Purpose

Molecular organic markers are an effective tool to detect the adverse effects of anthropogenic inputs in the aquatic environment. Linear alkylbenzenes (LABs) are sewage molecular organic markers that are released into the environment as a consequence of the incomplete sulphonation step of industrial detergents. In the current work, the characterisation, sources and degradation of LABs in the surface sediments of Muar River and Johor Bahru Coast, Malaysia, were identified.

Materials and methods

The surface sediment samples were obtained from the Muar River and Johor Bahru Coast area using an Ekman dredge sampler. Both locations were selected to represent the current anthropogenic pollution situation. The sediment samples were subjected to Soxhlet extraction, first purification step, second fractionation step column chromatography and then gas chromatography-mass spectrometry (GC-MS) analysis.

Results and discussion

The results revealed that the LAB concentrations in the samples of the Muar River and Johor Bahru Coast ranged from 87.4 to 188.1 ng g⁻¹ dry weight (dw) and from 87.6 to 188.7 ng g⁻¹ dw, respectively. The ratios of internal isomer (the benzene ring is closed to the centre of the linear alkyl chain) to external isomer (the benzene ring nears the end of the linear alkyl chain) (I/E ratio) of LABs were between 1.7 and 2.2 in Muar River and between 1.8 and 2.7 in Johor Bahru Coast samples.

Conclusions

These findings indicate that the concentrations of LABs in the sediments ranged from low to moderate contamination and the aquatic environment received both primary and secondary sewage effluents. This study emphasises that continuous monitoring of sewage pollution to minimise the environmental pollution in coastal areas is highly recommended.

中文翻译：

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使用线性烷基苯（LABs）作为分子标记物监测沿海生态系统表层沉积物中的污水污染

目的

分子有机标记物是检测人为输入对水生环境的不利影响的有效工具。直链烷基苯（LABs）是污水分子有机标记物，由于工业洗涤剂的不完全磺化步骤而释放到环境中。在当前的工作中，确定了麻坡河和马来西亚新山海岸表层沉积物中的LABs的特征，来源和降解。

材料和方法

使用埃克曼挖泥机从麻坡河和新山海岸地区获得了地表沉积物样品。选择两个地点来代表当前的人为污染状况。将沉淀物样品进行索氏提取，第一步纯化步骤，第二步分馏步骤柱色谱，然后进行气相色谱-质谱（GC-MS）分析。

结果和讨论

结果表明，麻坡河和新山海岸样品中的乳酸菌浓度分别为87.4至188.1 ng g ^-1干重（dw）和87.6至188.7 ng g ^-1 dw。LABs的内部异构体（苯环在直链烷基链的中心附近封闭）与外部异构体（苯环在直链烷基链末端附近）之间的比率（I / E比）在1.7和2.2之间。麻坡河和新山海岸样本中的1.8至2.7之间。

结论

这些发现表明，沉积物中LABs的浓度范围从低到中度污染，并且水生环境同时接受了一级和二级污水。这项研究强调，强烈建议对污水污染进行连续监测，以最大程度地减少沿海地区的环境污染。