近岸海域水质污染因子空间特征和来源研究——以浙南瑞安市近岸海域为例

近岸海域的环境污染特征和污染来源是区域海洋环境保护的两大关键问题。以浙南瑞安市近岸海域为例,于2020年5月开展16个站位的海洋环境调查和表层海水采样,通过室内分析测试,共获得12项水质参数(盐度、溶解氧、化学需氧量、无机氮、活性磷酸盐、汞、镉、铅、铬、砷、锌、铜)数据,采用污染评价、多元数理统计分析(通过SPSS实现)及空间异质性分析(通过ArcGIS实现)等方法,较深入地探究了瑞安市近岸海域环境污染的空间特征和污染来源。研究结果表明,瑞安市近岸海域水质总体情况良好,各水质参数变异系数较大,部分海域的无机氮和活性磷酸盐明显超标。采用营养指数法进行评价,得到飞云江近口段和河口段的富营养化最严重;采用氮磷比法进行评价,得到北麂列岛周边海域发生赤潮灾害的风险更大。依据聚类分析结果,可将研究海域分为污染特征各异的4个区域。依据主成分分析结果,推测瑞安市近岸海域水体中营养盐、化学需氧量的主要污染源为农业,而重金属污染的可能来源为电镀、零件加工企业和船舶等。

规模化畜禽养殖污染的空间分布特征及减排潜力分析——基于吉林省松辽流域典型区

随着畜禽养殖业的发展,规模化养殖的环境影响日益突出,笔者基于2007年、2011年和2012年的污染源普查数据和环境统计数据,采用地理信息系统(GIS)对吉林省松辽流域典型地区的规模化畜禽养殖状况及污染的空间分布特征进行了研究,并在此基础上分析了污染物的减排潜力。结果表明:5年间研究区规模化畜禽养殖的数量逐年减少,但是畜禽养殖所产生的污染物排放量逐年增加。研究区内畜禽养殖污染主要分布在榆树市、九台区、桦甸市和双辽市,化学需氧量(COD)排放量增长速率最快的地区为舒兰县和磐石县,总氮(TN)排放量增长速率最快的地区是东丰县。污染物COD减排潜力较大的地区是梨树县,TN减排潜力较大的地区是双辽市和扶余市。

Source-sink landscape spatial characteristics and effect on non-point source pollution in a small catchment of the Three Gorge Reservoir Region

The source and sink landscape patterns refer to landscape types or units that can either promote positive evolvement of non-point source(NPS) pollution process, or can prevent/defer the ecological process, respectively. Therefore, the role of a catchment landscape pattern in nutrient losses can be identified based on the spatial arrangement of source and sink landscapes. To reveal the relations between landscape spatial characteristics and NPS pollution in small catchment, a case study was carried out in a Wangjiagou small catchment of the Three Gorges Reservoir Region(TGRR), China. Google earth imagery for 2015 were processed and used to differentiate source and sink landscape types, and six subcatchments were selected as sample regions for monitoring nitrogen and phosphorus nutrients.Relative elevation, slope gradient and relative flow length was used to construct the Lorenz curves of different source and sink landscape types in the catchment, in order to assess the source and sink landscape spatial characteristics. By calculating the location-weighted landscape indices of each subcatchment and total catchment, the landscape spatial load characteristics affecting the NPS pollution was identified, with a further Pearson correlation analysis for location-weighted landscape indices and nitrogen-phosphorus monitoring indicators. The analysis of Lorenz curve has revealed that the obtained distribution trend of Lorenz curve and curve area quantified well the spatial characteristics of source and sink landscape pattern related to the relative elevation, slope gradient and relative flow length in small catchment. Results of Pearson correction analysis indicated that location-weighted landscape index(LWLI) combining of terrain and landscape type factor did better in reflecting the status of nitrogen and phosphorus loss than the indices related to relative elevation, slope gradient and relative flow length.

长庆油田产油区周边农田重金属分布特征及生态风险评价

[背景]随着国家能源开发布局的变化,庆阳地区出现了石油开采和农业并重的局面,如果不引起重视,极易造成当地土壤污染。[目的]评价长庆油田主产区周边农田土壤重金属的分布特征、可能来源及生态风险。[方法]采集长庆油田主产区周边的庆阳市正宁县、镇原县、庆城县三县农田土壤样本60份,按GB15618—2018《土壤环境质量农用地土壤污染风险管控标准(试行)》的方法检测农田土壤重金属铅(Pb)、汞(Hg)、铬(Cr)、镉(Cd)、砷(As)的质量分数(后称:含量),以甘肃省土壤背景值作为计算污染指数的分母,采用单因子污染指数(P)法、内梅罗综合污染指数(P)法和潜在生态风险指数法评价农田土壤5种重金属的污染及生态特征。[结果]长庆油田周边农田土壤5种重金属中Pb、As、Hg以及庆城县Cr、Cd和正宁县Cd水平超过甘肃省土壤背景值,但均低于国家土壤环境质量标准。单因子污染指数(P)分别为Hg(2.14)、Pb(1.24)、As(1.13)、Cr(0.78)、Cd(0.67),提示Hg属于中污染,Pb和As属于轻污染,Cd和Cr为未污染状态;内梅罗综合污染指数(P)分别为Cr(0.92)、Cd(1.08)、As(1.20)、Pb(1.68)、Hg(3.85),提示Cr为尚清洁,Cd、Pb和As属于轻度污染,Hg属于重度污染。镇原县Hg、Cd和庆城县Hg含量值的变异系数分别为60.00%、50.00%和50.00%,均大于50%,提示所在地相应重金属的污染受人为影响较大。农田土壤中Pb、Cr、Cd、As和Hg 5种重金属潜在生态风险指数(E)分别为6.20、1.55、20.05、11.28和81.64,即Hg属于强生态风险水平,其余4种重金属属轻微生态风险水平;综合潜在生态风险(R)为124.48,结合Hg的潜在生态风险指数,认为当地农田土壤中5种重金属的综合潜在生态风险属强生态风险水平。[结论]长庆油田主产区农田土壤中5种重金属水平均值虽未超过国家土壤环境质量标准,但已超过甘肃省土壤相应元素的背景值,且存在人为影响的迹象和不同程度的潜在生态风险。