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As a precursor to risk assessment and risk management through consuming contaminated seafood, food safety needs to be quantified and assured. Seaweed is an increasing dietary component, especially in developing countries, but there are few studies assessing uptake rates of contaminants from this route. As such, the present study determined likely human uptake due to the trace elemental (Fe, Mn, Ni, Cu, Zn, Se, Hg, and As) concentrations in the edible red seaweeds (Rhodophyta) Gelidium pusillum and Hypnea musciformis, growing in the industrialised Cox's Bazar coastal area of Bangladesh. Metal and metalloid concentrations in G. pusillum were in the order (mg/kg): Fe (797 ± 67) > Mn (69 ± 4) > Ni (12 ± 5) > Zn (9 ± 4) > Cu (9 ± 4) >Se (0.1 ± 0.1) > Hg (0.1 ± 0.01), and in H. musciformis: Fe (668 ± 58) > Mn (28 ± 5) > Ni (14 ± 2) > Zn (11 ± 5) > Cu (6 ± 4) >Se (0.2 ± 0.03) > Hg (0.04 ± 0.01). Despite the industrial activities in the area, and based on 10 g. day -1 seaweed consumption, it is concluded that these concentrations pose no risk to human health as part of a normal diet according to the targeted hazard quotient and hazard index (THQ and HI) (values < 1). In addition, and as a novel aspect for seaweeds, Selenium Health Benefit Values (Se-HBV) were determined and found to have positive values. Seaweed can be used as an absorber of inorganic metals for removing contamination in coastal waters. The results are a precursor to further research regarding the efficiency and rate at which seaweeds can sequester metal contamination in water. In addition, management techniques need to be developed thereby to control the contaminant inputs., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

In recent decades, water quality is a great concern for the human being as it is the most important natural resource but water is polluted by increasing population activities. In this study, surface water samples were collected in the wet and the dry season from Halda River, Bangladesh, and 12 physicochemical properties and 10 traces elements (Cd, Cr, Mn, Fe, Co, Cu, Zn, As, Pb, and Hg) were analyzed to assess the metal toxicity, identify the possible sources, and determine possible carcinogenic and noncarcinogenic risk for adults and child residents. During wet season, the mean concentrations of Cd, Cr, Mn, Fe, Co, Cu, Zn, As, Pb, and Hg were 0.032 ± 0.028, 0.004 ± 0.002, 0.010 ± 0.012, 0.38 ± 0.08, 0.010 ± 0.017, 3.33 ± 1.16, 0.062 ± 0.008, 1.34 ± 1.17, 0.030 ± 0.014, and 0.007 ± 0.002 mg/L, respectively, whereas the concentrations were measured as 0.04 ± 0.017, 0.060 ± 0.036, 0.150 ± 0.134, 0.58 ± 0.11, 0.049 ± 0.017, 0.172 ± 0.166, 0.393 ± 0.212, 1.07 ± 0.989, 0.104 ± 0.121, and 0.003 ± 0.002 mg/L, respectively, during the dry season. The levels of trace elements in water samples were much higher than the guideline values for safe limits of drinking water and the protection of freshwater aquatic life, indicated that water from this river is not safe for drinking and/or cooking purposes. Trace element evaluation index indicated that water was found to be high contamination while ecological risk index showed low to very high contamination. All hazard quotient and hazard index (HI) values were higher than the risk threshold of unity. HI values for child were higher than those for adult, indicating that the health of children is at dramatically higher risk than adults. Arsenic for water ingestion and dermal pathways was the primary contributors to total health risk (HI/THI) indicated that As in surface water of the Halda River might pose health risks to residential users. [ABSTRACT FROM AUTHOR]

The surface salt marsh sediments from marine ecosystems in the Bay of Bengal, Bangladesh was assessed for trace elements like iron (Fe), calcium (Ca), titanium (Ti), potassium (K), strontium (Sr), rubidium (Rb), zirconium (Zr), zinc (Zn), copper (Cu) and lead (Pb), their potential sources, and associated ecological risks. The range of trace elements in sediment (mg/kg) followed the decreasing order: Fe (25020–35176) > Ca (8679–16323) >Ti (2678–3340) > K (23680–16770) > Sr (138.32–209.64) > Rb (124–186.57) > Zr (96.21–161.35) > Zn (37.71–44.95) > Cu (36.51–51.66) > Pb (1.35–10.42). The concentrations of trace elements were under the average shale values of metals in sediment except for Fe, Cu and Rb, which can occasionally be associated with adverse biological effects. Contamination level and ecological risk were evaluated using contamination factor (CF), enrichment factor (EF), geo-accumulation index (Igeo), pollution load index (PLI), and potential ecological risk index (PERI). Multivariate statistical technique was used to classify the metal sources. The results showed that Fe was significantly enriched in the sediments. Ecological risk factors illustrated a pollution-free condition of the salt marsh ecosystem in Bangladesh. [ABSTRACT FROM AUTHOR]