Aelion C Marjorie, Davis Harley T, McDermott Suzanne, Lawson Andrew B
University of South Carolina, Department of Environmental Health Sciences, 921 Assembly Street, Columbia, SC 29208, United States.
Sci Total Environ. 2008 Sep 1;402(2-3):149-56. doi: 10.1016/j.scitotenv.2008.04.043. Epub 2008 Jun 6.
Rural areas are often considered to have relatively uncontaminated soils; however few studies have measured metals in surface soil from low population areas. Many metals, i.e., arsenic (As), lead (Pb), and mercury (Hg), have well-documented negative neurological effects, and the developing fetus and young children are particularly at risk. Using a Medicaid database, two areas were identified: one with no increased prevalence of mental retardation and developmental delay (MR/DD) (Strip 1) and one with significantly higher prevalence of MR/DD (Strip 2) in children compared to the state-wide average. These areas were mapped and surface soil samples were collected from 0-5 cm depths from nodes of a uniform grid laid out across the sampling areas. Samples were analyzed for As, barium (Ba), beryllium (Be), chromium (Cr), copper (Cu), Pb, manganese (Mn), nickel (Ni), and Hg. Inverse distance weighting (IDW) was used to estimate concentrations throughout each strip area, and a principal component analysis (PCA) was used to identify common sources. All metal concentrations in Strip 2, the MR/DD cluster area, were significantly greater than those in Strip 1 and similar to those found in more urban and highly agricultural areas. Both Strips 1 and 2 had a high number of significant correlations between metals (33 for Strip 1 and 25 for Strip 2), suggesting possible similar natural or anthropogenic sources which was corroborated by PCA. While exposures were not assessed and direct causation between environmental soil metal concentrations and MR/DD cannot be concluded, the high metal concentrations in areas with an elevated prevalence of MR/DD warrants further consideration.
农村地区通常被认为土壤污染相对较少；然而，很少有研究测量过低人口密度地区表层土壤中的金属含量。许多金属，如砷（As）、铅（Pb）和汞（Hg），都有充分记录的对神经系统的负面影响，发育中的胎儿和幼儿尤其面临风险。利用医疗补助数据库，确定了两个区域：一个区域儿童智力迟钝和发育迟缓（MR/DD）的患病率没有增加（地带1），另一个区域儿童MR/DD的患病率明显高于全州平均水平（地带2）。绘制了这些区域的地图，并从横跨采样区域布置的均匀网格节点处采集了0-5厘米深度的表层土壤样本。对样本进行了砷、钡（Ba）、铍（Be）、铬（Cr）、铜（Cu）、铅、锰（Mn）、镍（Ni）和汞的分析。使用反距离加权法（IDW）估计每个地带区域内的浓度，并使用主成分分析（PCA）来识别共同来源。MR/DD聚集区地带2中的所有金属浓度均显著高于地带1中的浓度，且与在城市化程度更高和农业化程度更高的地区发现的浓度相似。地带1和地带2中的金属之间都有大量显著相关性（地带1为33个，地带2为25个），这表明可能存在类似的自然或人为来源，主成分分析证实了这一点。虽然未评估暴露情况，也无法得出环境土壤金属浓度与MR/DD之间的直接因果关系，但MR/DD患病率较高地区的高金属浓度值得进一步考虑。
