冷排水中余氯对虾类毒理效应和资源损失量估算方法研究

Toxicological Effects on Shrimp of Residual Chlorine from Cooling Water Discharge and the Estimation Method of Fishery Resources Loss

在实验室条件下模拟某LNG工程冷排水中的余氯排放，并通过毒理实验研究海洋中余氯对南美白对虾（PenaeusvannameiBoone，1931）幼体的毒理效应。结果表明，南美白对虾幼体在设定的0．00、0．02、0．08、0．14、0．20，0．26mg／L浓度条件下，存活率分别为1D0％、100％、88．89％、61．25％、56．25％、20．83％，表现出存活率随着余氯浓度的升高而降低的趋势，得到其拟合趋势线为Y=-2．7257x2＋3．2307X＋101．24。根据余氯扩散场预测数模，0．01、0．05、0．10mg／L3个余氯浓度的最大扩散面积分别为0．248、0．047、0．010km2，内插值法求出水体中对应的虾类幼体的致死率分别为0．00％、5．56％、20．32％。结合渔业资源损失评估公式W=DXVXM估算，该LNG工程余氯排放对临近海域幼虾的损失量为0．583×10^3ind。2010年9月调查数据表明，该海域幼虾的尾数密度为9．17×103ind／km2，远低于2009年同期该海域调查所得虾类幼体的尾数密度125．41×103ind／km2。但根据调查资料，2010年9月该海域调查所得的虾类幼体比（7．76％）远低于2009年9月（69．38％）。由此推测，该海域2010年9月虾类幼体数量显著减少并不是佘氯排放引起的。

In the laboratory, residual chlorine releasing from cooling water discharge of an LNG project was simulated, and a series of experiments of toxicological effects on Penaeus vannamei larvae were conducted. Results showed that the survival rates of larvae were 100%, 100%, 88.89%, 61.25%, 56.25% and 20.83% when the residual chlorine contents were at levels of 0.00, 0.02, 0.08, 0.14, 0.20 and 0.26 mg/L, respectively. The survival rates tended to decline with an increase of the chlorine concentration by fitting the curve of y = -2.7257 x2 ＋ 3.2307 x ＋ 101.24. According to a diffusion model, areas in which residual chlorine concentrations in water were 0.01,0.05 and 0.10 mg/L would cover maxima of 0.248, 0.047 and 0.010 km2 by diffusion, and mortalities of the larvae would correspondingly be 0.00%, 5.56% and 20.32%, respectively, based on an interpolation method. Combined with the evaluation formula W -D x V xM, the loss of shrimp larvae in the surrounding waters affected by residual chlorine discharge from the LNG project was estimated to be 0.583 × 10^3 individuals. In September of 2010, the average density of larvae was observed 9.17 ×10^3 individuals per square kilometre, far lower than 125.41 × 10^3 individuals per square kilometre in the same period of 2009. The surveys also showed that, however, the larvae accounted for only 7.76% in whole shrimp population in September of 2010, obviously far less than 69.38% observed in the same period of 2009. It seemed that the marked decline of shrimp larva population in 2010 was unlikely to be caused by the residual chlorine discharge from the LNG project.