State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, PR China; Department of International Environmental and Agricultural Science (IEAS), Tokyo University of Agriculture and Technology (TUAT), 3-5-8, Saiwai-Cho, Fuchu-Shi, Tokyo 1838509, Japan.
Centre for Environmental Sciences, Central University of South Bihar, BIT Campus Patna, Bihar 800014, India.
Chemosphere. 2018 Jan;190:114-123. doi: 10.1016/j.chemosphere.2017.09.112. Epub 2017 Sep 25.
Despite soil being the major terrestrial environmental reservoir and one of the significant sinks for many hydrophobic organic compounds including organophosphate ester flame retardants (OPFRs), limited information is available about concentration and fate of OPFRs contamination in urban soil in general and especially in case of Nepal. This study investigates the environmental concentration, spatial distribution and source apportionment of eight OPFRs in surface soil (n = 28) from four major cities of Nepal with special interest on air-soil exchange. Overall, significantly high concentrations of ∑OPFR were measured in soil ranging from 25-27,900 ng/g dw (median 248 ng/g dw). In terms of compositional pattern, tris(methyl phenyl) phosphate (TMPP) was the most abundant phosphorus chemical in soil, followed by tris(2-chloroisopropyl) phosphate (TCIPP), and accounted for 35-49% and 8-25% of ∑OPFRs, respectively. The high level of these OPFRs was attributed to local sources as opposed to transboundary influence from remote areas. A Spearman's rank correlation analysis exhibited weak correlation of ∑OPFRs with TOC (Rho = 0.117, p < 0.05) and BC (Rho = 0.007, p < 0.05), suggesting little or no influence of TOC and BC on the concentration of ∑OPFRs. The fugacity fraction (ff) results indicated a strong influence of soil contamination on atmospheric level of OPFRs via volatilization.
尽管土壤是陆地环境的主要储库之一，也是许多疏水性有机化合物（包括有机磷酸酯阻燃剂（OPFRs））的重要汇之一，但关于 OPFRs 污染在城市土壤中的浓度和归宿的信息有限，一般来说，特别是在尼泊尔的情况下。本研究调查了尼泊尔四个主要城市表层土壤（n=28）中八种 OPFRs 的环境浓度、空间分布和来源分配，特别关注空气-土壤交换。总体而言，土壤中∑OPFR 的浓度非常高，范围从 25-27,900ng/g dw（中位数 248ng/g dw）。就组成模式而言，三（甲基苯基）磷酸酯（TMPP）是土壤中最丰富的磷化学物质，其次是三（2-氯异丙基）磷酸酯（TCIPP），分别占∑OPFRs 的 35-49%和 8-25%。这些 OPFRs 的高浓度归因于本地来源，而不是来自偏远地区的跨境影响。Spearman 等级相关分析显示，∑OPFRs 与 TOC（Rho=0.117，p<0.05）和 BC（Rho=0.007，p<0.05）呈弱相关，表明 TOC 和 BC 对∑OPFRs 浓度的影响很小或没有。逸度分数（ff）结果表明，土壤污染通过挥发对大气中 OPFRs 水平有很强的影响。
