Historical Record and Flux of DDTs and PCBs to the Palos Verdes Shelf Superfund Site,California
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- 英文论文题名：Historical Record and Flux of DDTs and PCBs to the Palos Verdes Shelf Superfund Site,California
- 论文作者：Chunyang Liao ; Allison R.Taylor ; Jay Gan
- 英文论文作者：Chunyang Liao ; Allison R.Taylor ; Jay Gan ; State Key Laboratory of Environmental Chemistry and Ecotoxicology ; Research Center for Eco-Environmental Sciences ; Chinese Academy of Sciences ; Department of Environmental Sciences ; University of California
- 年：2016
- 作者机构：State Key Laboratory of Environmental Chemistry and Ecotoxicology,Research Center for Eco-Environmental Sciences,Chinese Academy of Sciences;Department of Environmental Sciences,University of California;
- 英文论文关键词：Palos Verdes Shelf ; Sediment Core ; DDTs ; PCBs ; Temporal Trend
- 会议召开时间：2016-07-01
- 会议录名称：中国化学会第30届学术年会摘要集-第二十六分会：环境化学
- 语种：英文
- 分类号：X55;X592
- 学会代码：ZGHY
- 会议名称：中国化学会第30届学术年会-第二十六分会 ; 环境化学
- 会议地点：中国辽宁大连
- 主办单位：中国化学会
- 学会名称：中国化学会
- 页数：1
- 文件大小：171k
- 原文格式：D
- 会议级别：全国
摘要
Marine sediments at many locations in the world are contaminated with a wide range of persistent organic pollutants.The Palos Verdes Shelf(PVS) is located in the ocean off the coast of Los Angeles,California and has been proposed as a Superfund site by the US EPA since 1997,because of heavy contamination of DDTs and PCBs.Nevertheless,little is known about the magnitude of DDTs and PCBs contamination in the PVS Superfund site or historical trend and associated risks as a result of wastewater discharge of these contaminants.In this study,sediment cores were taken from the PVS site and determined for DDT and its metabolites including DDE and DDD(denoted as DDTs) and selected PCBs.Individual DDTs were found in the majority(95%) of the samples analyzed,and the highest ΣDDTs(sum of o,p'-and p,p'-DDTs,DDEs,DDDs;geometric mean:31300,median:82400 ng/g dry weight(dw)) was found in sediment samples from the core 8C,followed by that found for the core 7.5C(7490,17300 ng/g dw) and 6C(5010,5200 ng/g dw).Among DDT congeners,p,p'-DDE,o,p'-DDE and p,p'-DDD were predominant,contributing to approximately 54%,27%,and 14% of the ΣDDTs in sediment.Comparably,the concentrations and detection frequency of PCBs were notably lower.The sediment cores were dated by 210 Pb with measuring the unsupported and supported 210 Pb activities and the vertical profiles of concentrations of contaminants in the sediment cores were examined.The core 8C showed a steady increase in the concentrations of DDTs and PCBs during 1940 s to 1980 s,and the concentrations declined gradually in the surficial layers.Similar trend was found for other sediment cores with the exception of the core 3C,for which a much sharper peak in sections from the 1940-1960 s was exhibited.On the basis of the mass flux of DDTs calculated and the area of the PVS Superfund site,we estimated the total deposition amount of DDTs in sediment and the deposition amount of ΣDDTs in this region during 1947-1971 was 132 tons.The deposited DDTs in sediment can be released to surrounding water column,bioaccumulated by invertebrates and microorganisms that live within or above the sediment,and transported to other areas.In view of these,the deposition amount of ΣDDTs estimated in the present study is consistent with that(870-1450 tons) reported in earlier studies for industrial wastewater discharge in the PVS site.Our findings suggest that the elevated levels of DDTs and PCBs in sediment from the PVS site are linked to the discharge of these contaminants between the 1940s-1980 s.
Marine sediments at many locations in the world are contaminated with a wide range of persistent organic pollutants.The Palos Verdes Shelf(PVS) is located in the ocean off the coast of Los Angeles,California and has been proposed as a Superfund site by the US EPA since 1997,because of heavy contamination of DDTs and PCBs.Nevertheless,little is known about the magnitude of DDTs and PCBs contamination in the PVS Superfund site or historical trend and associated risks as a result of wastewater discharge of these contaminants.In this study,sediment cores were taken from the PVS site and determined for DDT and its metabolites including DDE and DDD(denoted as DDTs) and selected PCBs.Individual DDTs were found in the majority(95%) of the samples analyzed,and the highest ΣDDTs(sum of o,p'-and p,p'-DDTs,DDEs,DDDs;geometric mean:31300,median:82400 ng/g dry weight(dw)) was found in sediment samples from the core 8C,followed by that found for the core 7.5C(7490,17300 ng/g dw) and 6C(5010,5200 ng/g dw).Among DDT congeners,p,p'-DDE,o,p'-DDE and p,p'-DDD were predominant,contributing to approximately 54%,27%,and 14% of the ΣDDTs in sediment.Comparably,the concentrations and detection frequency of PCBs were notably lower.The sediment cores were dated by 210 Pb with measuring the unsupported and supported 210 Pb activities and the vertical profiles of concentrations of contaminants in the sediment cores were examined.The core 8C showed a steady increase in the concentrations of DDTs and PCBs during 1940 s to 1980 s,and the concentrations declined gradually in the surficial layers.Similar trend was found for other sediment cores with the exception of the core 3C,for which a much sharper peak in sections from the 1940-1960 s was exhibited.On the basis of the mass flux of DDTs calculated and the area of the PVS Superfund site,we estimated the total deposition amount of DDTs in sediment and the deposition amount of ΣDDTs in this region during 1947-1971 was 132 tons.The deposited DDTs in sediment can be released to surrounding water column,bioaccumulated by invertebrates and microorganisms that live within or above the sediment,and transported to other areas.In view of these,the deposition amount of ΣDDTs estimated in the present study is consistent with that(870-1450 tons) reported in earlier studies for industrial wastewater discharge in the PVS site.Our findings suggest that the elevated levels of DDTs and PCBs in sediment from the PVS site are linked to the discharge of these contaminants between the 1940s-1980 s.
Marine sediments at many locations in the world are contaminated with a wide range of persistent organic pollutants.The Palos Verdes Shelf(PVS) is located in the ocean off the coast of Los Angeles,California and has been proposed as a Superfund site by the US EPA since 1997,because of heavy contamination of DDTs and PCBs.Nevertheless,little is known about the magnitude of DDTs and PCBs contamination in the PVS Superfund site or historical trend and associated risks as a result of wastewater discharge of these contaminants.In this study,sediment cores were taken from the PVS site and determined for DDT and its metabolites including DDE and DDD(denoted as DDTs) and selected PCBs.Individual DDTs were found in the majority(95%) of the samples analyzed,and the highest ΣDDTs(sum of o,p'-and p,p'-DDTs,DDEs,DDDs;geometric mean:31300,median:82400 ng/g dry weight(dw)) was found in sediment samples from the core 8C,followed by that found for the core 7.5C(7490,17300 ng/g dw) and 6C(5010,5200 ng/g dw).Among DDT congeners,p,p'-DDE,o,p'-DDE and p,p'-DDD were predominant,contributing to approximately 54%,27%,and 14% of the ΣDDTs in sediment.Comparably,the concentrations and detection frequency of PCBs were notably lower.The sediment cores were dated by 210 Pb with measuring the unsupported and supported 210 Pb activities and the vertical profiles of concentrations of contaminants in the sediment cores were examined.The core 8C showed a steady increase in the concentrations of DDTs and PCBs during 1940 s to 1980 s,and the concentrations declined gradually in the surficial layers.Similar trend was found for other sediment cores with the exception of the core 3C,for which a much sharper peak in sections from the 1940-1960 s was exhibited.On the basis of the mass flux of DDTs calculated and the area of the PVS Superfund site,we estimated the total deposition amount of DDTs in sediment and the deposition amount of ΣDDTs in this region during 1947-1971 was 132 tons.The deposited DDTs in sediment can be released to surrounding water column,bioaccumulated by invertebrates and microorganisms that live within or above the sediment,and transported to other areas.In view of these,the deposition amount of ΣDDTs estimated in the present study is consistent with that(870-1450 tons) reported in earlier studies for industrial wastewater discharge in the PVS site.Our findings suggest that the elevated levels of DDTs and PCBs in sediment from the PVS site are linked to the discharge of these contaminants between the 1940s-1980 s.
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