Assessing and Mapping Vulnerability and Risk Perceptions to Groundwater Arsenic Contamination : Towards Developing Sustainable Arsenic Mitigation Models

This study focuses on the arsenic-affected rural communities in Bihar located within the mid-Gangetic Plain in India. A random stratified sampling method is applied to survey 340 households in three villages (Suarmarwa, Rampur Diara, and Bhawani Tola), through a structured questionnaire. A reliable arsenic field testing kit is used to analyze the drinking water sources in the field, followed by a confirmatory test of a subset of water samples through Atomic Absorption Spectrophotometry. The study has two major goals: 1) Develop sustainable arsenic-mitigation models; and 2) Create a “composite vulnerability index,” and present the information as a map for use in targeting of areas for intervention and policy-making. Arsenic levels exceeding the World Health Organization and the Bureau of Indian Standards (max=300μg/L) were observed in all three villages. The hazard quotient and cancer risks for children in all three villages were high and very high, respectively. Arsenic treatment units and piped water supply systems were the most preferred sustainable arsenic-mitigation options in the surveyed villages, followed by deep tube wells, dug-wells, and rainwater harvesting systems. Arsenic awareness, willingness to pay for arsenic-free water, trust in agencies, trust in institution, and social capital were found to be the most significant factors for decision-making to prefer one arsenic-mitigation technology to others. The surveyed respondents perceive health and economic risks more so than social discrimination risks with regard to arsenic-contaminated groundwater, and were more willing to adopt arsenic-mitigation technologies. The strongest predictors of health-risk perception were caste, education, agricultural-landholdings, housing status, and social capital. Predictors of economic-risk perception were caste, education, income, sanitation practices, people’s prioritization of socio-environmental problems, arsenic awareness, social capital, institutional trust, and social trust. Predictors of social discrimination risk were agricultural landholdings, people’s prioritization of social problems, arsenic awareness, institutional trust, and social capital. Katihar in Bihar, with the least adaptive capacity and high vulnerability to arsenic contamination, should be prioritized in arsenic-mitigation policies. With a high level of adaptive capacity in Bhojpur district, the likelihood of success of arsenic-mitigation technology is the highest. A program utilizing expensive arsenicmitigation technologies will not work in the Vaishali, Samastipur, Khagaria, and Purnia districts

DD-dimensional Bardeen-AdS black holes in Einstein-Gauss-Bonnet theory

We present a $D$-dimensional Bardeen like Anti-de Sitter (AdS) black hole solution in Einstein-Gauss-Bonnet (EGB) gravity, \textit{viz}., Bardeen-EGB-AdS black holes. The Bardeen-EGB-AdS black hole has an additional parameter due to charge ($e$), apart from mass ($M$) and Gauss-Bonnet parameter ($\alpha$). Interestingly, for each value of $\alpha$, there exist a critical $e = e_E$ which corresponds to an extremal regular black hole with degenerate horizons, while for $e< e_E$, it describes non-extremal black hole with two horizons. Despite the complicated solution, the thermodynamical quantities, like temperature ($T$), specific heat($C$) and entropy ($S$) associated with the black hole are obtained exactly. It turns out that the heat capacity diverges at critical horizon radius $r_+ = r_C$, where the temperature attains maximum value and the Hawking-Page transition is achievable. Thus, we have an exact $D$-dimensional regular black holes, when evaporates lead to a thermodynamical stable remnant.Comment: 25 pages, 48 figure

Shadows of rotating five-dimensional charged EMCS black holes

Higher dimensional theories admit astrophysical objects like supermassive black holes, which are rather different from standard ones, and their gravitational lensing features deviate from general relativity. It is well known that a black hole shadow is a dark region due to the falling geodesics of photons into the black hole and, if detected, a black hole shadow could be used to determine which theory of gravity is consistent with observations. Measurements of the shadow sizes around the black holes can help to evaluate various parameters of the black hole metric. We study the shapes of the shadow cast by the rotating five-dimensional charged Einstein-Maxwell-Chern-Simons (EMCS) black holes, which is characterized by the four parameters, i.e., mass, two spins, and charge, in which the spin parameters are set equal. We integrate the null geodesic equations and derive an analytical formula for the shadow of the five-dimensional EMCS black hole, in turn, to show that size of black hole shadow is affected due to charge as well as spin. The shadow is a dark zone covered by a deformed circle, and the size of the shadow decreases with an increase in the charge $q$ when compared with the five-dimensional Myers-Perry black hole. Interestingly, the distortion increases with charge $q$. The effect of these parameters on the shape and size of the naked singularity shadow of five-dimensional EMCS black hole is also discussed.Comment: 27 pages, 9 figures, matches with published versio