The evaluation of spatial variation of water quality in Sungai Setiu Basin, Terengganu

This study investigates the spatial variation of water quality parameters in Sungai Setiu Basin at ten different locations from March 2010 to February 2011. The water quality was assessed using the Water Quality Index by Malaysian Department of Environment (DOE-WQI) and classified according to the Malaysia Interim National Water Quality Standard (INWQS). Six water quality parameters embedded in the DOE-WQI were dissolved oxygen (DO), biochemical oxygen demand (BOD), chemical oxygen demand (COD), pH, ammoniacal nitrogen (AN) and total suspended solid (TSS). In addition, this study also examined the changes in water quality over the past 10 years by comparing the present water quality to the previous works. The overall mean WQI value obtained was 84.0 which indicate that the Sungai Setiu basin is in clean condition and all measured water quality parameters gave value within the permissible limits of the INWQS classification except for pH which fall in Class III. It can be concluded that water quality in Sungai Setiu does not varies greatly over a decade. Hence continuous monitoring is needed to improve the water quality and minimize water pollution

Seasonal Variability and Fractionation of P-Based Nutrients in Setiu River Basin, Terengganu, Malaysia

A seasonal study of phosphorus (P)-based nutrients was carried out in Sungai Setiu basin which is located in the southern region of the South China Sea (Malaysia) from July 2010 until June 2011. Parameters measured were dissolved inorganic P (DIP), dissolved organic P (DOP) and total particulate P (TPP). In addition, DOP concentration was size fractionated into high molecular weight (HMW, 0.7 μm-100 kDa), middle MW (MMW, 100-30 kDa) and low MW (LMW, <30 kDa). The results show that the mean concentration of P-based nutrients ranged between 3.2-7.0 μg/L P for DIP, 5.6-12.1 μg/L P for DOP and 9.2-119.4 μg/L P for TPP. Higher mean concentrations of P were recorded at urban and agricultural areas. In addition, the distribution of P was affected by season as higher mean concentrations of P were observed during the north-east monsoon due to the surface runoff of nutrients during this heavy raining season. The fractionation study of DOP further revealed that HMW fraction was abundant in Sungai Setiu, making up approximately 60% of the total DOP. This high percentage of HMW DOP was recorded at stations in the vicinity of agriculture area and towns suggesting an important contribution from anthropogenic activities. The LMW DOP fraction was not significantly associated with chlorophyll-a, suggesting that the phytoplankton might not be the predominant contributor for LMW fraction in this river. We suggest that these organic nutrient inputs should be monitored as part of the management of the aquatic system

Distribution and behaviour of nitrogen compounds in the surface water of Sungai Terengganu Estuary, Southern Waters of South China Sea, Malaysia

A study was carried out to determine the distribution and behaviour of nitrogen (N) compounds (nitrite, nitrate, ammonia, dissolved and particulate organic nitrogen) in Sungai Terengganu estuary (TRE). Surface water samples were collected during ebb neap and spring tides for the longitudinal survey along the salinity gradient. The results indicated that all N compounds behave non-conservatively with addition during both tidal cycles, except for nitrate which exhibited removal behaviour during spring tide. In general, higher concentration of N compounds was observed during spring tide compared to neap tide. It is suggested that during spring tide, stronger water turbulence resulted in resuspension of nutrients in bottom sediment and lead to the increase in N compounds concentrations in the surface water. The diurnal survey for the freshwater station showed that the concentrations of N compounds follow the ebb and flood variations, whereas for the coastal station the reverse trend was observed. Comparisons with a previous study under similar tidal conditions show there was an increase in nitrite and ammonia concentrations in TRE, which was probably due to increase in discharge from the rapid development activities around this area. In addition, the presence of a breakwater at the lower part of the estuary may also contribute to the high nutrient content in the estuary due to restricted outflow of nutrients to the coastal area. Overall, the results from this study highlighted the importance of monitoring the N compounds for future protection of the estuary

Wavelets operational methods for fractional differential equations and systems of fractional differential equations

In this thesis, new and effective operational methods based on polynomials and wavelets for the solutions of FDEs and systems of FDEs are developed. In particular we study one of the important polynomial that belongs to the Appell family of polynomials, namely, Genocchi polynomial. This polynomial has certain great advantages based on which an effective and simple operational matrix of derivative was first derived and applied together with collocation method to solve some singular second order differential equations of Emden-Fowler type, a class of generalized Pantograph equations and Delay differential systems. A new operational matrix of fractional order derivative and integration based on this polynomial was also developed and used together with collocation method to solve FDEs, systems of FDEs and fractional order delay differential equations. Error bound for some of the considered problems is also shown and proved. Further, a wavelet bases based on Genocchi polynomials is also constructed, its operational matrix of fractional order derivative is derived and used for the solutions of FDEs and systems of FDEs. A novel approach for obtaining operational matrices of fractional derivative based on Legendre and Chebyshev wavelets is developed, where, the wavelets are first transformed into corresponding shifted polynomials and the transformation matrices are formed and used together with the polynomials operational matrices of fractional derivatives to obtain the wavelets operational matrix. These new operational matrices are used together with spectral Tau and collocation methods to solve FDEs and systems of FDEs

Spatial and temporal trends of polycyclic aromatic hydrocarbons in sediment cores of Brunei Bay, East Malaysia

The spatial and temporal distribution of polycyclic aromatic hydrocarbons (PAHs) in three sediment cores from Brunei Bay, Southern South China Sea was investigated. The total concentrations of 16 priority PAHs (∑PAH16) and their alkyl-substituted derivatives ranged from 10.4 to 376 ng g−1 and 30.7 to 2263 ng g−1, respectively. PAH biomarker diagnostic ratios and principal component analysis (PCA) combined with absolute principal component score (APCS) and multiple linear regression (MLR) were performed to apportion the source contribution. The results revealed mixed inputs of fuel combustion residues and uncombusted petrogenic products. The downcore PAH profile revealed that the highest peaks could be related to past human activities using biofuel and coal during the industrialization/agriculture revolution period. The 1,7/(2,6+1,7)-dimethylphenanthrene ratio also highlighted wood combustion during forest fire outbreaks, which appeared to coincide with the past climate events

Datasets on spatial and temporal distribution of heavy metals concentration in recent sediment at merang river system, Terengganu, Malaysia

Heavy metal pollution in an aquatic environment has become of the main concern to the world due to their nonbiodegradable properties, toxicity, persistence, and their ability to adsorb into food chains. With rapid industrialization and development nowadays, heavy metals are introduced continuously into the estuaries and coastal region through rivers, runoff, and land-based point sources. These heavy metals may degrade the aquatic environment and harm the living organisms and toward human indirection through secondary contact. The dataset provided is to give an overview of the spatial and temporal distribution of the heavy metals concentration in Merang River surficial sediment collected from September 2017 to July 2018, subsequently every two months dataset. Sediment samples were collected in 44 sta- tions along the river and 20 stations in the coastal area, which total up to 64 stations. Teflon Bomb closed digestion method with mixed acid was used to digest the sediments. The concentration of heavy metals in the sediment were analysed by using Inductively Coupled Plasma Mass Spectrometer (ICP-MS). The spatial distribution of heavy metals shows the effect of monsoon and wet and dry seasons in the sampling area. Thus, this dataset reveals six months of information on natural and anthropogenic sources intrusion at the Merang River and may also help in monitoring the pollution in the area

Distribution and sources of linear alkyl benzenes (LABs) in surface sediments from Johor Bahru Coast and the Kim Kim River, Malaysia

This study focuses on sewage pollution, which is one of the most important issues concerning Malaysians. The main location of this study is in Johor Bahru as it is one of the most populated areas in Malaysia. The distribution and sources of linear alkyl benzenes (LABs) were evaluated in surface sediments collected from Johor Bahru Coast and the Kim Kim River, Peninsular Malaysia. The samples were extracted, fractionated and analyzed using gas chromatography-mass spectrometry (GC-MS). This study found that LABs concentrations ranged from 87.6 to 188.7 ng/g dw and 88.2 to 119.02 ng/g dw in surface sediments from Johor Bahru Coast and the Kim Kim River, respectively. Johor Bahru Coast showed an increasing trend of LABs concentrations due to rapid industrialization and population growth. The ratio of internal to external isomers (I/E ratio) of LABs in sediment samples from Johor Bahru Coast ranged from 1.76 to 2.04 while the I/E ratios in sediments from the Kim Kim River ranged from 1.72 to 1.91. All I/E ratios at Johor Bahru Coast and the Kim Kim River stations indicate that the areas were receiving primary and secondary effluents

Study on the implementation of different biofloc sedimentable solids in improving the water quality and survival rate of mud crab, Scylla paramamosain larvae culture

Microbial communities in biofloc technology (BFT) are responsible in minimalize water exchange and producing microbial proteins that are beneficial as a supplementals diet for mud crab, Scylla paramamosain larvae culture. Therefore, a study was conducted to determine the effect of bacterial communities in different sedimentable solids in order to improve the water quality and survival rate of S. paramamosain larvae culture. The results successfully identified that the number of pathogenic bacteria, Vibrio spp. decreased when the heterotrophic bacteria thrived in treatment tank with 4 ml/L sedimentable solids. The group of heterotrophic bacteria were able to adapt in developing their population while effectively uptake the ammonium and nitrite components. The ammonium and nitrite level in treatment tank depleting at an early stage of the experiment, and constantly low until the end of experiments (ammonium <0.20 mg/L, nitrite <0.10 mg/L). The survival rates of S. paramamosain larvae in both control and treatment tanks were identified <2.0%, however, sedimentable solids of 2 ml/L was identified suitable to be applied in crab larvae culture as it can help to reach megalopa stages within 17 days of culture period. Overall, it can be concluded that bacteria communities in biofloc are able to regulate nutrients load and maintaining water quality and also help in increased survival rate and development performance in the low sedimentable solids of biofloc culture treatment. Therefore, sedimentable solids of 2 ml/L is suggested to be potentially applied in S. paramamosain larvae cultures from this research finding

Assessment of Sewage Molecular Markers in Port Dickson Coast and Kim Kim River with Sediment Linear Alkylbenzenes

The present study aimed to determine linear alkylbenzenes (LABs) concentrations as organic molecular marker for sewage pollution in the sediment samples collected from Coast of Port Dickson and Kim Kim River, Peninsular Malaysia. The adverse effects of anthropogenic inputs into the rivers and coastal environment could be detected by molecular organic markers such as LABs. The sediments were processed; their sources were identified and tested by gas chromatography-mass spectrometry (GC-MS). The significance of the differences among sampling stations for LAB concentrations and distribution at p < 0.05 was performed by analysis of variance and Post Hoc Tests, LSD procedures (ANOVA) and Pearson correlation coefficient. LABs indices which include internal to external (I/E) congeners, long to short chains L/S and homologs C13/C12 were used to identify the sewage treatment and degradation levels. Results of this study are statistically uncovered that the range of RLABs concentration in the investigated locations was between 112.0; 88.3 and 256.0; 119.0 ng�g1 dw, respectively. There was significant difference (p < 0.05) of LAB homologs with high percentage of C13-LAB homologs along sampling locations. The calculated LAB ratios (I/E) were within the range between 2.0; 1.7 and 4.1, 2.0, demonstrated that, the treated effluents from primary and secondary sources were discharged to the study areas. The degradation of LABs was 40–64% and 34–38% in the studied locations. The findings of this study suggested the powerfully indicators of LABs in tracing anthropogenic sewage contamination and the necessity of continuing wastewater treatment system improvemen

PM2.5 and associated ionic species in a sub-urban coastal area of Kuala Terengganu, Southern South China Sea (Malaysia)

PM2.5 mass concentration and associated water-soluble ionic species in a sub-urban coastal area of Kuala Terengganu, Malaysia were investigated intermittently from year 2006 to 2009. A total of 78 weekly PM2.5 samples were analyzed. The mass concentration of PM2.5 exhibited annual, seasonal and diurnal variations. Temporal distributions of rainfall, sporadic haze episodes and local air flow (sea breeze circulation) were factors controlling PM2.5 mass variations in the study area. Although the PM2.5 concentrations were increased during haze episodes in 2006 (August and October) and 2007 (October), their concentrations however, were still within the international guidelines. The average concentration of individual ions was in decreasing trend; SO42-> NH4+> K+> Na+> NO3-> Cl-> Ca2+. The concentrations of SO42- and NH4+ accounted for > 70% of the water-soluble aerosol mass. More than 80% of ionic species associated with PM2.5 are from non-marine sources. Major processes affecting the ionic composition of PM2.5 are biomass burning, crustal loading and sea spray. Air quality mitigation strategies should focus on anthropogenic activities emitting SO2, which promotes aerosol SO42- formation