Groundwater quality and human health risk assessment in selected coastal and floodplain areas of Bangladesh.

Groundwater aquifers are a common source of drinking water in Bangladesh. However, groundwater contamination is a major public health concern across the country. This research aims to examine the groundwater quality and health concerns using a random sampling process. Multivariate statistical and health risk analyses of elements were performed to determine the source of contaminants and their effects on human health. A total of 24 parameters were analyzed, where Na+, NH4+, K+, Mg2+, F-, NO3-, Mn, Fe, Se, U, and As concentrations were found to be high in different sampling points compared to the Department of Environment of Bangladesh (DoE), and the World Health Organization (WHO) groundwater quality standards. Principal Component Analysis (PCA) and Cluster Analysis (CA) identified the dominant and potential sources of contaminants in the groundwater aquifer, including geogenic, salinity intrusion, industrial, and agricultural. The results of the degree of contamination level (Cd) and the heavy metal pollution index (HPI) showed that 28% and 12% of the sampling points had high levels of heavy metal contamination, indicating a high risk for human health issues. Cr concentrations were found to have a higher carcinogenic (cancer) risk than As and Cd concentrations. Hazard quotient (HQ) and hazard index (HI) scores expressed the hazardous status and possible chronic effects in the context of individual sampling points. For both child and adults, 44% and 36% of the sampling points had a high HI score, indicating the possibility of long-term health risks for local populations.

Groundwater salinization and associated co-contamination risk increase severe drinking water vulnerabilities in the southwestern coast of Bangladesh.

Household drinking water security is one of the major issues among coastal communities in Bangladesh. To examine the groundwater quality and social consequences, groundwater samples and household questionnaires were administered across the study area. Instrumental and statistical tools were used to analyze the water quality and social survey data. The average concentrations of electrical conductivity (EC) (7135.67 µS/cm), total dissolved solids (TDS) (3691 mg/L), Na+ (1569.51 mg/L), Ca2+ (289.5 mg/L), Mg2+ (340.51 mg/L), Cl- (2940.78 mg/L), F- (11.85 mg/L), NO3- (54.44 mg/L), NO2- (162.95 mg/L), PO43- (105.19 mg/L), Fe (4.9 mg/L), Mn (1.22 mg/L), As (16.55 µg/L), B (833.28 µg/L), and Pb (34.22 µg/L) were observed in groundwater, and exceeded the drinking water standards from 30% to 100% depending on the sampling location. Thus, the remarkably high contents of EC, TDS, Cl-, and Na+ represented possible saltwater intrusion along the coastal aquifer. The positive correlations between EC and trace and toxic elements indicated the potential influence of groundwater salinization on the dissolution of more chemical contaminants in the aquifer. These results showed that 100% of samples were unsuitable for drinking purposes. Severe drinking water scarcity is a serious issue, and local people have been affected by water-related diseases owing to the long-term consumption of contaminated water. Salinity problems in drinking water and related health diseases have increased significantly in the past several years. In addition, climate change and its associated hazards, including sea-level rise, cyclonic storm surges, flooding, and resulting inundation problems, have intensified the drinking water scarcity and health problems at the community level. To ensure household water security, environmental exposure, hydrogeology, and anthropogenic interventions must be considered to determine future sustainable water policies.

An investigation of coastal vulnerability and internal consistency of local perceptions under climate change risk in the southwest part of Bangladesh.

Climatic threats force disruption on community lifestyles by impairing social factors, the fundamental components of ensuring social sustainability. This study investigates the situational factors affecting the consequences on coastal livelihoods, and social activities; it also considers the effectiveness of traditional knowledge in reducing possible risks. Both qualitative and quantitative methods were employed, including questionnaire survey for identifying the local perception of climatic impacts alongside the impacts on daily activities. Interviews, field observations, and multivariate analyses were performed to explain the vulnerability status in coastal communities. Results show that most livelihood sectors were severely affected by the long-term and repeated actions of climatic hazards, such as cyclones, associated with a number of unavoidable risks making people susceptible to damages in social wellbeing. In addition, saltwater intrusion damages drinking water supply and crop farming, which can cause diseases among coastal communities, but very few attempts have been made to provide alternative sources of drinking water at a household level. Moreover, principal component analysis (PCA) and cluster analysis (CA) revealed significant interfaces between local perceptions and the socio-and agro-environmental factors changing the overall status of regional hazards. Thus, the situation exhibits coastal hazards, social vulnerability, and social crisis. Local people use their traditional knowledge to cope with various levels of crisis under vulnerable conditions, but sometimes doing so exceeds their capacity owing to the unwanted changes in climatic variables and knowledge gaps or uncertainties. Challenges on the basis of the problematic points should be noted, however, it would be more significant to achieve social sustainability under adverse climatic conditions.

Evaluation of hazardous metal pollution in irrigation and drinking water systems in the vicinity of a coal mine area of northwestern Bangladesh.

An integrated approach of pollution evaluation indices, principal component analysis (PCA) and cluster analysis (CA) was employed to evaluate the intensity and sources of pollution in irrigation and drinking water systems of northwestern Bangladesh. Temperature, BOD, chemical oxygen demand (COD), Mn, Fe, Co, Ni, Cu and Pb levels in most of the water samples exceed the Bangladesh and international standards. The heavy metal pollution index (HPI) and degree of contamination (C(d)) yield different results despite significant correlations between them. The heavy metal evaluation index (HEI) shows strong correlations with HPI and C(d), and gives a better assessment of pollution levels. Modifications to the existing HPI and C(d) schemes show comparable results with HEI, and indicate that about 55% of the mine drainage/irrigation waters and 50% of the groundwaters are moderately to highly contaminated. The CA, PCA and pollution indices suggest that the mine drainage water (DW) is contaminated by anthropogenic (mining operation and agrogenic) sources, and the proximal parts are more contaminated than the distal part. The groundwater system in the vicinity of the coal mine site is also heavily polluted by anthropogenic sources. The pollution status of irrigation and drinking water systems in the study area are of great environmental and health concerns.

Heavy metal pollution of coal mine-affected agricultural soils in the northern part of Bangladesh.

Total concentrations of heavy metals in the soils of mine drainage and surrounding agricultural fields in the northern part of Bangladesh were determined to evaluate the level of contamination. The average concentrations of Ti, Mn, Zn, Pb, As, Fe, Rb, Sr, Nb and Zr exceeded the world normal averages and, in some cases, Mn, Zn, As and Pb exceeded the toxic limit of the respective metals. Soil pollution assessment was carried out using enrichment factor (EF), geoaccumulation index (I(geo)) and pollution load index (PLI). The soils show significant enrichment with Ti, Mn, Zn, Pb, As, Fe, Sr and Nb, indicating inputs from mining activities. The I(geo) values have revealed that Mn (1.24+/-0.38), Zn (1.49+/-0.58) and Pb (1.63+/-0.38) are significantly accumulated in the study area. The PLIs derived from contamination factors indicate that the distal part of the coal mine-affected area is the most polluted (PLI of 4.02). Multivariate statistical analyses, principal component and cluster analyses, suggest that Mn, Zn, Pb and Ti are derived from anthropogenic sources, particularly coal mining activities, and the extreme proximal and distal parts are heavily contaminated with maximum heavy metals.