TY - JOUR
T1 - Field Validation of Anaerobic Degradation Pathways for Dichlorodiphenyltrichloroethane (DDT) and 13 Metabolites in Marine Sediment Cores from China
AU - Yu, Huan Yun
AU - Bao, Lian Jun
AU - Liang, Yan
AU - Zeng, Eddy Y.
N1 - The present study was financially supported by the Natural Science Foundation of Guangdong Province (No. 9251064004000002), the Ministry of Science and Technology of China (No. 2007AA06Z410), and the National Natural Science Foundation of China (No. 40821003). We are also grateful to Ru-Lang Shen, Bao-Zhong Zhang, Yan-Li Wei, Kai Zhang and Ye-Tian Li for sample collection and Xiao-Min Lin for laboratory support. This is contribution No. IS-1337 from GIGCAS.
Publisher copyright:
© 2011 American Chemical Society
PY - 2011/6/15
Y1 - 2011/6/15
N2 - Although the production and use of dichlorodiphenyltrichloroethane (DDT), a legacy component of persistent organic pollutants, have been highly restricted worldwide, the environmental fate of DDT has remained a great concern as it is not only ubiquitous and bioaccumulative but can also be degraded to a series of metabolites that may be more hazardous ecologically. The present study, taking advantage of the abundant levels of DDT and its metabolites in a subtropical coastal region of China, investigated into the degradation pathways of DDT in natural coastal sediment. Sediment profiles indicated that degradation of 1,1,1-trichloro-2,2-bis-(p-chlorophenyl)ethane (p,p?-DDT) to 1,1-dichloro-2,2-bis-(p-chlorophenyl)ethane (p,p?-DDD) mainly occurred in sediment of the top 20 cm layer. 1,1-dichloro-2,2-bis-(p-chlorophenyl)ethylene (p,p?-DDE), aerobically transformed from p,p?-DDT prior to sedimentation, was likely to degrade to 1-chloro-2,2-bis-(p-chlorophenyl)ethylene (p,p?-DDMU) which was further converted to 2,2-bis(p-chlorophenyl)ethylene (p,p?-DDNU). In addition, p,p?-DDNU could be transformed to 2,2-bis(p-chlorophenyl)ethane (p,p?-DDNS) and other high-order metabolites. On the other hand, the conversions of p,p?-DDD to p,p?-DDMU and 1-chloro-2,2-bis-(p-chlorophenyl)ethane (p,p?-DDMS) to p,p?-DDNU were deemed slow in anaerobic sediment. Therefore, the present study confirmed all the degradation pathways involving reductive dechlorination and p,p?-DDE being a more important precursor for p,p?-DDMU than p,p?-DDD in anaerobic sediment, as proposed previously. On the other hand, the present study suggested that p,p?-DDMU instead of p,p?-DDMS was more likely the precursor for formation of high-order metabolites. Based on the current assessments, use of (DDD+DDE)/DDTs to indicate whether there is fresh DDT input may lead to large uncertainties if the concentrations of high-order metabolites are not negligible. Similarly, ecological risk assessment associated with DDT should be conducted with consideration of high-order DDT metabolites.
AB - Although the production and use of dichlorodiphenyltrichloroethane (DDT), a legacy component of persistent organic pollutants, have been highly restricted worldwide, the environmental fate of DDT has remained a great concern as it is not only ubiquitous and bioaccumulative but can also be degraded to a series of metabolites that may be more hazardous ecologically. The present study, taking advantage of the abundant levels of DDT and its metabolites in a subtropical coastal region of China, investigated into the degradation pathways of DDT in natural coastal sediment. Sediment profiles indicated that degradation of 1,1,1-trichloro-2,2-bis-(p-chlorophenyl)ethane (p,p?-DDT) to 1,1-dichloro-2,2-bis-(p-chlorophenyl)ethane (p,p?-DDD) mainly occurred in sediment of the top 20 cm layer. 1,1-dichloro-2,2-bis-(p-chlorophenyl)ethylene (p,p?-DDE), aerobically transformed from p,p?-DDT prior to sedimentation, was likely to degrade to 1-chloro-2,2-bis-(p-chlorophenyl)ethylene (p,p?-DDMU) which was further converted to 2,2-bis(p-chlorophenyl)ethylene (p,p?-DDNU). In addition, p,p?-DDNU could be transformed to 2,2-bis(p-chlorophenyl)ethane (p,p?-DDNS) and other high-order metabolites. On the other hand, the conversions of p,p?-DDD to p,p?-DDMU and 1-chloro-2,2-bis-(p-chlorophenyl)ethane (p,p?-DDMS) to p,p?-DDNU were deemed slow in anaerobic sediment. Therefore, the present study confirmed all the degradation pathways involving reductive dechlorination and p,p?-DDE being a more important precursor for p,p?-DDMU than p,p?-DDD in anaerobic sediment, as proposed previously. On the other hand, the present study suggested that p,p?-DDMU instead of p,p?-DDMS was more likely the precursor for formation of high-order metabolites. Based on the current assessments, use of (DDD+DDE)/DDTs to indicate whether there is fresh DDT input may lead to large uncertainties if the concentrations of high-order metabolites are not negligible. Similarly, ecological risk assessment associated with DDT should be conducted with consideration of high-order DDT metabolites.
UR - http://www.scopus.com/inward/record.url?scp=79959247050&partnerID=8YFLogxK
U2 - 10.1021/es2006397
DO - 10.1021/es2006397
M3 - Journal article
C2 - 21595473
AN - SCOPUS:79959247050
SN - 0013-936X
VL - 45
SP - 5245
EP - 5252
JO - Environmental Science and Technology
JF - Environmental Science and Technology
IS - 12
ER -
