Trend in metals variation in Tasik Chini, Pahang, Peninsular Malaysia

Mapping Chini Lake (Pahang, Malaysia) using Sentinel-2 images to determine the effect of acid mine drainage in the pre- to post-COVID-19 restriction period

Mining activities in the Chini Lake catchment area have been extensive for several years, contributing to acid mine drainage (AMD) events with high concentrations of iron (Fe) and other heavy metals impacting the surface water. However, during the restriction period due to the COVID-19 outbreak, anthropogenic activities have been suspended, which clearly shows a good opportunity for a better environment. Therefore, we aimed to analyze the variation of AMD-associated water pollution in three main zones of the Chini Lake catchment area using Sentinel-2 data for the periods pre-movement control order (MCO), during MCO, and post-MCO from 2019 to 2021. These three zones were chosen due to their proximity to mining areas: zone 1 in the northeastern part, zone 2 in the southeastern part, and zone 3 in the southern part of the Chini Lake area. The acid mine water index (AMWI) was a specific index used to estimate acid mine water. The AMWI values from Sentinel-2 images exhibited that the mean AMWI values in all zones during the MCO period decreased by 14% compared with the pre-MCO period. The spatiotemporal analysis found that the highest polluted zones were recorded in zone 1, followed by zone 3 and zone 2. As compared with during the MCO period, the maximum percentage of increment during post-MCO in all zones was up to 25%. The loosened restriction policy has resulted in more AMD flowing into surface water and increased pollution in Chini Lake. As a whole, our outputs revealed that Sentinel-2 data had a major potential for assessing the AMD-associated pollution of water.

Source of metal contamination in sediment, their ecological risk, and phytoremediation ability of the studied mangrove plants in ship breaking area, Bangladesh

Samples for sediment and two species of native mangrove plants were collected from seven sampling sites for assessing the level of metal contamination. Results of the studied metals displayed the order of pollution as Fe > Ti > Zr > Rb > Zn > Sr > Pb > Y > Cu > Cr > As accordingly. Geoaccumulation index and contamination factor revealed that the sediment samples were unpolluted to moderately polluted by Zn, Fe, Ti, Rb, Y, and Zr. Ecological risk factor depicted a pollution-free condition in the study areas. PCA, CA, and correlation coefficient indicated that the source of the metals in the environment was anthropogenic. Bioconcentration factor values were found to be below 1 in both plant species. Conversely, transfer factor values for most heavy metals were found to be >1 in both plant species, which reflects the phytoremediation ability of plants.

Waterborne parasites and physico-chemical assessment of selected lakes in Malaysia

The objective of this study was to assess the physico-chemical parameters and waterborne parasites in selected recreational lakes from Malaysia. Samples were collected from seven stations of Recreational Lake A (RL-A) and six stations of Recreational Lake B (RL-B). The samples were processed to detect the presence of Giardia spp. and Cryptosporidium spp. using immunomagnetic separation kit, helminth eggs or ova by bright field microscopy and Acanthamoeba spp. by cultivation in non-nutrient agar. Chemical parameters such as ammonia, chlorine, fluoride, nitrate and nitrite and physical parameters such as dissolved oxygen, electrical conductivity, pH, salinity, temperature and total dissolved solid were also measured. Both lakes were freshwater with salinity ranging from 0.05 to 0.09 ppt. Most stations of these lakes were contaminated with Cryptosporidium spp., Giardia spp., Ascaris spp. and hookworm. Schistosoma spp. was found in RL-B only, while Acanthamoeba spp. was found in all stations. Of all sampling sites, station 5 of RL-B is the most contaminated. Linear regression and correlation analysis revealed that Giardia spp. and Schistosoma spp. showed a significant negative correlation with turbidity (p < 0.01). Based on the preliminary data obtained, it is clearly shown that there is a necessity to implement the detection of waterborne parasites and physico-chemical analysis in Malaysia. Future work on heavy metals (chromium, copper, mercury and zinc) is recommended to enhance the overall water quality monitoring and to take appropriate safety measures to ensure maintenance of good water standards.

Deriving freshwater quality criteria for copper, cadmium, aluminum and manganese for protection of aquatic life in Malaysia

Freshwater quality criteria for copper (Cu), cadmium (Cd), aluminum (Al), and manganese (Mn) were developed with particular reference to aquatic biota in Malaysia, and based on USEPA's guidelines. Acute toxicity tests were performed on eight different freshwater domestic species in Malaysia, which were Macrobrachiumlanchesteri (prawn), two fish -Poeciliareticulata and Rasborasumatrana, Melanoidestuberculata (snail), Stenocyprismajor (ostracod), Chironomusjavanus (midge larvae), Naiselinguis (annelid), and Duttaphrynusmelanostictus (tadpole), to determine 96-h LC50 values for Cu, Cd, Al, and Mn. The final acute values (FAVs) for Cu, Cd, Al, and Mn were 2.5, 3.0, 977.8, and 78.3 μgL(-1), respectively. Using an estimated acute-to-chronic ratio (ACR) of 8.3, the value for final chronic value (FCV) was derived. Based on FAV and FCV, a Criterion Maximum Concentration (CMC) and a criterion Continuous Concentration (CCC) for Cu, Cd, Al, and Mn of 1.3, 1.5, 488.9, and 39.1 μgL(-1) and 0.3, 0.36, 117.8, and 9.4 μgL(-1), respectively, were derived. The results of this study provide useful data for deriving national or local water quality criteria for Cu, Cd, Al, and Mn based on aquatic biota in Malaysia. Based on LC50 values, this study indicated that R.sumatrana, M.lanchesteri, C.javanus, and N.elinguis were the most sensitive to Cu, Cd, Al, and Mn, respectively.

Risk assessment of exposure to lead in tap water among residents of Seri Kembangan, Selangor state, Malaysia

Introduction:

A cross sectional study was conducted to estimate risk of exposure to lead via tap water ingestion pathway for the population of Seri Kembangan (SK).

Methodology:

By using purposive sampling method, 100 respondents who fulfilled the inclusive criteria were selected from different housing areas of SK based on geographical population distribution. Residents with filtration systems installed were excluded from the study. Questionnaires were administered to determine water consumption-related information and demographics. Two water samples (first-flushed and fully-flushed samples) were collected from kitchen tap of each household using HDPE bottles. A total of 200 water samples were collected and lead concentrations were determined using a Graphite Furnace Atomic Absorption Spectrophotometer (GFAAS).

Results:

Mean lead concentration in first-flushed samples was 3.041± SD 6.967µg/L and 1.064± SD 1.103µg/L for fully-flushed samples. Of the first-flushed samples, four (4) had exceeded the National Drinking Water Quality Standard (NDWQS) lead limit value of 10µg/L while none of the fully-flushed samples had lead concentration exceeded the limit. There was a significant difference between first-flushed samples and fully-flushed samples and flushing had elicited a significant change in lead concentration in the water (Z = -5.880, p<0.05). It was also found that lead concentration in both first-flushed and fully flushed samples was not significantly different across nine (9) areas of Seri Kembangan (p>0.05). Serdang Jaya was found to have the highest lead concentration in first-flushed water (mean= 10.44± SD 17.83µg/L) while Taman Universiti Indah had the highest lead concentration in fully-flushed water (mean=1.45± SD 1.83µg/L). Exposure assessment found that the mean chronic daily intake (CDI) was 0.028± SD 0.034µgday^-1kg^-1. None of the hazard quotient (HQ) value was found to be greater than 1.

Conclusion:

The overall quality of water supply in SK was satisfactory because most of the parameters tested in this study were within the range of permissible limit and only a few samples had exceeded the standard values for lead and pH. Non-carcinogenic risk attributed to ingestion of lead in SK tap water was found to be negligible.

Deriving freshwater quality criteria for iron, lead, nickel, and zinc for protection of aquatic life in Malaysia

Freshwater quality criteria for iron (Fe), lead (Pb), nickel (Ni), and zinc (Zn) were developed with particular reference to aquatic biota in Malaysia, and based on USEPA's guidelines. Acute toxicity tests were performed on eight different freshwater domestic species in Malaysia which were Macrobrachium lanchesteri (prawn), two fish: Poecilia reticulata and Rasbora sumatrana, Melanoides tuberculata (snail), Stenocypris major (ostracod), Chironomus javanus (midge larvae), Nais elinguis (annelid), and Duttaphrynus melanostictus (tadpole) to determine 96 h LC(50) values for Fe, Pb, Ni, and Zn. The final acute value (FAV) for Fe, Pb, Ni, and Zn were 74.5, 17.0, 165, and 304.9 μg L(-1), respectively. Using an estimated acute-to-chronic ratio (ACR) of 8.3, the value for final chronic value (FCV) was derived. Based on FAV and FCV, a criterion maximum concentration (CMC) and a criterion continuous concentration (CCC) for Fe, Pb, Ni, and Zn that are 37.2, 8.5, 82.5, and 152.4 μg L(-1) and 9.0, 2.0, 19.9, and 36.7 μg L(-1), respectively, were derived. The results of this study provide useful data for deriving national or local water quality criteria for Fe, Pb, Ni, and Zn based on aquatic biota in Malaysia. Based on LC(50) values, this study indicated that N. elinguis, M. lanchesteri, N. elinguis, and R. sumatrana were the most sensitive to Fe, Pb, Ni, and Zn, respectively.

Adsorption of Ba2+ by Ca-exchange clinoptilolite tuff and montmorillonite clay

The adsorption of barium by Ca-exchanged clinoptilolite and montmorillonite is presented. The kinetics of adsorption of Ba(2+) were evaluated contacting 1g portion of each adsorber with 100mL 0.1N BaCl(2) for 200 h. Adsorption by Ca-clinoptilolite is defined by second-order kinetics of rate constant K(v) 8.232 x 10(-2) g mg(-1)h(-1) and maximum removal of 71.885 mg g(-1). It is a two-stage process initiated by a rapid uptake of Ba(2+) followed by more moderate kinetics. The adsorption isotherms were determined contacting 0.2g of each adsorber with 10 mL 0.1-0.005N BaCl(2)+CaCl(2) solution, Ba(2+)/Ca(2+) ratio 1, for periods of 7 days for the tuff and 2 days for the clay. The equilibrium adsorption is described by the Langmuir model, of equilibrium constant K 0.0151 L mg(-1) and maximum adsorption of 15.29 mg g(-1). The adsorption of Ba(2+) by Ca-exchanged montmorillonite also follows a second-order reaction of rate constant K(v) 3.179 x 10(-2) g mg(-1)h(-1), and calculated separation of 36.74 mg g(-1); the Langmuir isotherm is defined by the constant K 0.034 L mg(-1) and maximum adsorption of 15.29 mg g(-1). X-ray diffraction shows that the exchange of Ba(2+) modifies the d(001) of Ca-montmorillonite from 15.4 to 12.4A.

Seasonal and spatial variability of metals concentrations in Lake Beyşehir, Turkey

Lake Beyşehir is the largest fresh water lake and also the largest reservoir for drinking, and irrigation water in Turkey. The lake has an area of 656 km2 with an average depth of 5 m. Metal concentrations of aluminium (Al), cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), nickel (Ni), lead (Pb) and zinc (Zn) were determined in Lake Beyşehir on 9 June and 19 August 2005, and 12 June and 22 August 2006. The water samples were collected from 40 sampling stations. The aim of this research is to determine metal concentrations and their seasonal and spatial variability in the lake. Generally, metal concentrations of Lake Beyşehir were found to decrease in the sequence of Fe > Al > Zn > Cr > Ni > Pb > Cu > Cd as 92.8, 81.8, 7.4, 2.7, 2.2, 1.9, 1.7 and 0.5 microg L(-1), respectively. The results showed that the mean concentrations of the metals in the lake water did not exceed WHO (World Health Organization), US EPA (Environmental Protection Agency) or TWQCR (Turkish Water Pollution and Control Regulations) drinking water guidelines. On the other hand, maximum levels of metals sporadically exceeded these standards in some sampling stations, especially for Al, Cr, Fe, and Pb.