Mining activities are responsible for the elevated input levels of suspended sediment and hazardous metals into the riverine ecosystem. These have been shown to threaten the riverine fish populations and can even lead to localized population extinction. To date, research on the effects of mining activities on fish has been focused within metal contamination and bioaccumulation and its threat to human consumption, neglecting the effects of suspended sediment. This paper reviews the effects of suspended sediment and metal pollution on riverine ecosystem and fish population by examining the possibilities of genetic changes and population extinction. In addition, possible assessments and studies of the riverine fish population are discussed to cope with the risks from mining activities and fish population declines.
This study applied the use of sequential extraction technique and simple bioaccessibility extraction test to quantify the bioavailable fractions and the human bioaccessible concentration of metals collected from nine stations in surface sediment of the Langat River. The concentrations of total and bioaccessible metals from different stations were in the range of 0.49-1.04, 0.10-0.32 μg g-1 for T-Cd, Bio-Cd, respectively, and 12.9-128.03, 2.06-8.53 μg kg-1 for T-Hg, Bio-Hg, respectively. The results revealed highest R-Bio-Cd in Banting station (55.3 %), while the highest R-Bio-Hg was in Kajang station (49.61 %). The chemical speciation of Cd in most sampling stations was in the order of oxidisable-organic > residual > exchangeable > acid-reducible, while speciation of Hg was in the order of exchangeable > residual > oxidisable-organic > acid-reducible. The correlation matric of mean content showed that the TOM, particle size and Mg++ in polluted surface sediments was highly correlated with total mercury. The PCA showed that the main factors influencing the bioaccessibility of Hg in surface sediments were the sediment TOM, F1 (EFLE) and F3 (oxidation-organic), while the factor influencing the bioaccessibility of Cd was the F3 (oxidation-organic) and T-Cd.
The Bernam River is one of the most important rivers in Malaysia in that it provides water for industries and agriculture located along its banks. The present study was conducted to assess the level of contamination of heavy metals (Cd, Ni, Cr, Sn, and Fe) in surface sediments in the Bernam River. Nine surface sediment samples were collected from the lower, middle, and upper courses of the river. The results indicated that the concentrations of the metals decreased in the order of Sn > Cr > Ni > Fe > Cd (56.35, 14.90, 5.3, 4.6, and 0.62 μg/g(1) dry weight). Bernam River sediments have moderate to severe enrichment for Sn, moderate for Cd, and no enrichment for Cr, Ni, and Fe. The contamination factor (CF) results demonstrated that Cd and Sn are responsible for the high contamination. The pollution load index (PLI), for all the sampling sites, suggests that the sampling stations were generally unpolluted with the exception of the Bagan Tepi Sungai, Sabak Bernam, and Tanjom Malim stations. Multivariate techniques including Pearson's correlation and hierarchical cluster analysis were used to apportion the various sources of the metals. The results suggested that the sediment samples collected from the upper course of the river had lower metal concentrations, while sediments in the middle and lower courses of the river had higher metal concentrations. Therefore, our results can be useful as a baseline data for government bodies to adopt corrective measure on the issues related to heavy metal pollution in the Bernam River in the future.
The interaction and the interplay of climate change with oil palm production in the Southeast Asia region are of serious concern. This particularly applies in Malaysia due to its rank as the second largest palm oil producer in the world. The anthropogenic activities and the agroecological practices in oil palm plantation, including excessive use of fertilisers, bush fire due to land clearing, and cultivation on peatland, have exacerbated the effects of climate change featuring extreme events, drought, flooding, heatwave, as well as infestation of pest and diseases. These adverse impacts on oil palm production highlight the significance of deploying effective adaptation strategies. The study aims to examine the impact of climate change on oil palm production and identify the farmers' adaptation strategies to the impacts of climate change in Malaysia. This study was conducted a comprehensive review of the articles published from 2000 to 2021 in the contexts of climate change and oil palm production in Malaysia. The review shows that climate change has a range of impacts on the oil palm production in Malaysia. As a result, several adaptation options were identified, such as breeding of hybrid varieties that are tolerant and resistant to heat; sustainable management of soil; pit and tranches to enhance water management in plantation areas; minimal use of fertilisers, herbicides, and pesticides; zero burning; and minimum tillage. The reviewed studies recommended the following to mitigate the adverse impacts of climate change: sustainable national policy on climate change, conservation of the existing carbon stock, effective management of tropical rainforest biodiversity, afforestation for carbon sequestration, and reduction in greenhouse gas (GHG) emission.
The concentration of four metals: Cd, Ni, Cr, and Sn, in the surface sediment samples from the Langat River were evaluated. Multivariate techniques were used to apportion the sources of the metals. The results showed that the highest concentration of metals in the Langat River were found at Jenjarom station, with the concentration of these metals decreasing in the order of Sn>Cr>Ni>Cd (114.27, 21.03, 7.84, 0.59 μg g(-1) dry weight). The level of pollution in the sediment was assessed using contamination factor (CF), pollution load index (PLI), geo-accumulation index (Igeo), and enrichment factor (EF). The results of the pollution assessment showed that the Langat River sediments have severe enrichment of Sn and moderate to severe enrichment of Cd. The results of the PLI for the Langat River suggest that the sampling stations are not polluted with the exception of the Jugra, Jenjarom, and Jalan Hulu Langat stations.
The present study applied the use of sequential extraction technique and simple bioaccessibility extraction test to investigate the bioavailable fractions and the human bioaccessible concentration of metals collected from nine stations in surface sediment of the Bernam River. The concentrations of total and bioaccessible metals from different stations were in the range of 0.30-1.43 μg g(-1) and 0.04-0.14 μg g(-1) for total cadmium and bioaccessibility of cadmium, respectively, 6.20-288 μg kg(-1) and 2.06-8.53 μg kg(-1) for total mercury and bioaccessibility of mercury, respectively, and 9.2-106.59 μg g(-1) and 0.4-2.75 μg kg(-1) for total tin and bioaccessibility of tin, respectively. The chemical speciation of Cd in most sampling stations was in the order of oxidisable-organic > acid-reducible > residual > exchangeable, while the chemical speciation of Hg was in the order of exchangeable > residual > oxidisable-organic > acid-reducible and the chemical speciation of Hg was in the order of residual > oxidisable-organic > acid-reducible > exchangeable. The principal component analysis showed that the main factors influencing the bioaccessibility of mercury in surface sediments were the sediment total organic matter, cation exchange capacity, and easily, freely, or leachable and exchangeable fraction, and the factors influencing the bioaccessibility of tin were the total tin and cation exchange capacity, while the bioaccessibility of Cd in surface sediments was influenced by the only factor which is the easily, freely, or leachable and exchangeable fraction.
Improper treatment during recycling of e-waste materials by means of open burning is on the rise which has led to an increase in air pollution. This study looked at heavy metal concentrations, concentrations in relation to threshold values, and assessments of risk for noncarcinogenic and cancer risk threat. The Microwave Plasma-Atomic Emission Spectrometry (MP-AES 4210) series instrument of Agilent Technology, United States of America (USA), was used in analyzing heavy metal (Cd, Cu, and Pb) concentrations. The result of the analysis of the Kuka Bulukiya treatment point revealed that Pb has the highest mean concentration of 0.0693 ppm, Cu 0.0525 parts per million (PPM), and Cd 0.0042 ppm. The mean concentration at PRP Gidan Ruwa for Cd was found to be 0.0059 ppm, Cu 0.0363 ppm, and Pb 0.049 ppm. The result of the adult and children population calculated shows that the hazard quotient (HQ) and hazard index (HI) values are not up to 1 in all the pathways (inhalation, ingestion, and dermal) at both treatment points (1.2 ˟ 10-4 and 9.8 ˟ 10-5) and (6.4 ˟ 10-4 and 5.9 ˟ 10-4), respectively. The cancer risk for Kuka Bulukiya 6 ˟ 10-10 and PRP G/Ruwa 5 ˟ 10-10 for adults and 7 ˟ 10-10 and 4 ˟ 10-10 for children were both lower than the threshold set for cancer risk by the United States Environmental Protection Agency (USEPA). This meant that both adults and children were not at risk of cancer and noncarcinogenic threat based on the assessment in this study. The study concluded that informal e-waste burning has substantially helped in the relatively high levels of air pollution identified in the treatment points and in turn posed environmental and public health concerns to people around the area. This study recommends that samples of the vegetable products at the PRP G/Ruwa treatment point should be investigated immediately and adequate restrictions and regulations should be enacted and enforced in order to safeguard the environment and the populace. There is need for caution from the authorities to avert the possible implications (e-waste extractors and the public) of being affected with noncarcinogenic or carcinogenic ailments over time.