辽东湾优先控制污染物的筛选

辽东湾是我国重要沿海经济区,多年来承载着沿海地区排放的大量污染物,近岸海域重金属和有机物污染较为严重。基于辽东湾2016—2018年近岸海域水体12种污染物的监测数据,采用综合评分法和潜在危害指数法筛选优先控制污染物。结果表明:12种污染物的综合评分为29.4~83.2分,其中Hg和Cd(均为83.2分)、Pb(75.8分)为Ⅰ级污染物,Cu(68.4分)、Cr(63.2分)和As(60.8分)为Ⅱ级污染物;12种污染物的潜在危害指数总分为4~22分,其中Cd(22分)、Cu和As(均为20分)为Ⅰ级污染物,Hg、Cr和Pb(均为19分)为Ⅱ级污染物。综合2种筛选方法,考虑到2种方法筛选出的共同Ⅰ级污染物为Cd,目前辽东湾Hg、Pb、Cr、As和Cu的平均检出浓度分别为0.04、2、7.1、1.8、3.8 μg/L,而对应的美国国家环境保护局推荐水质基准连续浓度分别为0.94、5.6、50、36、3.1 μg/L,仅Cu超过了水质基准连续浓度,同时辽东湾Cu平均浓度(3.8 μg/L)远高于保护95%的水生生物物种的有害浓度定值(1.90 μg/L),因此,提出将Cd、Cu纳入辽东湾优先控制污染物名单。

Screening of priority pollutants in Liaodong Bay

Liaodong Bay is an important coastal economic zone in China and has carried a large number of pollutants discharged from coastal areas for many years. Heavy metal and organic pollution are serious in coastal waters. The composite scoring method and potential risk index method were used to screen the priority pollutants based on the 12 pollutants of water quality monitoring data in the coastal waters of Liaodong Bay in 2016-2018. The results showed that the total score of the 12 pollutants using the composite scoring method was 29.4-83.2. There were three types of class Ⅰ pollutants, including Hg (83.2), Cd (83.2) and Pb (75.8), and there were three categories of class Ⅱ pollutants, namely Cu (68.4), Cr (63.2) and As (60.8). The results of potential risk index method ranged from 4 to 22. There were three types of class Ⅰ pollutants, including Cd (22), Cu (20) and As (20), and there were three categories of class Ⅱ pollutants, including Hg (19), Cr (19) and Pb (19). Combining the two grading methods, considering that the common primary pollutant screened by the two methods was Cu and the average detected concentrations of Hg, Pb, Cr, As and Cu in Liaodong Bay was 0.04, 2, 7.1, 1.8, 3.8 μg/L, respectively, while the corresponding water quality criterion continuous concentration recommended by US EPA was 0.94, 5.6, 50, 36, 3.1 μg/L, respectively, only Cu exceeded the water quality criterion continuous concentration. At the same time, the average concentration of Cu (3.8 μg/L) in Liaodong Bay was much higher than the set value of harmful concentration (1.90 μg/L) that protected 95% aquatic species. Therefore, Cd and Cu were proposed to be included in the list of priority pollutants for control in Liaodong Bay.