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Intensive anthropogenic activities along the coastal plains of Andhra Pradesh (such as urbanisation, agriculture and aquaculture) rely extensively on coastal fresh groundwater resources that are pumped at unsustainable rates causing groundwater decline and water quality problems due to saline water intrusion. Hydrogeological studies are imperative to implement groundwater conservation strategies in coastal Andhra Pradesh, which is experiencing a severe freshwater shortage due to overexploitation and saline water intrusion as well as clean water loss through the aquifer system close to the coastal plains. An attempt is made in this study to demarcate the submarine groundwater discharge (SGD) and saline water intrusion (SWI) zones adopting a three-tier validation system, i.e. groundwater dynamic, LANDSAT resultant sea surface temperature (SST) variance and site-specific water characteristics along the southeast coast of Andhra Pradesh, India. A total of 234 water samples (139 porewater, 31 groundwater and 64 seawater samples) were evaluated along ~ 450 km southeast coastline of Andhra Pradesh. In situ porewater physio-chemical parameters, i.e. EC, TDS, pH, DO, temperature, and salinity, at every 1 km except non-accessible areas and groundwater for every 5 km were analysed and used for identification of SGD zones in the study area. The hydraulic gradient values vary from - 11 to 250 m in post-monsoon and - 14 to 250 m in pre-monsoon. And sea surface temperature anomaly for 2017, 2018 and 2019 varies between 21-39 °C, 15-34 °C and 20-39 °C. Three districts out of the four districts studied (Krishna, Guntur and Nellore) were shown to be prone to SWI, whereas Prakasam district was susceptible for SGD. For the first time, this kind of preliminary study was carried out in the coastal Andhra Pradesh region, and it will serve as a basis for the meticulous analysis of the fresh and saline water mixing zones/process as well as to develop and manage the groundwater resources along the water-stressed coastal plains of Andhra Pradesh, India.

The quality of the groundwater in the study area was evaluated through various water quality indexes for drinking and irrigation purposes. To evaluate the water quality index, 186 groundwater samples were sampled during 2 different seasons, likely pre-monsoon (PRM) and post-monsoon (POM). The collected samples were measured for physical-chemical parameters like pH, EC, TDS, Na, K, Ca, Mg, Cl, HCO3, PO4, SO4, NO3 and H4SiO4. The research findings indicated that groundwater of the study area is approaching an alarming stage of its suitability for drinking purpose because a major percentage (i. e. 56%: PRM, 46%: POM) of samples are within poor category. Thus, the proper management strategy for water resources must be developed and a preventive management practice to address this issue must be implemented. Various water quality parameters such as electrical conductivity (EC), pH, salinity hazard, sodium hazard and permeability indexes (PI) were considered for irrigation water quality evaluation and it is inferred that the groundwater of the study area is suitable for irrigation. The PRM and POM samples with higher Na + and Cl concentrations were identified. The primary source of groundwater contamination is anthropogenic factors like domestic, agriculture effluents and mining activities. However, the groundwater of these regions is also greatly influenced by geogenic factors like weathering, rock-water interaction and precipitation which results in groundwater water level fluctuation. The research findings suggest the groundwater quality of this region is approaching an alarming stage for drinking purposes. Thus, developing a management strategy for drinking water sources and implementing preventive management practices to address this issue becomes imperative.

The study aims to determine the impact of global meteorological parameters on SARS-COV-2, including population density and initiation of lockdown in twelve different countries. The daily trend of these parameters and COVID-19 variables from February 15th to April 25th, 2020, were considered. Asian countries show an increasing trend between infection rate and population density. A direct relationship between the time-lapse of the first infected case and the period of suspension of movement controls the transmissivity of COVID-19 in Asian countries. The increase in temperature has led to an increase in COVID-19 spread, while the decrease in humidity is consistent with the trend in daily deaths during the peak of the pandemic in European countries. Countries with 65°F temperature and 5 mm rainfall have a negative impact on COVID-19 spread. Lower oxygen availability in the atmosphere, fine droplets of submicron size together with infectious aerosols, and low wind speed have contributed to the increase in total cases and mortality in Germany and France. The onset of the D614G mutation and subsequent changes to D614 before March, later G614 in mid-March, and S943P, A831V, D839/Y/N/E in April were observed in Asian and European countries. The results of the correlation and factor analysis show that the COVID-19 cases and the climatic factors are significantly correlated with each other. The optimum meteorological conditions for the prevalence of G614 were identified. It was observed that the complex interaction of global meteorological factors and changes in the mutational form of CoV-2 phase I influenced the daily mortality rate along with other comorbid factors. The results of this study could help the public and policymakers to create awareness of the COVID-19 pandemic. Supplementary Information The online version contains supplementary material available at 10.1007/s11356-021-17481-8.

In recent years, the extraction of groundwater (GW) in coastal aquifers has rendered the fragile aquifers more saline due to the sea water intrusion. Groundwater from the coastal aquifers of the Pudhucherry region were sampled to study the process of salinization. An integrated approach was adopted to identify the salinization process, by coordinating the results of borehole geophysics, rainfall pattern, water level variation, hydrochemical characters and multivariate statistical analysis. A total of 136 groundwater samples were collected during two different seasons, southwest monsoon (SWM) and northeast monsoon (NEM). The major cations and anions were analyzed adopting standard procedures. Resistivity and litholog indicate that the southeastern (SE) part of the study region has lower resistivity than in north. Based on electrical conductivity (EC) and total dissolved solids (TDS) values, most of the samples are potable, except for few samples from southeastern region. The study results indicated that higher values of Na, EC, K, SO4, Mg and Cl were observed during NEM, indicating leaching of salt into the aquifer and ion exchange process. The predominant hydrochemical facies of groundwater was Na-Cl and Ca–Mg–Cl type reflecting the saline water and the mixing process of saltwater and fresh groundwater, respectively. Though more number of samples with higher EC was noted in NEM, the results of PCA and correlation analysis indicate the predominance of leaching of salts and intense agricultural activities. The process of sea water intrusion was observed to be dominant during SWM.

A study has been carried out in KT (Cretaceous-Tertiary) boundary along the contact zones of hard rock, limestone and sedimentary formations to discern the geochemical processes governing the groundwater chemistry. A total of sixty-three groundwater samples were collected from the handpumps covering the entire study area and measured for hydrochemical species. Principal component analysis of the hydrochemical data inferred three major processes governing the geochemistry of the groundwater of the region as leaching, ion exchange and weathering. It was also inferred that there are few samples depicting the mixtures of these processes (what are they mention it) and few samples not representing any of these processes with adequate statistical significance. Hence, in order to know the geochemical behaviour of the samples representing each process, their combinations along with the samples which are not- representative samples of these processes were inferred using various standards plots to get an insight into their geochemical characteristics and affinity. This also inferred the samples representing different processes have a significant signature of geochemical facies. The major ions and the stable isotopes of groundwater were used to understand these processes. The carbonate and sulphate saturation states of these samples were calculated by PHREEQC and compared with major variations with the identified three geochemical processes. The state of saturation of Halite, Anhydrite, Gypsum, Aragonite, Dolomite, Calcite, Talc and Chrysolite were determined in all the samples. Inverse modeling was carried out considering the non-representative samples as initial solution and the samples representing each factor as final solution to understand the phase mole transfer in each process. An attempt was also made in this study to compare the geochemical behaviour of groundwaters from different KT boundaries. The samples representing these processes were plotted on an integrated map representing lithology, lineaments, drainage and elevation to determine their interrelationships. The study groups the samples into anthropogenic or geogenic. The leaching process is controlled by lithology and landuse, ion exchange processes is influenced by lithology and drainage patterns whereas weathering processes were controlled by lithology, drainage and lineaments. Non representation of samples (NRS) were mainly controlled by drainage and lineaments of the region.

Interrelationships among mass balance, meteorology, discharge, and surface velocity on Chhota Shigri Glacier over 2002-2019 using in-situ measurements Arindan MANDAL1, AL. RAMANATHAN1*, Mohd. Farooq AZAM2, Thupstan ANGCHUK1, Mohd. SOHEB1, Naveen KUMAR1, Jose George POTTAKKAL3, Sarvagya VATSAL1, Somdutta MISHRA1, Virendra Bahadur SINGH1,4 *Corresponding author email: alrjnu@gmail.comThe Himalayan glaciers contribute significantly to regional water resources. However, limited field observations restrict our understanding of glacier dynamics and behavior. Here, we investigated the long-term in-situ mass balance, meteorology, ice velocity, and discharge of the Chhota Shigri Glacier over the past two decades. With 17 years of uninterrupted glacier-wide mass balance datasets, Chhota Shigri Glacier is one of the most studied glaciers in the Hindu-Kush Himalayan region in terms of mass balance record. The mean annual glacier-wide mass balance was negative, -0.46±0.40 m w.e. a-1 during 2002-2019 corresponding to a cumulative wastage of about -8 m w.e. Mean winter mass balance was 1.15 m w.e. a-1 and summer mass balance was -1.35 m w.e. a-1 over 2009-2019. Surface ice velocity has decreased on average by 25-42% in the lower and middle ablation zone (below 4700 m a.s.l.) since 2003; however, no substantial change was observed at higher altitudes. The decrease in velocity suggests that the glacier is adjusting its flow in response to negative mass balance. The summer discharge begins to rise from May and peaks in July, with a contribution of 43%, followed by 38% and 19% in August and September, respectively. The discharge pattern closely follows the air temperature. The long-term observation on the Chhota Shigri — a benchmark — glacier, shows a mass wastage that corresponds to the glacier’s slowdown in the past two decades.