东莞市农业土壤多环芳烃污染及其空间分布特征研究

选取位于珠江三角洲的东莞市为研究区域, 采集 59 个代表性表层农业土壤样品, 分析了16 种优控 PAHs 的含量。结果显示, 13 种 PAHs 检出率均在 90% 以上, 其中Fle, Phe, Chr 和 Bbf 的检出率为 100% , Ant 的检出率最低(13.56%)。6 PAHs 介于 29 ～2184 μg/ kg 之间, 远超出土壤内源性 PAHs 含量, 分别有44. 07% , 8. 47% 和 3. 39% 的土壤样品达到了PAHs 的轻、中、重度污染水平。主成分分析及源解析结果表明, 该市农业土壤 PAHs 主要有燃烧源、石油源和煤燃烧源 3 个主要来源。与国内其他地区相比, 东莞市农业土壤 PAHs 含量处于相对较高的水平。还对可能影响 PAHs 环境行为的因素进行了分析, 认为环境因素( 温度、湿度、光照) 、土壤性质( pH 值、有机质含量) 以及其他污染物(重金属) 均会对 PAHs 环境行为产生影响。采用克里格插值法对东莞市农业土壤 PAHs 的空 间分布特征进行了分析, 发现不同PAHs 组分的空间分布差别很大, 总体上该市西北部土壤 PAHs 含量较高, PAHs异常的富集中心在东莞市望牛墩镇附近, 该区域可能存在一些有毒废物焚烧污染源。

PAHs Pollution and Spatial Distribution in Agricultural Soils of Dongguan

Investigation on PAHs in agricultural soils in Dongguan, South China were conducted. A total of 59 agricultural soil samples were collected from sites representative of the region for analysis of contents of 16 PAHs. Results show that 13 PAHs were detected with detectable ratios above 90% , Fle, Phe, Chr and Bbf were detected in all 59 samples, the detectable ratio of Ant was the lowest ( 13.56% ) . ∑PAHs in soil samples is ranged from29 to 2184 μg/ kg, and 44.07%, 8.47% and 3. 39% soilsamples were slightly, moderately and heavily polluted by PAHs, respectively. Compared with other regions, Dongguan city is higher in soil PAHs contents, which can be confirmed that the increase of PAHs in agricultural soils is connected with human activities closely. Principal component analysis demonstrate that the above-said 16 PAHs in agricultural soils may have three major contributors, corresponding to biomass burning, volatilization of oil production, and coal burning respectively. It is found that environmental factors (temperature, humidity), soil characters ( pH, organic materials) and other pollutants( heavy metals) can affect environmental behaviors of PAHs. By means of ordinary Kriging interpolation, spatial distribution of 16 PAHs were studied. The results indicate that 16 PAHs vary greatly in spatial distribution between types, PAHs contents in west-north soils are much higher than that in south-east soils, and the highest PAHs contents area is in Wangniudun town, which hint that there are some pollutant sources connected with poisonous wastes combustion.