Explore the vast range of titles available.

Accumulation of Radon in groundwater from aquifer lithologies can pose significant health risks. This study investigates its concentration in coastal Alappuzha from the Kerala state in India to assess health risks from ingestion and inhalation in groundwater samples of both the pre-monsoon and post-monsoon seasons. The activity(RAD7detector)in post-monsoon samples remained relatively higher (2.59–66.46 Bq/L; average:20.25 Bq/L) compared to the pre-monsoon (1.63–46.38 Bq/L; average: 13.78 Bq/L), reflecting the effect of precipitation on enhanced Radon contamination. However, the samples presently do not exceed the World Health Organization recommended maximum value (100 Bq/L). Relatively higher average radiation doses for stomach and lungs (6.12–6.20 Svy -1 ) in post-monsoon samples compared to pre-monsoon (4.12–4.22 Svy -1 ) show more exposures in the post-monsoon season. Our estimations of the total effective dose from two different pathways provide valuable baseline data on radon exposure in a coastal region of India, where health risks could increase due to higher precipitation and more frequent heavy rainfall events in the near future. Such conditions may enhance groundwater recharge and promote the downward migration of radon-rich soil gases into aquifers, potentially elevating radon concentrations, particularly in uranium-bearing lithological settings.

The main objective of the present research was to examine the risk of fluoride-rich groundwater in the Shanmuganadhi River basin, south India on human health. The non-carcinogenic risks were estimated into two classes: (1) risks associated with oral intake of water and (2) risks associated with dermal contact. Hazard Quotient for oral intake and dermal contact was separately calculated for adult men, adult women and children from the geochemical results of 61 representative samples collected from the wells constructed in hard rock aquifers during the post- (January-2018) and pre-monsoon (May-2018) seasons. The collected samples were analyzed immediately after the field work for all the major ions and fluoride. Finally, total hazard index was calculated for adults (men and women) and children to evaluate the risk. It directed that 41%, 49% and 74% of post-monsoon samples and 30%, 43% and 62% of pre-monsoon samples possessed a non-carcinogenic risk for men, women and children, respectively. Because the basin falls in the drought-prone region, the water supply for drinking and cultivation are commonly based on groundwater resources. The study revealed that the minerals such as apatite, fluorite, biotite and pyroxene in the hornblende–biotite gneiss formation contribute fluoride ions to the groundwater system due to water–rock interaction mechanism. The Durov diagram depicted that dissolution of silicate minerals and cation exchange are the foremost hydrogeochemical activities, which decide the overall chemical composition of groundwater in this region. The ionic concentrations including fluoride increased with respect to depth of occurrence of groundwater. Escalation of the water table due to monsoon recharge and artificial recharge through a check dam decreased the total dissolved solids and fluoride ion concentration. The investigation conducted around the existing check dam at Kaldurai village highlighted that the fluoride concentration is below the allowable limit of 1.5 mg/l (WHO in World health statistics 2017: monitoring health for the SDGs, Sustainable Development Goals. World Health Organization, Geneva, 2017) in the wells closer to the check dam toward the downstream side. The concentration increased with distance, which lead the groundwater unsuitable for consumption. Therefore, it is recommended to implement the managed aquifer recharge using check dams in the other parts of the basin to enrich the quantity and applicability of groundwater.

The massive influx of pelagic Sargassum spp. (sargasso) into the Mexican Caribbean Sea has caused major deterioration of the coastal environment and has affected the tourism industry as well as livelihoods since 2015. Species of Sargassum have high capacity to absorb metals; thus, leachates of sargasso may contribute to contamination by potentially toxic metals when they drain into the sea and into the groundwater when dumped in inadequate land deposits. Valorization of sargasso would contribute to sustainable management; therefore, knowledge on potentially toxic metal content is necessary to define possible uses of the algae. We present concentrations of 28 elements measured using a non-destructive X-ray fluorescence analyzer (XRF) in 63 samples of sargasso collected between August 2018 and June 2019 from eight localities along ∼370 km long coastline of the Mexican Caribbean Sea. The sargasso tissues contained detectable concentrations of Al, As, Ca, Cl, Cu, Fe, K, Mg, Mn, Mo, P, Pb, Rb, S, Si, Sr, Th, U, V, and Zn. The element concentration in sargasso varied on spatial and temporal scales, which likely depended on the previous trajectory of the pelagic masses, and whether these had (or had not) passed through contaminated areas. Total arsenic concentration varied between 24–172 ppm DW, exceeding the maximum limit for seaweed intended as animal fooder (40 ppm DW) in 86% of the samples. For valorization, we recommend analyses of metal contents as a mandatory practice or avoiding uses for nutritional purposes. The high arsenic content is also of concern for environmental contamination of the sea and aquifer.

Trace amounts of certain heavy metals, including iron, zinc, and copper, are essential for human health; however, many others are toxic even at low concentrations, posing significant risks in vulnerable coastal regions. This study assessed concentrations of heavy metals in shallow groundwater (1–4 m depth) along the coastline of Alappuzha, Kerala (India) during the pre- (2021) and post-monsoon (2022) seasons, applying the Origin-Source-Pathways-Receptor-Consequence (OSPRC) framework. Concentrations of arsenic (As), cadmium (Cd), strontium (Sr), nickel (Ni), copper (Cu), iron (Fe), barium (Ba), chromium (Cr), lead (Pb), aluminum (Al), manganese (Mn), and cobalt (Co) were analyzed with respect to the WHO (2017) standards. Arsenic in 8–10% samples and aluminum in 8% samples across the seasons, exceeding the WHO limits, were largely from commercial debris, agricultural runoff, domestic sewage, and tourism-related activities. The elevated iron (4–8% of samples), however, was predominantly geogenic. The heavy metal pollution index (HMPI) indicated that 32% of pre-monsoon and 34% of post-monsoon samples exhibited medium to high pollution levels with the critical hotspots at Ambalapuzha, Anandheswaram, and Thottapalli for arsenic; Alappuzha, Kanjikuzhi and Paravoor for aluminum; and Paravoor, Alappuzha, Chennakari, and Ambalapuzha for iron. The presence of these trace metals at unsafe levels underscores an urgent need for comprehensive quality monitoring and mitigation strategies in this coastal zone. The findings in this study deliver a replicable model for integrating risk-based assessment frameworks like OSPRC into groundwater management practices for policymakers, public health authorities, and local communities to prioritize interventions for developing sustainable and long-term solutions.

Submarine groundwater discharge (SGD) acts as a carrier for elements, nutrients and pollutants into the ocean. This study estimated SGD along the Kanyakumari coast of India, using the Radon and nutrient mass balance approach. Groundwater and porewater samples during the high-tide and low-tide conditions showed Radon ( 222 Rn) concentrations between 11.68 and 66.96 Bq/L during the pre-monsoon and between 18.9 and 189.56 Bq/L during the post-monsoon, with an inverse relationship with EC (256–52400 µS/cm: pre-monsoon and 329–48000 µS/cm: post-monsoon). SGD, estimated using the radon mass balance approach, ranged from 0.01 to 0.54 m 3 m −2 d −1 in pre-monsoon and 0.04 to 0.98 m 3 m −2 d −1 in post-monsoon. Mean nutrient concentrations for DIN, DIP, and DSi in both seasons were 0.79-2.0, 0.21–0.28, and 17.22–20.75 µmol L − 1 , respectively. In a strategic part of Indian coast, this study enabled the location and determination of SGD and thereby provided valuable data for adopting proper methodology to mitigate the issue of groundwater scarcity and pollution.

The relationship between the climate and societal transformation in Maya lowlands has long been debated, particularly the role of drought in shaping the civilization trajectory during the Classic Period. A high‐resolution, multi‐proxy, geochemical record from Lake Kaná, located in the underexplored Uaymil region of the Yucatán Peninsula in Mexico, helped to reconstruct the dynamics of detrital input, redox condition, organic productivity, and carbonate precipitation over the past 2800 cal. years. Principal component analysis (PCA) of selected elements and their ratios integrated the responses to hydroclimate dynamics by yielding two rainfall‐sensitive indices, that is a focused Rainfall Index (from Al/Sr, Ti/Sr, and −Sr/Ca) and a broader element‐based Rainfall Index, for the effective and meteoric rainfalls, respectively. This new record revealed diminished detrital flux, enhanced redox stratification and low‐carbonate precipitation around 1652, 1200–900 and 600–540 cal. a BP, suggesting drought episodes and more water column anoxia. Inorganic carbon content below 5% in most of the sequence, notably, a rare condition in karstic lakes, likely resulted from sustained redox environment, siliciclastic dilution and clay‐mediated inhibition of calcite nucleation. Our results also indicated human activities between 1600–1200 cal. a BP, but of low influence. Both the climatic and anthropogenic responses captured here contribute to the growing evidence of complex climate‐society interactions across Mesoamerica and highlight the importance of an integrated geochemical approach in neotropical palaeoenvironmental reconstructions.

The possible zones of submarine groundwater discharge (SGD) and seawater intrusion (SWI) along the west coast of Kanyakumari in the southernmost Indian Peninsula were identified by integrating the surface temperature anomaly, water table fluctuation, and water quality analysis. Temperature map of the sea surface from Landsat 8 satellite data, which helped to demarcate SGD in areas with significant thermal contrast, exists between the seawater and discharging groundwater. Monitoring data of 2019–2021 illustrated patchy, diffuse, and temporally variable groundwater seepage. The spatial distribution map created from groundwater level, and water quality parameters depicted high SGD in areas of high groundwater level and high chances of SWI in regions with low groundwater level. This study identified that the areas with low groundwater level, high EC, and high chloride contents are prone to SWI. Similarly, the regions with high thermal contrast, high groundwater level, and low EC have more SGD. These methods have the potential to be used as preliminary screening tools before implementing detailed studies about the mixing process.

A framework was set up to monitor drought in the semi-arid regions of eastern Tamil Nadu, southern India, for the period of 2014–2018 CE with the application of the standardized precipitation index (SPI), the scaled drought-condition index (SDCI), and the standardized water-level index (SWI). The results emphasized that this region had a negative precipitation anomaly and vegetative stress, both of which triggered meteorological and agricultural droughts and caused significant losses in the farming sector. The distributions of extreme and high-level hydrological droughts were at their maximum in 2017 CE. The multi-drought severity index (MDSI), implemented to assess the combined impact and highlighting the gradient of affected areas, illustrated that the eastern region (i.e., Jayankondam block) was the most extremely affected, followed by the northern and southern regions (i.e., T.Palur and Andimadam), which were moderately affected by droughts. The extremely affected eastern region has less of an ability to overcome droughts due to its socio-economic vulnerability, with its greater population and household density leading to the over-exploitation of potential resources. Therefore, the focus of this study is on the monitoring of drought severity in micro-administrative units to suggest an appropriate management plan. Hence, the extreme-drought-prone block (Jayankondam) should be given high priority in monitoring and implementing long-term management practices for its conservation and resilience against the effects of severe droughts.

A study was conducted to evaluate the suitability of groundwater in the drought-prone Shanmuganadhi River basin of south India for best agricultural practices since the surface water that exists in this basin is not sufficient to meet out the demand. As the quality of groundwater is not uniform in the hard rock aquifers of this basin, the work was carried out to demarcate the suitable groundwater quality zones for the agricultural activities. Sixty-one groundwater samples were collected and analyzed for various parameters such as electrical conductivity (EC), pH, TDS, major cations (Ca 2+ , Mg 2+ , Na + , and K + ) and anions (Cl − , SO 4 2− , HCO 3 − , PO 4 3− , NO 3 − , and F − ). To demarcate the feasible zones for agricultural practices, irrigation water quality parameters like EC, sodium adsorption ratio (SAR), percent sodium (Na %), residual sodium carbonate (RSC), magnesium hazard ratio (MHR), Kelly’s ratio (KR), and permeability index (PI) were computed. Furthermore, the irrigation water quality representation diagrams like USSL, Wilcox, and Doneen were prepared, and their outputs were spatially plotted using the Geographical Information System (GIS) to identify the suitability domains of groundwater for irrigational practices. Interpretation of irrigation water quality parameters and diagrams indicate that 2% of groundwater samples represented “low” salinity, 26% of samples represented “medium” salinity, 66% of samples represented “high” salinity, and 6% of samples represented “very high” salinity. Similarly, about 59% of samples represented the low alkaline/sodium category and 41% of them represented the medium alkaline category. The USSL output shows that about 2% of samples of the basin signified “low salinity with low alkalinity” category (C1S1), 28% of samples signified the “medium salinity with low alkalinity” category (C2S1), 33% of samples signified “high salinity with low alkalinity” category (C3S1), 28% of samples signified the “high salinity with medium alkalinity” category (C3S2), and 10% of samples signified the “very high salinity with medium alkalinity” category (C4S2). Groundwater is suitable for irrigation in 277.52 km 2 area of the basin. It is moderately suitable in an area of 318.46 km 2 and poorly suitable over 38.64 km 2 . This study recommends that groundwater with moderate suitability could only be used for irrigating permeable soils and for cultivating salt-tolerant crops. The addition of gypsum to soil might be helpful to increase the infiltration capacity and osmotic activity. However, poorly suitable area should be avoided for agricultural practices.