Polycyclic aromatic hydrocarbons (PAHs) released from diverse sources passing through water column carry information into the sediment where they can be used to assess the environmental status of an ecosystem over specified geologic time frame. The vertical distributions of PAHs in two recent sediment cores (RS and RC, 30 cm long) from Refome Lake, South–South Nigeria, were investigated using gas chromatography–mass spectrometry in order to evaluate their sources and historical trends of deposition over the last ca. century. The total PAHs (TPAHs—sum of parent and retene) concentrations ranged from 66.99 ng/g dry weight (dw) at the middle layer of RC core (RC3 10–15 cm) to 182.24 ng/g dw at the near-bottom layer of RS core (RS5 20–25 cm) with a mean of 102.21 ± 24.32 ng/g. The elevated TPAH level at the near-bottom layer of the RS core, corresponding to geologic time-frame ca. 1930–1947, coincided with the period of inhabitation of the European settlers along the lake’s catchments when utilization of coal and/or coal products for domestic/recreational activity was at its peak. A decline in TPAH levels up-cores thereafter reflected the periods of gradual evacuation of inhabitants of the lake area hinterland following the departure of the White after the Nigerian independence in 1960. Evaluation of PAH category according to ring size coupled with data from specific molecular ratios revealed inputs dominated by wood/coal combustion with a moderate contribution from petrochemical/liquid fossil fuel exhaust emissions and a minor diagenetic sources. Principal component analysis result not only distinctively separated RS from RC core samples but also revealed that the RS samples were more impacted by wood/coal combustion emissions than the RC, while liquid fossil fuel exhaust emission dominated the RC over the RS samples. Although short-range eolian transport did play a role in the delivery of PAHs to the lake, localization of source contamination was more important.

中文翻译：

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尼日利亚南南南部Refome湖沉积性多环芳烃的来源特征和历史趋势

从各种来源释放出的多环芳烃（PAH）穿过水柱，将信息带入沉积物中，在沉积物中，它们可用于评估指定地质时期内生态系统的环境状况。利用气相色谱-质谱法研究了尼日利亚南南南部Refome湖最近两个沉积岩心（RS和RC，长30厘米）中PAHs的垂直分布，以便评估它们的来源和过去沉积的历史趋势。 ca. 世纪。PAHs（TPAHs –母体和视黄酮之和）的总浓度范围从RC核心中间层（RC3 10–15 cm）的66.99 ng / g干重（dw）到近底层的182.24 ng / g dw RS芯（RS5 20–25 cm）的平均值为102.21±24.32 ng / g。RS核心近底层的TPAH升高，对应于地质时间框架 1930年至1947年，恰逢欧洲定居者沿湖小流域居住的时期，当时用于家庭/娱乐活动的煤炭和/或煤炭产品利用达到顶峰。此后TPAH水平下降，这反映了1960年尼日利亚独立后白人离开后，湖区腹地居民逐渐撤离的时期。根据环的大小和特定分子比的数据评估PAH类别揭示了以木材/煤炭燃烧为主的投入物，其中石化/液体化石燃料的尾气排放量和少量成岩作用贡献不大。主成分分析结果不仅将RS与RC核心样品区别开来，而且还表明，与RC相比，RS样品受木材/煤炭燃烧排放的影响更大，而液体化石燃料废气排放在RS样品中占主导地位。尽管短程风沙运输确实在向湖中输送多环芳烃中发挥了作用，但污染源的定位更为重要。