黄河三角洲自然保护区土壤PAHs的风险评估和空间特征

Risk Assessment and Spatial Characteristics of PAHs in Soils in the Yellow River Delta Nature Reserve

黄河三角洲自然保护区在经济和生态上的作用越来越重要,该地区的生态环境也不断发生着变化。为了解黄河三角洲国家级自然保护区内土壤PAHs的含量、分布及风险状况,更好地保护和治理环境,在保护区不同功能区内设置71个点位,采集0—10 cm土壤测定16种优控PAHs的含量并结合效应区间低、中值法和各PAHs单体致癌斜率因子参数评估法评价其生态风险和健康风险,探究土壤PAHs的空间分布状况。结果表明:研究区域PAHs污染水平相对较低,16种优控PAHs的检出率为100%,其含量介于10.92—125.98 ng·g^(−1),远低于效应区间低值,潜在生态风险水平极低。利用各PAHs单体致癌斜率因子参数进行健康风险评价,结果显示区域内成人和儿童的致癌风险值为1.14×10^(−6)—1.23×10^(−6),略大于健康管控值(1.0×10^(−6)),表明存在潜在致癌风险。利用Kriging插值法分析空间格局,PAHs的块基比为0.59,为中等空间相关性,呈现北高南低的趋势;而健康风险值的块基比为0.88>0.75,空间相关性弱,其中南部地区的健康风险最低。研究区域PAHs污染水平相对较低,潜在生态风险水平极低,但存在潜在致癌风险。因此要注意对河三角洲自然保护区PAHs致癌风险的监测。结合空间分布图可以看出PAHs含量和PAHs健康风险值空间分布特征相似,说明PAHs的致癌风险与其含量呈正比关系。该研究对于黄河三角洲国家级自然保护区生态环境保护和治理具有重要的理论意义。

The content,distribution and risk status of PAHs in the soil from Yellow River Delta National Nature Reserve were investigated,in order to provide data support for environmental protection and management of this region.In different functional areas of the reserve,71 sampling sites were set up,and topsoil(0-10 cm)samples were collected.The contents of 16 priority PAHs were measured for risk assessment and spatial analysis.The results showed that the contents of 16 priority PAHs in soil ranged from 10.92 ng·g^(−1)to 125.98 ng·g^(−1),which were far lower than the smallest value of effect range,and indicated that the potential ecological risk level of 16 priority PAHs in this region was extremely low.The carcinogenic slope factor of single PAHs was used to evaluate the health risk.The carcinogenic risk values of adults and children in the region ranged from 1.14×10^(−6)to 1.23×10^(−6),which were slightly higher than the health control value(1.0×10^(−6)),indicating the potential carcinogenic risk.Furthermore,Kriging interpolation method was used to analyze the spatial distribution.The nugget-to-sill ratio of PAHs was 0.59,showing a moderate spatial correlation and a trend of high content in the north and low content in the south.The nugget-to-sill ratio of health risk value was 0.88,which was greater than 0.75,showing a weak spatial correlation.The health risk in the southern region was the lowest.The PAHs pollution level in the study area was relatively low,and their potential ecological risk level was extremely low,but there was a potential carcinogenic risk of PAHs.This study was important for the ecological environment protection and management of the Yellow River Delta National Nature Reserve.