Papers by Zulfahmi Ali Rahman
Fisheries and Aquaculture Journal, 2017
Pollution and food safety are concerning issues in recent years. For that, the present investigat... more Pollution and food safety are concerning issues in recent years. For that, the present investigation was aimed to determine the levels of heavy metals (Lead, Cadmium and Nickel) in different organs of three fish (Labeo rohita, Gibelion catla and Pangasius hypophthalmus) and to compare the present value with Food and Agriculture Organization (FAO)/World Health Oraganization (WHO) acceptable limit. These commonly consumed fish were collected from Kawran Bazar fish market, Bangladesh and the concentrations of heavy metals were carried out using Atomic Absorption Spectrophotometer. The highest (48.33 ± 2.52 ppm) concentration of Lead (Pb) was found in the gill of Pangus fish and the lowest (23.33 ± 2.52 ppm) was found in the gonad of Rui fish. In case of Cadmium (Cd), the highest (0.96 ± 0.08 ppm) concentration was found in the gill of Rui fish whereas the lowest (0.02 ± 0.01 ppm) was found in the kidney of Pangus fish. The highest (6.63 ± 1.00 ppm) concentration of Nickel (Ni) was found in the gill of Katla fish and the lowest (0.10 ± 0.10 ppm) was found in the liver of the same species. The metal concentrations in the muscle of Rui, Katla and Pangus fish were in the decreasing order of Pb>Ni>Cd, Pb>Cd>Ni and Pb>Ni>Cd respectively. In the study, it was found that Pb has exceeded the limits in every case whereas Cd was within the limits except for a few and Ni was completely within the maximum allowable limits provided by FAO/ WHO. However, all these concentrated metals in different parts of fish body could be concentrated into human body, if they are consumed and if so happen; there will be a massive health risk for us.
Sains Malaysiana
There is a considerable interest in making alternative bricks using wastes. Firing temperature ha... more There is a considerable interest in making alternative bricks using wastes. Firing temperature has been significantly improved the mechanical qualities of bricks. The aim of this study was to investigate into the impact of firing temperature and rice husk ash content on the mechanical properties of drinking water sludge bricks (DWS). Two types of bricks were produced; bricks made of 100% DWS (DWS100) and bricks with 80% DWS and 20% RHA (DWS80). These samples were subjected to different thermal variations of 300 °C and 700 °C for three hours. The unfired brick samples were also prepared for reference. The volume changes of the DWS100 bricks increased as the firing temperature climbed up to 500 °C, before dropped at 700 °C. A similar behaviour was also exhibited by DWS80 bricks, however it shrunk at earlier temperature of 500 °C. At 500 °C and 700 °C, the density of bricks decreased dramatically, with DWS80 bricks consistently being lesser than DWS100 bricks. The water absorption of D...
Site suitability analysis for sanitary landfills using geospatial methods in a part of southern Peninsular Malaysia
Environmental Science and Pollution Research
Heavy metals in topsoil under selected vegetable cultivation areas in Cameron highlands, Pahang, Malaysia
Malaysian journal of science, 2006
Heavy metal contents of soil under vegetable cultivation in the Cameron Highlands were determined... more Heavy metal contents of soil under vegetable cultivation in the Cameron Highlands were determined. Five stations selected for this purpose were Kg. Raja (forest reserve), Kuala Terla (cabbage), Tringkap (cabbage) and two stations at Blue Valley (cabbage and an abandoned tea plantation). Soil samples were collected during the harvesting season for cabbage. Soil in the tea plantation and forest were used for comparison. The mean of all of the heavy metals examined, except arsenic, were high in soil cultivated with cabbage compared to the soil under natural forest and tea plantation. The increase in heavy metal content for the agricultural area was attributed to the common practice of fertilizing, liming and pest control. Heavy metal content in all stations was within the normal range in soils but As and Zn concentrations were already within the potential toxic threshold in soil. Soil parameters such as pH, organic matter, silt and phosphorus content in soil had an influence on the enr...
Géotechnique, 2017
This paper presents the results of a set of 22 triaxial tests on an unsaturated artificially ceme... more This paper presents the results of a set of 22 triaxial tests on an unsaturated artificially cemented sand. The results are used to explore the applicability of a number of unsaturated soil frameworks for interpreting the shear strength. Constant water content triaxial tests were carried out on unsaturated specimens, using the axis translation technique to measure suctions during shearing. The test results on the unsaturated material were referenced against a series of drained and undrained triaxial tests that were carried out on saturated specimens. The results of the unsaturated tests were analysed to investigate the effect of the suction and degree of saturation on the shear strength at the critical state. The results show that the critical state stress ratio in terms of net stress (Ma) was found to be larger than the saturated critical state stress ratio (Ms). It was also found that the stress ratio in terms of suction (Mb) reduced as suction increased (when the degree of satura...
Sains Malaysiana, 2012
Amang or tin tailing is commonly found in the vicinity of disused mining area and responsible in ... more Amang or tin tailing is commonly found in the vicinity of disused mining area and responsible in downgrading the water quality, landscape and mechanical behaviour of soils. It was generated from extraction process of separating valuable metal from particular ore. This paper presents the geotechnical characteristics of amang-contaminated clay soil. The geotechnical properties of uncontaminated soils were studied in order to compare to that of amangcontaminated soils. The base soil used in this study represents completely weathered horizon of metasedimentary rock. Meanwhile, tin tailing sample was taken from the disused mine at Sungai Lembing, Pahang. The geotechnical characterisations of base soil and contaminated soils were determined based on consistency index, compaction behaviour, hydraulic conductivity and undrained shear strength (UU tests). Contaminated soil samples were prepared by adding 5, 10 and 20% of tailing, based on dry weigh of the studied base soil. The results from the particle size distribution analysis showed that residual soil from metasedimentary rock comprised 42.6% clay, 32.2% silt and 25.2% sand whilst tailing was dominated by 98% of sand fraction. XRD analysis indicated the presence of quartz, kaolinite and muscovite minerals in the studied soil. The specific gravity of soil used is 2.67 and the pH is 3.88. Tailing found to have higher specific gravity of 3.37. The consistency index of contaminated soils showed that liquid limit, w L and plastic limit, w P decreased with the increase in the percentage of tailing added to the soil samples. The value of maximum dry density, ρ dry max increased while optimum moisture content decreased due to the increase in tailing content in soil sample. The permeability of contaminated soil also increased with the increase in tailing contents ranged from 19.8 cm/hr to 23.8 cm/hr. The undrained shear strength, C u , of contaminated soil decreased from 646 kPa (5% of tailing) to 312 kPa (20% of tailing) suggesting that the presence of tailing has influenced the geotechnical properties on the studied soil. 
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Papers by Zulfahmi Ali Rahman