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Total alkalinity is one of the important parameter in the regulation of seawater carbonate chemistry system to determine the capacity of water to neutralize acid. In this paper, a new proton pump membrane was successfully modified using polyvinylpyrrolidone (PVP) as a supporting material due to its excellent chemical properties. The surface morphology of the membrane was thoroughly studied using Scanning Electron Microscope (SEM), which showed the presence of pore structure, ascribed to the presence of low molecular weight of PVP. The absorption of membrane was studied using Ultraviolet-Visible (UV-Vis) spectrophotometer, where the peak appeared at 539 nm-1. The functional group of the modified membrane was analyzed using Fourier Transform Infrared Spectroscopy (FTIR), and the spectra showed almost similar between modified membrane with PVP and without PVP. The electrochemical behaviour of the membrane was evaluated by cyclic voltammetry (CV) using gold (Au) electrode and the resulting voltammogram showed that the modified membrane with PVP has higher current reading compared to the membrane without PVP, indicating that there is redox reaction occured during the immobilization. The condition and perfomance of modified proton pump membrane with PVP was compared and analyzed.

Endocrine disrupting compounds (EDCs) are currently a global issue and have been ubiquitously found in various environmental compartment particularly in surface water. An analytical method employing a solid phase extraction in combination with HPLC-DAD was optimized for analysis of EDCs in surface river water. The optimized method showed a high mean extraction recovery for BPA at 73.84% while satisfactory recovery was achieved for E2 at 35.78%. It was then applied to analyse the level of BPA and E2 in the surface water of Ibai River, Terengganu. BPA and E2 were detected in this river with the concentration for both compounds ranging from 0.54 μg/L to 50.10 μg/L and 1.14 μg/L to 8.64 μg/L, respectively. Domestic waste discharge and animal manure might contribute to the presence of BPA and E2 in this river system as both compounds exhibited higher concentrations at sampling locations near those sources.

Irgarol 1051 and diuron are photosystem II inhibitors in agricultural activities and antifouling paints in the shipping sector. This study focused on three major ports (western, southern, and eastern) surrounding Peninsular Malaysia to construct the distribution of both biocides on the basis of the seasonal and geographical changes. Surface seawater samples were collected from November 2011 to April 2012 and pretreated using the solid-phase extraction technique followed by quantification with GC-MS and LC-MS-MS for Irgarol 1051 and diuron, respectively. Generally, the distribution of Irgarol 1051 was lowest during November 2011 and highest during April 2012, and similar patterns were observed at all ports, whereas the distribution of diuron was rather vague. The increasing pattern of Irgarol 1051 from time to time is probably related to its accumulation in the seawater as a result of its half-life and consistent utilization. On the basis of the discriminant analysis, the temporal distribution of Irgarol 1051 varied at Klang North Port, Klang South Port, and Pasir Gudang Port, whereas diuron was temporally varied only at Kemaman Port. Furthermore, Irgarol 1051 was spatially varied during November 2011, whereas diuron did not show any significant changes throughout all sampling periods. Ecological risk assessment exhibited a high risk for diuron and Irgarol 1051, but Irgarol 1051 should be of greater concern because of its higher risk compared to that of diuron. Thus, it is recommended that the current Malaysian guidelines and regulations of biocide application should be reevaluated and improved to protect the ecosystem, as well as to prevent ecological risks to the aquatic environment.

In December 2019, a novel coronavirus called severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) outbreak was reported for the first time in Wuhan, Hubei province, China. This coronavirus has been referred as Coronavirus Disease 2019 or COVID-19 by World Health Organization (WHO). The spread of COVID-19 has become unstoppable, infecting around 93.5 million people worldwide, with the infections and deaths still increasing. Today, the entire planet has changed due to the greatest threat on the planet since the introduction of this lethal disease. This pandemic has left the world in turmoil and various measures have been taken by many countries including movement control order or lockdown, to slow down or mitigate the infection. Since the lockdown has been implemented almost in all affected countries, there has been a significant reduction in anthropogenic activity, including a reduction in industrial operations, vehicle numbers, and marine-related activities. All of these changes have also led to some unexpected environmental consequences. As a result of this lockdown, it had a positive and negative impact on the environment including the aquatic environment. Hence this review will therefore focus on the good and bad perspectives of the lockdown toward the aquatic environment. © 2021 Penerbit Universiti Kebangsaan Malaysia. All rights reserved.

The occurrence, level, and distribution of multiclass emerging organic contaminants (EOCs) in fish and mollusks from the Klang River estuary were examined. The targeted EOCs for this assessment were phenolic endocrine disrupting compounds (bisphenol A, 4-OP, and 4-NP), organophosphorous pesticides (quinalphos, chlorpyrifos, and diazinon), estrogenic hormones (E2, E1, and EE2), and pharmaceutically active chemicals (primidone, sulfamethoxazole, dexamethasone, diclofenac, amoxicillin, progesterone, and testosterone). Results from this study showed that the prevalent contamination of the Klang River estuary by EOCs with diclofenac, bisphenol A, progesterone, and amoxicillin were predominantly detected in fish and mollusks. Among the EOCs, diclofenac and progesterone had the highest concentrations in fish and mollusk samples, respectively. The concentrations of diclofenac and progesterone in fish and mollusk samples range from 1.42 ng/g to 10.76 ng/g and from 0.73 ng/g to 9.57 ng/g, respectively. Bisphenol A should also be highlighted because of its significant presence in both fish and mollusks. The concentration of bisphenol A in both matrices range from 0.92 ng/g to 5.79 ng/g. The calculated hazard quotient (HQ) for diclofenac, bisphenol A, and progesterone without consideration to their degradation byproduct were less than one, thus suggesting that the consumption of fish and mollusks from the Klang River estuary will unlikely pose any health risk to consumers on the basis of the current assessment. Nonetheless, this preliminary result is an important finding for pollution studies in Malaysian tropical coastal ecosystems, particularly for organic micropollutant EOCs, and can serve as a baseline database for future reference.

The concentration profile, distribution and risk assessment of pharmaceutically active compounds (PhACs) in the coastal surface water from the Klang River estuary were measured. Surface coastal water samples were extracted using offline solid phase, applying polymeric C18 cartridges as extraction sorbent and measuring with liquid chromatography mass spectrometry–mass spectrometry (LC MS–MS) technique. Extraction method was optimized for its recovery, sensitivity and linearity. Excellent recoveries were obtained from the optimized method with percentage of recoveries ranging from 73 to 126%. The optimized analytical method achieved good sensitivity with limit of detection ranging from 0.05 to 0.15 ng L−1, while linearity of targeted compounds in the LC MS–MS system was more than 0.990. The results showed that amoxicillin has the highest concentration (102.31 ng L−1) followed by diclofenac (10.80 ng L−1) and primidone (7.74 ng L−1). The percentage of contribution (% of total concentration) for the targeted PhACs is in the following order; amoxicillin (92.90%) > diclofenac (3.95%) > primidone (1.23%) > dexamethasone (0.75%) > testosterone (0.70%) > sulfamethoxazole (0.33%) > progesterone (0.14%). Environmental risk assessment calculated based on deterministic approach (the RQ method), showed no present risk from the presence of PhACs in the coastal water of Klang River estuary. Nonetheless, this baseline assessment can be used for better understanding on PhACs pollution profile and distribution in the tropical coastal and estuarine ecosystem as well as for future comparative studies.

Marine biota is one of the important components of an ecosystem, and it has been widely used as a pollution indicator for emerging organic contaminants (EOCs) in the coastal zone. Previous studies divulged the concentration of EOCs in various types of biota matrices at trace level detection. EOCs have been associated with several adverse human health effects. Bioaccumulation of EOCs in the food web has been the main concern, and thus a sensitive and selective method for trace quantification of EOCs in biota matrices need to be developed and optimized. Considering various matrix interferences for EOC analysis in marine biota, a combination technique of QuEChERS and solid phase extraction cleanup with detection based on liquid chromatography with tandem mass spectrometry (LC MS/MS) is presented in this study. A method for 16 compounds grouped into four different classes, namely, pharmaceutically active chemicals, phenolic endocrine disrupter compounds, estrogenic hormones, and pesticides, was developed and validated for biota extraction. Satisfactory extraction was obtained for the optimized method with percentage of recovery from 64% to 114% and excellent sensitivity with detection limit in the range of 0.02–3.50 ng/g. Linearity of the standards (in the solvent) in the LC MS-MS analysis ranged from 0.991 to 0.999. The relative standard deviation for intra-day and inter-day repeatability was less than 20%, indicating good-precision analysis. Assessment on the matrix effects showed ionization suppression for all the developed compounds. The developed method was verified by analyzing biota matrices collected from the Klang River estuary. Trace concentrations of EOCs, ranging from 0.05 to 10.76 ng/g, were found in those matrices. Of the 16 targeted compounds, 10 were detected, namely, diclofenac, bisphenol A, sulfamethoxazole, amoxicillin, E2, E1, progesterone, testosterone, primidone, and 4-octylphenol. The other compounds were below the method detection limit.

The presence and distribution of endocrine-disrupting chemicals (EDCs) in the mariculture fish from Pulau Kukup, Johor of Malaysia have been studied along with the impact on human health. Six different species of mariculture fish were collected, due to their high consumption in the Asian region-especially Malaysia, to assess their levels of EDCs. The highest concentration of EDCs detected in the muscle was dexamethasone (2.37-15.84 ng/g) and (0.77-13.41 ng/g), in the liver was dexamethasone (2.54-43.56 ng/g) and progesterone (2.23-9.78 ng/g), and in the reproductive organ are dexamethasone (2.54-37.23 ng/g) and caffeine (0.21-18.92 ng/g). The human health risk assessment in the current study suggested that there is no potential risk to the consumer because the hazard index was below 1 (HI 1). The present study provides information on the pollution profile of EDCs and the associated human health risk with EDCs in mariculture fish.

Endocrine disrupting compounds (EDCs) have been widely reported as potential carcinogenic threats to the human population. The release of EDCs to environmental compartments, such as water, sediment, and biota, has been monitored extensively. Considering the typically low levels of EDC concentrations found in environmental samples and the complexity of biota matrices, the main challenge is with the extraction and cleanup of samples, as well as with finding a sensitive enough instrumentation system for analyte detection. This paper presents a review of recent trends in the analysis of EDCs in environmental matrices. The focus of this review is three classes of environmentally important EDCs; namely, pharmaceuticals, estrogenic hormones, and alkylphenol compounds. Discussions about state-of-the-art instrumentation and sample preparation techniques, as well as a review of sample storage and preservation, are highlighted. Overall, the use of LC-MS-MS as an instrumentation technique has increased over the past 15 years.

Pesticide contamination in the environment is a contemporary global issue. As agricultural production through crop planting in Malaysia now supports both energy and food productions, the concentration and distribution of pesticides in surface water may have changed. Therefore, this study assesses the concentration and distribution of organophosphorus pesticides (quinalphos, diazinon and chlorpyrifos) contamination in the Langat River, Selangor. The Langat River Basin is one of the most populated river basins in Malaysia. As a result, it is surrounded by various environmental stresses of which agricultural activity is a dominant cause. An analytical method has been developed and optimised based on solid-phase extraction and high-performance liquid chromatography, coupled with a diode array detector (SPE–HPLC–DAD). This method allowed for the determination and quantification of selected organophosphorus pesticides. The optimised method displays a high mean recovery for both quinalphos and diazinon (100.21 and 100.15 %, respectively) but relatively low recovery for chlorpyrifos (32.40 %). The low recovery of chlorpyrifos is due to limitations in the determination of multi-residues in a single analytical run, optimisation of chromatographic conditions and the recovery of each compound. The method detection limit was found to be 0.003 μg/L for quinalphos and diazinon, and 0.006 μg/L for chlorpyrifos. Sample analyses revealed the occurrence of quinalphos, diazinon and chlorpyrifos in the Langat River with chlorpyrifos found to have the highest mean concentration of 0.0202 μg/L. The quinalphos and diazinon sample concentrations were 0.0178 μg/L and 0.0094 μg/L, respectively. The concentrations of organophosphorus pesticides in this monitoring study were found to be below the Maximum Contaminant Levels (MCLs) established under the European Union (Drinking Water) Regulation 2014. This study was the first to detect concentrations of quinalphos and diazinon in the Langat River, Selangor.

This baseline assessment reports on the occurrence, distribution, and sources of emerging organic contaminants (EOCs) in tropical coastal sediments of anthropogenically impacted Klang River estuary, Malaysia. Bisphenol A was the highest concentration detected at 16.84 ng g-1 dry weight, followed by diclofenac (13.88 ng g-1 dry weight) and E1 (12.47 ng g-1 dry weight). Five compounds, namely, amoxicillin, progesterone, diazinon, bisphenol A, and E1, were found in all sampling stations assessed, and other compounds such as primidone, diclofenac, testosterone, E2, and EE2 were ubiquitously present in sediment samples, with percentage of detection range from 89.04% to 98.38%. Organic carbon content and pH were the important factors controlling the fate of targeted compounds in the tropical estuarine sediment. On the basis of the literature from other studies, the sources of EOCs are thought to be from wastewater treatment plants, domestic/medical waste discharge, livestock activities, industrial waste discharge, and agricultural activities.

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.

Samples of palm oil and palm kernel oil (PKO) products were collected from two palm oil processing premises which were named as premise A and B. These samples were then analysed for dioxins and dioxin-like polychlorinated biphenyls (PCBs) content. The concentration of dioxins in the palm oil and PKO samples from premise A ranged from 0.128 World Health Organization-toxic equivalency (WHO-TEQ) pg/g fat to 0.189 WHO-TEQ pg/g fat while the concentration in samples collected from premise B ranged from 0.149 WHO-TEQ pg/g fat to 0.540 WHO-TEQ pg/g fat. Meanwhile, dioxin-like PCBs concentration ranged from 0.336 WHO-TEQ pg/g fat to 0.546 WHO-TEQ pg/g fat for premise A and 0.345 WHO-TEQ pg/g fat to 0.346 WHO-TEQ pg/g fat for premise B. The total numbers of samples analysed were 35 and the levels exhibited were below the maximum level of 0.75 WHO-TEQ pg/g fat and 1.25 WHO-TEQ pg/g fat imposed by the European Commission for dioxins and the sum of dioxins + dioxin-like PCBs content in vegetable oils.