This study aimed to determine the spatial distribution of PM2.5 and PM10 collected in four regions (North, Central, South and East Coast) of Peninsular Malaysia during the southwest monsoon. Concurrent measurements of PM2.5 and PM10 were performed using a high volume sampler (HVS) for 24 h (August to September 2018) collecting a total of 104 samples. All samples were then analysed for water soluble inorganic ions (WSII) using ion chromatography, trace metals using inductively coupled plasma-mass spectroscopy (ICP-MS) and polycyclic aromatic hydrocarbon (PAHs) using gas chromatography-mass spectroscopy (GC-MS). The results showed that the highest average PM2.5 concentration during the sampling campaign was in the North region (33.2 ± 5.3 μg m-3) while for PM10 the highest was in the Central region (38.6 ± 7.70 μg m-3). WSII recorded contributions of 22% for PM2.5 and 20% for PM10 mass, with SO42- the most abundant species with average concentrations of 1.83 ± 0.42 μg m-3 (PM2.5) and 2.19 ± 0.27 μg m-3 (PM10). Using a Positive Matrix Factorization (PMF) model, soil fertilizer (23%) was identified as the major source of PM2.5 while industrial activity (25%) was identified as the major source of PM10. Overall, the studied metals had hazard quotients (HQ) value of <1 indicating a very low risk of non-carcinogenic elements while the highest excess lifetime cancer risk (ELCR) was recorded for Cr VI in the South region with values of 8.4E-06 (PM2.5) and 6.6E-05 (PM10). The incremental lifetime cancer risk (ILCR) calculated from the PAH concentrations was within the acceptable range for all regions.
Rapid increase in industrialization and urbanization in the west coast of Peninsular Malaysia has led to the intense release of petroleum and products of petroleum into the environment. Surface sediment samples were collected from the Selangor River in the west coast of Peninsular Malaysia during four climatic seasons and analyzed for PAHs and biomarkers (hopanes). Sediments were soxhlet extracted and further purified and fractionated through first and second step column chromatography. A gas chromatography-mass spectrometry (GC-MS) was used for analysis of PAHs and hopanes fractions. The average concentrations of total PAHs ranged from 219.7 to 672.3 ng g-1 dw. The highest concentrations of PAHs were detected at 964.7 ng g-1 dw in station S5 in the mouth of the Selangor River during the wet inter-monsoonal season. Both pyrogenic and petrogenic PAHs were detected in the sediments with a predominance of the former. The composition of hopanes was homogeneous showing that petroleum hydrocarbons share an identical source in the study area. Diagnostic ratios of hopanes indicated that some of the sediment samples carry the crankcase oil signature.
Poly(β-cyclodextrin-ionic liquid) grafted magnetic nanoparticles combined with 1-octanol as supramolecular solvents (SUPRASs) presenting new ferrofluid was developed and successfully applied in the dispersive liquid-phase microextraction of seven representative polycyclic aromatic hydrocarbons. One variable at-a-time (OVAT) analysis and response surface methodology (RSM) were used for efficient optimization of the main variables. The calibration curves were found to be linear in the range of 0.1-150 ng mL-1 with correlation of determinations (R2) ranging from 0.9944 to 0.9986. Detection limits ranged at 0.02-0.07 ng mL-1 for all studied PAHs. The intra and inter-day precision values (RSD %) were in the range of 1.80%-7.56% and 2.97%-8.23%, respectively. The ferrofluid showed a satisfactory reproducibility between 1.72% and 5.90%, and acceptable recovery values at 84%-110% were obtained for the real samples analysis. The optimized method was successfully applied to access the content safety of the PAHs studied in a variety of commercial food and beverages available in Malaysia.
With more than 80 cytochrome P450 (CYP) encoding genes found in the nematode Caenorhabditis elegans (C. elegans), the cyp35 genes are one of the important genes involved in many biological processes such as fatty acid synthesis and storage, xenobiotic stress response, dauer and eggshell formation, and xenobiotic metabolism. The C. elegans CYP35 subfamily consisted of A, B, C, and D, which have the closest homolog to human CYP2 family. C. elegans homologs could answer part of the hunt for human disease genes. This review aims to provide an overview of CYP35 in C. elegans and their human homologs, to explore the roles of CYP35 in various C. elegans biological processes, and how the genes of cyp35 upregulation or downregulation are influenced by biological processes, upon exposure to xenobiotics or changes in diet and environment. The C. elegans CYP35 gene expression could be upregulated by heavy metals, pesticides, anti-parasitic and anti-chemotherapeutic agents, polycyclic aromatic hydrocarbons (PAHs), nanoparticles, drugs, and organic chemical compounds. Among the cyp35 genes, cyp-35A2 is involved in most of the C. elegans biological processes regulation. Further venture of cyp35 genes, the closest homolog of CYP2 which is the largest family of human CYPs, may have the power to locate cyps gene targets, discovery of novel therapeutic strategies, and possibly a successful medical regime to combat obesity, cancers, and cyps gene-related diseases.
This study investigated the simultaneous formation of polycyclic aromatic hydrocarbons (PAHs) and heterocyclic aromatic amines (HCAs) in gas-grilled beef satay at different temperatures (150, 200, 250, 300, and 350°C). Solid-phase extraction (SPE) was used for sample clean-up. Fifteen PAHs were determined using high performance liquid chromatography with fluorescence detection (HPLC-FLD) and nine HCAs were quantified using liquid chromatography tandem-mass spectrometry (LC-MS/MS) with a gradient programme. The lowest significantly concentrations of PAHs and HCAs were generated at 150°C; the formation of PAHs and HCAs simultaneously increased with temperatures. Benzo[a]pyrene was detected in all samples and increased markedly at 300 and 350°C. The sums of 4 PAHs (PAH4) in marinated beef satay at 300 and 350°C exceeded the maximum level in Commission Regulation (EU) 2015/1125. Significant reductions of polar and non-polar HCAs (except PhIP) were found in marinated beef satay across all temperatures. Overall, PAHs and HCAs showed opposite trends of formation in beef satay with marination.
Novel aromatic embedded Schiff bases have been synthesized in ionic liquid [bmim]Br and evaluated in vitro for their acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes inhibitory activities. Among the newly synthesized compounds, 5f, 5h and 7j displayed higher AChE enzyme inhibitory activities than standard drug, galanthamine, with IC50 values of 1.88, 2.05 and 2.03μM, respectively. Interestingly, all the compounds except for compound 5c displayed higher BChE inhibitories than standard with IC50 values ranging from 3.49 to 19.86μM. Molecular docking analysis for 5f and 7j possessing the most potent AChE and BChE inhibitory activities, disclosed their binding interaction templates to the active site of AChE and BChE enzymes, respectively.
The contamination of water bodies from heavy metals, either from natural sources or
anthropogenic sources, has become a major concern to the public. Industrial activities with improper
water treatment, and then leach into the water body, have become contaminated and harmful to
consume. Passive remediation is one of the treatments introduced to counter this problem as it is a low
cost but effective technique. After being widely acknowledged and through research conducted, the
most suitable remediation technique found is the permeable reactive barriers (PRBs). PRB is defined
as an in situ permeable treatment zone filled with reactive materials, designed to intercept and
remediate a contaminant plume under natural hydraulic gradients. There have been many findings
made from PRB which can be used to remove contaminants such as heavy metal, chlorinated solvents,
carbonates and aromatic hydrocarbons. The most crucial criteria in making a successful PRB is the
reactive media used to remove contaminants. The current paper presents an overview of the PRB
selective medias that have been used and also the unresolved issue on the long term performance of
PRB. The overall methodology for the application of PRB at a given site is also discussed in this
paper. This inexpensive but effective technique is crucial as a sustainable technology in order to treat
the drainage before it enters water tables to prevent water pollution and can be used as an alternative
raw water source.
Surface sediment samples were collected from five locations at the downstream of Klang River in January 2007 to examine the spatial distribution, composition, and sources of 19 parent polycyclic aromatic hydrocarbons (PAHs) and aliphatic hydrocarbon (n-alkanes) using gas chromatographymass spectrometry. The total concentrations of the 19 PAHs in the sediments were found to range from 1304 to 2187 ng g-1 sediment. Meanwhile, total concentrations of n-alkanes ranged from 17008 to 27116 μg g-1 sediment. The concentration of n-alkanes in the sediment was significantly correlated (r = 0.991, p = 0.001) with the content of sediment organic carbon. In this study, all the sediments exhibited phenanthrene/anthracene (PHE/ANT >15) fluoranthene/(fluorantene+pyrene) (FLT/FLT+PYR < 0.4), ethylphenanthrenes/phenanthrene (MP/P >1), combustion PAHs/total PAHs (CombPAH/Σ19PAH
In this study, caged calcium alginate-caged multiwalled carbon nanotubes dispersive microsolid phase extraction was described for the first time for the extraction of polycyclic aromatic hydrocarbons (PAHs) from water samples prior to gas chromatographic analysis. Fluorene, phenanthrene and fluoranthene were selected as model compounds. The caged calcium alginate-caged multiwalled carbon nanotubes was characterized by Fourier transform infrared spectroscopy, scanning electron microscopy and thermal gravimetry analyses. The effective parameters namely desorption solvent, solvent volume, extraction time, desorption time, the mass of adsorbent and sample volume were optimized. Under the optimum extraction conditions, the developed method showed good linearity in the range of 0.5-50 ng mL-1 (R2 ≥ 0.996), low limits of detection and quantification (0.42-0.22 ng mL-1) (0.73-1.38 ng mL-1) respectively, good relative recoveries (71.2-104.2%) and reproducibility (RSD 1.8-12.4%, n = 3) for the studied PAHs in water sample. With high enrichment factor (1,000), short extraction time (<30 min), low amounts of adsorbent (100 mg) and low amounts of solvent (0.1 mol) have proven that the microsolid phase extraction method based on calcium alginate-caged multiwalled carbon nanotubes are environmentally friendly and convenient extraction method to use as an alternative adsorbent in the simultaneous preconcentration of PAHs from environmental water samples.
Polycyclic aromatic hydrocarbons (PAHs) in soil have been recognised as a serious health and environmental issue due to their carcinogenic, mutagenic and teratogenic properties. One of the commonly employed soil remediation techniques to clean up such contamination is soil washing or solvent extraction. The main factor which governs the efficiency of this process is the solubility of PAHs in the extraction agent. Past field-scale soil washing treatments for PAH-contaminated soil have mainly employed organic solvents or water which is either toxic and costly or inefficient in removing higher molecular weight PAHs. Thus, the present article aims to provide a review and discussion of the alternative extraction agents that have been studied, including surfactants, biosurfactants, microemulsions, natural surfactants, cyclodextrins, vegetable oil and solution with solid phase particles. These extraction agents have been found to remove PAHs from soil at percentages ranging from 47 to 100% for various PAHs.
Agarose film liquid phase microextraction (AF-LPME) procedure for the extraction and preconcentration of polycyclic aromatic hydrocarbons (PAHs) in water has been investigated. Agarose film was used for the first time as an interface between donor and acceptor phases in liquid phase microextraction which allowed for selective extraction of the analytes prior to gas chromatography-mass spectrometry. Using 1-octanol as acceptor phase, high enrichment factors in the range of 57-106 for the targeted analytes (fluorene, phenanthrene, fluoranthene and pyrene) were achieved. Under the optimum extraction conditions, the method showed good linearity in the range of 0.1-200 μgL(-1), good correlation coefficients in the range of 0.9963-0.9999, acceptable reproducibility (RSD 6.1-9.2%, n=3), low limits of detection (0.01-0.04 μgL(-1)) and satisfactory relative recoveries (92.9-104.7%). As the AF-LPME device was non-expensive, reuse or recycle of the film was not required, thus eliminating the possibility of analytes carry-over between runs. The AF-LPME technique is environment-friendly and compatible with the green chemistry concept as agarose is biodegradable polysaccharide extracted from seaweed and the procedure requires small volume of organic solvent and generates little waste. The validated method was successfully applied to the analysis of the four analytes in river water samples.
In this study, the ranges of pollutants found in the soft tissues of Perna viridis collected from Kg. Masai and Kg. Sg. Melayu, both located in the Straits of Johore, were 0.85-1.58 μg/g dry weight (dw) for Cd, 5.52-12.2 μg/g dw for Cu, 5.66-8.93 μg/g dw for Ni and 63.4-72.3 μg/g dw for Zn, and 36.4-244 ng/g dry weight for ∑PAHs. Significantly (p < 0.05) higher concentrations of Cd, Cu, Ni, Zn and ∑PAHs in the mussels were found in the water of a seaport site at Kg. Masai than a non-seaport site at Kg. Sg. Melayu population. The ratios of low molecular weight/high molecular weight hydrocarbons (2.94-3.42) and fluoranthene/pyrene (0.43-0.45) in mussels from both sites indicated the origin of the PAHs to be mainly petrogenic. This study has demonstrated the utility of using the soft tissues of P. viridis as a biomonitor of PAH contamination and bioavailability in the coastal waters of Peninsular Malaysia.
Roasting is an important process in cocoa production which may lead to formation of non-desirable compounds such as polycyclic aromatic hydrocarbons (PAHs). Therefore, PAH4 (sum of four different polycyclic aromatic hydrocarbons; benz[a]anthracene, chrysene, benzo[b]fluoranthene, and benzo[a]pyrene) in roasted cocoa beans was determined using a modified method (combination of QuEChERS and DLLME), and quantified by HPLC-FLD. The modified method was validated and met the performance criteria required by the EU Regulation (No. 836/2011). Results show a significant (p
The present study aimed to determine the degradation and transformation of three-ring PAHs phenanthrene and anthracene by Cryptococcus sp. MR22 and Halomonas sp. BR04 under halophilic conditions. The growth progress of Cryptococcus sp. MR22 and Halomonas sp. BR04 on anthracene and phenanthrene was monitored by colony-forming unit (CFU) technique. The growth of the bacteria was maintained at a maximum concentration of 200 mg/L of all tested hydrocarbon, indicating that Cryptococcus sp. MR22 and Halomonas sp. BR04 significantly perform in the removal of the PAH-contaminated medium at low concentrations. The fit model to represent the biodegradation kinetics of both PAHs was first-order rate equation The extract prepared from cells supplemented with three different substrates exhibited some enzymes such as hydroxylase, dioxygenase, laccase and peroxidase. The results suggest that both strains had an impressive ability in the degradation of aromatic and aliphatic hydrocarbon but also could tolerate in the extreme salinity condition.
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.
Bioremediation is an effective strategy for cleaning up organic contaminants, such as polycyclic aromatic hydrocarbons (PAHs) and volatile organic compounds (VOCs). Advanced bioremediation implies that biotic agents are more efficient in degrading the contaminants completely. Bioremediation by microbial degradation is often employed and to make this process efficient, natural and cost-effective materials can serve as supportive matrices. Clay/modified clay minerals are effective adsorbents of PAHs/VOCs, and readily available substrate and habitat for microorganisms in the natural soil and sediment. However, the mechanism underpinning clay-mediated biodegradation of organic compounds is often unclear, and this requires critical investigation. This review describes the role of clay/modified clay minerals in hydrocarbon bioremediation through interaction with microbial agents in specific scenarios. The vision is on a faster, more efficient and cost-effective bioremediation technique using clay-based products. This review also proposes future research directions in the field of clay modulated microbial degradation of hydrocarbons.
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.
In this study, the surface sediments of the Malacca and Prai Rivers were analyzed to identify the distributions, and sources of Polycyclic Aromatic Hydrocarbons (PAHs). The total PAH concentrations varied from 716 to 1210 and 1102 to 7938 ng g(-1)dw in the sediments of the Malacca and Prai Rivers, respectively. The PAH concentrations can be classified as moderate and high level of pollution in the sediments of the Malacca and Prai Rivers, respectively. The comparison of PAHs with the Sediment Quality Guidelines (SQGs) indicates that the PAHs in the sediments of the Malacca and Prai Rivers may have the potential to cause adverse toxicity effects on the sampled ecosystems. The diagnostic ratios of individual PAHs indicate both petrogenic- and pyrogenic-origin PAHs with dominance of pyrogenic source in both rivers. These findings demonstrate that the environmental regulations in Malaysia have effectively reduced the input of petrogenic petroleum hydrocarbons into rivers.
The concentration of carcinogenic poly aromatic hydrocarbons (c-PAHs) present in water and sediment of Klang Strait as well as in the edible tissue of blood cockle (Anadara granosa) was investigated. The human health risk of c-PAHs was assessed in accordance with the standards of the United States Environmental Protection Agency (US EPA). The cancer risks of c-PAHs to human are expected to occur through the consumption of blood cockles or via gastrointestinal exposure to polluted sediments and water in Kalng Strait. The non-carcinogenic risks that are associated with multiple pathways based on ingestion rate and contact rates with water were higher than the US EPA safe level at almost all stations, but the non-carcinogenic risks for eating blood cockle was below the level of US EPA concern. A high correlation between concentrations of c-PAHs in different matrices showed that the bioaccumulation of c-PAHs by blood cockles could be regarded as a potential health hazard for the consumers.
Concentration, source, and ecological risk of polycyclic aromatic hydrocarbons (PAHs) were investigated in 22 stations from surface sediments in the areas of anthropogenic pollution in the Klang Strait (Malaysia). The total PAH level in the Klang Strait sediment was 994.02±918.1 µg/kg dw. The highest concentration was observed in stations near the coastline and mouth of the Klang River. These locations were dominated by high molecular weight PAHs. The results showed both pyrogenic and petrogenic sources are main sources of PAHs. Further analyses indicated that PAHs primarily originated from pyrogenic sources (coal combustion and vehicular emissions), with significant contribution from petroleum inputs. Regarding ecological risk estimation, only station 13 was moderately polluted, the rest of the stations suffered rare or slight adverse biological effects with PAH exposure in surface sediment, suggesting that PAHs are not considered as contaminants of concern in the Klang Strait.