Abstract

Intensive land clearing for development, urbanisation, and agricultural activities on highlands has caused environmental pollution. Unsustainable agricultural activities such as farming on steep slopes and the excessive use of pesticides and fertilisers have led to an influx of pollutants and high sedimentation rate in water bodies. This has triggered a continuous deterioration of the river ecosystem and poses a threat to the ecological niche. Therefore, this study aimed to measure the distribution of bioavailable metals (Al, Cd, Cr, Cu, Fe, Pb, and Zn) in sediment samples of Bertam River and to study the spatial distribution of the metals. The ecological risk due to heavy metals contamination, the relationship between the studied parameters, and the possible sources of pollution were analysed. Surface sediment samples from 18 sampling points were collected and tested via Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The spatial distribution showed that all the studied metals’ concentration was higher at the upstream area compared to the downstream area, except for Cd and Pb. No significant difference between the upstream and downstream areas was obtained for Cd. Nevertheless, the highest concentration was found at a sampling point located upstream (0.07 mg/kg). Meanwhile, the mean concentration for Pb was higher at the downstream area (4.49 ± 1.07 mg/kg) compared to the upstream area (3.57 ± 0.97 mg/kg). All the calculated indexes, namely contamination factor (CF), geo-accumulation index (I_geo), and pollution load index (PLI), showed a low ecological risk and the overall concentration of bioavailable fraction of metals in the river sediment was still within the safe limit. Furthermore, this study confirmed that the potential sources of river sediment were domestic activities and sand dredging that caused a high level of Cd in the sediment. Results from this research can serve as the preliminary information for further assessment of sediment quality in the study area.

摘要

在高地上为开发，城市化和农业活动进行的大量土地清理已造成环境污染。不可持续的农业活动，例如在陡峭的山坡上耕种以及过量使用农药和化肥，导致了污染物的大量涌入和水体的高沉积率。这引发了河流生态系统的持续恶化，并对生态位构成了威胁。因此，本研究旨在测量Bertam河沉积物样本中生物有效性金属（Al，Cd，Cr，Cu，Fe，Pb和Zn）的分布，并研究金属的空间分布。分析了重金属污染的生态风险，研究参数之间的关系以及可能的污染源。收集了18个采样点的表面沉积物样品，并通过电感耦合等离子体质谱（ICP-MS）进行了测试。空间分布表明，除Cd和Pb外，所有研究金属在上游区域的浓度均高于下游区域。镉的上游和下游区域之间没有显着差异。然而，在上游的采样点发现最高浓度（0.07 mg / kg）。同时，与上游区域（3.57±0.97 mg / kg）相比，下游区域（4.49±1.07 mg / kg）的Pb平均浓度更高。所有计算出的指标，即污染因子（CF），地质累积指数（I 空间分布表明，除Cd和Pb外，所有研究金属在上游区域的浓度均高于下游区域。镉的上游和下游区域之间没有显着差异。然而，在上游的采样点发现最高浓度（0.07 mg / kg）。同时，与上游区域（3.57±0.97 mg / kg）相比，下游区域（4.49±1.07 mg / kg）的Pb平均浓度更高。所有计算出的指标，即污染因子（CF），地质累积指数（I 空间分布表明，除Cd和Pb外，所有研究金属在上游区域的浓度均高于下游区域。镉的上游和下游区域之间没有显着差异。然而，在上游的采样点发现最高浓度（0.07 mg / kg）。同时，与上游区域（3.57±0.97 mg / kg）相比，下游区域（4.49±1.07 mg / kg）的Pb平均浓度更高。所有计算出的指标，即污染因子（CF），地质累积指数（I 在上游的采样点发现最高浓度（0.07 mg / kg）。同时，与上游区域（3.57±0.97 mg / kg）相比，下游区域（4.49±1.07 mg / kg）的Pb平均浓度更高。所有计算出的指标，即污染因子（CF），地质累积指数（I 在上游的采样点发现最高浓度（0.07 mg / kg）。同时，与上游区域（3.57±0.97 mg / kg）相比，下游区域（4.49±1.07 mg / kg）的Pb平均浓度更高。所有计算出的指标，即污染因子（CF），地质累积指数（I_地理），和污染负荷指数（PLI），呈低生态风险，并在河流泥沙金属的生物可利用部分的总浓度仍是安全的范围内。此外，这项研究证实，河床沉积物的潜在来源是家庭活动和疏sand沙土，导致沉积物中镉含量高。这项研究的结果可作为进一步评估研究区沉积物质量的初步信息。