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.
As the division of work within the world economic system becomes increasingly complex, the impact of disturbing events on the economic system is expanding. Recently, Japan proposed to discharge nuclear wastewater into the Pacific Ocean, which will cause damage to marine fisheries, thereby seriously affecting fisheries and other industries in Japan and other countries and regions around the world. Considering different scenarios of final and intermediate demand shifting, this paper uses the Inoperability Input-Output Model (IIM) and Multi-Region Input-Output Model (MRIO) to simulate the economic consequences of nuclear wastewater discharge in Japan and calculate the economic changes of each industry and country (region). The results show that: In the short term, when only the final demand for Japanese fishery products decreases. (1) The ten countries (regions) with significant economic losses are Japan, the United States, Chinese Taipei, Canada, Chile, South Africa, Mexico, Peru, the United Kingdom, and Ireland. (2) The ten countries (regions) with a significant increase in total output due to demand shift are China (People's Republic of), the Rest of the World, India, Indonesia, Viet Nam, the Philippines, Brazil, Myanmar, the Russian Federation, and Malaysia. (3) A ranking of changes in the total output of different industries. In the long term, when both intermediate and final demand for Japanese fishery products decrease. (4) The change in value added in Japan. (5) The change in value added of 67 countries (regions) worldwide. The ten countries (regions) with the most significant increase in value-added are the Russian Federation, China (People's Republic of), the Rest of the World, the United States, Indonesia, Australia, Norway, Korea, Viet Nam, and Myanmar. The ten countries (regions) with the most significant decrease in value-added are Japan, Chinese Taipei, Chile, South Africa, Peru, Thailand, Mexico, Cambodia, Costa Rica, and Morocco. Changes in value added of 45 industrial sectors worldwide.
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.
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.
In this study, the climate change, tsunami and biodiversity for 336 km coastline endangered at the South China Sea was investigated with the review for the past, current and prediction models for the future. The hydraulic study of the coastal area was conducted using a well-established 2D numerical model suite Delft3D. The study revealed that the generated earthquakes at the convergence zone in the last century are small (Mw7.3), the possibility that a megathrust earthquake event in the SCS basin occurs in the future. The study area comprises a narrow strip of vegetation notably dominated by Casuarina equisetifolia with other coastal plants. Mangrove forests are found along the coastline and estuaries that are overlaid with marine alluvial soils. The current paper is the first comprehensive study of the South China Sea, and the findings increase the awareness among the public to understand the risk associated with environmental pollution.
The dynamics of the coastal aquifers are well-expressed by geochemical and isotopic signatures. Coastal regions often exhibit complex groundwater recharge pattern due to the influence of depression in the Bay of Bengal, tidal variations on surface waters, saline water intrusion and agricultural return flows. In this research, groundwater recharge processes occurring in coastal Tamil Nadu, South India were evaluated using major ion chemistry and environmental isotopes. A total of 170 groundwater samples were collected from shallow and deep aquifers during both post-monsoon (POM) and pre-monsoon (PRM) seasons. The isotopic results showed a wide variation in the shallow groundwater, suggesting contribution from multiple recharge sources. But, the deeper groundwater recharge is mainly from precipitation. The northern part of the study area showed more depleted isotopic values, which rapidly changed towards south from -6.8 to -4.4‰. Alternatively, central and southern parts exhibited relatively enriched isotopic content with variation from -0.58 to -2.7‰. Groundwater was discerned to be brackish to saline with chloride content, 600-2060 mgL-1 and δ18O ranging from -5.8 to -4.5‰, suggesting influence of the saline water sources. A minor influence of anthropogenic activities was also observed in the deeper groundwater during PRM, which was confirmed by tritium and Cl- trends. The old groundwater with depleted isotopic content infer recharged by distant sources while modern groundwater with enriched isotopes points to the influence of evaporated recharge.
Macro-sized marine litter (>2.5 cm) was collected, characterized, and enumerated along the Cox's Bazar Coast, Bangladesh. Marine litter abundance was converted to density (number of items/m2). Beach cleanliness was evaluated using the clean-coast index (CCI). Plastic polythene bags were the most abundant litter items, followed by plastic cups. Total marine litter abundance was 54,401 ± 184 items. Major sources of marine litter were from tourism, fishery and residential activities. Of 10 sites surveyed, two were classified as dirty, two were moderate, four were clean and two were very clean using the CCI. Marine litter pollution along the Cox's Bazar Coast represents a potential threat to coastal and marine environments. This baseline study will help to establish mitigation strategies that are urgently required to reduce marine litter pollution along the Cox's Bazar Coast.
Extensive global plastic production has led to microplastic (MP) pollution of marine ecosystems. This study analysed the abundance of MPs in the surface water of tropical coastal and estuarine zones in Malaysia affected by rapid urbanisation and intense human activity. It also estimated the risk posed by MPs to the marine environment. Mean MP abundance ranged from 2.10 to 6.80 particles/L. Fourier-transform infrared spectroscopic analysis found that the MP polymers were dominated by cellophane (54%), followed by polyester (33%) and polyethylene (2%). The risk posed by MPs was estimated with the risk quotient (RQ) method which found no potential ecological risk to both coastal and estuarine areas (RQ
This study aimed to identify the toxicity effect of Diuron on Tegillarca granosa by determining accumulation in the soft tissues and alteration on the gill tissue structure. Wild stocks T. granosa were grouped to identify the initial Diuron concentration and 48-h exposure in different concentrations (0, 1, 2, 3, and 4 mg·L-1). The Diuron in tissue was extracted using an established procedure and identified using High-Performance Liquid Chromatography (HPLC). Gills were analysed for histopathological study; tissue structure was classified and scored using a developed scoring system. Diuron concentration in the soft tissue of exposed T. granosa was in the range 1.27-8.09 mg·kg-1, w/w and not proportionately increase along with the exposure concentration. The mean index values of the gill histopathology ranged from 5.25-7.67 and classified as moderate to severe. Gills characteristics and T. granosa protective behaviour potentially limit Diuron accumulation in the soft tissue.
Marine litter is recognized as an increasing component of marine ecosystem pollution. In this baseline study, we document the magnitude, types, sources, and potential impacts of litter on six coral reefs in East Sabah. We applied a simplified classification of litter to extract abundance data from video transects. The average density was 10.7 items per 100 m2. Plastics represent 91% and the remaining 9% were metal, glass, and wood. Most (~70%) plastics are single-use items derived from dumping. Discarded fishing gear accounts for ~25%. Litter pollution increases closer to urban developments, with Sakar reef having higher densities (51 items per 100 m2), and higher Clean Coast Index (CCI = 10.2, dirty) and higher Plastic Abundance Index (PAI = 4.68) scores. This method could and should be readily integrated into ongoing monitoring programs to support assessments of the extent and magnitude of marine litter pollution on reefs worldwide.
We studied the concentrations of terrestrial and anthropogenic radionuclides in seawater and shore sediment/sand of three selected regions; Khafji, Safaniyah and Menifah along the Saudi Arabian Gulf coast. The mean activity concentrations of the 228Ra, 226Ra, and 40K in the analyzed sand samples are 5.9, 3.5 and 113.5 Bq/kg, and the respective values in seawater samples are 1.6, 0.8 and 10.4 Bq/L. All data show lower than the corresponding UNSCEAR (2000) reported world average values of 35, 30 and 400 Bq/kg for soil matrix. A few relevant radiological hazards were quantified by the estimation of the absorbed dose rate, and the results are compared with the prescribed limits set by international regulatory bodies. Measured data indicates that the studied coastal regions pose a negligible radiological hazards to the public, and show an insignificant radioactive loading to this coastal region by the Busher nuclear power plant.
In this study, we have analyzed how geo-ecological cues for endangered Olive Ridley turtles' mass nesting behavior got modified by impact of four severe cyclones during 2010-2019 that made landfall in the vicinity of Rushikulya estuary, which is one of the largest mass nesting congregation (arribada) sites in the world. Analyzing last 10 years of shoreline dynamics, we show that even the slightest modification in beach morphology influenced their nesting behavior in Rushikulya rookery. Shoreline change analysis showed periodic phases of high/low erosion and the northward longshore sediment movement, which becomes impeded by the southern spit, the length of which increased by about 1800 m. During the analyzed period, the nesting behavior of Olive Ridley turtle was greatly influenced by changes in land use and land cover pattern around the Rushikulya rookery. Such reductions in tree cover and marshy land areas were majorly driven by anthropogenic activities and extreme weather events, such as cyclones. We also report increased mortality of turtles, no or false mass nesting events due to significant loss and/or erosion of the nesting sites due to cyclones. The results indicate that conservation of Olive Ridley turtles should be more holistic, or ecosystem centric, rather than species centric. It is important to maintain the ecological integrity of their habitat for highly synchronized mass nesting event and eventually their survival.
The Baram River is one of the largest rivers in Sarawak, where many large industries, such as plywood, sawmills, shipyards, interisland ports, and other wood-based industries are located along the river. Microplastic contamination has become a widespread and growing concern worldwide because of the small sizes of microplastics and their presence in seafood such as fish, squid, scallop, crabs, shrimp, and mussels. In this study, microplastics were found in all sampling stations. Out of the 4017 microplastics found in the water and sediment, microplastics fragment accounted for 67.8% of total microplastics, followed by fiber, film, pellet, and foam. Five microplastic polymer types were detected by ATR-FTIR, including polyethylene (PE), polyester (PET) fibers, silicon polymer, nitrile, and polystyrene (PS). The most common microplastics size range in Baram River was 0.3-1 mm, with blue as the highly abundant color.
This study investigates bacterial diversity and potential pathogens in the international ships' ballast water at Tanjung Pelepas Port, Malaysia, using 16S rRNA amplicon sequencing. Thirty-four bacterial phylum, 305 families, 577 genera, and 941 species were detected in eight ballast water samples of different origins. The similarity of the bacterial composition between samples was found to be random and not tied to geographical locations. The bacterial abundance did not seem to be affected by related physicochemical except for temperature. Ballast water samples with a temperature lower than 25 °C showed a relatively lower bacterial abundance. A total of 33 potential pathogens were detected from all ballast water samples. Pseudomonas spp., Tenacibaculum spp., Flavobacteriaceae spp., Halomonas spp., and Acinetobacter junii are the potential pathogens with more than 10% OTU prevalence. This study would provide beneficial information for further enhancing ballast water microorganism guidelines in Malaysia.
Petroleum hydrocarbon pollution in marine waters has been an extremely significant environmental and health issue worldwide. This study aims at constructing an efficient indigenous bacterial consortium to biodegrade Tapis Light Crude Petroleum Oil (TLCO). The local agro-industrial wastewater of palm oil mill effluent final discharge (POME FD) was used as biostimulant to enhance the biodegradation efficiency. In this study, three TLCO degrading bacteria were isolated from seawater samples collected. Molecular identification using 16S rRNA genes sequencing was done and results show that these isolated strains belong to: Bacillus tropicus, Bacillus licheniformis and Bacillus subtilis. Bacterial consortium tested using four different concentrations of POME FD (0.1, 0.25, 0.5, and 1%) as biostimulant and TLCO (0.5 and 1.0%) degradation capability was investigated. The residual TLCO in culture medium after 40 days was analysed. The results confirmed that POME FD dosage of 0.25% is optimum for the bacterial consortium and can degrade 99.85% of TLCO at 0.5%. However, TLCO degradation with POME FD dosage (0.25%) in TLCO (1.0%) was found optimum, with biodegradation reaching up to 95.23% in 40 days. This study is a beginning for the future development of a consortium of petroleum hydrocarbon degrading bacteria to mitigate oil spills in the Malaysian shoreline.
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