Water security and health risk assessment of an urban household-level drinking water and sanitation system, Punjab, India.

The water scarcity and deteriorating water quality are major issues of concern to the agrarian state of Punjab, India. The focus of the study is to assess the status of drinking water and sanitation systems of Punjab using an exhaustive dataset of 1575 drinking water samples from 433 sampling locations in 63 urban local bodies of Punjab. Water security index (WSI) indicate that out of 63 urban local bodies, 13 are categorized into good class, 31 fall under fair class, and 19 fall under poor class. The access indicator under sanitation dimension shows that Bathinda region has maximum sewerage network coverage relative to other regions, whereas ca. 50% of the ULBs in Amritsar region do not have sewerage facility. It is clearly depicted that the variation in WSI is mainly attributable to sanitation dimension (10-22.5) as variation in water supply dimension (29-35) is relatively less. Hence, emphasis on indicators and variables of sanitation dimension is required for the improvement of overall WSI. The assessment of qualitative aspects of drinking water and health risk depicts that the drinking water quality of southwest part of the state (i.e. Malwa region) is under good quality class contrary to its poor groundwater quality. Kapurthala district shows high health risk due to the presence of trace metals despite being classified into good class within water security index. The drinking water quality is better and health risks are minimal in regions where drinking water is supplied via treated surface water sources (e.g. Bathinda region). Furthermore, the results of health risk assessment correlate with M[Formula: see text]-Water Quality Index outcome owing to presence of trace metals in groundwater above permissible limits. These results will help in identification of shortcomings in water supply and sanitation infrastructure and its management in urban areas.

An assessment of subsurface contamination of an urban coastal aquifer due to oil spill.

Incidences of leakages of chemicals from underground oil storage tanks or oil-carrying pipelines have posed huge threat to the coastal aquifers around the world. One such leak was recently identified and notified by the people of Tondiarpet, Chennai, India. The assessment of the contamination level was done by obtaining electrical resistivity maps of the subsurface, drilling of 20 new borewells for soil and water analysis, and testing the water quality of 30 existing borewells. Samples were collected from the borewells, and observations were made that included parameters such as odor, moisture, contamination characteristics, lithology, groundwater level, thickness of the free product that are used to demarcate the extent of soil, and water contamination. Furthermore, a multigas detector was used to detect hydrocarbon presence as soil vapor. Moreover, to capture the transport of dissolved hydrocarbons, 10 samples were collected in the periphery of the study area and were analyzed for the presence of petroleum hydrocarbon and polyaromatic hydrocarbon. Analysis of the data indicated the presence of free-phase hydrocarbon in soil and groundwater close to the junction of Thiruvottiyur high (TH) road (TH) and Varadaja Perumal Koil (VPK) street. Although the contaminant plume is confined to a limited area, it has spread more to the southern and eastern side of the pipeline possibly due to continuous abstraction of groundwater by residential apartments. After cutting a trench along the VPK street and plotting of the plume delineation map, observations indicated that the source of the hydrocarbon leak is present in VPK street close to TH road. A multipronged strategy was suggested targeting the remediation of oil in various phases.

U(VI) mitigation via forward osmosis: Elucidation of retention mechanisms and co-ion effects.

Uranium (U) is a chemical and radioactive toxic contaminant affecting many groundwater systems. The focus of this study was to evaluate the suitability of forward osmosis (FO) for uranium rejection from contaminated groundwater under field-relevant conditions. Laboratory experiments with aqueous solution containing uranium were performed with FO membrane to understand the uranium rejection mechanism under varied pH, draw solution concentration, and presence of co-ions. Further, experiments were performed with U-contaminated field groundwater. Results of the hydrogeochemcial modelling using PHREEQC indicated that the rejection mechanism of uranium was highly dependent on aqueous speciation. Uranium rejection was maximum at alkaline pH with ca. 99% rejection due to charge-based interactions between membrane and dominant uranyl complexes. The results of the co-ion study indicated that nitrate and phosphate ions decrease uranium rejection. Whereas, bicarbonates, calcium, and magnesium ions concentrated uranium in feed solution. Further, the uranium adsorption onto the membrane surface primarily depended on pH of the aqueous solution with maximum adsorption at pH 5.5. Our results show that the World Health Organization's drinking water guideline value of 30 µgL-1 for U could be achieved via FO process in field groundwater containing low dissolved solids.

Multifaceted analysis of microplastic pollution dynamics in the Yamuna river: Assessing anthropogenic impacts and ecological consequences.

Microplastics (MPs) are pervasive contaminants that pose significant ecological and human health risks, emerging as one of the most widespread anthropogenic pollutants in natural environments. This study investigates the abundance, characteristics, and distribution of microplastics (MPs) in the Yamuna River, encompassing 29 sampling points across urban, rural, and industrial zones in and around Delhi, Mathura, Haryana, and Agra. Microplastics were identified and quantified using Nile red dye staining and Micro-Raman spectroscopy, with particle size distribution predominantly between 2 µm to 80 µm and the largest detected particle measuring 256.5 µm. The average MPs concentration was 14,717 ± 4444 L-1, with a significant abundance of hazardous polymers such as polyethylene terephthalate (PET), polypropylene (PP), and polystyrene (PS). The study found that MPs were predominantly fragments and films (65.6 %) and fibers (30.6 %), with transparent particles being the most prevalent. The Pollution Load Index (PLI) consistently indicated high-risk levels (PLI > 100) at all sampling sites, highlighting substantial MP contamination. These results underscore the urgent need for continuous monitoring and the development of robust management strategies to address microplastic pollution in the Yamuna River. This study provides valuable insights into MPs spatial distribution and persistence, contributing to an improved understanding of their environmental impacts and guiding future mitigation and regulatory efforts.

An Assessment of U(VI) removal from groundwater using biochar produced from hydrothermal carbonization.

The ever-increasing growth of biorefineries is expected to produce huge amounts of lignocellulosic biochar as a byproduct. The hydrothermal carbonization (HTC) process to produce biochar from lignocellulosic biomass is getting more attention due to its inherent advantage of using wet biomass. In the present study, biochar was produced from switchgrass at 300 °C in subcritical water and characterized using X-ray diffraction, fourier transform infra-red spectroscopy, scanning electron micrcoscopy, and thermogravimetric analysis. The physiochemical properties indicated that biochar could serve as an excellent adsorbent to remove uranium from groundwater. A batch adsorption experiment at the natural pH (~3.9) of biochar indicated an H-type isotherm. The adsorption data was fitted using a Langmuir isotherm model and the sorption capacity was estimated to be ca. 2.12 mg of U g(-1) of biochar. The adsorption process was highly dependent on the pH of the system. An increase towards circumneutral pH resulted in the maximum adsorption of ca. 4 mg U g(-1) of biochar. The adsorption mechanism of U(VI) onto biochar was strongly related to its pH-dependent aqueous speciation. The results of the column study indicate that biochar could be used as an effective adsorbent for U(VI), as a reactive barrier medium. Overall, the biochar produced via HTC is environmentally benign, carbon neutral, and efficient in removing U(VI) from groundwater.