海洋环境影响评价中溶解氧评价方法的改进初探:以官井洋为例

摘要

2014年官井洋增养殖区溶解氧含量在4.24～8.62 mg/L之间,平均值为6.70 mg/L,在夏季形成低氧环境(＜5 mg/L),使得鲍鱼在养殖中受到溶解氧影响,虽影响不大(溶解氧标准指数不超过1.5),应引起重视.水温对全年溶解氧含量变化起到主要因素.海洋环境影响评价中溶解氧评价方法的改进:1)首先在《环境影响评价技术导则地面水环境》 (HJ/T 2.3-1993)中饱和溶解氧含量计算公式基础上增加盐度影响因子,统一饱和溶解氧含量的计算方法;2)并针对现有评价方法存在赋值不正常以及结果无法描述实际情况等的不足,在建议修改《海水水质标准》中溶解氧的分类范围的基础上,提出新的溶解氧标准指数算法,并将取样层次内所有(或特定)生物安全生存的溶解氧浓度作为溶解氧评价标准.%The concentration of dissolved oxygen (DO) in the culture area of the Guanjingyang Bay is from 4.24 mg/L to 8.62 mg/L,with the average value of 6.70 mg/L.The low DO concentration (＜5 mg/L) arises in summer,which could affect the cultivation of abalone with the standard index of DO less than 1.5.The temperature of seawater is the main influencing factor for the change of dissolved oxygen.The authors first added the salinity as the influence factor to calculate the saturated concentration of DO based on the formula in the technical guidelines for environmental impact assessment (HJ/T 2.3-1993).As for the problems about the pollution index of DO,such as the abnormal values or the normal value not according with the reality,we made a new equation for computing the standard index of DO with the safe concentration of DO for all (or specific) marine organisms as the assessment standard concentration of DO in the sampling layer.