b-, gand d-HCH, respectively, are degraded after 12 weeks of incubation. Thus, the bacterium causes microbial degradation and detoxification of HCH-isomers, and can be used for the bioremediation of contaminated soils. r
Journal of Chromatography A, 1994
Solid-phase microextraction (SPME) is a method for the extraction of organic compounds from aqueous samples. The analytes are extracted into a stationary phase placed on a fused-silica fibre and are thermally desorbed in the injector of a gas chromatograph. The connection of GC with electron-capture (ECD) and mass spectrometric (MS) detection with the SPME method makes it possible to determine low concentrations of organochlorine compounds in aqueous solutions. With hexachlorocyclohexanes (HCHs) detection limits between 5 rig/l (for a-and y-HCH with the combination of SPME and GC-ECD) and 80 rig/l (for /I-HCH with the combination of SPME and GC-MS) were calculated. The SPME-GC method was used to investigate the mobility of HCHs in wetland soils near Bitterfeld. The results of this study show the high mobility of P-HCH despite the low water solubility and the long persistence of /3-HCH in soils. The proportion of p-HCH in the total HCH concentration is higher in soil solutions (80-90%) than in soils.
Contamination levels and spatial distribution of organochlorine pesticides in soils from India
Ecotoxicology and Environmental Safety, 2011
Organochlorine pesticides, dichlorodiphenyltrichloroethane (DDT) and hexachlorocyclohexane (HCH), are potential chemical pollutants extensively used for agriculture and vector control purposes due to low cost and high effectiveness. Concentrations of HCH and DDT were determined in 175 surface soil samples from different agricultural fields, fallow and urban lands of districts Nagaon and Dibrugarh, Assam, India. The mean concentrations of total HCH and total DDT were 825 ng/g (range: 98-1945 ng/g) and 903 ng/g (range: 166-2288 ng/g) in district Nagaon while 705 ng/g (range: 178-1701 ng/g) and 757 ng/g (range: 75-2296 ng/g) in district Dibrugarh, respectively. The soils from paddy fields contained highest amounts of HCH and DDT residues. Total organic carbon was found to be positively associated with soil HCH and DDT residues. Ratios of DDT/(DDD þDDE) were 1.25 and 1.82 while of a/g HCH were 2.78 and 2.51 for districts Dibrugarh and Nagaon, respectively. Source identification revealed that soil residue levels have originated from long past and recent mixed source of technical HCH and Lindane for HCHs and mainly technical DDT for DDTs. Spatial distribution was also investigated to identify the areas with higher pesticide loadings in soil.