Seasonal investigation of heavy metals in marine fishes captured from the Bay of Bengal and the implications for human health risk assessment

To investigate the seasonal contamination levels and to evaluate the potential human health risks, ten heavy metals (As, Cd, Co, Cr, Cu, Mn, Ni, Pb, Se, and Zn) were measured in ten different marine fish species from the Bay of Bengal during four seasons. The metal concentrations varied significantly (p 10) due to exposure to arsenic indicated that consumers remain at risk of cancer

Cellular response of oxidative stress when sub1A QTL of rice receives water deficit stress

In this experiment, sub1A quantitative trait loci (sub1A QTL) of rice were evaluated for dehydration responses through different aspects of cellular responses. Through variations of dehydration exposure, rice seedlings recorded a significant increase in superoxide (O2.-) and hydrogen peroxide (H2O2), the former by 1.80 fold and the latter by 2.10 fold. Nicotinamide adenine dinucleotide phosphate oxidase activity fairly correlated with lipid peroxidation (r = 1.96). Both 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) had similar IC50 values over the control at p ? 0.05. Reducing power of the extract had 1.31 fold increase. The antioxidant moieties like total phenolics and flavonoids were 1.04 and 1.23 fold upregulated under stress. On the other hand anthocyanin and glutathione (GSH) did not vary much under stress except at maximum duration of stress. Superoxide dismutase (SOD) was initially stable but maximized at 8 days by 1.30 fold increase. On the contrary, guaiacol peroxidase (GPX) was seen to be downregulated by 40.94% all through the days of stress. Catalase (CAT) activity followed a similar trend, but was not significant as compared to control

Concentration of selected toxic metals in groundwater and some cereals grown in Shibganj area of Chapai Nawabganj, Rajshahi, Bangladesh

This study is an attempt to assess the extent of toxic metals, including Pb, Cd, Cr, Mn and As in groundwater and some cereals collected from Shibganj area of Chapai Nawabganj, Rajshahi, Bangladesh. The chemical results of groundwater show that the mean concentrations of Pb, Cd and Mn exceed the values of WHO, USEPA as well as Bangladesh Drinking Water Standards. However, As content is within the permissible limits in terms of Bangladesh Drinking Water Standards, but exceeds the WHO and USEPA values. Cr is in negligible quantity in the examined groundwater samples. Results reveal wide variation in toxic metal content among the three cereal samples. In general, the mean toxic metal concentrations in cereals (rice, wheat and urid bean) are lower than the respective established safe limits for these elements, except for lead concentration in all samples

Groundwater hydrogeochemistry and probabilistic health risk assessment through exposure to arsenic-contaminated groundwater of Meghna floodplain, central-east Bangladesh

A clear understanding of various hydrogeochemical processes is essential for the protection of groundwater quality, which is a prime concern in Bangladesh. The present study deals with the geochemistry of groundwater at various depths to investigate the hydrogeochemical processes controlling the water quality of Meghna floodplain, the sources and mechanisms of arsenic (As) liberation, and the estimation of carcinogenic and non-carcinogenic health risks (using probabilistic and deterministic approaches) to the adults and children of the Comilla district, central-east Bangladesh. The groundwaters were generally of Ca–Mg–HCO type, and water-sediment interaction was the dominant factor in evolving the chemical signatures. The dissolution of carbonates, weathering of silicates, and cation exchange processes governed the major ion chemistry. Dissolved As concentration ranged from 0.002 to 0.36 mg/L and Monte Carlo simulation-based probabilistic estimation of cancer risk suggested that; (1) ~ 83% of the waters exceeded the higher end of the acceptable limit of 1 × 10; (2) the probability of additional cases of cancer in every 10,000 adults and children were on average ~9 and ~5, respectively; (3) adults were more susceptible than children; and (4) ingestion was the main pathway of As poisoning and the contribution of dermal contact was negligible

Multivariate statistical analysis of metal contamination in surface water around Dhaka export processing industrial zone, Bangladesh

Deterioration of water quality by anthropogenic heavy metal pollution is a critical issue, especially in the least developed countries. This study, therefore, utilizes multivariate statistical approaches to report on the sources of heavy metals contamination in water bodies close to Dhaka Export Processing Zone industrial area in Bangladesh. Correlation matrix showed a number of significant associations (p < 0.01 and p < 0.05) among the metals, with no major seasonal influence on metal associations. Spatial variability of metal concentrations, however, was observed with lowering of concentration as distance increased from the pollution sources. Principal component and cluster analysis identified three major sources of metal pollution including untreated industrial effluents, municipal wastes, and atmospheric deposition of metals from burning of fossil fuels. These three sources were responsible for the data structure explaining 79.97% of total variance. Hierarchical cluster analysis demonstrated three clusters of nine sampling stations depending on the similarity of the data. Overall, the levels of metal concentrations determined in this study clearly illustrated the anthropogenic disturbances on water quality

Heavy metals in fish, fruits and vegetables from Rajshahi, Bangladesh: a statistical approach

Vegetables, fruits, and fishes are the main routes of exposure to heavy metals formost of the Bangladeshi population.Thus, the present study was conducted to determine the content of lead (Pb),manganese (Mn), chromium, (Cr), cadmium (Cd), and arsenic (As) in some keyvegetables, fruits, and fishes purchased from the city market of Rajshahi using atomicabsorption spectrometry.The Pb, Mn, Cr, Cd, and As concentrations ranged from 0.42 to 23.99, 1.13 to 8.11,0.17 to 2.50, 0.15 to 3.02, and 0.07 to 0.15 mg/kg dry weight respectively. The estimatedamounts of heavy metals were lower than the recommended values, but considerableattention should be paid to the Pb and Cd concentrations. Especially, among five heavymetals in three food categories, fish samples were highly contaminated by Pb. The resultsrevealed that the estimated daily intakes of heavy metals were within the respectiverecommended daily dietary allowance established internationally. The biggestcontribution of daily intakes of heavy metals came from the vegetables, which could bedue to its high consumption rate.Results of one way ANOVA test demonstrated that heavy metal concentrations werestatistically significant (p < 0.05) among the different vegetable, fruit, and fish species. Furthermore, no significant correlation was found between the heavy metals invegetables, fruits, and fishes except Pb-Cd (r = 0.899, α = 0.05) in fruits

Potential ecological risk assessment of heavy metal contamination in sediment and water body around Dhaka export processing zone, Bangladesh

Sediments and surface water contamination by the industrial effluents containing heavy metals is the most detrimental environmental impact. Therefore, the present work attempts to determine the status of eight heavy metal distribution in sediments and water samples, and their ecological risks' assessment in the studied area. The distribution pattern of heavy metals in the water and sediment follows the sequences: Zn > Cu > Pb > Cr > Mn > Ni > As > Cd and Mn > Zn > Cr > Pb > Cu > Ni > As > Cd, respectively. Gross water pollution is observed at different sampling points of Dhalai Beel and Bangshi River. The comparison of sedimentary mean metal concentrations with several environmental contamination monitoring parameters, viz, threshold effect level (TEL), probable effect level (PEL), and severe effect lever (SEL) indicates that the metal levels are less than PEL except Cr. Moreover, the level of contamination degree (C (d)) and modified degree of contamination (mC (d)) indicates 'low' and 'nil to low' degree of contamination, respectively. Pollution load indices (PLI) of the studied area are lower than unity, indicates no pollution. Furthermore, a toxic-response factor is applied to assess the potential ecological risk of these heavy metals into the water body. The results of this study exhibit a low potential ecological risk of heavy metals. The Pearson's correlation and cluster analysis are also performed to assess the heavy metal interactions in water and sediment samples

Degradation of Bisphenol A from aqueous solutions using Fe3O4 as a persulfate activator

The present study investigated the degradation of bisphenol A (BPA) from aqueous solution using Fe3O4/persulfate process. The effects of pH (3, 5, 7 and 11), persulfate (PS) concentrations (1, 2, 5 and 10 mM), Fe3O4 magnetic nanoparticle doses (0.5, 1, 1.5 and 2 g/L), and contact time (5, 10, 20 and 30 min) on BPA removal were examined. The effect of all factors was significant (p < 0.05), and the optimal conditions were: pH value of 3, Fe3O4 dose of 2 g/L, BPA concentration of 0.1 mg/L, and contact time of 30 min. The BPA removal efficiency under optimal conditions was 98%. The results of this work indicate that Fe3O4 nanoparticles can be used as an effective catalyst and adsorbent for the removal of BPA from water and industrial wastewater. Analysis of by-products of BPA using GC-MS detected the presence of compounds with lower molecular weights (4-hydroxyacetophenone, 4-isopropenylphenol, benzoquinone and succinic acid) relative to BPA

Coral skeletal geochemistry as a monitor of inshore water quality

Coral reefs maintain extraordinary biodiversity and provide protection from tsunamis and storm surge, but inshore coral reef health is degrading in many regions due to deteriorating water quality. Deconvolving natural and anthropogenic changes to water quality is hampered by the lack of long term, dated water quality data but such records are required for forward modelling of reef health to aid their management. Reef corals provide an excellent archive of high resolution geochemical (trace element) proxies that can span hundreds of years and potentially provide records used through the Holocene. Hence, geochemical proxies in corals hold great promise for understanding changes in ancient water quality that can inform broader oceanographic and climatic changes in a given region. This article reviews and highlights the use of coral-based trace metal archives, including metal transported from rivers to the ocean, incorporation of trace metals into coral skeletons and the current 'state of the art' in utilizing coral trace metal proxies as tools for monitoring various types of local and regional source-specific pollution (river discharge, land use changes, dredging and dumping, mining, oil spills, antifouling paints, atmospheric sources, sewage). The three most commonly used coral trace element proxies (i.e., Ba/Ca, Mn/Ca, and Y/Ca) are closely associated with river runoff in the Great Barrier Reef, but considerable uncertainty remains regarding their complex biogeochemical cycling and controlling mechanisms. However, coral-based water quality reconstructions have suffered from a lack of understanding of so-called vital effects and early marine diagenesis. The main challenge is to identify and eliminate the influence of extraneous local factors in order to allow accurate water quality reconstructions and to develop alternate proxies to monitor water pollution. Rare earth elements have great potential as they are self-referencing and reflect basic terrestrial input