Residue And Bioaccumulation Of Dechloranes And Mirex In Zhalong Wetland

Dechloranes, including Mirex (also used under the trade name Dechlorane), Dechlorane Plus (DP, C18H12Cl12; also called Dechlorane 605), Dechlorane 602 (Dec 602,C14H4Cl12O), Dechlorane 603 (Dec 603, C17H8Cl12), and Dechlorane 604 (Dec 604, C13H4Br4Cl6), which have been used as flame retardant in plastics, rubber, paint, paper, and electrical goods. They existe in the environment and bioaccumulated in biota, disrupteing the respiratory system and reproduction system. They have been detected and identified in ambient air, water, soil, sediment, and biota in the world. As emerging contaminants, however, it is still not clear about the mechanism of their biomagnification and bioaccumulation along food chain. In this research, we chose Zhalong Wetland with a partially close hydrological environment and stable biological community ecological systems to study the biomagnification and bioaccumulation of Dechloranes in ecological system and along the food chain.Inorganic environment is an important part of the ecological system, 8 soil, 11 sediment and 16 water samples from Zhalong Wetland were collected and treated by Soxhlet extraction and liquid-liquid extraction method, and Dechloranes were measured by using GC/MS. The experimental results have shown that DP (including syn-DP and anti-DP)and Mirex were detected in variety samples, while Dec 602, Dec 603 and Dec 604 were below detection limit. The distribution trend of DP and Mirex in inorganic environment was in the order of entry zone>core zone>outlet zone of the Wetland.Dechloranes could be bioaccumulated from abiota environment to biota at different trophic levels, and may eventually enter human body. Thirteen biological samples from different species were collected from Zhalong Wetland and treated by Soxhlet extraction, and Dechloranes were analyzed by using GC/MS. The results indicated that DP and Mirex were detected in biota at different trophic levels, but Dec 602, Dec 603, Dec 604 were below detection limit. Then we study the bioaccumulation by the concentration of the stable isotopesδ15N‰as nutrition level evaluation standard. The results showed that syn-DP, anti-DP, and Mirex can biological accumulate, and the bioaccumulation abilities and concentration levels of these chemicals follow the trend of birds > fish > arthropods > benthic animals > algae microorganisms > plants.The trophic magnification factors(TMF) of syn-DP, anty-DP, andΣDP were 2.31, 3.27, 3.14, respectively. The concentration of Mirex has no significant correlation (p > 0.15) with the trophic level. The bioaccumulation of DP in biota in Zhalong wetland was affected by food chain and the specific growth habit and feeding of different species as well.