HCH residues in point-source contaminated samples of the Teltow Canal in Berlin, Germany

Abstract

Contaminated groundwater and a riverine sediment core heavily affected by the same industrial point source were analysed for hexachlorocyclohexanes (HCH) and its degradation products. A detailed quantification by GC/MS revealed contamination levels up to 730 lg/L and 396 ng/g in sum for the water and sediment samples, respectively. The isomer pattern differed significantly in both compartments. The ground water samples were depleted in c-HCH, whereas a significant loss of a-HCH was evident in the sediments as compared to the technical composition. The data obtained revealed interesting insights into the transformation behaviour and fate of HCH mixtures in anaerobic environmental compartments. In the affected groundwater system an ongoing microbial degradation was pointed out by the identification of indicative anaerobic metabolites. On the contrary in the sedimentary system a high environmental stability or rather a hindered degradation was observed as indicated by unaltered concentration levels as compared to production rates as well as by the absence of metabolites. Interestingly, the environmental fate of HCH in subaquatic sediments as well as in anaerobic ground water differs highly in contrast to the behaviour in anaerobic soil or surface water systems. Further on, it has to be stated, that the knowledge about the long-term behaviour of HCH residues in sedimentary material under anaerobic conditions is rather limited so far.

Biochemistry of Microbial Degradation of Hexachlorocyclohexane and Prospects for Bioremediation

“…74,2010 MICROBIAL DEGRADATION OF HCH 59 the environment with lower HCH concentrations due either to dispersal from stockpiles or to the use of the insecticide. The majority of HCH waste has been discarded in the open or stored at various levels of containment near the production sites, although in some cases, the top layer of soil at such sites has been removed for use in filling material for the construction of roads and buildings (97,145,181). HCH residues at many of the sites have percolated into the soil and thence contaminated groundwater (145).…”

“…The majority of HCH waste has been discarded in the open or stored at various levels of containment near the production sites, although in some cases, the top layer of soil at such sites has been removed for use in filling material for the construction of roads and buildings (97,145,181). HCH residues at many of the sites have percolated into the soil and thence contaminated groundwater (145). Residues of HCH isomers have now been reported for many countries in samples of air (76,79,138), water (8,71,139), soil (29,50,71,139,144), food commodities (7,17,175,184), milk (153,197), fish (44,87), and mammals (48) and even from human blood samples (15,169) and adipose tissue (14,73).…”

The effect of distribution processes on the isomeric composition of hexachlorocyclohexane in a contaminated riverine system

“…50 lL at ambient temperature. Soil and sediment subsamples of 10 g were extracted by sequential ultrasonic agitation (according to Ricking and Schwarzbauer 2008) with 100 mL acetone and 100 mL nhexane. Each extraction step involved 15-min treatment by ultrasonication followed by a stirring period of 1 h and a second 15-min treatment by ultrasonication.…”

“…Numerous studies were performed on the occurrence of HCHs in various environmental compartments such as air (e.g., Karlsson et al 2000;Ding et al 2007), soil (e.g., Manz et al 2001;Schwartz et al 2006), sediment (e.g., Heim et al 2005;Ricking and Schwarzbauer 2008;Li et al 2011a), water (e.g., Heemken et al 2000), plants (e.g., Abhilash et al 2008) and animals (e.g., Marth et al 1997;Willett et al 1998). Most of these studies focused either on selected isomers or on reported cumulated concentrations of all HCH isomers.…”

“…Various studies have been performed on metabolization (Macrae et al 1967;Willett et al 1998;Rodriguez-Garrido et al 2004;Li et al 2011b) and isomerization (Huhnerfuss et al 1992;Wu et al 1997;Phillips et al 2005) of HCH isomers under different environmental conditions (redox environment, biotic/abiotic). Slightly different biotic transformations under aerobic and anaerobic conditions were proposed involving stepwise dechlorination to less chlorinated derivatives such as pentachlorocylohexene (e.g., Bachmann et al 1988;Rodriguez-Garrido et al 2004;Phillips et al 2005;Ricking and Schwarzbauer 2008;Bhatt et al 2009;Li et al 2011b). Hydrolysis was reported as the dominant abiotic degradation pathway for HCHs (Bhatt et al 2009).…”