This study investigated the distribution, sources, and ecological risk of polycyclic aromatic hydrocarbons (PAHs) in the surface sediments of the Western Bay of Bengal (WBoB). Coastal, shelf and slope sediments from the WBoB, collected from different research cruises, were analysed for 16 priority PAH pollutants. Total PAHs (TPAHs) were in the range of 1.87–918.79 ng/g and exhibited a significant association with organic matter and silt content with a predominance of high molecular weight (HMW) PAHs congeners. The preferential degradation of the labile low-molecular-weight (LMW) PAHs resulted in the sedimentary accumulation of HMW congeners. A comparison with reported values from other oceanic areas revealed a relatively low concentration of PAHs in WBoB. The isomeric ratios of PAHs could suggest a pyrogenic or petrogenic (crude oil) origin of PAHs. Principal component analysis indicated the dominance of HMW PAHs (petrogenic or combustion) over the LMW fraction. Based on sediment quality guidelines, four congeners [Pyrene (Py), Benzo[a]anthracene (BaA), Chrysene (Ch), and Dibenzo[a,h]anthracene (DbA)] exceeded the threshold effect levels, indicating an adverse impact of these PAHs on the benthic fauna occasionally. The corresponding risk quotients further indicated a moderate risk caused by Py, BaA, and Benzo[b]fluoranthene (BbF) to the biota. This study underscores the importance of proactive management and mitigation strategies to safeguard these vital oceanic ecosystems from the adverse effects of PAHs and other hazardous materials.

中文翻译：

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孟加拉湾西部表层沉积物中多环芳烃的分布、来源和生态风险评估


本研究调查了多环芳烃 （PAH） 在孟加拉西部湾 （WBoB） 表层沉积物中的分布、来源和生态风险。分析了从不同研究游轮收集的 WBoB 的沿海、大陆架和斜坡沉积物中的 16 种优先 PAH 污染物。总 PAHs （TPAHs） 在 1.87–918.79 ng/g 范围内，与有机质和淤泥含量呈显著关联，以高分子量 （HMW） PAHs 同系物为主。不稳定的低分子量 （LMW） PAHs 的优先降解导致 HMW 同系物的沉积积累。与其他海洋区域的报告值进行比较，发现 WBoB 中 PAH 的浓度相对较低。PAHs 的异构体比率可能表明 PAH 的成热或产岩（原油）来源。主成分分析表明 HMW PAHs （石油成因或燃烧） 优于 LMW 馏分。根据沉积物质量指南，四种同系物 [芘 （Py）、苯并 [a] 蒽 （BaA）、Chrysene （Ch） 和二苯并 [a，h] 蒽 （DbA）] 超过了阈值效应水平，表明这些多环芳烃偶尔会对底栖动物产生不利影响。相应的风险商进一步表明 Py、BaA 和苯并[b]荧蒽 （BbF） 对生物群造成中等风险。这项研究强调了主动管理和缓解策略的重要性，以保护这些重要的海洋生态系统免受 PAH 和其他有害物质的不利影响。