辽东湾近岸表层海水重金属污染分析与评价

Evaluation of Heavy Metal Pollution in the Offshore Surface Seawater of the Liaodong Bay

中文关键词: 辽东湾  环境质量  重金属

英文关键词: Liaodong Bay  Environmental quality  Heavy metals

中文摘要:

      根据2013年春季、夏季和秋季对辽东湾近岸表层海水重金属的调查数据，分析了该调查区域海水重金属浓度的季节变化，并运用内梅罗(Nemerow)指数法和综合质量指数法对该海域海水重金属污染状况进行了综合评价。结果显示，辽东湾调查海域表层海水中重金属浓度夏季最高，仅Pb超过第一类海水水质标准，且Pb的站位超标率为66.67%。按照美国国家海洋与大气管理局(National Oceanic and Atmospheric Administration, NOAA)推荐的海水中重金属生物慢性安全浓度下限，仅Cu在个别站位的浓度高于NOAA推荐的生物慢性安全浓度下限，其余所有元素的浓度均未超出，不会对生物体产生显著影响。内梅罗指数法和综合质量指数法评价结果显示，辽东湾调查海域属于清洁–轻污染等级，水环境分级属于尚清洁–允许级别，重金属污染较重的区域主要有3个，分别是绥中近岸海域、辽东湾北部河口区、复州湾和金州湾近岸海域。

英文摘要:

      Human activities have aggravated the offshore ecologic environment in the Liaodong Bay and endangered aquatic bioresources in these areas. The Liaodong Bay used to be an important fishing ground and the habitat of a variety of fish species such as Larimichthys polyactis, Trichiurus lepturus, and Fenneropenaeus chinensis. However, in recent years the fish resources have been diminishing because of water pollution, over-fishing and other human activities. Sustainable development is the key to healthy marine economy, which depends on good marine ecological environment. In this study we evaluated the offshore surface water quality of the Liaodong Bay by analyzing 18 samples collected in three consecutive seasons in 2013 including May (spring), August (summer), and October (autumn). We monitored the concentrations of six typical metallic pollutants (Cu, Pb, Zn, Cd, Hg, As) and employed the Nemerow Pollution Index and the Comprehensive Quality Index to evaluate the degree of heavy metal pollution. The concentrations of these heavy metals were highest in summer. The concentration of Pb did not meet the first-class seawater standard, which was 66.67% higher than the limit, however, all others complied with the first-class seawater standard. Concentrations of all heavy metals were below chronic safe concentration of organisms recommended by National Oceanic and Atmospheric Administration (NOAA) except for Cu. The Nemerow Pollution Index of the offshore surface seawater of the Liaodong Bay was in the range of 0.43-2.37, which was lower than 2.6, thus the pollution degree in 2013 was determined to be clean to slightly polluted. The Comprehensive Quality Index was between 0.39-0.97, which was lower than 1.0, therefore the water environment was acceptable and ranked as clean to slight clean. There were three areas that were relatively heavily polluted, including the Suizhong offshore area, north of the Liaodong Bay estuary area, and the Fuzhou Bay and Jinzhou Bay offshore areas.