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, SH-7, Gaya-Panchanpur, Post-Fatehpur, P.S-Tekari, District-Gaya 824236, Bihar, India.
Ecotoxicol Environ Saf. 2019 Jan 30;168:304-314. doi: 10.1016/j.ecoenv.2018.10.089. Epub 2018 Nov 1.
Under the Stockholm Convention, signatory countries are obliged to direct source inventories, find current sources, and provide ecological monitoring evidence to guarantee that the encompassing levels of persistent organic pollutants (POPs) are declining. However, such monitoring of different types of POPs are to a great degree constrained in most developing countries including Nepal and are primarily confined to suspected source area/ densely populated regions. In this study, 9 polybrominated diphenyl ethers (PBDEs), 2 dechlorane plus (DPs), 6 novel brominated flame retardants (NBFRs) and 8 organophosphate ester flame retardants (OPFRs) were investigated in indoor dust from a rural area (Kopawa) in Nepal in order to evaluate their occurrence/level, profile, spatial distribution and their sources. Additionally, health risk exposure was estimated to anticipate the possible health risk to the local population. The results showed that OPFRs was the most abundant FR measured in the dust. The concentration of ∑OPFRs was about 2, 3 and 4 orders of magnitude higher than the ∑NBFRs, ∑PBDEs, and ∑DPs, respectively. Tris (methylphenyl) phosphate (TMPP) and Tris (2-ethylhexyl) phosphate (TEHP) were the most abundant OPFRs analyzed in the dust; while decabromodiphenyl ethane (DBDPE) exceeded among NBFRs. Likewise, 2,2',3,3',4,4',5,5',6,6'-decabromodiphenylether (BDE-209) was the most identified chemical among PBDEs. The total organic carbon (TOC) content in dust was significantly and positively connected with octa-BDEs (Rho = 0.615, p < 0.01), BTBPE (Rho = 0.733, p < 0.01), TPHP (Rho = 0.621, p < 0.01), TEHP (Rho = 0.560, p < 0.01) and TMPPs (Rho = 0.550, p < 0.01), while black carbon (BC) was either weakly related or not related, suggesting little or no impact of BC in the distribution of FRs. Principal component analysis indicated the contribution from commercial penta-, octa- and deca-BDEs formulation, the adhesive substance, food packaging and paints, and degradation of BDE-209 as the essential sources of FRs. Health risk exposure estimates showed that dermal absorption via dust as the primary route of FRs intake. The estimated daily exposure of PBDEs, NBFRs and OPFRs were 2-10 orders of magnitude lower than their corresponding reference dose (RfD), suggesting insignificant risk. However, other routes such as inhalation and dietary intake might still be significant in the case of Kopawa which should be tested in future.
根据《斯德哥尔摩公约》，签署国必须对源清单进行定向、发现当前的污染源，并提供生态监测证据，以确保持久性有机污染物（POPs）的总体水平正在下降。然而，在包括尼泊尔在内的大多数发展中国家，对不同类型的 POPs 的这种监测在很大程度上受到限制，主要限于疑似源区/人口稠密地区。在这项研究中，对尼泊尔农村地区（Kopawa）的室内灰尘中 9 种多溴二苯醚（PBDEs）、2 种氯丹加（DPs）、6 种新型溴化阻燃剂（NBFRs）和 8 种有机磷酸酯阻燃剂（OPFRs）进行了调查，以评估其存在/水平、分布、空间分布及其来源。此外，还估计了健康风险暴露，以预测当地居民可能面临的健康风险。结果表明，OPFRs 是灰尘中含量最高的阻燃剂。∑OPFRs 的浓度分别比∑NBFRs、∑PBDEs 和∑DPs 高 2、3 和 4 个数量级。三（甲基苯基）磷酸酯（TMPP）和三（2-乙基己基）磷酸酯（TEHP）是灰尘中分析出的最丰富的 OPFRs；而十溴二苯乙烷（DBDPE）在 NBFRs 中含量最高。同样，二苯醚-209（BDE-209）是 PBDEs 中最常见的化学物质。灰尘中的总有机碳（TOC）含量与八溴二苯醚（Rho = 0.615，p < 0.01）、四溴双酚 A 醚（Rho = 0.733，p < 0.01）、三（2-氯乙基）磷酸酯（Rho = 0.621，p < 0.01）、TEHP（Rho = 0.560，p < 0.01）和 TMPPs（Rho = 0.550，p < 0.01）呈显著正相关，而黑碳（BC）与阻燃剂的分布相关性较弱或不相关，这表明 BC 对阻燃剂的分布几乎没有或没有影响。主成分分析表明，商用五溴、八溴和十溴二苯醚制剂、粘合剂、食品包装和涂料以及 BDE-209 的降解是阻燃剂的主要来源。健康风险暴露评估表明，皮肤吸收是阻燃剂摄入的主要途径。估计的 PBDEs、NBFRs 和 OPFRs 的日暴露量比相应的参考剂量（RfD）低 2-10 个数量级，表明风险可忽略不计。然而，在 Kopawa 等情况下，其他途径，如吸入和饮食摄入，仍可能具有重要意义，这需要在未来进行测试。
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