Recharge and Aquifer Response: Manukan Island’s Aquifer, Sabah, Malaysia

Manukan Island is a small island located in North-West of Sabah, Malaysia was used as a case study area for numerical modeling of an aquifer response to recharge and pumping rates. The results in this study present the variations of recharge into the aquifer under the prediction simulations. The recharge rate increases the water level as indicated by hydraulic heads. This shows that it can alter groundwater of Manukan Island which has been suffering from an overexploration in its unconfined the aquifer. The increase in recharge rate (from 600 mm/year to 750 mm/year) increases the water level indicated by hydraulic heads. A reduction in pumping rate (from 0.072 m3/day to 0.058 m3/day) not only increases the amount of water levels in aquifer but also reduces the supply hence a deficit in supply. The increase in hydraulic heads depends on the percentage reduction of pumping and recharges rates. The well water has 1978.3 mg/L chloride with current pumping (0.072 m3/day) and recharge rates (600 mm/year). However, with an increased of recharge rate and current pumping rate it has decreased about 1.13%. In addition, reduction in pumping rate made the chloride concentration decreased about 2.8%. In general, a reduction in pumping with an increase in recharge rate leads to a decreased in chloride concentrations within the vicinity of cone of depression. Next, to further develop the numerical model, the model should focus on climate change variables such as consequences of climate change are increase in air temperature, increase in sea surface temperature, and more extreme weather conditions. These parameters are considered critical parameters for climate change impact modeling in aquifers. The behavior of the aquifer and its sustainable pumping rate can be done by applying a computer modeling component

Spatial eco-risk assessment and prediction of heavy metal pollution in surface soil: a preliminary assessment of an urban area from a developing country

This study was conducted to investigate the total concentrations of heavy metals (Al, Cd, Co, Cr, Cu, Fe, Pb, and Zn), evaluate potential ecological risks, and predict the heavy metal contamination of surface soil in Klang District (Malaysia). Iron (Fe) was discovered as the highest while Cadmium (Cd) was the lowest heavy metal concentration in the surface soil of Klang district. Based on the data collected, the mean values for potential ecological risk index of single elements decreased from cadmium to chromium. Predicted fixed numbers of years were 11 and 21 for Cd accumulations at accelerated and uniform modes, respectively

A baseline study of tropical coastal water quality in Port Dickson, Strait of Malacca, Malaysia

Tidal variation in tropical coastal water plays an important role on physicochemical characteristics and nutrients concentration. Baseline measurements were made for nutrients concentration and physicochemical properties of coastal water, Port Dickson, Malaysia. pH, temperature, oxidation reduction potential, salinity and electrical conductivity have high values at high tides. Principal Components Analysis (PCA) was used to understand spatial variation of nutrients and physicochemical pattern of Port Dickson coastal water at high and low tide. Four principal components of PCA were extracted at low and high tides. Positively loaded nutrients with negative loadings of DO, pH and ORP in PCA outputs indicated nutrients contribution related with pollution sources. This study output will be a baseline frame for future studies in Port Dickson involving water and sediment samples. Water and sediment samples of future monitoring studies in Port Dickson coastal water will help in understanding of coastal water chemistry and pollution sources

A review of groundwater in islands using SWOT analysis

This paper has focused and reviewed the groundwater of 55 islands around the world using Strength, Weakness, Opportunities and Threats (SWOT) analyses selected based on existing literatures and studies conducted. The SWOT analysis output fills in the gap of scientific knowledge and helps in groundwater management. The overall of groundwater management in islands should be conducted by the highest government level. The institutional framework must make sure that any development and management of water resources in these islands take place in national level planning. The main thing is to ensure collaborations between agencies for sustainable management of groundwater in islands

Status, source identification, and health risks of potentially toxic element concentrations in road dust in a medium-sized city in a developing country

This study aims to determine the status of potentially toxic element concentrations of road dust in a medium-sized city (Rawang, Malaysia). This study adopts source identification via enrichment factor, Pearson correlation analysis, and Fourier spectral analysis to identify sources of potentially toxic element concentrations in road dust in Rawang City, Malaysia. Health risk assessment was conducted to determine potential health risks (carcinogenic and non-carcinogenic risks) among adults and children via multiple pathways (i.e., ingestion, dermal contact, and inhalation). Mean of potentially toxic element concentrations were found in the order of Pb > Zn > Cr(IV) > Cu > Ni > Cd > As > Co. Source identification revealed that Cu, Cd, Pb, Zn, Ni, and Cr(IV) are associated with anthropogenic sources in industrial and highly populated areas in northern and southern Rawang, cement factories in southern Rawang, as well as the rapid development and population growth in northwestern Rawang, which have resulted in high traffic congestion. Cobalt, Fe, and As are related to geological background and lithologies in Rawang. Pathway orders for both carcinogenic and non-carcinogenic risks are ingestion, dermal contact, and inhalation, involving adults and children. Non-carcinogenic health risks in adults were attributed to Cr(IV), Pb, and Cd, whereas Cu, Cd, Cr(IV), Pb, and Zn were found to have non-carcinogenic health risks for children. Cd, Cr(IV), Pb, and As may induce carcinogenic risks in adults and children, and the total lifetime cancer risk values exceeded incremental lifetime

Groundwater resources assessment using numerical model : a case study in low-lying coastal area.

The impacts of climate change and human pressure in groundwater have been greatest threats facing small islands. This paper represents a case study of groundwater responses towards the climate change and human pressures in Manukan Island Malaysia. SEAWAT-2000 was used for the simulations of groundwater response in study area. Simulations of six scenarios representing climate change and human pressures showed changes in hydraulic heads and chloride concentrations. Reduction in pumping rate and an increase in recharge rate can alter the bad effects of overdrafts in Manukan Island. In general, reduction in pumping rate and an increase in recharge rate are capable to restore and protect the groundwater resources in Manukan Island. Thus, for groundwater management options in Manukan Island, scenario 2 is capable to lessen the seawater intrusion into the aquifer and sustain water resources on a long-term basis. The selection of scenario 6 is the preeminent option during wet season. The output of this study provides a foundation which can be used in other small islands of similar hydrogeological condition for the purpose of groundwater resources protection

Statistical perspective and pollution indicator in Mengkabong Mangrove Sediment Sabah

The role of tidal processes on intertidal surface sedimentsis frequently stated but rarely investigated due to the methodological restrictions. This study provides a basis for describing the tidal effects on the mangrove sediment. It reports investigations into the chemical composition of mangrove surface sediment in Mengkabong lagoon, Sabah, Malaysia. The levels of 16 parameters were determined in 33 surface sediment samples at high and low tides. The studied parameters showed high values at high tide compared to low tide. The tidal process showed there is a high contribution of seawater that brings additional ions such as Na, Mg and K into the mangrove system at high tide whereas at low tide, lower contribution of seawater was observed. Spearman correlation coefficient was used for the statistical characterizations of mangrove surface sediment at high and low tides. Relationships between physicochemical parameters, metals, granulometric fractions, organic matter and base cations at high and low tides were observed. Geoaccumulation Index calculations showed current sediment quality of Mengkabong mangrove sediments could be classified as having background concentrations of Al, Cu, Fe, and Zn, and as unpolluted with regard to Pb. These findings are important for future research which will explain the chemistry that lies in mangrove sediment

Heavy metal exposure from cooked rice grain ingestion and its potential health risks to humans from total and bioavailable forms analysis

Heavy metal in rice studies has attracted a greater concern worldwide. However, there have been limited studies on marketed rice samples although it represents a vital ingestion portion for a real estimation of human health risk. This study was aimed to determine both total and bioaccessible of trace elements and heavy metals (Cd, Cr, Cu, Co, Al, Zn, As, Pb and Fe) in 22 varieties of cooked rice using an inductively coupled plasma-optical emission spectroscopy. Both total and bioaccessible of trace elements and heavy metals were digested using closed-nitric acid digestion and Rijksinstituut voor Volksgezondheid en Milieu (RIVM) in vitro digestion model, respectively. Human health risks via Health Risk Assessment (HRA) were conducted to understand exposure risks involving adults and children representing Malaysian population. Zinc was the highest while As was the lowest contents for total and in their bioavailable forms. Four clusters were identified: (1) Pb, As, Co, Cd and Cr; (2) Cu and Al; (3) Fe and (4) Zn. For HRA, there was no any risks found from single element exposure. While potential carcinogenic health risks present for both adult and children from single As exposure (Life time Cancer Risk, LCR > 1 × 10−4). Total Hazard Quotient values for adult and children were 27.0 and 18.0, respectively while total LCR values for adult and children were 0.0049 and 0.0032, respectively

Sources, mechanisms, and fate of steroid estrogens in wastewater treatment plants: a mini review

Steroid estrogens, such as estrone (E1), 17β-estradiol (E2), estriol (E3), and 17α-ethinylestradiol (EE2), are natural and synthetic hormones released into the environment through incomplete sewage discharge. This review focuses on the sources of steroid estrogens in wastewater treatment plants (WWTPs). The mechanisms and fate of steroid estrogens throughout the entire wastewater treatment system are also discussed, and relevant information on regulatory aspects is given. Municipal, pharmaceutical industry, and hospitals are the main sources of steroid estrogens that enter WWTPs. A typical WWTP comprises primary, secondary, and tertiary treatment units. Sorption and biodegradation are the main mechanisms for removal of steroid estrogens from WWTPs. The fate of steroid estrogens in WWTPs depends on the types of wastewater treatment systems. Steroid estrogens in the primary treatment unit are removed by sorption onto primary sludge, followed by sorption onto micro-flocs and biodegradation by microbes in the secondary treatment unit. Tertiary treatment employs nitrification, chlorination, or UV disinfection to improve the quality of the secondary effluent. Activated sludge treatment systems for steroid estrogens exhibit a removal efficiency of up to 100%, which is higher than that of the trickling filter treatment system (up to 75%). Moreover, the removal efficiency of advance treatment systems exceeds 90%. Regulatory aspects related to steroid estrogens are established, especially in the European Union. Japan is the only Asian country that implements a screening program and is actively involved in endocrine disruptor testing and assessment. This review improves our understanding of steroid estrogens in WWTPs, proposes main areas to be improved, and provides current knowledge on steroid estrogens in WWTPs for sustainable development

Preliminary analysis of selected tropical fruit seed extracts potential as natural coagulant in water

In this preliminary study, active coagulant extract from tropical fruit (jackfruit, durian, date, Malaysian Longan, tarap) seeds were explored as a potential natural coagulant for turbidity removal in water through multiple parameters (mass, dosage and settling time) by means of response surface methodology and adsorption isotherms. Extraction of active coagulant extracts from these tropical fruit seeds was conducted using sodium chloride solution and characterized using Fourier transform infrared spectrometer (FTIR). FTIR results have indicated the functional groups present in active coagulant extract solution from tropical fruit seeds are mainly proteins. Active coagulant extracts from tropical (jackfruit, durian, date, Malaysian longan, tarap) seeds have displayed total turbidity removal between 31.6 and 72%. Various models of Box-Behnken design for turbidity removal indicated that the linear model was the most suitable model for jackfruit, durian, Malaysian Longan and tarap fruit seeds, while the quadratic model was optimal for date fruit seed. In addition, active coagulant extract from date fruit seed was selected as the best active coagulant extract for turbidity removal in water using the highest R2 value (R2 = 0.984). Furthermore, results obtained from regression analysis and three-dimensional surface plots revealed that mass (3 g) and the settling time (90 min) were significant parameters for turbidity removal. Moreover, Langmuir adsorption model was observed to be the most suitable for the adsorption process by coagulant active extract from date fruit seeds with maximum adsorption capacity of 48.08 mg/g. This preliminary study has demonstrated active coagulant extracts from date seed as a promising natural coagulant which can be investigated further