海洋疏浚物对连云港局部海域生态环境的影响评价

为考察海洋疏浚物对海域生态环境的影响,2014年3月对连云港倾倒区及附近海域17个站位的水质和11个站位的沉积物以及海洋生物进行了调查采样。调查将所研究海域划分为倾倒区、倾倒外围区、养殖区,对这3个区域的水质、沉积物中污染物等指标的水平差异及浮游植物、浮游动物、底栖生物的群落现状和差异进行了分析,在此基础上全面评价了海洋疏浚物对该海域生态环境的影响。结果表明:(1)海水和沉积物中重金属含量的分布特征为倾倒区倾倒外围区养殖区,疏浚物为倾倒区重金属的重要污染源,且在扩散作用下对倾倒外围区海域有一定影响;(2)各海区间叶绿素a和浮游植物多项指标差异不大,倾倒活动对浮游植物的影响尚不明显;(3)海区间底栖动物群落组成差异性大,倾倒区底栖动物种类、密度、多样性指数等降低,表明倾倒活动可能导致环境变化从而对底栖动物产生了显著的负面作用。

Evaluation of the impact of ocean dredged materials upon the ecology and environment in certain Lianyungang sea areas

To explore the impact of dredged materials upon the marine ecological environment, surveys of water quality, sediments and marine organisms were conducted respectively at seventeen sites in Lianyungang dumping area and nearby waters in March, 2014. For the sake of study the sea area was divided into dumping zone, external dumping zone and mariculture zone. Marine pollutants and biological indicators of the three zones were compared in pairs with an aim to explore the status quo of phytoplankton, zooplankton and benthic communities and the differences in between. Hence a more comprehensive evaluation can be made over the impact of dredged materials upon the marine ecological environment. The survey results were presented as follows: (1)Dredged materials constituted the major source of heavy metals in the dumping zone, and exerted influence upon the external dumping zone under the diffusion effect. The heavy metals content in seawater and sediments ranked as dumping zone>external dumping zone>mariculture zone. (2) Indicators like chlorophyll a and phytoplankton did not differ much among the three zones, which implied that phytoplankton were not seriously affected by dredging activities. (3) By comparison the benthos in dumping zone displayed fewest species, relatively lower habitat density and biodiversity index, which indicated the obvious change in ecological environment and apparent negative impact from dredged materials in the zone.