Present study was conducted to evaluate current status of trace elements contamination in the surface sediments of the Johor Strait. Iron (2.54 +/- 1.24%) was found as the highest occurring element, followed by those of zinc (210.45 +/- 115.4 microg/g), copper (57.84 +/- 45.54 microg/g), chromium (55.50 +/- 31.24 microg/g), lead (52.52 +/- 28.41 microg/g), vanadium (47.76 +/- 25.76 microg/g), arsenic (27.30 +/- 17.11 microg/g), nickel (18.31 +/- 11.77 microg/g), cobalt (5.13 +/- 3.12 microg/g), uranium (4.72 +/- 2.52 microg/g), and cadmium (0.30 +/- 0.30 microg/g), respectively. Bioavailability of cobalt, nickel, copper, zinc, arsenic and cadmium were higher than 50% of total concentration. Vanadium, copper, zinc, arsenic and cadmium were found significantly different between the eastern and western part of the strait (p < 0.05). Combining with other factors, Johor Strait is suitable as a hotspot for trace elements contamination related studies.
Rice ingestion is one of the major pathways for heavy metal bioaccumulation in human. This study aimed to measure the heavy metal content of paddy soils and its bioavailability in paddy grain in order to assess the health risk. In total, 10 rice samples (50 g each) of paddy plants were harvested from the Selangor and Terengganu areas of Malaysia to assess the bioavailability of heavy metal (As, Cd, Cu, Cr, and Pb) using the in vitro digestion model of Rijksinstituut voor Volksgezondheid en Milieu. The bioavailability of heavy metal concentrations in rice samples were analyzed using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The findings showed the bioavailability of heavy metal concentrations was decreased in the order Cr > Cu > Pb > As > Cd. Chromium was found to be the most abundant bioavailable heavy metal in cooked rice, which was the result of its high content in paddy soil. Hazard Quotient values for the bioavailability of the heavy metal studied were less than one indicating no non-carcinogenic health risks for adults and children. Meanwhile, the total Lifetime Cancer Risk exceeded the acceptable value showing a potential of carcinogenic health risk for both adults and children. The application of in vitro digestion model in assessing bioavailability of heavy metal produces a more realistic estimation of human health risks exposure. However, a regular monitoring of pollution in Selangor and Terengganu areas is crucial since the exposure of heavy metals through rice consumption poses the potential non-carcinogenic and carcinogenic health risk to the local residents.
In a reconnaisance soil geochemical and plant survey undertaken to study the heavy metal uptake by major food crops in Malaysia, 241 soils were analysed for cation exchange capacity (CEC), organic carbon (C), pH, electrical conductivity (EC) and available phosphorus (P) using appropriate procedures. These soils were also analysed for arsenic (As), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), mercury (Hg), nickel (Ni), lead (Pb) and zinc (Zn) using aqua regia digestion, together with 180 plant samples using nitric acid digestion. Regression analysis between the edible plant part and aqua regia soluble soil As, Cd, Cr, Cu, Hg, Ni, Pb and Zn concentrations sampled throughout Peninsular Malaysia, indicated a positive relationship for Pb in all the plants sampled in the survey (R2 = 0.195, p < 0.001), for Ni in corn (R2 = 0.649, p < 0.005), for Cu in chili (R2 = 0.344, p < 0.010) and for Zn in chili (R2 = 0.501, p < 0.001). Principal component analysis of the soil data suggested that concentrations of Co, Ni, Pb and Zn were strongly correlated with concentrations of Al and Fe, which is suggestive of evidence of background variations due to changes in soil mineralogy. Thus the evidence for widespread contamination of soils by these elements through agricultural activities is not strong. Chromium was correlated with soil pH and EC, Na, S, and Ca while Hg was not correlated with any of these components, suggesting diffuse pollution by aerial deposition. However As, Cd, Cu were strongly associated with organic matter and available and aqua regia soluble soil P, which we attribute to inputs in agricultural fertilisers and soil organic amendments (e.g. manures, composts).
Some of the major concerns when applying sewage sludge to land include the potential effect on pH and cation exchange capacity; the mobility and the accumulation of heavy metals in sludge treated soil; the potential of applying too much nutrients and the problems associated with odors and insects. The main objective of this study is to identify the effects of sewage sludge application on the physical and chemical properties of sludge treated soil. Sewage sludge was applied to soil at various rates ranging from 0 L/m2 to 341 L/m2. In order to simulate the natural environment, the study was carried out at a pilot treatment site (5.2 m x 6.7 m) in an open area, covered with transparent roofing material to allow natural sunlight to pass through. Simulated rain was applied by means of a sprinkler system. Data obtained from sludge treated soil showed that the pH values decreased when the application rates were increased and the application period prolonged. The effect of sewage sludge on cation exchange capacity was not so clear; the values obtained for every application rate of sewage sludge did not indicate any consistent behaviour. The mobility of heavy metals in soils treated with sludge were described by observing the changes in the concentration of the heavy metals. The study showed that Cd has the highest mobility in sludge treated soil followed by Cu, Cr, Zn, Ni and Pb.
Urban environmental quality is vital to be investigated as the majority of people live in cities. However, given the continuous urbanization and industrialization in urban areas, heavy metals are continuously emitted into the terrestrial environment and pose a great threat to human. In this study, a total of 76 urban surface soil samples were collected in the Klang district (Malaysia), and analyzed for total and bioavailable heavy metal concentrations by inductively coupled plasma-optical emission spectrometry. Results showed that the concentrations of bioavailable heavy metals declined in the order of Al, Fe, Zn, Cu, Co, Cd, Pb, and Cr, and the concentrations of total heavy metals declined in the order of Fe, Al, Cu, Zn, Pb, Cr, Co, and Cd. Principal component analysis (PCA) showed that heavy metals could be grouped into three principal components, with PC1 containing Al and Fe, PC2 comprising Cd, Co, Cr, and Cu, and PC3 with only Zn. PCA results showed that PC1 may originate from natural sources, whereas PC2 and PC3 most likely originated from anthropogenic sources. Health risk assessment indicated that heavy metal contamination in the Klang district was below the acceptable threshold for carcinogenic and non-carcinogenic risks in adults, but above the acceptable threshold for carcinogenic and non-carcinogenic risks in children.
Runoff quality draining from 17.14 km2 urban catchment in Johor Bahru, Malaysia, was analysed. The land-use consists of residential (30.3%), agricultural (27.3%), open space (27.9%), industrial (8.1%) and commercial (6.4%) areas. Three storm events were sampled in detail. These storms produced stormflow between 0.84 mm and 27.82 mm, and peakflow from 2.19 m3/s to 42.36 m3/s. Water quality showed marked variation during storms especially for TSS, BOD and COD with maximum concentrations of 778 mg/l, 135 mg/l and 358 mg/l, respectively. Concentrations of TOC, DOC, NH3-N, Fe and level of colour were also high. In general, the river quality is badly polluted and falls in Class V based on the Malaysian Interim National Water Quality Standards. Event Mean Concentrations (EMC) for various parameters varied considerably between storms. The largest storm produced higher EMC for TSS, NO3-N and SS whereas the smaller storms tend to register higher EMC for BOD, COD, NH3-N, TOC, Ca, K, Mg, Fe and Zn. Such variations could be explained in terms of pollutant availability and the effects of flushing and dilution. Based on a three-month average recurrence interval (ARI) of rainfall, the estimated event loadings (ton/ha) of TSS, BOD, COD, TOC, NH3-N and NO3-N were 0.055, 0.016, 0.012, 0.039, 0.010, 0.0007 and 0.0002, respectively. Heavy metals present in trace quantities. Storms with 3 months ARI could capture about 70% of the total annual loads of major pollutants.
Since landfilling is the common method of waste disposal in Malaysia, river water is greatly exposed to the risk of contamination from leachate unless proper leachate management is carried out. In this study, leachates from three different types of landfills, namely active uncontrolled, active controlled and closed controlled, were characterized, and their relationships with river water chemistry were examined monthly for a year. The influence of leachate on river water chemistry from each type of landfill depended on many factors, including the presence of a leachate control mechanism, leachate characteristics, precipitation, surface runoff and the applied treatment. The impact of leachate from an active uncontrolled landfill was the highest, as the organic content, NH(4)(+)-N, Cd and Mn levels appeared high in the river. At the same time, influences of leachate were also observed from both types of controlled landfills in the form of inorganic nitrogen (NH(4)(+)-N, NO(3)(-)-N and NO(2)(-)-N) and heavy metals (Fe, Cr, Ni and Mn). Improper treatment practice led to high levels of some contaminants in the stream near the closed controlled landfill. Meanwhile, the active controlled landfill, which was located near the coastline, was exposed to the risk of contamination resulting from the pyrite oxidation of the surrounding area.
Thirty snakehead fish, Channa micropeltes (Cuvier, 1831) were collected at Lake Kenyir, Malaysia. Muscle, liver, intestine and kidney tissues were removed from each fish and the intestine was opened to reveal cestodes. In order to assess the concentration of heavy metal in the environment, samples of water in the surface layer and sediment were also collected. Tissues were digested and the concentrations of manganese (Mn), zinc (Zn), copper (Cu), cadmium (Cd) and lead (Pb) were analysed by using inductively-coupled plasma mass-spectrometry (ICP-MS) equipment. The results demonstrated that the cestode Senga parva (Fernando and Furtado, 1964) from fish hosts accumulated some heavy metals to a greater extent than the water and some fish tissues, but less than the sediment. In three (Pb, Zn and Mn) of the five elements measured, cestodes accumulated the highest metal concentrations, and in remaining two (Cu and Cd), the second highest metal accumulation was recorded in the cestodes when compared to host tissues. Therefore, the present study indicated that Senga parva accumulated metals and might have potential as a bioindicator of heavy-metal pollution.
In this study, the ranges of pollutants found in the soft tissues of Perna viridis collected from Kg. Masai and Kg. Sg. Melayu, both located in the Straits of Johore, were 0.85-1.58 μg/g dry weight (dw) for Cd, 5.52-12.2 μg/g dw for Cu, 5.66-8.93 μg/g dw for Ni and 63.4-72.3 μg/g dw for Zn, and 36.4-244 ng/g dry weight for ∑PAHs. Significantly (p < 0.05) higher concentrations of Cd, Cu, Ni, Zn and ∑PAHs in the mussels were found in the water of a seaport site at Kg. Masai than a non-seaport site at Kg. Sg. Melayu population. The ratios of low molecular weight/high molecular weight hydrocarbons (2.94-3.42) and fluoranthene/pyrene (0.43-0.45) in mussels from both sites indicated the origin of the PAHs to be mainly petrogenic. This study has demonstrated the utility of using the soft tissues of P. viridis as a biomonitor of PAH contamination and bioavailability in the coastal waters of Peninsular Malaysia.
Multivariate analysis including correlation, multiple stepwise linear regression, and cluster analyses were applied to investigate the heavy metal concentrations (Cd, Cu, Fe, Ni, Pb, and Zn) in the different parts of bivalves and gastropods. It was also aimed to distinguish statistically the differences between the marine bivalves and the gastropods with regards to the accumulation of heavy metals in the different tissues. The different parts of four species of bivalves and four species of gastropods were obtained and analyzed for heavy metals. The multivariate analyses were then applied on the data. From the multivariate analyses conducted, there were correlations found between the soft tissues of bivalves and gastropods, but none was found between the shells and the soft tissues of most of the molluscs (except for Cerithidea obtusa and Puglina cochlidium). The significant correlations (P < 0.05) found between the soft tissues were further complemented by the multiple stepwise linear regressions where heavy metals in the total soft tissues were influenced by the accumulation in the different types of soft tissues. The present study found that the distributions of heavy metals in the different parts of molluscs were related to their feeding habits and living habitats. The statistical approaches proposed in this study are recommended for use in biomonitoring studies, since multivariate analyses can reduce the cost and time involved in identifying an effective tissue to monitor the heavy metal(s) bioavailability and contamination in tropical coastal waters.
Genetic variation due to heavy metal contamination has always been an interesting topic of study. Because of the numerous contaminants being found in coastal and intertidal waters, there is always much discussion and argument as to which contaminant(s) caused the variations in the genetic structures of biomonitors. This study used a Single Primer Amplification Reaction (SPAR) technique namely Random Amplified Polymorphic DNA (RAPD) to determine the genetic diversity of the populations of the green-lipped mussel Perna viridis collected from a metal-contaminated site at Kg. Pasir Puteh and those from four relatively' uncontaminated sites (reference sites). Heavy metal levels (Cd, Cu, Pb and Zn) were also measured in the soft tissues and byssus of the mussels from all the sites. Cluster analyses employing UPGMA done based on the RAPD makers grouped the populations into two major clusters; the Bagan Tiang, Pantai Lido, Pontian and Kg. Pasir Puteh populations were in one cluster, while the Sg. Belungkor population clustered by itself. This indicated that the genetic diversity based on bands resulting from the use of all four RAPD primers on P. viridis did not indicate its potential use as a biomarker of heavy metal pollution in coastal waters. However, based on a correlation analysis between a particular metal and a band resulting from a specific RAPD primer revealed some significant (P < 0.01) correlations between the primers and the heavy metal concentrations in the byssus and soft tissues. Thus, the correlation between a particular metal and the bands resulting from the use of a specific RAPD primer on P. viridis could be used as biomonitoring tool of heavy metal pollution.
Fish tilapia Oreochromis mossambicus were collected from a contaminated Seri Serdang (SS) pond potentially receiving domestic effluents and an uncontaminated pond from Universiti Putra Malaysia (UPM). The fish were dissected into four parts namely gills, muscles, intestines, and liver. All the fish parts were pooled and analyzed for the concentrations of Cd, Cu, Fe, Ni, Pb, and Zn. Generally, the concentrations of all metals were low in the edible muscle in comparison to the other parts of the fish. It was found that the levels of all the heavy metals in the different parts of fish collected from the SS were significantly (P<0.05) higher than those from UPM, indicating greater metal bioavailabilities in the SS pond. The sediment data also showed a similar pattern with significantly (P<0.05) higher metal concentrations in SS than in UPM, indicating higher metal contamination in SS. Potential health risk assessments based on provisional tolerable weekly intake (PTWI) and the amount of fish required to reach the PTWI values, estimated daily intake (EDI), and target hazard quotient (THQ) indicated that health risks associated with heavy metal exposure via consumption of the fish's muscles were insignificant to human. Therefore, the consumption of the edible muscles of tilapia from both ponds should pose no toxicological risk of heavy metals since their levels are also below the recommended safety guidelines. While it is advisable to discard the livers, gills, and intestines of the two tilapia fish populations before consumption, there were no potential human health risks of heavy metals to the consumers on the fish muscle part.
It has been widely reported that heavy metal contamination in coastal waters can modify the allozyme profiles of marine organisms. Previous studies have recorded elevated metal concentrations in sediments and mussel tissues off Peninsular Malaysia. In the present study, horizontal starch gel electrophoresis was carried out to estimate the levels of allelic variation of the green-lipped mussel, Perna viridis, collected from one contaminated and three relatively uncontaminated sites off Peninsular Malaysia. Fourteen polymorphic loci were observed. In addition, the concentrations of cadmium, copper, lead, mercury and zinc were determined in the sediments and in the soft tissues of the mussels. Mussels from contaminated site, evidenced by high metal pollution indices (MPI) of the sediment and the mussel tissues, showed the highest percentage of polymorphic loci (78.6%), while those collected from the uncontaminated sites had lower MPI of the sediment and mussel tissue, and exhibited lower percentages of polymorphic loci (35.7-57.1%). The population from the contaminated site showed the highest excess of heterozygosity (0.289) when compared to that of the populations from the three uncontaminated sites (0.108-0.149). Allozyme frequencies at the phosphoglucomutase (PGM; E.C. 2.7.5.1) locus also differed between the contaminated and uncontaminated populations. Previous studies have shown that exposure to heavy metals can select or counter-select for particular alleles at this locus. The present results suggest that allozyme polymorphism in P. viridis is a potential biomonitoring tool for heavy metal contamination but further validation is required.
Total concentrations and speciation of cadmium (Cd), copper (Cu), lead (Pb) and zinc (Zn) in surface sediment samples were correlated with the respective metal measured in the total soft tissue of the green-lipped mussel Perna viridis, collected from water off the west coast of Peninsular Malaysia. The aim of this study is to relate the possible differences in the accumulation patterns of the heavy metals in P. viridis to those in the surface sediment. The sequential extraction technique was employed to fractionate the sediment into 'freely leachable and exchangeable' (EFLE), 'acid-reducible,' 'oxidisable-organic' and 'resistant' fractions. The results showed that significant (P .05) was found between Zn in P viridis and all the sediment geochemical fractions of Zn and total Zn in the sediment. This indicated that Zn was possibly regulated from the soft tissue of P. viridis. The present results supported the use of P viridis as a suitable biomonitoring agent for Cd, Cu and Pb.
The present study aimed to assess the effects of anthropogenic activities on the heavy metal levels in the Langat River by transplantation of Corbicula javanica. In addition, potential ecological risk indexes (PERI) of heavy metals in the surface sediments of the river were also investigated. The correlation analysis revealed that eight metals (As, Co, Cr, Fe, Mn, Ni, Pb and Zn) in total soft tissue (TST) while five metals (As, Cd, Cr, Fe and Mn) in shell have positively and significantly correlation with respective metal concentration in sediment, indicating the clams is a good biomonitor of the metal levels. Based on clustering patterns, the discharge of dam impoundment, agricultural activities and urban domestic waste were identified as three major contributors of the metals in Pangsun, Semenyih and Dusun Tua, and Kajang, respectively. Various geochemical indexes for a single metal pollutant (geoaccumulation index (I geo), enrichment factors (EF), contamination factor (C f) and ecological risk (Er)) all agreed that Cd, Co, Cr, Cu, Fe, Mn, Ni and Zn are not likely to cause adverse effect to the river ecosystem, but As and Pb could pose a potential ecological risk to the river ecosystem. All indexes (degree of contamination (C d), combined pollution index (CPI) and PERI) showed that overall metal concentrations in the tropical river are still within safe limit. River metal pollution was investigated. Anthropogenic activities were contributors of the metal pollution. Geochemical indexes showed that metals are within the safe limit.
To understand the source-to-sink of pollutants in the Kelantan River estuary and the adjacent shelf area in Malaysia, a total of 42 surface sediment samples were collected in the Kelantan River-estuary-shelf system to analyze for grain size, total organic carbon (TOC) content, Al and heavy metals (Cr, Ni, Cu, Zn, Cd and Pb). The surficial sediments were mainly composed of clayey silt and the TOC content in sediments decreased from the river to the shelf. The surficial sediments experienced Pb pollution; Cr only showed a certain level of pollution in the coastal area of the estuary but not in other areas, and Ni, Cu, Zn, and Cd showed no pollution. The heavy metals mainly originated from natural weathering and erosion of rocks and soils in the catchment and enriched near the river mouth. Total organic carbon can promote the enrichment of heavy metals in sediments.
This study aims to determine the composition and sources of particulate matter with an aerodynamic diameter of 10 μm or less (PM10) in a semi-urban area. PM10 samples were collected using a high volume sampler. Heavy metals (Fe, Zn, Pb, Mn, Cu, Cd and Ni) and cations (Na(+), K(+), Ca(2+) and Mg(2+)) were detected using inductively coupled plasma mass spectrometry, while anions (SO4 (2-), NO3 (-), Cl(-) and F(-)) were analysed using Ion Chromatography. Principle component analysis and multiple linear regressions were used to identify the source apportionment of PM10. Results showed the average concentration of PM10 was 29.5 ± 5.1 μg/m(3). The heavy metals found were dominated by Fe, followed by Zn, Pb, Cu, Mn, Cd and Ni. Na(+) was the dominant cation, followed by Ca(2+), K(+) and Mg(2+), whereas SO4 (2-) was the dominant anion, followed by NO3 (-), Cl(-) and F(-). The main sources of PM10 were the Earth's crust/road dust, followed by vehicle emissions, industrial emissions/road activity, and construction/biomass burning.
This study aimed to assess the concentrations and health effect of trace metals [cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), nickel (Ni), and zinc (Zn)] on the road dust of selected locations in the city of Kuala Lumpur. Sampling was conducted thrice at four locations, namely, Tun Razak Road, Raja Abdullah Road, Tunku Abdul Rahman (TAR) Road, and Ayer Molek Road. The concentrations of trace metals in road dust were analyzed by inductively coupled plasma mass spectrometry. TAR Road presented the highest Cd, Cu, Ni, and Pb contents compared with the other roads. The pollution level of trace metals in road dust was assessed by pollution index and pollution load index (PLI), showing that all studied locations were highly contaminated except Ayer Molek Road. Based on the PLI value, the sequence of pollution in descending order is as follows: TAR Road > Raja Abdullah Road > Tun Razak Road > Ayer Molek Road. Health risk assessment was performed to assess the health effects of carcinogenic and noncarcinogenic pollutants caused by the exposure to trace metals in road dust on adults and children. Based on the integrated hazard index values for children at all locations, >1 indicates a possible noncarcinogenic effect. All incremental lifetime cancer risk values for adult and children at all locations are within acceptable limits and are considered safe.