Janneh Mariama, Qu Chengkai, Zhang Yuan, Xing Xinli, Nkwazema Oscar, Nyihirani Fatuma, Qi Shihua
State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences Wuhan 430074 China
School of Environmental Studies, China University of Geosciences Wuhan 430074 China.
RSC Adv. 2023 Mar 1;13(11):7102-7116. doi: 10.1039/d2ra07955k.
This study investigates the concentration and distribution of polycyclic aromatic hydrocarbons (PAHs) in soils, potential sources, risk assessment, and soil physicochemical properties influencing PAH distribution in developed and remote cities in Sierra Leone. Seventeen topsoil samples (0-20 cm) were collected and analyzed for 16 PAHs. The average concentrations of ΣPAH in soils in the surveyed areas were 1142 ng g dw, 265 ng g dw, 79.7 ng g dw, 54.3 ng g dw, 54.2 ng g dw, 52.3 ng g dw, and 36.6 ng g dw in Kingtom, Waterloo, Magburaka, Bonganema, Kabala, Sinikoro, and Makeni, respectively. Based on the European soil quality guidelines, Kingtom and Waterloo soils were categorized as heavily and weakly contaminated soil PAHs respectively. The main PAH compounds of this study were 2-ring, 4-ring, and 5-ring PAHs. High molecular weight PAHs (4-6 rings) made up 62.5% of the total PAHs, while low molecular weight PAHs (2-3 rings) was 37.5%. In general, HMWPAHs were predominant in Kingtom, followed by Waterloo. The appointment of PAH sources using different methods revealed mixed sources, but predominantly pyrogenic sources (petroleum, biomass, coal, and fossil fuel contributions). Soil pH has a significant impact on PAH distribution. The toxicity equivalent quantity (TEQ) levels in soils pose a potential health risk to residents in developed cities but pose a negligible health risk to residents in remote cities. This study is significant as its findings reveal the status of PAH soil contamination in Sierra Leone. The results have important implications for policymakers and stakeholders to identify high-risk zones and establish proper environmental monitoring programs, pollution control measures, and remediation strategies to prevent future risks.
本研究调查了塞拉利昂发达城市和偏远城市土壤中多环芳烃（PAHs）的浓度与分布、潜在来源、风险评估以及影响PAH分布的土壤理化性质。采集了17份表层土壤样本（0 - 20厘米）并分析其中的16种PAHs。调查区域土壤中ΣPAH的平均浓度在金顿、滑铁卢、马格布拉卡、邦加内马、卡巴拉、西尼罗和马克尼分别为1142纳克/克干重、265纳克/克干重、79.7纳克/克干重、54.3纳克/克干重、54.2纳克/克干重、52.3纳克/克干重和36.6纳克/克干重。根据欧洲土壤质量指南，金顿和滑铁卢的土壤分别被归类为PAHs重度污染土壤和轻度污染土壤。本研究的主要PAH化合物为2环、4环和5环PAHs。高分子量PAHs（4 - 6环）占总PAHs的62.5%，而低分子量PAHs（2 - 3环）为37.5%。总体而言，HMWPAHs在金顿占主导地位，其次是滑铁卢。采用不同方法确定PAH来源显示为混合源，但主要是热解源（石油、生物质、煤炭和化石燃料贡献）。土壤pH对PAH分布有显著影响。土壤中的毒性当量（TEQ）水平对发达城市的居民构成潜在健康风险，但对偏远城市的居民构成的健康风险可忽略不计。本研究意义重大，因为其结果揭示了塞拉利昂PAH土壤污染状况。研究结果对政策制定者和利益相关者识别高风险区域以及制定适当的环境监测计划、污染控制措施和修复策略以预防未来风险具有重要意义。
