Tourism-related activities such as the heavy use of boats for transportation are a significant source of petroleum hydrocarbons that may harm the ecosystem of Langkawi Island. The contamination and toxicity levels of polycyclic aromatic hydrocarbon (PAH) in the sediments of Langkawi were evaluated using sediment quality guidelines (SQGs) and toxic equivalent factors. Ten samples were collected from jetties and fish farms around the island in December 2010. A gas chromatography/flame ionization detector (GC/FID) was used to analyse the 18 PAHs. The concentration of total PAHs was found to range from 869 ± 00 to 1637 ± 20 ng g⁻¹ with a mean concentration of 1167.00 ± 24 ng g⁻¹, lower than the SQG effects range-low (3442 ng g⁻¹). The results indicated that PAHs may not cause acute biological damage. Diagnostic ratios and principal component analysis suggested that the PAHs were likely to originate from pyrogenic and petrogenic sources. The toxic equivalent concentrations of the PAHs ranged from 76.3 to 177 ng TEQ/g d.w., which is lower compared to similar studies. The results of mean effects range-median quotient of the PAHs were lower than 0.1, which indicate an 11% probability of toxicity effect. Hence, the sampling sites were determined to be the low-priority sites.
Organic pollution continues to be an important worldwide obstacle for tackling health and environmental concerns that require ongoing and prompt response. To identify the LAB content levels as molecular indicators for sewage pollution, surface sediments had obtained from the South region of Malaysia. The origins of the LABs were identified using gas chromatography-mass spectrometry (GC-MS). ANOVA and a Pearson correlation coefficient at p
The concentrations of 137Cs and 134Cs in Malaysian marine sediments were measured by gamma-ray spectrometry with a high-purity germanium (HPGe) detector connected to a multichannel analyzer. In general, the 137Cs concentration in Malaysian marine sediments has been found to be very low and less than 5 Bq/kg dry weight with the exception of those from a few sampling locations. The concentration of 134Cs was found to be less than the minimum detectable activity for the measuring condition used. Data reported in this paper were found to be comparable with results from within the region and thus can be used as reference data for the country.
This study is on the distribution of rare earth elements (REEs) concentrations in sediments collected from 113 sampling locations of Linggi River. The analysis of sediment samples was performed by Neutron Activation Analysis (NAA) and Inductively Coupled Plasma - Mass spectrometer (ICP-MS). The main compositions of Linggi river sediments were silt > sand > clay. The mean of total concentrations of REEs (ΣREE), light REEs (ΣLREE) and heavy REEs (ΣHREE) in Linggi sediment were 249, 228, and 22.0 mg/kg, respectively. The results of Linggi river sediment were normalised to several reference shale values. REEs of Linggi river sediments were comparable to MUQ reference shale values. Enrichment factors (EF) of mean values indicate Linggi River sediment can be categorised as having minor to moderate enrichment.
Remote Sensing (RS) and Geographical Information Systems (GIS) are widely used for change detection in rivers caused
by erosion and accretion. Digital image processing techniques and GIS analysis capabilities are used for detecting
temporal variations of erosion and accretion characteristics between the years 1999 and 2011 in a 40 km long Marala
Alexandria reach of River Chenab. Landsat satellite images for the years 1999, 2007 and 2011 were processed to analyze
the river channel migration, changes in the river width and the rate of erosion and accretion. Analyses showed that the
right bank was under erosion in both time spans, however high rate of deposition is exhibited in middle reaches. The
maximum erosion was 1569843 m2
and 1486160 m2
along the right bank at a distance of 24-28 km downstream of the
Marala barrage in the time span of 1999-2007 and 2007-2011, respectively. Along right bank mainly there is trend of
accretion but erosion is much greater between 20 and 28 km reach. Maximum accretion was 5144584 m2
from 1999-2007
and 2950110 m2
from 2007-2011 on the right bank downstream of the Marala Barrage. The derived results of channel
migration were validated by comparing with SRTM data to assess the accuracy of image classification. Integration of remote
sensing data with GIS is efficient and economical technique to assess land losses and channel changes in large rivers.
A study on distribution and diversity of benthic foraminifera in surface sediments was carried out in Northwestern Sarawak waters, Malaysia. The range of water depth at the study site was between 43 m and 71 m. A total of seven sediment samples were taken for this study. As a result, 11 genera were identified from a total of 1,222 individuals of foraminifera. 200 individuals were picked out from each sample. The 11 genera that were identified from the study site included Heterolepaspp., Textulariaspp., Quinqueloculinaspp.,Operculina spp. Pseudorotaliaspp., Amphisteginaspp., Cylindroclavulinaspp., Elphidiumspp., Ammobaculitesspp., Asterorotaliaspp. and Bolivinaspp.. The common genera found in the sediments of the study areas were Heterolepa, Textularia, Quincoloculina, Operculinaand Pseudorotalia. The highest and lowest values of Fisher alpha and Shannon-Wiener indices were shown at Station C287 and Station B482 respectively. The highest value of Fisher alpha was 3.23 and the lowest value was 1.97. The highest and lowest values of Shannon-Wiener were 2.30 and 1.91. The highest index value of diversity was 3.23 at depth 67.76 m and the lowest value was 1.53 at depth 45.54 m and 68.45 m. From this study, depth is not the main factor that influencesthe diversity of benthic foraminiferal in northwestern Sarawak waters.
The heavy metal contents (Cr, Cu, Zn, Cd, Pb, Hg, and As) of 88 surface sediment samples from the western Sunda Shelf were analyzed to determine their spatial distribution patterns and contamination status. The results demonstrated that high enrichment regions of heavy metals were focused in the Kelantan, Pahang, and Ambat river estuaries, and deep water regions of the study area. These high enrichment regions were mainly controlled by riverine inputs and their hydrodynamic conditions. The enrichment factor (EF), geoaccumulation index (Igeo), and potential ecological risk index (PERI) were used to assess heavy metal accumulation. The results indicated that the study area was not significantly contaminated overall at the time of the study; however, Cd, As, and Hg were at levels corresponding to moderate contamination at many stations located in the Pahang River estuary, Kelantan River estuary, and north-eastern region of the study area, primarily because of anthropogenic activities.
The present study examines historical perspectives of the macrobenthic community in response to different phases of anthropogenic perturbations in Kakinada Bay, a tropical embayment on the east coast of India. Multivariate analysis of the snapshot data (1958-2017) revealed considerable changes in the Bay environment following a breakwater construction across the Bay mouth in 1997. Subsequently, port expansion activities, industrialization, urbanization, and geomorphic alterations in the Godavari delta brought deterrent changes in the Bay. The fluctuations over the years in hydrographical and sediment characteristics increased environmental heterogeneity and caused significant spatio-temporal shifts in the macrobenthic community between 1995-1996 and 2016-2017. The observed variabilities were suggestive of anthropogenic perturbations of the system with future repercussions on Bay ecosystem functioning. Overall, this study provides evidence on the long-term impact of anthropogenic activities on coastal marine communities and stresses the importance of macrobenthos as bioindicators of such changes in tropical systems.
This study investigates the textural characteristics of sediments collected at eroded and deposited areas of highly severed eroded coastline of Batu Pahat, Malaysia. Samples were taken from systematically selected 23 locations along the 67km stretch of coastline and are extended to the fluvial sediments of the main river of Batu Pahat. Grain size distribution analysis was conducted to identify its textural characteristics and associated sedimentary transport behaviours. Sediments obtained along the coastline were fine-grained material with averaged mean size of 7.25 ϕ, poorly sorted, positively skewed and has wide distributions. Samples from eroded and deposition regions displayed no distinctive characteristics and exhibited similar profiles. The high energy condition transported the sediments as suspension, mostly as pelagic and the sediments were deposited as shallow marine and agitated deposits. The fluvial sediments of up to 3km into the river have particularly similar profile of textural characteristics with the neighbouring marine sediments from the river mouth. Profiles were similar with marine sediments about 3km opposite the main current and can go up to 10km along the current of Malacca Straits.
Surface sediments were collected from the north western intertidal area (14 sites), drainage (3 sites), and rivers (3 sites) of Peninsular Malaysia in April 2005. The samples were analyzed for their concentrations of Cd, Ni, and Zn. The ranges for the total concentrations (µg/g dry weight) of Cd, Ni, and Zn were found to be 0.79-2.48, 6.46-73.92, and 33.6-484.14, respectively. Factory drainage site at Juru exceeded the established sediment quality values (Effect Range Median-ERM) for Zn and Ni, while the concentrations of Zn were also found to have exceeded the ERM at drainages at Kuala Kurau Town and Sg. Juru sites. The geochemical study, based on the sequential extraction technique on the sediments, revealed that the metal percentages of non-resistant fractions of the drainage at Kuala Kurau Town (drainage), Sg. Juru (river), Kuala Juru (intertidal), and factory drainage site at Juru were higher than the resistant fractions of the metals. These indicated that the sites (intertidal, river, and drainages) received anthropogenic inputs of these metals. Therefore, the point source of anthropogenic input in these sites should be given attention in future in order to mitigate the environmental problem on the living resources in the north western of Peninsular Malaysia. The present monitoring data are useful for future establishment of sediment quality guideline for Malaysian aquatic environment.
The objectives of this review are to determine the types of indices to use, to assess the current sediment quality index (SQI) of a mangrove forest and to select the appropriate index to describe the mangrove sediment quality index. Amongst the many indices considered in this review are the enrichment factors (EFs), the geo-accumulation index (Igeo), the pollution load index (PLI), the marine sediment pollution index (MSPI) and sediment quality index (SQI). The different indices give diverse perspectives of the status of mangrove sediment quality. This review also highlights the appropriate parameters that need to be used in assessing sediment quality, such as the physical, chemical and biological properties. As the comparison review, the sediment quality can be utilized for Mangrove quality index (MQI) development like to assess the heavy metal, complete laboratory parameters and a classification following the Interim Sediment Quality Guidelines ISQG, PCA and HACA. For the heavy metal content of sediment, the suggested parameters are Pb, Zn, Cu, Co and Mn. Lastly, for the indices, the enrichment factor (EFs), geo-accumulation index (Igeo), pollution load index (PLI) and marine sediment pollution index (MPSI) are used in develop SQI on mangrove forest.
We employ complementary field and laboratory-based incubation techniques to explore the geochemical environment where siderite concretions are actively forming and growing, including solid-phase analysis of the sediment, concretion, and associated pore fluid chemistry. These recently formed siderite concretions allow us to explore the geochemical processes that lead to the formation of this less common carbonate mineral. We conclude that there are two phases of siderite concretion growth within the sediment, as there are distinct changes in the carbon isotopic composition and mineralogy across the concretions. Incubated sediment samples allow us to explore the stability of siderite over a range of geochemical conditions. Our incubation results suggest that the formation of siderite can be very rapid (about two weeks or within 400 hr) when there is a substantial source of iron, either from microbial iron reduction or from steel material; however, a source of dissolved iron is not enough to induce siderite precipitation. We suggest that sufficient alkalinity is the limiting factor for siderite precipitation during microbial iron reduction while the lack of dissolved iron is the limiting factor for siderite formation if microbial sulfate reduction is the dominant microbial metabolism. We show that siderite can form via heated transformation (at temperature 100°C for 48 hr) of calcite and monohydrocalcite seeds in the presence of dissolved iron. Our transformation experiments suggest that the formation of siderite is promoted when carbonate seeds are present.
Miocene larger benthic foraminifera have been discovered from a limestone unit of the Kalumpang Formation. The limestone is exposed at the Teck Guan Quarry, Tawau, southeast Sabah. The Kalumpang Formation consists predominantly of interbedded mudstone and sandstone (graywacke), conglomerate, limestone, marl, chert and volcanic rocks. Five limestone samples have been collected and processed for petrographic analysis and identification of larger benthic foraminifera. The limestone is classified as packstone and mudstone. A total of seventeen species of larger benthic foraminifera have been identified. The foraminifera are divided into two assemblages namely Assemblage I and Assemblage II. Assemblage I is characterized by the presence of Lepidocyclina (Nephrolepidina) parva, Operculina sp. and Lepidocyclina (Eulepidina) formosa. This assemblage is an indicative of Aquitanian to Burdigalian in age (Early Miocene). Assembalge II comprises of Lepidocyclina (Nephrolepidina) sumatrensis, Lepidocyclina (Nephrolepidina) angulosa, Lepidocyclina (Nephrolepidina) ferreroi Lepidocyclina sp., Miogypsina sp., Katacycloclypeus annulatus, Katacyloclypeus martini, Cycloclypeus carpenteri, Cycloclypeus indopacificus, Cycloclypeus sp., Flosculinella bontangensis, Operculina complanata, Amphistegina bowdenensis and Amphistegina sp. This assemblage is an indicative of Langhian to Serravallian age (Middle Miocene). The foraminiferal assemblages suggest that the depositional environment was a warm tropical shallow-marine at the fore-reef shelf zone.
Three short sediment cores (12-32 cm) from South China Sea off Southern Terengganu were collected during May (postNortheast monsoon) and September (pre-Northeast monsoon) 2007. The concentration of total organic carbon (TOC) obtained ranged from 0.41-2.23 and 0.38-2.31% during post and pre-monsoon, respectively. TOC concentration was found to decrease with depth and distance from the coast and river mouth. In particular, station with close proximity to the coast exhibits most pronounced variation of TOC with depth. Besides spatial variation, it is noted that the seasonal variations also considerably affect the distribution and concentrations of TOC, where both near and offshore sampling stations showed significant variations in TOC content during May and September sampling. These findings suggest the importance of terrestrial organic carbon flux, physical mixing and seasonal variations in regulating the concentration and distribution of the organic carbon in the study area.
This paper presents data on nitrogen characteristics in a tropical seagrass meadow located in Sungai Pulai estuary (Johor, Malaysia) and is related to the article "Nitrogen dynamics in tropical seagrass meadows under heavy anthropogenic influence" [1]. Field sampling conducted from August 2015 to May 2016 aimed to collect sediments and seagrass tissues for analysis of nitrogen elemental content and stable isotope values. Sediment samples and seagrass tissue (above-ground and below-ground parts) were collected by using PVC cores. The information is presented as unprocessed and partially data, which incorporates nitrogen content (in %) and δ15N values (‰) of sediment and seagrass tissue samples. Nitrogen loadings in the seagrass sediments, as based on down-core data of sediment samples up to 30 cm depths, should be read with [1] to comprehend the baseline nitrogen dynamics of the study area.
Miri city has a dynamic coastal environment, mainly influenced by intensive sedimentation from the Baram River and excessive trace metal loading by the Miri River, which are significant environmental concerns. As the mobility, bioavailability, and toxicity of the trace metals in the sediments are largely controlled by their particulate speciation, the modified BCR sequential extraction protocol was applied to determine the particulate speciation of trace metals in the coastal sediments of Miri, to unravel the seasonal geochemical processes responsible for known observations, and to identify possible sources of these trace metals. The granulometric analysis results showed that littoral currents aided by the monsoonal winds have influenced the grain size distribution of the sediments, enabling us to divide the study area into north-east and south-west segments where the geochemical composition are distinct. The Cu (>84%) and Zn (82%) concentrations are predominantly associated with the exchangeable fraction, which is readily bioavailable. Pb and Cd are dominant in non-residual fractions and other metals viz., Fe, Mn, Co, Ni, and Cr are dominant in the residual fraction. Using Pearson's correlation and factor analysis, the major mechanisms controlling the chemistry of the sediments are identified as association of Cu and Zn with fine fraction sediments, sulphide oxidation in the SW segment of the study area, atmospheric fallout of Pb and Cd in the river basins, precipitation of dissolved Fe and Mn supplied from the rivers and remobilization of Mn from the coastal sediments. Based on various pollution indices, it is inferred that the coastal sediments of NW Borneo are contaminated with Cu and Zn, and are largely bioavailable, which can be a threat to the local aquatic organisms, coral reefs, and coastal mangroves.
This study reports the concentrations of trace metals in core sediments profile from the coastal and four rivers estuary in the Kuching Division of Sarawak, Malaysia, and the controlling mechanisms influencing their availability in sediments of the studied area. The bonding of trace metals with non-mobile fractions was confirmed with the sequential extraction. Inductively coupled plasma-optical emission spectroscopy (ICP-OES) was used to measure the concentrations of the trace metals. Granulometric analyses were performed using normalized sieve apertures to determine the textural characteristics of the sediments. Enrichment factor was used to evaluate the level of metal enrichment. Heavy metals concentrations in sediment samples varied in the range: Pb (8.9-188.9 mg/kg d.w.), Zn (19.4-431.8 mg/kg d.w.), Cd (0.014-0.061 mg/kg d.w.), Ni (6.6-33.4 mg/kg d.w.), Mn (2.4-16.8 mg/kg d.w.), Cu (9.4-133.3 mg/kg d.w.), Ba (1.3-9.9 mg/kg d.w.), As (0.4-7.9 mg/kg d.w.), Co (0.9-5.1 mg/kg d.w.), Cr (1.4-7.8 mg/kg d.w.), Mg (68.8-499.3 mg/kg d.w.), Ca (11.3-64.9 mg/kg d.w.), Al (24.7-141.7 mg/kg d.w.), Na (8.8-29.4 mg/kg d.w.), and Fe (12,011-35,124.6 mg/kg d.w.). The estimated results of the enrichment factor suggested enrichments of Pb, Zn, and Cu in all the core sediment samples and depths at all sites. The other trace metals showed no enrichments in almost all the sampled stations. Continuous accumulation of Pb, Zn, and Cu metals over a period can be detrimental to living organisms and the ecology. The results obtained from the statistical analyses suggested that the deposition of trace metals in the studied sites is due to anthropogenic inputs from the adjacent land-based sources.
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
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.
Sediment is a great indicator for assessing coastal mercury contamination. This work profiled the magnitude of mercury pollution in the tropical estuaries and coastal sediments of the Strait of Malacca. Mercury was extracted through the ultrasound-assisted mercury extraction method and analyzed using the flow injection mercury system. The mean concentration of mercury in the sediment samples was 61.43 ± 23.25 μg/kg, ranging from 16.55 ± 0.61 to 114.02 ± 1.54 μg/kg. Geoaccumulation index revealed that a total of 13% of sampling sites were moderately enriched with mercury. The northern part of the Strait of Malacca had the highest mean mercury (Hg) concentration (76.36 ± 27.25 μg/kg), followed by the southern (64.59 ± 16.09 μg/kg) and central (39.33 ± 12.91 μg/kg) parts. Sediment mercury concentration in the current study was lower than other regions like Japan, China, Indian, east Mediterranean, and Taiwan. When compared to the Canadian interim marine and freshwater sediment, China's soil interim environmental guidelines, mercury contamination in the Strait of Malacca was found to be below these permissible limits. Sediment organic matter content was found to have significant correlation with sediment mercury concentration. This study could provide the latest benchmark of mercury pollution and prove beneficial to future pollution studies in relation to monitoring works in tropical estuaries and coastal sediments.