Mohammadreza Gharibreza

Historical variations of Bera Lake (Malaysia) sediments geochemistry using radioisotopes and sediment quality indices.

The Bera Lake basin is a lacustrine mire system and the largest natural lake in Peninsular Malaysia. Three cores were collected from the lake sediments in order to assess sediment quality and ecological risks for aquatic life and human health. An index analysis approach (Cf, Cd, Er, and IR) and fallout 210Pb and 137Cs radioisotopes were applied to assess the impacts of environmental evolutionary changes. Sediment chronology was determined using the Constant Rate of Supply model with the resultant ages verified by 137Cs horizons. Although the general contamination factors indicate low risk conditions in Bera Lake the risks associated with individual layers ranged from moderate to considerable. Five deforestation phases can be identified in the dated sediment cores with distinct variations in heavy metal influxes since 1972. These phases are in excellent agreement with the dates of land clearance and development projects undertaken over the past four decades. This study has highlighted the capability of contamination factors and chronological methods in environmental evolutionary studies where catchments have experienced extensive land use changes. The destiny of heavy metal influxes into a lake can also be revealed using this methodology.

Synthetic polymer composite membrane for the desalination of saline water

Abstract Development of desalination technologies has been identified as vital to fulfilling future water demand. In this research, composite membrane with polyvinyl alcohol (PVA) as separating layer material while cellulose acetate (CA) and polyethylene glycol (PEG) as supporting layer material were used. In the present research work, the synthesis and characterization of a multilayer PVA/CA/PEG membrane was attempted where membrane performance and applicability were investigated for reverse osmosis desalination of different feed concentrations of groundwater, brackish, highly saline, and also extremely saline water (seawater). Values of both salt rejection and water flux were assessed as a measure of membrane efficiency. In addition to suitable application of the prepared synthetic membranes, the antimicrobial sustainability was also evaluated where prospective function against gram-positive and gram-negative bacteria was depicted. It can be concluded by this work that multilayer PVA/CA/PEG membrane per...

Sedimentation rates in Bera Lake (Peninsular Malaysia) using 210Pb and 137Cs radioisotopes

The evolutionary environmental history of Bera Lake was studied using the fallout radioisotopes137Cs and 210Pb. 317Cs horizons in the all ten studied cores showed a constant rate of 210Pb supply along all distinctive layers in each core. The lithology of layers significantly affected the variation of 210Pb value with depth. The chronology of Bera Lake sediment was conducted using the Constant Rate of Supply (CRS) model. The 1963 fallout maximum 137Cs from atmospheric testing of nuclear weapons found in all selected master cores at the depth of 40 cm. The mean pre-1950 sediment accumulation rate was ranged between 0.06 ± 0.02 and 0.16 ± 0.2 g cm−2 y−1. Environmental impacts of five deforestation projects performed from 1972 to 1995 at the catchment area, contributed significantly toward increasing the sedimentation rate within Bera Lake. Besides the 137Cs horizons, the charcoal horizon at the lower contact of white sandy mud revealed the datum of maximum deforestation in the study area. 210Pb dates using the CRS model correlated historical sediment fluxes to anthropogenic changes in Bera Lake catchment area. Organicrich sediments deposited mostly at the top of the Bera Lake sediment columns with a mean rate of 0.2 ± 0.1 g cm−2 y−1 since 1994. High biomass productivity of mature oil palm plantations, which were developed in the catchment area, dictated organic-rich deposit distribution. This study highlighted capability of radioisotopes to reconstruct long-term (100–150 years) history of a natural lake at a tropical area where surrounding catchment has extensively deforested over the recent decades.

Intercationic effect on biosorbent efficacy.

The efficacy of the biosorbent coconut hust (Cocos nucifera) was tested for the removal of lead, copper, zinc, and nickel metal ions using batch experiments in multimetal solution system under controlled experimental conditions. It is found that metal sorption increases when the equilibrium metal concentration rises. At highest experimental solution concentration (150mg/L), the removal of metal ions was 92.52% for lead, 79.55% for copper, 63.23% for zinc, and 68.10% for nickel, while at lowest experimental solution concentration (25mg/L), the removal of metal ions was 94.80% for lead, 86.81% for copper, 84.63% for zinc, and 82.36% for nickel. Biosorption equilibrium isotherms were plotted for metal uptake capacity (q) against residual metal concentrations (Cf) in solution. The q vs. Cf sorption isotherm relationship was mathematically expressed by Langmuir and Freundlich models. The values of separation factor were between zero and one indicating favorable sorption for four tested metals on the biosorbent. The surface coverage values were approaching unity with increasing solution concentration, indicating effectiveness of the biosorbent.

An Evaluation of Bera Lake (Malaysia) Sediment Contamination Using Sediment Quality Guidelines

Bera Lake is known as the first RAMSAR site and is the largest natural lake in Malaysia. Sediment quality guidelines (SQGs) and Geoaccumulation index were used to evaluate Bera Lake sediment contamination. Five undisturbed cores were collected from Bera Lake sediment. Major and trace levels of elements were determined for 132 subsamples using an inductively coupled plasma mass spectrometry (ICP-MS). The results marked two major groups of metallic elements bonded to the terrestrial and organic-rich sediments. Terrestrial sediments were strongly associated with accumulation of Li, Al, Pb, Cu, Cr, Na, Mg, Sr, and K during main fluxes of metals. However, a strong positive correlation was obtained between Fe, Mn, As, Zn, Cu, Ni, Ca, and Cd elements and TOC and TN. The Mn/Fe ratio revealed a long-term redox and acidic condition at Bera Lake. Geoaccumulation index for all individual metals has classified Bera Lake sediment as low to moderately polluted. However, elemental values when compared with thresholds limits of SQG indicated that Bera Lake sediments were contaminated by arsenic and iron. Results prove that deforestation during the five phases of land developments since 1972 has significantly contributed to the existence of metals fluxes into the area.

Experimental study on the impact of vegetation coverage on flow roughness coefficient and trapping of sediment

Abstract The roughness coefficient is function of physical characteristics of flow, such as water depth, velocity, type and density of vegetation coverage. Impact assessment of vegetation coverage on flow roughness coefficient and trapping of sediment in experimental condition were the research aims. The research tests were conducted in different water discharge, various slope of substrate and three density of coverage using physical model. Relations for estimation of the Manning’s coefficient were developed using statistical analysis. The best performance of model in estimation of the flow roughness was gained at 12% density of coverage and steady injection of sediments.

Sedimentation Rate in Bera Lake

The evolutionary environmental history of Bera Lake was studied using the fallout radioisotopes137Cs and 210Pb. 317Cs horizons in the all ten studied cores showed a constant rate of 210Pb supply along all distinctive layers in each core. The lithology of layers significantly affected the variation of 210Pb value with depth. The chronology of Bera Lake sediment was conducted using the Constant Rate of Supply (CRS) model. The 1963 fallout maximum 137Cs from atmospheric testing of nuclear weapons found in all selected master cores at the depth of 40 cm. The mean pre-1950 sediment accumulation rate was ranged between 0.06 ± 0.02 and 0.16 ± 0.2 g cm−2 year−1. Environmental impacts of five deforestation projects performed from 1972 to 1995 at the catchment area, contributed significantly toward increasing the sedimentation rate within Bera Lake. Besides the 137Cs horizons, the charcoal horizon at the lower contact of white sandy mud revealed the datum of maximum deforestation in the study area. 210Pb dates using the CRS model correlated historical sediment fluxes to anthropogenic changes in Bera Lake catchment area. Organic-rich sediments deposited mostly at the top of the Bera Lake sediment columns with a mean rate of 0.2 ± 0.1 g cm−2 year−1 since 1994. High biomass productivity of mature oil palm plantations, which were developed in the catchment area, dictated organic-rich deposit distribution. This study highlighted capability of radioisotopes to reconstruct long-term (100–150 years) history of a natural lake at a tropical area where surrounding catchment has extensively deforested over the recent decades.

Soil Erosion Rate and Nutrient Loss at the Bera Lake Catchment

The catchment of Bera Lake in Pahang State, Peninsular Malaysia has experienced severe land use changes since 1972 with some 340 km2 (out of a total area of ~600 km2) having been converted to oil palm and rubber plantations and in some places, newly cleared for monoculture. The proportional model using the 137Cs radionuclide was recognized as being the most suitable conversion model for estimating soil redistribution in the catchment as the deforested land has been cultivated once in a medium-term range of 30–40 years. Thirty-five bulk core soil samples were taken to a depth of 25 cm in areas of different land use and known dates of tillage commencement in the catchment. Ten bulk core samples were also collected in the bottom sediments of wetlands and open waters to estimate accumulation rates in these sink areas. Individual land development districts with known elapsed times from start of tillage allowed determination of soil redistribution rates and preparation of a soil redistribution map. A mean soil erosion rate of 915 ± 345 t h−1 year−1 was determined in areas of cleared land, whereas rates of 117 ± 36, and 70 ± 35 t h−1 year−1, were determined in areas of developing, and developed, oil palm and rubber plantations, respectively. The overall accumulation rate of eroded soils within the wetlands and open waters was determined to be 1.025 cm year−1 since 1995. The Bera Lake catchment soil redistribution map is the first attempt in Malaysia to map soil redistribution using the 137Cs technique on a catchment scale. The soil redistribution map will provide good guidelines for future soil conservation practices and sustainable land use programs.

Sediment Quality and Ecological Risk Assessment of Bera Lake

The Bera Lake basin is a lacustrine mire system and the largest natural lake in Peninsular Malaysia. Three cores were collected from the lake sediment column in order to assess Bera Lake sediment quality and ecological risks for aquatic life and human health. An index analysis approach (Cf, Cd, Er, and IR) and the fallout 210Pb and 137Cs radioisotopes were applied to assess impacts of environmental evolutionary Changes at Bera Lake. Sediment chronology was conducted using the Constant Rate of Supply (CRS) model with the resultant sediment ages being verified by 137Cs horizons. Although the general contamination factors indicates low risk conditions in the Bera Lake basin, the risks associated with individual layers is regarded as moderate to considerable. Five deforestation phases were manifested in the dated sediment cores with distinct variations in heavy metal fluxes since 1972. These phases are in excellent agreement with the dates of land clearance and development projects undertaken over the recent decades. This study highlighted capability of contamination factors and chronological methods in environmental evolutionary studies which its catchment has extensively experienced land use changes. The destiny of fluxed heavy metal into a lake could be revealed using this methodology.

Watershed Management Practices

Soil and sediment management plan is important part of an applied limnology in order to mitigate soil erosion and sediment delivery to the sink areas. This chapter is addressed some management practices for approaching sustainable land use scheme and soil and lake conservation. Further, it aimed to achieve sustainable planning regulation for assessing environmental impacts of land uses and relevant guidelines and policies. Application of radioisotopes for soil conservation and watershed management also is presented in this chapter. Management issues involving the catchment as well as the open waters and wetlands of Bera Lake have been revealed through previous chapters. A broad and integrated management practice is proposed for each of these management issues. Specific management actions, including on-ground works and targeted scientific investigations, are recommended to meet each of the management objectives. On-ground practices comprise mechanical and agronomic methods which are supported by research and monitoring and socio-economic controlling practices. This book firmly recommends applying an integrated management plan from watershed to lake area in order to protect natural resources and to achieve the sustainable land use scheme.