渤海中部海区水域夏季环境质量综合评价

Assessment of Environmental Water Quality in the Central Region of the Bohai Sea in Summer

中文关键词: 渤海中部  水质  环境质量评价  富营养化

英文关键词: Central region of Bohai Sea  Water quality  Environmental quality assessment  Eutrophication

中文摘要:

      基于2012 年夏季渤海中部海域21个站点的调查数据，采用内梅罗(Nemerow)指数、富营养指数(EI)和潜在富营养化法对渤海中部海域水体环境质量现状进行了评价。内梅罗指数评价结果显示，对参与评价的酸碱度、溶解氧、无机氮、活性磷酸盐、化学耗氧量、石油类、重金属(Cu、Zn、Pb、Cd、Hg和As)等12项指标而言，表层、10 m层、底层受污染站位比例分别为57.1%、33.3%、23.8%。表层海水石油类浓度超标率为57.1%，10 m层水体超标率为42.9%，底层水体超标率为14.3%，石油类是主要污染因素。从分布位置看，受污染站位主要集中在调查区域的西南部，中部海域水质等级较高。海水环境质量呈现出由沿岸水域向中央海盆逐渐升高的趋势。渤海中部海域无明显富营养化状态，除表层13号站位外，表层、10 m层、底层海水富营养状态指数法EI均小于1，表现为贫营养级水平。绝大部分海域氮磷比值高于Redfield比值，但未呈现富营养化水平，无机氮浓度升高，活性磷酸盐浓度降低，渤海中部水域营养盐结构由氮限制向磷限制转变，已经开始转变成磷限制中度营养状态。

英文摘要:

      Based on the investigation data from 21 sampling stations in the central region of the Bohai Sea in 2012, and by using Nemerow index, eutrophication index (EI), and potential eutrophication assessment model, an assessment was conducted on the environmental quality of water body in the Bohai Sea area. According to the Nemerow index assessment on the 12 indicators including pH, dissolved oxygen (DO), dissolved inorganic nitrogen (DIN), dissolved inorganic phosphorous (DIP), chemical oxygen demand (COD), total petroleum hydrocarbons (TPHs), Cu, Zn, Pb, Cd, Hg, and As, 57.1% of the surface water quality was at slight pollution level or more serious pollution level, 33.3% of the ten meter water quality was at slight and moderate pollution level, 23.8% of the bottom water quality was at slight or more serious pollution level. TPHs was the most important factor in all the contamination factors. Among the 21 surface sea water samples, 12 (corresponding to 57.1%) were above the second marine water quality standards when evaluated with single factor index method. The standard-exceeding rates of ten-meter water and bottom water were 42.9% and 14.3% respectively. The polluted area was located in the southeast of survey area, next to the Bohai Bay and the Laizhou Bay. The horizontal distribution of sea water quality showed an increasing trend from the coastal area to the middle area. The sea water EI value of the central region of the Bohai Sea except 13 stations in the surface water was less than 1, the results showed that most of the seawater quality in the investigated area was at the poorly eutrophication level. The ratios of N/P in most of the sea water were much higher than Redfield ratios, and the situation of nitrogen limiting in the central Bohai Sea was gradually changing to that of relative lack of phosphate. The nutrients structure has changed into potential eutrophication of phosphorus limiting.