Department of Biological Sciences, Alex Ekwueme Federal University Ndufu-Alike, P.M.B 1010, Abakaliki, Ebonyi State, Nigeria; Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, United Kingdom.
Centre for Marine Pollution Monitoring and Seafood Safety, University of Port Harcourt, P.M.B 5323, Choba, Rivers State, Nigeria.
Mar Pollut Bull. 2020 Dec;161(Pt A):111684. doi: 10.1016/j.marpolbul.2020.111684. Epub 2020 Oct 6.
Chemical-surveys of sediments are source of information about historical-pollution in aquatic-ecosystems, because ecological/human-health risks may arise from polycyclic-aromatic-hydrocarbons (PAHs) and nitrogen-PAHs presence in aquatic-environments, particularly sediments, where they partition. Despite this, sediment-PAHs/N-PAHs have not been reported in the Niger Delta. This study investigated vertical-profiles of PAHs/N-PAHs in 2 cm-intervals-segments from Bonny Estuary, Niger Delta. Analysis showed that ƩPAHs/ƩN-PAHs in segments ranged from 8699 to 22,528 μg/kg and 503 to 2020 μg/kg, respectively. Abundant-PAH/N-PAH are 2,6-dimethyl-naphthalene and benzo[a]acridine. PAHs/N-PAHs in the samples appeared to be from petrogenic and pyrogenic-sources. Petrogenic-PAHs/N-PAHs were predominated by 2-, 3-rings, alkylated-substituents, while, pyrogenic-PAHs/N-PAHs were dominated by 4-, 5-, 6-rings. Surface-sediments were dominated by petrogenic-PAHs/N-PAHs while, deeper-cores were heavily-contaminated with pyrogenic-PAHs/N-PAHs. ƩPAHs exceeded the ISQGs and PELs of CSQGs. Ʃ-quinoline/Ʃ-acridine exceeded the guidelines for protection of aquatic-life. Furthermore, there are concerns over toxic-ratios >70% in the estuary. Such surveys may be helpful in future sediment-management-decisions for contaminated-systems and long-term-monitoring of sediments to assess remediation/recovery. CAPSULE: Distinct sources of PAHs and N-PAHs exist in the Niger Delta ecosystem and, there are concerns over toxic ratios >70% in the oil rich region and the potential for adverse biological effects.
沉积物中的化学物质调查是水生生态系统历史污染信息的来源，因为多环芳烃 (PAHs) 和氮代多环芳烃 (N-PAHs) 存在于水生环境中，特别是在沉积物中，它们会发生分配，这可能会带来生态/人类健康风险。尽管如此，尼日尔三角洲尚未报告沉积物中的 PAHs/N-PAHs。本研究调查了尼日尔三角洲邦尼河口的 2cm 间隔段沉积物中 PAHs/N-PAHs 的垂直分布。分析表明，段内的 ΣPAHs/ΣN-PAHs 分别在 8699 至 22528μg/kg 和 503 至 2020μg/kg 之间。丰富的 PAH/N-PAH 是 2,6-二甲基萘和苯并[a]吖啶。样品中的 PAHs/N-PAH 似乎来自于生源和热成因源。生源源的 PAHs/N-PAH 以 2-、3-环为主，具有烷基取代基，而热成因源的 PAHs/N-PAH 以 4-、5-、6-环为主。表层沉积物主要以生源源的 PAHs/N-PAHs 为主，而更深层的核心则受到热成因源的 PAHs/N-PAHs 的严重污染。ΣPAHs 超过了 CSQGs 的 ISQGs 和 PELs。Σ-喹啉/Σ-吖啶超过了保护水生生物的指南。此外，河口地区还存在毒性比 >70%的问题。这种调查可能有助于未来对受污染系统的沉积物管理决策，以及对沉积物的长期监测，以评估修复/恢复情况。总结：尼日尔三角洲生态系统中存在明显的 PAHs 和 N-PAHs 来源，在富油地区，毒性比 >70%的情况令人担忧，可能会对生物产生不利影响。
