摘要
柘林湾是广东养殖规模最大的海湾之一,其海水养殖污染问题日益突出。本文通过对柘林湾表层沉积物中OCPs的含量,评价了柘林湾沉积物的生态风险,分析了沉积物中HCHs和DDTs的来源。本文采用沉积物质量标准(SQG)和商值法(RQ),通过采用OCPs的测定浓度与表征污染物危害的ERM相比,计算柘林湾沉积物中OCPs的风险商RQERM,进而对毒害污染物进行风险评价。Fig.1为柘林湾表层沉积物的生态风险程度分布图,在靠近湾口和网箱养殖区的位点,OCPs具有强烈的负面生态风险影响,需采取严格措施降低风险;靠近牡蛎养殖区的4个位点OCPs具有中度负面生态风险影响,需要限制风险;航道及湾口的5个位点的OCPs存在低生态风险影响。沉积物样品中HCHs的α-HCH/γ-HCH的比值都接近1,说明该海湾沉积物中除未检出HCHs的位点,均有林丹类农药的使用,没有新的工业品HCHs输入。近岸位点和湾口处DDT/(DDD+DDE)>1,表明这些区域均有新的DDT输入该水域;而湾内养殖区附近位点(DDD+DDE)/DDTs>0.5,DDD/DDE都超过1,说明这些位点DDT可能主要来自早期残留或是施用农药长期风化后的沉积物。
The ecological risk of 20 OCPs in surface sediments of Zhelin Bay has been evaluated by risk quotient(RQ) and sediment quality guideline of NOAA and the possible sources of HCHs and DDTs in sediments were preliminary discussed.There were inevitable adverse biological effects and high ecological risk of p,p'-DDD and p,p'-DDT,high integrated ecological risk at S8 and S10.The possible sources of HCHs in surface sediments of Zhelin Bay were mainly from the application of Lindane pesticides.At the sites of waterways and outlet of bay,there were the input of DDT into Zhelin bay;and at the sites nearby mariculture areas,the sources of DDT were from the early residue in sediments or the long-term weathering sediments of using pesticides.
引文
[1]Hu G C.;Luo X J.;Li F C.;Dai J Y.Journal of Environmental Sciences,2010,22(2):176.
[2]Long E R.;Ingersoll C G.;Mac Donald D D.Environmental Science and Technology,2006,40(6):1726.