Diuron is an alternative biocide suggested to replace organotin in formulating antifouling paints to be applied on water-going vessels hull. However, it is potentially harmful to various non-targeted marine organisms due to its toxic properties. Present study aimed to isolate, screen and identify the potential of Diuron-degrading bacteria collected from the marine sediments of Port Klang, Malaysia. Preliminary screening was conducted by exposing isolated bacteria to 430ng/L (background level), followed by 600ng/L and 1000ng/L of Diuron concentrations. Nine bacteria colonies survived the exposure of the above concentrations. However, only two strains can tolerate to survive up to 1000μg/L, which were then characterised and identified using phenotypic tests and the standard 16S rRNA molecular identification. The strains were identified as Comamonas jiangduensis SZZ 10 and Bacillus aerius SZZ 19 (GenBank accession numbers: KU942479 and KU942480, respectively). Both strains have the potential of Diuron biodegradation for future use.
Revealing the potential of seagrass as a bioindicator for metal pollution is important for assessing marine ecosystem health. Trace metal (111Cd, 63Cu, 60Ni, 208Pb, 66Zn) concentrations in the various parts (root, rhizome, and blade) of tape seagrass (Enhalus acoroides) collected from Merambong shoal of Sungai Pulai estuary, Johor Strait, Malaysia were acid-extracted using a microwave digester and analysed via inductively coupled plasma-mass spectrometry (ICP-MS). The ranges of trace metal concentrations (in μgg-1 dry weight) were as follows: Cd (0.05-0.81), Cu (1.62-27.85), Ni (1.89-9.35), Pb (0.69-4.16), and Zn (3.44-35.98). The translocation factor revealed that E. acoroides is a hyperaccumulator plant, as its blades can accumulate high concentrations of Cd, Cu, Ni, and Zn, but not Pb. The plant limits Pb mobility to minimize Pb's toxic impact. Thus, E. acoroides is a potential bioindicator of metal pollution by Cd, Cu, Ni, and Zn in estuarine environments.
The Straits of Malacca is one of the world's busiest shipping routes where frequent oil spills occur. Rapid development in the west coast of Peninsular Malaysia is the other major source of petroleum pollution in this narrow waterway. In order to identify occurrence and origin of hydrocarbons in the Straits, mangrove oysters (Crassostrea belcheri) were collected from five sampling locations and analysed for n-alkanes and biomarkers. Soxhlet apparatus and two step column chromatography were used for extraction, purification and fractionation of the oysters. Petroleum origin n-alkanes were detected in majority of the sampling locations which is indicative of anthropogenic activities in this region. Using source and maturity diagnostic ratios for hopanes revealed used crankcase oil as the main source of petroleum hydrocarbons in oysters from all sampling locations except for the Pulau Merambong where signature of South East Asia crude oil (SEACO) was detected.
We investigated the appropriateness of faecal indicator bacteria in tropical waters. We compared total coliform (undetectable to 7.2 × 105 cfu 100 mL-1), faecal coliform (undetectable to 6.1 × 105 cfu 100 mL-1) and enterococci (undetectable to 3.1 × 104 cfu 100 mL-1) distribution in Peninsular Malaysia. Faecal indicator bacteria was highest in freshwater, and lowest in seawater (q > 4.18, p
Marine debris is often detected everywhere in the oceans after it enters the marine ecosystems from various sources. Marine litter pollution is a major threat to the marine ecosystem in Bangladesh. A preliminary study was conducted to identify the sources of marine litter (plastics, foamed plastic, clothes, glass, ceramic, metals, paper, and cardboard) along the Bay of Bengal coast. From the observations, the range of abundance of the collected marine litter was 0.14-0.58 items/m2. From the ten sampling sites, the highest amount of marine litter was observed for aluminium cans (3500), followed by plastic bottles (3200). The spatial distribution pattern indicated that all the study areas had beach litter of all types of materials. The present investigation showed that plastics were the dominating pollutants in the marine ecosystem in Bangladesh. The clean-coast index (CCI) value indicated that the Cox's Bazar coast was clean to dirty class. The abundance, distribution, and pollution of marine litter along the coastal belts pose a potential threat to the entire ecosystem. This study will help come up with ways to manage and get rid of marine litter along the coast in an effective way.
Plastic can be degraded into microplastic (<5 mm) and has been polluting worldwide marine environment and negatively impact human health. Microplastics in marine organisms are still understudied in Malaysia, let alone from a subclass Elasmobranchii. Five tropical shark species (Carcharhinus dussumieri, Carcharhinus sorrah, Chiloscyllium hasseltii, Chiloscyllium punctatum, and Scoliodon laticaudus) were examined for the presence of microplastics. 74 sharks were sampled from the local wet market and 100 % of samples contained microplastics. A total of 2211 plastic particles were found in gastrointestinal tracts (GIT) and gills, where 29.88 ± 2.34 particles per shark (mean ± SEM). Black (40.07 %) and fiber (84.44 %) microplastics were the most dominant. Extracted microplastic sizes ranged from 0.007 mm to 4.992 mm. This study suggests that microplastic uptake is gender-related for some shark species. A subsample of microplastics (10 %) was used for polymer type identification, where polyester was recorded the highest (43.95 %).
The study investigates the latent pollution sources and most significant parameters that cause spatial variation and develops the best input for water quality modelling using principal component analysis (PCA) and artificial neural network (ANN). The dataset, 22 water quality parameters were obtained from Department of Environment Malaysia (DOE). The PCA generated six significant principal component scores (PCs) which explained 65.40 % of the total variance. Parameters for water quality variation are mainlyrelated to mineral components, anthropogenic activities, and natural processes. However, in ANN three input combination models (ANN A, B, and C) were developed to identify the best model that can predict water quality index (WQI) with very high precision. ANN A model appears to have the best prediction capacity with a coefficient of determination (R2) = 0.9999 and root mean square error (RMSE) = 0.0537. These results proved that the PCA and ANN methods can be applied as tools for decision-making and problem-solving for better managing of river quality.
Concentrations, sources and interactions between black carbon (BC) and polycyclic aromatic hydrocarbons (PAHs) were investigated in 42 sediment samples collected from riverine, coastal and shelf areas in Peninsular Malaysia. The concentrations of BC measured by benzene polycarboxylic acid (BPCA) method and PAHs showed broad spatial variations between the relatively pristine environment of the East coast and developed environment of the West and South coast ranging from 0.02 to 0.36% dw and 57.7 ng g-1 dw to 19,300 ng g-1 dw, respectively. Among diagnostic ratios of PAHs, the ratios of Ant/(Ant+Phe) and LMW/HMW drew the clearest distinctions between the East coast versus the West and South coast sediments indicating the predominance of petrogenic sources in the former versus pyrogenic sources in the latter. PAHs significantly correlated with BC and total organic carbon (TOC) in the sediments (p
Metabarcoding analysis is an effective technique for monitoring the domoic acid-producing Pseudo-nitzschia species in marine environments, uncovering high-levels of molecular diversity. However, such efforts may result in the overinterpretation of Pseudo-nitzschia species diversity, as molecular diversity not only encompasses interspecies and intraspecies diversities but also exhibits extensive intragenomic variations (IGVs). In this study, we analyzed the V4 region of the 18S rDNA of 30 strains of Pseudo-nitzschia multistriata collected from the coasts of China. The results showed that each P. multistriata strain harbored about a hundred of unique 18S rDNA V4 sequence varieties, of which each represented by a unique amplicon sequence variant (ASV). This study demonstrated the extensive degree of IGVs in P. multistriata strains, suggesting that IGVs may also present in other Pseudo-nitzschia species and other phytoplankton species. Understanding the scope and levels of IGVs is crucial for accurately interpreting the results of metabarcoding analysis.
Water and soft drink bottles made from polyethylene terephthalate (PET) sink at sea unless they contain trapped air, whereas their lids are made from polymers that float and can drift long distances. We sampled loose lids and bottles at 21 South African beaches to compare their origins. The proportions of foreign-made bottles and lids were correlated, and increased away from urban centres, indicating that much land-based litter strands close to source areas. Over 80 % of foreign-made drink bottles and 90 % of lids came from Asia, but most bottles were manufactured in China, Malaysia-Singapore and the UAE, and were dumped from ships. By comparison, most loose lids were in poor condition after being carried across the Indian Ocean from Indonesia by the South Equatorial Current. Reducing PET drink bottles at sea requires enforcement of regulations banning dumping at sea, whereas reducing their lids requires better control of littering in source countries.
Coastal Mangroves are facing growing threats due to the harmful consequences of human activities. This first-ever detailed study of natural radioactivity in soil samples collected from seven tourist destinations within the Sundarbans, the world's largest mangrove forest, was conducted using HPGe gamma-ray spectrometry. Although the activity levels of 226Ra (11 ± 1-44 ± 4 Bq/kg) and 232Th (13 ± 1-68 ± 6 Bq/kg) generally align with global averages, the concentration of 40K (250 ± 20-630 ± 55 Bq/kg) was observed to surpass the worldwide average primarily due to factors like salinity intrusion, fertilizer application, agricultural runoff, which suggests the potential existence of potassium-rich mineral resources near the study sites. The assessment of the hazard parameters indicates that the majority of these parameters are within the recommended limits. The soil samples do not pose a significant radiological risk to the nearby population. The results of this study can establish important radiological baseline data before the Rooppur Nuclear Power Plant begins operating in Bangladesh.
The synthesis of new surfactants helps to mitigate the environmental and financial effects of oil spills by providing efficient cleanup options. Herein, this study provides the development of a binary mixture of Span 80 and Choline myristate [Cho][Mys], a surface-active ionic liquid (SAIL) as green dispersant for oil spill remediation. The synergistic interaction at a 60:40 (w/w) ratio significantly lowered the critical micelle concentration (cmc) to 0.029 mM. Dispersion efficiency tests with Arab crude oil showed optimal performance at a 60:40 ratio of Span 80 and [Cho][Mys] (1:25 dispersant to oil ratio, v/v), achieving 81.16 % dispersion effectiveness in the baffled flask test. The binary mixture demonstrated superior emulsion stability (6 h) and the lowest interfacial tension (1.12 mN/m). Acute toxicity experiments revealed the dispersant's practical non-toxicity with an LC50 value of 600 mg/L. Overall, this environmentally benign surfactant combination shows promise as a safe and effective oil spill dispersant.
The massive industrial growth in Gresik, East Java, Indonesia has the potential to result in metal contamination in the nearby coastal waters. The purpose of this study was to analyze the metal concentrations in edible species from the Gresik coastal waters and evaluate the potential health risks linked to this metal contamination. Metal concentrations (Cu, Fe, Pb, Zn, As, Cd, Ni, Hg, and Cr) in fish and shrimp samples mostly met the maximum limits established by national and international regulatory organizations. The concentrations of As in Scatophagus argus exceed both the permissible limit established by Indonesia and the provisional tolerable weekly intake (PTWI). The As concentration in Arius bilineatus is equal to the PTWI. The target cancer risk (TCR) values for both As and Cr in all analyzed species exceed the threshold of 0.0001, suggesting that these two metals possess the potential to provide a cancer risk to humans.
This study has examined the factors of fishing grounds footprint in Malaysia during 1961-2018, which has been used as the indicator of environmental degradation. The main contribution of this paper is that we have considered the role of aggregated and disaggregated fisheries production on pollution in the fishing industry. Another contribution of this study is that the environmental impact of activities of licensed fishermen has been examined. The results suggest that the total fisheries production and its components- capture fisheries production and aquaculture production generate an increase in fishing grounds footprint in Malaysia. The results suggest that an increase in total licensed fishermen facilitate an increase in fishing grounds footprint. There is mixed evidence on the impact of local fishermen on fishing footprint. The results indicate that an increase in foreign fishermen facilitate an increase in fishing grounds footprint. The results suggest mixed evidence for Environmental Kuznets Curve (EKC) hypothesis.
Plankton seasonality in tropical coastal waters is becoming more apparent as a result of monsoon-driven changes in environmental conditions, but research on the monsoonal variation of microplastics (MP) is still limited. We examined the monsoonal variation of MP in the water column and their ingestion by zooplankton in Sepanggar Bay, Sabah, Malaysia. MP concentrations were significantly higher during the Southwest monsoon whereas MP ingestions showed no monsoonal difference across major zooplankton taxa. Canonical Correspondence Analysis (CCA) and Generalized Additive Models (GAM) indicate that MP concentrations were driven by changes in rainfall and salinity while MP bioavailability to zooplankton was consistent regardless of monsoon. MP ingestion increased progressively up the planktonic food chain, and bioavailability of fibers and small-sized MP of high-density polymers to zooplankton was proportionately higher. Distinct changes in the MP concentration relative to the monsoons provide new insights into the seasonal variation of MP in tropical coastal ecosystems.
This paper analyzes CO2 flux between the atmosphere and a tropical coastal sea using the eddy covariance technique. Coastal carbon dioxide flux studies are limited, particularly in tropical regions. Data was collected from the study site in Pulau Pinang, Malaysia, since 2015. The research found that the site is a moderate CO2 sink and experiences seasonal monsoonal changes that affect its carbon-sink or carbon-source capability. The analysis showed that the coastal sea systematically shifted from being a carbon-sink at night to a weak carbon-source during the day possibly due to cause by the synergistic influence of wind speed and seawater temperature. The CO2 flux are also influenced by small-scale, unpredictable winds, limited fetch, developing waves, and high-buoyancy conditions caused by low wind speeds and an unstable surface layer. Furthermore, it exhibited a linear relationship with wind speed. In stable conditions, the flux was influenced by wind speed and drag coefficient, while in unstable conditions, it was mostly controlled by friction velocity and atmospheric stability. These findings could improve our understanding of the critical factors that drive CO2 flux at the tropical coast.
Bisphenol analogues are prevalent globally because of rampant usage and imprecise processing techniques, prompting alerts about environmental and health hazards. The method employed in this study by solid phase extraction (SPE) and liquid chromatography-tandem quadrupole mass spectrometer (LC-MS/MS) for both quantification and qualitative analysis of the bisphenol compounds in the surface water samples. The coastal and estuarine surface water of Port Dickson and Lukut ranges from 1.32 ng/L to 1890.51 ng/L of bisphenol analogues. BPF mean concentration at 1143.88 ng/L is the highest, followed by BPA and BPS at 59.01 ng/L and 10.96 ng/L, respectively. Based on RQm for bisphenol analogues, the highest for BPF at 2.49 (RQ > 1, high risk), followed by BPS at 0.12 (0.1
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
Miri River is a tropical river in Borneo that drains on flat terrain and urbanised area and debauches into the South China Sea. This paper documents the environmental status of this river, and provides an insight into the provenance using bulk chemistry of the sediments, and brings out the geochemical mobility, bioavailability, and potential toxicity of some critical elements based on BCR sequential extraction. The sediments are intense to moderately weathered and recycled products of Neogene sedimentary rocks. The hydrodynamic characteristics of the river favoured an upstream section dominated by fine sand, while the downstream sediments are medium silt. Based on the bulk geochemistry, the Miri River sediments are moderate to considerably contaminated by Cu, Mo, and As in the upstream and by Sb, As and Cu in the downstream. The potential ecological risk values are low except Cu and a significant biological impact is expected in downstream due to Cu, As, Zn and Cr. The mobility, bioavailability and Risk Assessment Code values for Zn and Mn are higher and thus may pose moderate to very high risk to aquatic organisms. Though a high bulk concentration of Cu is observed, the association of Cu with the bioavailable fraction is low.
This study investigated the impacts of the removal of sand bund on the macrobenthos community structure, seagrass cover, and sediment particle size in Merambong Shoal, Malaysia. The reclamation project deposited sand bund in the middle of Merambong seagrass shoal, resulting in its division into northern (NS) and southern (SS) halves. Ecosystem changes were monitored over a 31-month period using the transect lines method. Bi-monthly samples were collected for assessment. The results revealed a substantial decline in macrobenthos densities compared to previous studies. However, after the removal of the sand bund, there was a significant increase in macrobenthos density, specifically Polychaeta and Malacostraca, at NS. Seagrass cover at NS was initially lower than SS but showed an increase after the complete removal of the sand blockage. Sediment particle analysis reported a higher silt percentage at NS, indicating greater sedimentation at NS, which was partially sheltered from wave actions.