Spatial distribution of carbon and nitrogen stable isotope in soil of an oil palm plantation

The conversion of lowland tropical forests to oil palm plantations is known to reduce the amount of soil carbon and nitrogen. However, this has been criticised as the plantations also contribute to a net gain of the soil carbon (C) stock. In this study, carbon and nitrogen stable isotopes techniques was used to confirm the source of carbon stored in plantation soils and to prove the effects of plantation activities on soil organic carbon. The objective of this study was to investigated the total organic carbon (TOC) and nitrogen (TON) content, and δ 13C and δ 15N values of soil in an oil palm plantation at different soil depths: 0-30, 30-60 and 60-90 cm and at different distances ((1.5 m: weeded circle), 3.5 (inter-rows) and 4.5 m (frond heap)) away from the tree base. The results showed that the ratio of soil δ13C and δ15N increased with depth and unusual δ15N value was reported on topsoil 0-30cm, a non-uniform distribution of soil OM (%), TOC (%), TON (%) and C/N ratio in the surface soil among the distances were observed. Negative correlation between δ13C and δ15N and bulk density (Bd) in respect of TOC and TON content were found. Value of δ13C at 0-30, 30-60 and 60-90 cm depths was -26.50, -26.36 and -26.23% respectively. This study conclude that, a low proportion of C was lost from the plantation soil , a long phase of C3 species dominated the soil before the establishment of the oil palm plantation and that frond heaps and large concentration of roots had a significant influence on OM (%), TOC (%), TON (%) and C/N ratio in the surface soil among the distances. The δ15N value in the top soil might be a useful indicator of the source and limited level of nitrogen in the area of study, however, further research is needed to confirm our observations

Characterization of water quality conditions in the Klang River Basin, Malaysia using self organizing map and K-means algorithm

This study aimed to determine the spatiotemporal pattern of the water quality data and identifying the sources of pollution in the Klang River Basin. The self organizing map (SOM) combined with the K-means algorithm arranged the data based on the relationships of 25 variables. The data from 2006 to 2009 for 30 monitoring stations were classified into six clusters. Water pollution in this river basin originated primarily from urban runoff, construction sites, faulty septic systems and industrial activities. The application of machine learning approaches is highly recommended to extract valuable information from the data for a holistic river basin managemen

Analyzing the major ions and trace elements of groundwater wells in Kuala Langat, Selangor

The analysis of trace elements and major ions on groundwater wells in Kuala Langat become the aim of this paper for the purposes to investigate the quality of the groundwater to be considered as a suitable alternative water source for domestic purposes. The groundwater sampling was conducted in thirteen stations of groundwater wells. The groundwater samples were taken from the groundwater wells which scatter in agricultural areas in Kuala Langat, Selangor. The major ions parameters have analyzed in the groundwater samples were calcium, magnesium, potassium, bicarbonate, chloride, and sulfate (Ca2+, Mg2+, K+, Na+, HCO3 -, Cl-, SO4 2-). Meanwhile, the trace element parameters were aluminum, iron, manganese, strontium, zinc, and copper (Al, Fe, Mn, Sr, Zn, and Cu). Principal Component Analysis (PCA) was conducted to determine the influence of major ions and trace elements concentration in groundwater. Chloride, potassium, magnesium, strontium, calcium, and bicarbonate (Cl-, Na+, K+, Mg2+, Sr2+, Ca2+, and HCO3 -) were principal parameters in the first component of PCA analysis. The concentration of trace elements shows iron is the high concentration in groundwater samples. Hence, the concentration of iron in current sampling shows exceed the recommended level for raw water of the Ministry of Health. The influences from seawater intrusion and Sodium Adsorption Ratio (SAR) in groundwater also have been discussed

Determination of Median Lethal Concentration (LC50) and Nitrite Accumulation in the Blood and Tissue of Blood Cockle (Tegillarca granosa, Linnaeus 1758)

This study aimed to determine the nitrite toxicity of blood cockle Tegillarca granosa, with the objectives being to identify the median lethal concentration (LC50) and the accumulation level of nitrite in Tegillarca granosa, and to determine the relationship of nitrite accumulation with mortality percentage. The levels of LC50 and accumulation of nitrite were determined after 72 h of exposure to different nitrite concentrations (0, 0.5, 1.0, 1.5, and 2.0 mg/L). Nitrite accumulation was analysed using Method 8153 and a DR2800 spectrophotometer (HACH, Loveland, CO, USA). LC50 was identified at 1.53 mg/L, and nitrite accumulated in the ranges of 0.012 to 0.106 mg/L wet weight and 0.002 to 0.089 mg/L wet weight in the blood and soft tissue samples, respectively. Accumulation concentration in both tissue and blood cells increased proportionally with the exposure concentration, and had a strong positive relationship with the percentage of mortality. Our findings suggest that prolonged exposure of nitrite led to accumulation in the blood and tissues and caused cockle mortality