Mirza A.T.M. Tanvir Rahman

Bioaccumulation of Trace Metals in Selected Plants within Amin Bazar Landfill Site, Dhaka, Bangladesh

The presence of trace metals in landfill soil and plants pose a risk to the environment and human health. This study was conducted to determine trace metal concentrations in soil and different plant parts that grow in the Amin Bazar landfill, Bangladesh, to evaluate the possible human health risk on consumer. The collected soil and plant samples were analyzed for trace metals using a Flame Atomic Absorption Spectrophotometer. The mean concentrations of trace metal found in the soil were in the following order: zinc (Zn) > manganese (Mn) > lead (Pb) > copper (Cu) > chromium (Cr) > nickel (Ni). Considering all selected plant species, the mean concentrations of trace metals were in the following order: Zn > Ni > Mn > Cu. On the other hand considering all measured trace metals, the accumulation trend in plant species were in the following order: Carica papaya > Enhydra flactuans > Amaranthus gangeticus > Ipomoea aquatica > Sesbania cannabina > Musa sapientum. Pb and Cr were not accumulated in the studied plant species. Translocation factor (TF), bioaccumulation factor (BAF) and bioaccumulation coefficient (BAC) were calculated for the assessment of mobility of trace metals from root to shoot, soil to shoot and soil to whole plant, respectively. TF values showed that the plant species effectively translocate trace metals from roots to the shoots, suggesting that they are suitable for phytoextraction. According to BAF all studied plants were excluders for all metals except Ni, and according to BAC, all studied plants were hyperaccumulators of Ni. The daily metal intake and health risk index values of the studied metals, except of Ni, indicated that there is a relative absence of health risks associated with the ingestion of contaminated edible parts of plants.

Selection of minimum indicators of hydrologic alteration of the Gorai river, Bangladesh using principal component analysis

The use of a few indicators of hydrologic alteration can minimize statistical redundancy which can lead to take effective environmental flow management decisions. The aim of the research is to select representative dominant indicators of hydrological alteration through reducing the dimensionality of multivariate data for the Gorai river, Bangladesh. The required mean daily discharge data (1976–2006) of the Gorai have been collected from the Bangladesh Water Development Board. The Range of Variability Approach and anomaly of the river flow show hydrologic alteration in recent years comparing with past. Principal component analysis (PCA) in Kendall and Pearson methods has been performed by the XLSTAT software (version 2.9). Depending on eigenvalues (>1.0), seven and six Principal components (PCs) are selected for Kendall and Pearson methods, respectively, for further analysis. Since the eco-flow metrics of eco-deficit of the river has poor correlation with the indicators of hydrologic alteration, the resultant loadings are subjected to the Kaiser–Meyer–Olkin (KMO) Measure of Sampling Adequacy (MSA) method which is classified into marvelous, meritorious, middling, mediocre, and miserable based on the PC loading values. Seven indicators have been found whose PC loadings are in marvelous class and are common for both Kendall and Pearson methods. These indicators, named March mean flow, 1-day minimum mean, 3-day minimum mean, 7-day minimum mean, 30-day minimum mean, 90-day minimum mean, and 30-day maximum mean flows, are the desired indicators of hydrologic alteration of the Gorai river.