Malaysia is a developing country in Southeast Asia, with rapid industrial and economic growth. Speedy population growth and aggressive consumerism in the past five decades have resulted in environmental pollution issues, including products containing polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs). PCBs and PBDEs are classified as persistent organic pollutants (POPs) by the Stockholm Convention due to their persistence, bioaccumulation in the environment and toxicity to humans and wildlife. These compounds are known to cause liver dysfunction, thyroid toxicity, developmental neuro-toxicity and possibly cancer. PCBs in air, mussels, pellets, seawater, fresh water, and human breast milk samples were analyzed in Malaysia, while studies on the pollution level of PBDEs in Malaysia were conducted on mussels, soils, leachate and sediment samples. PCBs in breast milk collected from Malaysia was the highest among Asian developing countries, with mean concentration of 80 ng/g lipid weight. On the other hand, the mean concentration of PCBs in mussels collected from Malaysia recorded the second lowest, with 56 ng/g and 89 ng/g lipid weight in two studies respectively. The concentrations of PBDEs in mussels taken from Malaysia fall in the range of 0.84-16 ng/g lipid weight, which is considerably low compared to 104.5 ng/g lipid weight in Philippines and 90.59 ng/g in Korea. Nevertheless, there are limited studies on these compounds in Malaysia, particularly there is no research on PBDEs in breast milk and sediment samples. This review will summarize the contamination levels of PCBs and PBDEs in different samples collected from Asian countries since 1988 until 2010 with a focus on Malaysia and will provide needed information for further research in this field.
This study reports the concentrations and congener partners of polychlorinated biphenyls (PCBs) in commercially available paints. Polycyclic-type pigments containing dioxazine violet (pigment violet (PV) 23, PV37) and diketopyrrolopyrrole (PR254, PR255) were found to contain PCB-56, PCB-77, PCB-40, PCB-5, and PCB-12, and PCB-6, PCB-13, and PCB-15, respectively, as major congeners. Dioxazine violet is contaminated with by-products during synthesis from o-dichlorobenzene, which is used as a solvent during synthesis, and diketopyrrolopyrrole is contaminated with by-products during synthesis from p-chlorobenzonitrile. The concentration of PCBs in paint containing PV23 or PV37 was 0.050-29 mg/kg, and toxic equivalency (TEQ) values ranged 1.1-160 pg-TEQ/g. The concentration of PCBs in paint containing PR254 or PR255 was 0.0019-2.4 mg/kg. Naphthol AS is an azo-type pigment, and PCB-52 was detected in paint containing pigment red (PR) 9 with 2,5-dichloroaniline as its source. PCB-146, PCB-149, and PCB-153 were identified from paint containing PR112 produced from 2,4,5-trichloroaniline, as major congeners. These congeners have chlorine positions similar to aniline, indicating that these congeners are by-products obtained during the synthesis of pigments. The concentrations of PCBs in paints containing PR9 and PR112 were 0.0042-0.43 and 0.0044-3.8 mg/kg, respectively. The corresponding TEQ for PR112 was 0.0039-8.6 pg-TEQ/g.
The Changbai (also known as "Baekdu") Mountain, on the border between China and North Korea, is the highest mountain (2750 m) in northeastern China. Recently, this mountain region has experienced a dramatic increase in air pollution, not only because of increasing volumes of tourism-derived traffic but also because of the long-range transport of polluted westerly winds passing through major industrial and urban cities in the eastern region of China. To assess the relative importance of the two sources of pollution, 16 polycyclic aromatic hydrocarbons (PAHs) as model substances were determined in the mountain soil. A total of 32 soil samples were collected from different sides of the mountain at different latitudes between July and August of 2009. The ∑PAH concentrations were within the range 38.5-190.1 ng g(-1) on the northern side, 117.7-443.6 ng g(-1) on the southern side, and 75.3-437.3 ng g(-1) on the western side. A progressive increase in the level of ∑PAHs with latitude was observed on the southern and western sides that face the westerly wind with abundant precipitation. However, a similar concentration gradient was not observed on the northern side that receives less rain and is on the leeward direction of the wind. The high-molecular-weight PAH compounds were predominant in the soils on the southern and western sides, while low-molecular-weight PAHs dominated the northern side soils. These findings show that the distribution of PAHs in the mountain soil is strongly influenced by the atmospheric long-range transport and cold trapping.
In this study, we isolated two indigenous hydrocarbon-degrading bacteria from tarball found in Rhu Sepuluh beach, Terengganu, Malaysia. These bacteria were identified based on their physiological characteristic and 16S rRNA gene sequence analysis, and they showed 99% similarity with Cellulosimicrobium cellulans DSM 43879 and Acinetobacter baumannii ATCC 19606 respectively. Their hydrocarbon-degrading capabilities were tested using diesel-oil as sole carbon source. Results analysed using GC-MS, showed diesel-oil alkanes were degraded an average 64.4% by C. cellulans and 58.1% by A. baumannii with medium optical density reaching 0.967 (C. cellulans) and 1.515 (A. baumannii) in minimal salt media at 32°C for 10days. Individual diesel-oil alkanes were degraded between 10%-95.4% by C. cellulans and 0.2%-95.9% by A. baumannii. Both strains utilized diesel-oil for growth. The study suggests both strains are part of indigenous hydrocarbon-degrading bacteria in tarball with potential for bioremediation of oil-polluted marine environment.
Benzene, toluene, ethylbenzene and xylenes (BTEX) are well known hazardous volatile organic compounds (VOCs) due to their human health risks and photochemical effects. The main objective of this study was to estimate BTEX levels and evaluate interspecies ratios and ozone formation potentials (OFP) in the ambient air of urban Kuala Lumpur (KL) based on a passive sampling method with a Tenax® GR adsorbent tube. Analysis of BTEX was performed using a thermal desorption (TD)-gas chromatography mass spectrometer (GCMS). OFP was calculated based on the Maximum Incremental Reactivity (MIR). Results from this study showed that the average total BTEX during the sampling period was 66.06 ± 2.39 μg/m3. Toluene (27.70 ± 0.97 μg/m3) was the highest, followed by m,p-xylene (13.87 ± 0.36 μg/m3), o-xylene (11.49 ± 0.39 μg/m3), ethylbenzene (8.46 ± 0.34 μg/m3) and benzene (3.86 ± 0.31 μg/m3). The ratio of toluene to benzene (T:B) is > 7, suggesting that VOCs in the Kuala Lumpur urban environment are influenced by vehicle emissions and other anthropogenic sources. The average of ozone formation potential (OFP) value from BTEX was 278.42 ± 74.64 μg/m3 with toluene and xylenes being the major contributors to OFP. This study also indicated that the average of benzene concentration in KL was slightly lower than the European Union (EU)-recommended health limit value for benzene of 5 μg/m3 annual exposure.
Phthalates have been blended in various compositions as plasticizers worldwide for a variety of purposes. Consequently, humans are exposed to a wide spectrum of phthalates that needs to be researched and understood correctly. The goal of this review is to focus on phthalate's internal exposure pathways and possible role of human digestion on liver toxicity. In addition, special focus was made on stem cell therapy in reverting liver toxicity. The known entry of higher molecular weight phthalates is through ingestion while inhalation and dermal pathways are for lower molecular weight phthalates. In human body, certain phthalates are digested through phase 1 (hydrolysis, oxidation) and phase 2 (conjugation) metabolic processes. The phthalates that are made bioavailable through digestion enter the blood stream and reach the liver for further detoxification, and these are excreted via urine and/or feces. Bis(2-ethylhexyl) phthalate (DEHP) is a compound well studied involving human metabolism. Liver plays a pivotal role in humans for detoxification of pollutants. Thus, continuous exposure to phthalates in humans may lead to inhibition of liver detoxifying enzymes and may result in liver dysfunction. The potential of stem cell therapy addressed herewith will revert liver dysfunction and lead to restoration of liver function properly.
In this study, we analyzed hydroxylated polychlorinated biphenyls (OH-PCBs) in urine of both PCB transport workers and PCB researchers. A method to monitor OH-PCB in urine was developed. Urine was solid-phase extracted with 0.1% ammonia/ methanol (v/v) and glucuronic acid/sulfate conjugates and then decomposed using β-glucuronidase/arylsulfatase. After alkaline digestion/derivatization, the concentration of OH-PCBs was determined by HRGC/HRMS-SIM. In the first sampling campaign, the worker's OH-PCB levels increased several fold after the PCB waste transportation work, indicating exposure to PCBs. The concentration of OH-PCBs in PCB transport workers' urine (0.55~11 μg/g creatinine (Cre)) was higher than in PCB researchers' urine (
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.
Sewage pollution is one of major concerns of coastal and shoreline settlements in Southeast Asia, especially Brunei. The distribution and sources of LABs as sewage molecular markers were evaluated in surface sediments collected from Brunei Bay. The samples were extracted, fractionated and analyzed using gas chromatography- mass spectrometry (GC-MS). LABs concentrations ranged from 7.1 to 41.3 ng g(-1) dry weight (dw) in surficial sediments from Brunei Bay. The study results showed LABs concentrations variably due to the LABs intensity and anthropogenic influence along Brunei Bay in recent years. The ratio of Internal to External isomers (I/E ratio) of LABs in sediment samples from Brunei Bay ranged from 0.56 to 2.17 along Brunei Bay stations, indicating that the study areas were receiving primary and secondary effluents. This is the first study carried out to assess the distribution and sources of LABs in surface sediments from Brunei Bay, Brunei.
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 is the first extensive report on linear alkylbenzenes (LABs) as sewage molecular markers in surface sediments collected from the Perlis, Kedah, Merbok, Prai, and Perak Rivers and Estuaries in the west of Peninsular Malaysia. Sediment samples were extracted, fractionated, and analyzed using gas chromatography mass spectrometry (GC-MS). The concentrations of total LABs ranged from 68 to 154 (Perlis River), 103 to 314 (Kedah River), 242 to 1062 (Merbok River), 1985 to 2910 (Prai River), and 217 to 329 ng g(-1) (Perak River) dry weight (dw). The highest levels of LABs were found at PI3 (Prai Estuary) due to the rapid industrialization and population growth in this region, while the lowest concentrations of LABs were found at PS1 (upstream of Perlis River). The LABs ratio of internal to external isomers (I/E) in this study ranged from 0.56 at KH1 (upstream of Kedah River) to 1.35 at MK3 (Merbok Estuary) indicating that the rivers receive raw sewage and primary treatment effluents in the study area. In general, the results of this paper highlighted the necessity of continuation of water treatment system improvement in Malaysia.