A solid phase extraction (SPE) method has been developed using a newly synthesized titanium (IV) butoxide-cyanopropyltriethoxysilane (Ti-CNPrTEOS) sorbent for polar selective extraction of aromatic amines in river water sample. The effect of different parameters on the extraction recovery was studied using the SPE method. The applicability of the sorbents for the extraction of polar aromatic amines by the SPE was extensively studied and evaluated as a function of pH, conditioning solvent, sample loading volume, elution solvent and elution solvent volume. The optimum experimental conditions were sample at pH 7, dichloromethane as conditioning solvent, 10 mL sample loading volume and 5 mL of acetonitrile as the eluting solvent. Under the optimum conditions, the limit of detection (LOD) and limit of quantification (LOQ) for solid phase extraction using Ti-CNPrTEOS SPE sorbent (0.01-0.2; 0.03-0.61 µg L(-1)) were lower compared with those achieved using Si-CN SPE sorbent (0.25-1.50; 1.96-3.59 µg L(-1)) and C18 SPE sorbent (0.37-0.98; 1.87-2.87 µg L(-1)) with higher selectivity towards the extraction of polar aromatic amines. The optimized procedure was successfully applied for the solid phase extraction method of selected aromatic amines in river water, waste water and tap water samples prior to the gas chromatography-flame ionization detector separation.
Estuary sediments are one of the important components of coastal ecosystems and have been regarded as a sink for various types of organic pollutants. Organic pollutants such as endocrine disrupting compounds (EDCs) which have been associated with various environmental and human health effects were detected in the estuary sediment at trace level. Considering various interferences that may exist in the estuarine sediment, a sensitive and selective method, capable of detecting multiclass EDC pollutants at the trace levels, needs to be developed and optimized to be applied for environmental analysis. A combination of Soxhlet extraction followed by offline solid phase extraction (SPE) cleaned up with detection based on LC triple quadrupole MS was optimized and validated in this study. The targeted compounds consisted of ten multiclass EDCs, namely, diclofenac, primidone, bisphenol A, estrone (E1), 17β-estradiol (E2), 17α-ethynylestradiol (EE2), 4-octylphenol (4-OP), 4-nonylphenol (4-NP), progesterone, and testosterone. The method showed high extraction efficiency with percentage of recovery from 78% to 108% and excellent sensitivity with detection limit between 0.02ngg-1 and 0.81ngg-1. Excellent linearity from 0.991 to 0.999 was achieved for the developed compounds and the relative standard deviation was less than 18%, an indication of good precision analysis. Evaluation of the matrix effects showed ionization suppression for all the developed compounds. Verification of the method was carried out by analyzing the estuarine sediment collected from Langat River. The analyzed estuarine sediments showed a trace concentration of diclofenac, bisphenol A, progesterone, testosterone, primidone, and E1. However, E2, EE2, 4-OP, and 4-NP were below the method's detection limit. Diclofenac exhibited the highest concentration at 2.67ngg-1 followed by bisphenol A (1.78ngg-1) while E1 showed the lowest concentration at 0.07ngg-1.
Contamination by endocrine disrupting compounds (EDCs) concerns the security and sustainability of a drinking water supply system and human exposure via water consumption. This study analyzed the selected EDCs in source (river water, n = 10) and supply (tap water, n = 155) points and the associated risks. A total of 14 multiclass EDCs was detected in the drinking water supply system in Malaysia. Triclosan (an antimicrobial agent) and 4-octylphenol (a plasticizer) were only detected in the tap water (up to 9.74 and 0.44 ng/L, respectively). Meanwhile, chloramphenicol and 4-nonylphenol in the system were below the method detection limits. Bisphenol A was observed to be highest in tap water at 66.40 ng/L (detection: 100%; median concentration: 0.28 ng/L). There was a significant difference in triclosan contamination between the river and tap water (p
Environmental exposure to active pharmaceutical ingredients (APIs) can have negative effects on the health of ecosystems and humans. While numerous studies have monitored APIs in rivers, these employ different analytical methods, measure different APIs, and have ignored many of the countries of the world. This makes it difficult to quantify the scale of the problem from a global perspective. Furthermore, comparison of the existing data, generated for different studies/regions/continents, is challenging due to the vast differences between the analytical methodologies employed. Here, we present a global-scale study of API pollution in 258 of the world's rivers, representing the environmental influence of 471.4 million people across 137 geographic regions. Samples were obtained from 1,052 locations in 104 countries (representing all continents and 36 countries not previously studied for API contamination) and analyzed for 61 APIs. Highest cumulative API concentrations were observed in sub-Saharan Africa, south Asia, and South America. The most contaminated sites were in low- to middle-income countries and were associated with areas with poor wastewater and waste management infrastructure and pharmaceutical manufacturing. The most frequently detected APIs were carbamazepine, metformin, and caffeine (a compound also arising from lifestyle use), which were detected at over half of the sites monitored. Concentrations of at least one API at 25.7% of the sampling sites were greater than concentrations considered safe for aquatic organisms, or which are of concern in terms of selection for antimicrobial resistance. Therefore, pharmaceutical pollution poses a global threat to environmental and human health, as well as to delivery of the United Nations Sustainable Development Goals.
Soil temperature has a vital importance in biological, physical and chemical processes of terrestrial ecosystem and its modeling at different depths is very important for land-atmosphere interactions. The study compares four machine learning techniques, extreme learning machine (ELM), artificial neural networks (ANN), classification and regression trees (CART) and group method of data handling (GMDH) in estimating monthly soil temperatures at four different depths. Various combinations of climatic variables are utilized as input to the developed models. The models' outcomes are also compared with multi-linear regression based on Nash-Sutcliffe efficiency, root mean square error, and coefficient of determination statistics. ELM is found to be generally performs better than the other four alternatives in estimating soil temperatures. A decrease in performance of the models is observed by an increase in soil depth. It is found that soil temperatures at three depths (5, 10 and 50 cm) could be mapped utilizing only air temperature data as input while solar radiation and wind speed information are also required for estimating soil temperature at the depth of 100 cm.
Long-term (21-30 years) erosional responses of rainforest terrain in the Upper Segama catchment, Sabah, to selective logging are assessed at slope, small and large catchment scales. In the 0.44 km(2) Baru catchment, slope erosion measurements over 1990-2010 and sediment fingerprinting indicate that sediment sources 21 years after logging in 1989 are mainly road-linked, including fresh landslips and gullying of scars and toe deposits of 1994-1996 landslides. Analysis and modelling of 5-15 min stream-suspended sediment and discharge data demonstrate a reduction in storm-sediment response between 1996 and 2009, but not yet to pre-logging levels. An unmixing model using bed-sediment geochemical data indicates that 49 per cent of the 216 t km(-2) a(-1) 2009 sediment yield comes from 10 per cent of its area affected by road-linked landslides. Fallout (210)Pb and (137)Cs values from a lateral bench core indicate that sedimentation rates in the 721 km(2) Upper Segama catchment less than doubled with initially highly selective, low-slope logging in the 1980s, but rose 7-13 times when steep terrain was logged in 1992-1993 and 1999-2000. The need to keep steeplands under forest is emphasized if landsliding associated with current and predicted rises in extreme rainstorm magnitude-frequency is to be reduced in scale.
Muscle, stomach and gill from four dominant fish species, Mytus nemurus, Pristolepis fasciata, Ompok bimaculatus and Osteochilus hasseltii, caught from Bebar peat swamp forest river were analyzed for mercury (Hg). The concentration of Hg was measured with a fast and sensitive Flow Injector Mercury Spectrometer (FIMS). The average Hg concentration of all species caught was 0.169 microg g(-1) dry weights, lower than a limit for human consumption recommended by the World Health Organization, 0.5 microg g(-1) dry weights. The mean concentration of Hg was relatively high in stomach (0.28 +/- 0.12 microg g(-1) dry weights) followed by gill (0.17 +/- 0.06 microg g(-1) dry weights) and lowest in muscle (0.05 +/- 0.02 microg g(-1) dry weights). The positive relationship of Hg with fish length and weight suggesting that the accumulation of Hg were formed in the fish.
The molecular composition and distribution of sterols were investigated in the East China Sea to identify the origins of suspended particulate matter (SPM) in offshore waters influenced by Changjiang River Diluted Water (CRDW). Total sterol concentrations ranged from 3200 to 31,900pgL(-1) and 663 to 5690pgL(-1) in the particulate and dissolved phases, respectively. Marine sterols dominated representing 71% and 66% in the particulate and dissolved phases, respectively. Typical sewage markers, such as coprostanol, were usually absent at ~250km offshore. However, sterols from allochthonous terrestrial plants were still detected at these sites. A negative relationship was observed between salinity and concentrations of terrestrial sterols in SPM, suggesting that significant amounts of terrestrial particulate matter traveled long distance offshore in the East China Sea, and the Changjiang River Diluted Water (CRDW) was an effective carrier of land-derived particulate organic matter to the offshore East China Sea.
Polycyclic aromatic hydrocarbons (PAHs) and linear alkylbenzenes (LABs) were used as anthropogenic markers of organic chemical pollution of sediments in the Selangor River, Peninsular Malaysia. This study was conducted on sediment samples from the beginning of the estuary to the upstream river during dry and rainy seasons. The concentrations of ƩPAHs and ƩLABs ranged from 203 to 964 and from 23 to 113 ng g(-1) dry weight (dw), respectively. In particular, the Selangor River was found to have higher sedimentary levels of PAHs and LABs during the wet season than in the dry season, which was primarily associated with the intensity of domestic wastewater discharge and high amounts of urban runoff washing the pollutants from the surrounding area. The concentrations of the toxic contaminants were determined according to the Sediment Quality Guidelines (SQGs). The PAH levels in the Selangor River did not exceed the SQGs, for example, the effects range low (ERL) value, indicating that they cannot exert adverse biological effects.
This study aims to determine the concentration of sterols used as biomarkers in the surface microlayer (SML) in estuarine areas of the Selangor River, Malaysia. Samples were collected during different seasons through the use of a rotation drum. The analysis of sterols was performed using gas chromatography equipped with a flame ionisation detector (GC-FID). The results showed that the concentrations of total sterols in the SML ranged from 107.06 to 505.55 ng L(-1). The total sterol concentration was found to be higher in the wet season. Cholesterol was found to be the most abundant sterols component in the SML. The diagnostic ratios of sterols show the influence of natural sources and waste on the contribution of sterols in the SML. Further analysis, using principal component analysis (PCA), showed distinct inputs of sterols derived from human activity (40.58%), terrigenous and plant inputs (22.59%) as well as phytoplankton and marine inputs (17.35%).
This study aims to determine the levels of methylene blue active substances (MBAS) and ethyl violet active substances (EVAS) as anionic surfactants and of disulphine blue active substances (DBAS) as cationic surfactants in the surface microlayer (SML) around an estuarine area using colorimetric methods. The results show that the concentrations of surfactants around the estuarine area were dominated by anionic surfactants (MBAS and EVAS) with average concentrations of 0.39 and 0.51 μmol L⁻¹, respectively. There were significant between-station differences in surfactant concentrations (p<0.05) with higher concentrations found at the stations near the sea. The concentration of surfactants was higher during the rainy season than the dry season due to the influence of runoff water. Further investigation using total organic carbon (TOC) and total organic nitrogen (TON) shows that there is a significant correlation (p<0.05) between both anionic and cationic surfactants and the TON concentration.
This article describes design and application of feed-forward, fully-connected, three-layer perceptron neural network model for computing the water quality index (WQI)(1) for Kinta River (Malaysia). The modeling efforts showed that the optimal network architecture was 23-34-1 and that the best WQI predictions were associated with the quick propagation (QP) training algorithm; a learning rate of 0.06; and a QP coefficient of 1.75. The WQI predictions of this model had significant, positive, very high correlation (r=0.977, p<0.01) with the measured WQI values, implying that the model predictions explain around 95.4% of the variation in the measured WQI values. The approach presented in this article offers useful and powerful alternative to WQI computation and prediction, especially in the case of WQI calculation methods which involve lengthy computations and use of various sub-index formulae for each value, or range of values, of the constituent water quality variables.
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.
This study aimed to evaluate the spatial and temporal distribution of heavy metals (Cd, Cr, Cu, Co, Fe, Pb, Ni, V, and Zn) in the sediments of Bayan Lepas Free Industrial Zone of Penang, Malaysia. Ten sampling stations were selected and sediment samples were collected during low tide (2012-2013). Metals were analyzed and the spatial distribution of metals were evaluated based on GIS mapping. According to interim sediment quality guidelines (ISQG), metal contents ranged from below low level to above high level at different stations. Based on the geoaccumulation index (Igeo) of sediment, sampling stations were categorized from unpolluted to strongly polluted. The enrichment factor (EF) of metals in the sediment varied between no enrichment to extremely high enrichment. The potential ecological risk index (RI) indicated Bayan Lepas FIZ was at low risk.
The concentration, distribution, and risk assessment of parabens were determined in the surface water of the Terengganu River, Malaysia. Target chemicals were extracted via solid-phase extraction, followed by high-performance liquid chromatography analysis. Method optimization produced a high percentage recovery for methylparaben (MeP, 84.69 %), ethylparaben (EtP, 76.60 %), and propylparaben (PrP, 76.33 %). Results showed that higher concentrations were observed for MeP (3.60 μg/L) as compared with EtP (1.21 μg/L) and PrP (1.00 μg/L). Parabens are ubiquitously present in all sampling stations, with >99 % of detection. Salinity and conductivity were the major factors influencing the level of parabens in the surface water. Overall, we found no potential risk of parabens in the Terengganu River ecosystem due to low calculated risk assessment values (risk quotient
This study aimed to address the pressing issue of plastic pollution in aquatic ecosystems by assessing the prevalence and distribution of microplastics (MPs) in water and riverbank sediments of the Pekalongan River, a vital water source in Indonesia. From the present findings, MP concentrations in water ranged from 45.2 to 99.1 particles/L, while sediment concentrations ranged from 0.77 to 1.01 particles/g. This study revealed that fragment and film MPs constituted 30.1 % and 25.4 % of the total, respectively, with MPs measuring <1 mm and constituting 51.4 % of the total. Colored MPs, particularly blue and black MPs, accounted for 34 % of the total. The primary polymer components, as determined via Fourier transform infrared spectroscopy, were identified as polystyrene, polyester, and polyamide. In response to the escalating plastic waste crisis caused by single-use plastics, Pekalongan's local government implemented refuse segregation and recycling programs as part of its efforts to transition toward zero-waste practices.
The presence of endocrine disruptors in source water is of great concern because of their suspected adverse effects on humans, even when present at very low levels. As the main source of potable water supply, rivers in Malaysia are highly susceptible to contamination by various endocrine disruptors originating from anthropogenic activities. In this study, the contamination levels of 1,1,1-trichloro-2,2-bis (4-chlorophenyl) ethane (DDT) and its metabolites and di-(2-ethylhexyl) phthalate (DEHP) in rivers of Selangor were examined using gas chromatography-mass spectrometry. Samples were collected from sites representing source water for 18 drinking water treatment plants in Selangor between July 2008 and July 2009. DDT and its metabolites were detected in only 14% of the 192 samples analysed at levels ranging from 0.6 to 14.6 ng/L. Meanwhile DEHP was detected in 96.8% of the samples at levels ranging from below quantitation level (18 ng/L) to 970 ng/L. The detected levels of DDTs and DEHP were lower than the WHO and Malaysian Guidelines for Drinking Water Quality. Data obtained from this study should also serve as a reference point for future surveillance on these endocrine disruptors.
The study was performed to examine the occurrence of endocrine disrupting chemicals (EDCs), including four steroid estrogens, one plasticizer, and three preservatives in the Mahakam River, Indonesia. The physicochemical analysis of river water and sediment quality parameters were determined as well as the concentration of EDCs. The range of values for pH, total dissolved solids (TDS), dissolved oxygen (DO), biochemical oxygen demand (BOD), total suspended solids (TSS), nitrate, ammonium, phosphate, and oil/grease in river water and sediment were higher than recommended limits prescribed by the World Health Organization's Guidelines for Drinking-water Quality (GDWQ). Bisphenol A (BPA) was the most widely found EDC with the highest concentration level at 652 ng/L (mean 134 ng/L) in the river water and ranged from ND (not detected) to 952 ng/L (mean 275 ng/L) in the sediment. Correlation analysis to investigate the relationship between the EDCs' concentrations in water and sediment also revealed a significant correlation (R2 = 0.93) between the EDCs' concentrations. High concentrations of EDCs are found in urban and residential areas because these compounds are commonly found in both human and animal bodies, resulting in the disposal of EDCs into canals and rivers in urban and suburban areas, as well as livestock manure and waste that is generated from intensive livestock farming around the suburban area.
Sediment samples were analyzed for di-(2-ethylhexyl) phthalate (DEHP), an organic endocrine disruptor, in Houjing River in southern Taiwan. The average DEHP concentration at 10 sampling locations, spanning from upper, middle, and lower segments of the stream, was calculated at 3.81+/-6.36mgkg(-1)drywt. Highest concentration was recorded at the Jhongsing Bridge (20.22mgkg(-1)drywt.) near the Dashe Industrial Park, followed by the Renwu Bridge (8.93mgkg(-1)drywt.) near the Renwu Industrial Park. The surface sediment concentration of DEHP was found to be higher in the dry season (October and December), and lower in the wet (flood) season (August), indicating that sources of DEHP remained active and continued to recharge the Houjing River. Vertical sediment core analysis revealed that highest concentration occurred at the depth of 40-60cm, indicating that historical discharges of DEPH may have been higher than recent years. Domestic comparison of DEHP concentrations in sediment from highest to lowest could be categorized as northern, southern, central, and eastern Taiwan, respectively, and seemed to be positively correlated with population density and/or industrial activity. Compared to other countries, DEHP concentration of the Houjing River was relatively higher than rivers studied in Japan, Germany, Italy, and Malaysia, and was relatively lower than the Aire and Trent Rivers in the United Kingdom.
Malaysia has abundant sources of drinking water from river and groundwater. However, rapid developments have deteriorated quality of drinking water sources in Malaysia. Heavy metal studies in terms of drinking water, applications of health risk assessment and bio-monitoring in Malaysia were reviewed from 2003 to 2013. Studies on heavy metal in drinking water showed the levels are under the permissible limits as suggested by World Health Organization and Malaysian Ministry of Health. Future studies on the applications of health risk assessment are crucial in order to understand the risk of heavy metal exposure through drinking water to Malaysian population. Among the biomarkers that have been reviewed, toenail is the most useful tool to evaluate body burden of heavy metal. Toenails are easy to collect, store, transport and analysed. This review will give a clear guidance for future studies of Malaysian drinking water. In this way, it will help risk managers to minimize the exposure at optimum level as well as the government to formulate policies in safe guarding the population.