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The study assessed the composition, health risk, and sources of trace elements of road dust collected from three major metropolitan cities in Bangladesh. Pellets were prepared from the collected road dust samples and analyzed by the Energy Dispersive X-ray Fluorescence. The mean concentration of trace elements showed the order of K > Fe > Ca > Ti > Mn > Zr > Sr > Zn > Rb > Cr > Rb > Cu > Pb > Y > As > Ni. This research also presented the spatial distribution of the metals among three cities. The contamination factor and degree of contamination were assessed. The highest contamination factor was observed near BSRM steel manufacturing company, Chattogram could be due to the increased traffic in front of this industry. All the sampling sites showed pollution load index lower than one indicating unpolluted. However, K, Zn, and Zr showed a pollution load index values more significant than one. The result indicated that the ecological risk factor (Er) values fluctuated among metals tested across metropolitan cities. Negative geo-accumulation indexes were found for all the elements except K and Zn, suggesting moderate pollution. The Hazard Quotient values of all metals are < 1 for both adults and children. The cancer risks associated with Cr, Co, Ni, As, and Pb have been estimated individually for children and adults. The cancer risks associated with trace elements are below the European Union's acceptable limit, indicating that these five elements are not carcinogenic. The findings of principal component analysis followed by multiple linear regression showed that the sources of heavy metals were mixed natural (34.25%) and anthropogenic sources, vehicle emissions (38.92%), natural sources (5.80%), industrial sources (11.02%) and agricultural sources (10.02%). Four factors were concluded as sources of heavy metals confirmed by applying the positive matrix factorization model such as anthropogenic, industrial activities, natural process and agricultural activities. [ABSTRACT FROM AUTHOR]

A study was conducted on 16 sites in four Ramsar designated wetlands soils regarding soil properties and pollution indices in the Sylhet basin of Bangladesh. The wetlands sites' soil quality remained favorable for agricultural sustainability. Arsenic and cadmium contents were found at minimum detection levels. Rubidium and zirconium were found below critical levels. Pollution indices revealed that zinc and titanium content is slightly higher than the other elements. It was observed that Fe, Ti, Zr, and Mn originate from natural sources or sediments. In contrast, Zn and Cu originate from the artificial fertilizer sources used in and around agricultural lands of the wetland bodies. Moreover, the wetlands are used only for Boro rice crop, and for most of the year, they remain fallow. As a result, grazing activities are predominant. It is assumed that Cu and Zn are often used as additives for animal feed and enter animal wastes through incomplete absorption, and thus, the application of animal wastes in agriculture causes pollution with Zn and Cu. Pollution load index revealed that 42% of the study sites were polluted and 58% remained unpolluted. Principal component analysis and enrichment factors show that anthropogenic activities are responsible for the current pollution, where Zn and Cu predominate. The wetland sites are being polluted at a minor level. The main reasons for the higher level of metal pollution in Balai wetland might be its geomorphic nature and even anthropogenic activities. This wetland is located at the junction point of the Surma-Kushiyara River in Bangladesh, where an international river, Barak, intersects there, which originated from the upper territory. It is urgent to formulate an integrated action plan to prevent the source points of pollution. [ABSTRACT FROM AUTHOR]

This paper aims to measure the metals (Fe, Cu, Cr, Co, As, Zn, Hg, and Pb) concentration and assesses human health risks posed by these eight metals in the five most available cultured fish species (Pangasiuspangasius, Oreochromisniloticus, Heteropneustesfossilis, Anabustestudineus, Clariasbatrachus) collected from the Mymenshing Sadar Upazila. Both fishes and three fish feeds were analyzed using energy dispersive X-ray fluorescence (EDXRF). In fish feeds, the concentrations of metals were detected in the following order Fe > Zn > Cu > Hg > Pb. Besides, Hg concentration in three feeds samples was found higher than the maximum residue limit. Fe, Cu, Cr, Co, As, Zn, Hg, and Pb concentration in fishes were 82.45 to 104.55, 24.47 to 32.88, 2.62 to 6.73, < 0.28, < 0.41, 70.01 to 96.56, 0.57 to 1.07, and 0.34 to 0.49 µg/g respectively as dry weight basis. Health Risk Index (HRI) was observed > 1 both for adults and children and maximum HRI values for Pb was found in both P. pangasius and C. batrachus fish species. Additionally, PCA explained 73% variation in data and CA comprised the similarity within sampling stations. Pearson correlation implied a strong association amongst the trace metals. Finally, the accumulation of metals tends to the massive health hazard that should be mitigated by adopting several measures on fish feeds. [ABSTRACT FROM AUTHOR]

In industrial areas, increased human activities generate high emissions of metals that contaminate the environment, and eventually affect human health. Therefore, this study aims to investigate the sources of toxic elements in indoor dust samples, and to evaluate possible health risks due to expose of human body through dermal contact, inhalation, and ingestion. A total 36 indoor dust samples were collected from the windows of twelve (12) industrial buildings, which are facing the main roads in the biggest export process zone (DEPZ) in Dhaka City, Bangladesh. The indoor dust samples were analyzed using X-ray fluorescence (XRF) technique for the determination of Cu, Zn, As, Pb, Fe, Cr, Co, Ni, K, Ca, Ti, Rb, and Sr. This investigation revealed that Cu, Zn, Pb, Fe, and Sr concentrations were slightly higher in various degree than that of the background value in soil recommended by the Chinese Environmental Protection Administration (CEPA). Subsequently, ANOVA (α = 0.05, p < 0.001) test and %RSD values (33% to 168%) showed that the concentrations of these metals were present non-homogeneously in different sampling points. However, statistical analysis and several geochemical indices have been proposed that these heavy metals might be come in indoor dust samples because of anthropogenic events. This investigation also showed that the most-extreme permissible hazard index (HIs) levels known as non-cancer risk for As, Mn, and Zn because of dust exposure in the study area were below than that of the safe limit (HI = 1) but with an exception of Pb (HI = 1.9E+00) for children. On the other hand, the degree of cancer-causing risk linked with exposure to arsenic in indoor dust (i.e., 0.502E-06 to 0.121E-05) falls within the range of threshold values (10−6 to 10−4). Therefore, following USEPA health risk models, it has been suggested that these metals present in indoor dust samples might not have significant impact on causing non-cancer and cancer risk to children and to adult at this moment in the DEPZ area, Bangladesh. However, a continuous monitoring should be needed to assess more accurately the non-cancer and cancer risk to children and adult. [ABSTRACT FROM AUTHOR]