State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences , Guangzhou, Guangdong 510640, China.
Environ Sci Technol. 2013;47(23):13395-403. doi: 10.1021/es403138p. Epub 2013 Nov 19.
Nineteen pairs of gaseous and surface seawater samples were collected along the cruise from Malaysia to the south of Bay of Bengal passing by Sri Lanka between April 12 and May 4, 2011 on the Chinese research vessel Shiyan I to investigate the latest OCP pollution status over the equatorial Indian Ocean. Significant decrease of α-HCH and γ-HCH was found in the air and dissolved water phase owing to global restriction for decades. Substantially high levels of p,p'-DDT, o,p'-DDT, trans-chlordane (TC), and cis-chlordane (CC) were observed in the water samples collected near Sri Lanka, indicating fresh continental riverine input of these compounds. Fugacity fractions suggest equilibrium of α-HCH at most sampling sites, while net volatilization for DDT isomers, TC and CC in most cases. Enantiomer fractions (EFs) of α-HCH and o,p'-DDT in the air and water samples were determined to trace the source of these compounds in the air. Racemic or close to racemic composition was found for atmospheric α-HCH and o,p'-DDT, while significant depletion of (+) enantiomer was found in the water phase, especially for o,p'-DDT (EFs = 0.310 ± 0.178). 24% of α-HCH in the lower air over the open sea of the equatorial Indian Ocean is estimated to be volatilized from local seawater, indicating that long-range transport is the main source.
于 2011 年 4 月 12 日至 5 月 4 日，“实验 1 号”科学考察船从马来西亚航行至孟加拉湾南部，途经斯里兰卡，采集了 19 对气体和气载海水以及表层海水样本，旨在调查赤道印度洋最新的有机氯农药污染状况。由于全球范围内数十年的限制，α-HCH 和γ-HCH 在空气中和溶解水中的含量显著减少。在斯里兰卡附近采集的水样中，检测到了相当高浓度的 p,p'-DDT、o,p'-DDT、反式氯丹（TC）和顺式氯丹（CC），表明这些化合物是由新鲜的大陆河流输入的。逸度分数表明，在大多数采样点，α-HCH 达到平衡，而 DDT 异构体、TC 和 CC 主要发生净挥发作用。通过测定空气和水样中 α-HCH 和 o,p'-DDT 的对映体分数（EFs），追踪这些化合物在空气中的来源。空气和水样中的大气 α-HCH 和 o,p'-DDT 为外消旋或接近外消旋组成，而水中（EFs = 0.310 ± 0.178）的（+）对映体明显耗尽，尤其是 o,p'-DDT。赤道印度洋开阔海域低空大气中约有 24%的 α-HCH 估计是从当地海水中挥发而来的，表明长距离传输是其主要来源。
