Groundwater is the major resource for drinking and irrigation purposes in urban areas of Abaya-Chemo sub-basin of Great Rift Valley, Ethiopia. There is an incredible increase in demand in the ...sub-basin for good-quality groundwater resources. However, the exhaustive irrigation and rapid urbanization has posed a serious threat to groundwater quality in the urban districts of sub-basin like Arba Minch town. The aim of the study was to evaluate the groundwater quality status and to map their spatial distribution with respect to the suitability for drinking and irrigation purposes in Arba Minch town, Ethiopia. Fourteen bore well samples were examined for geochemical variations and groundwater qualities. The spatial distribution maps of quality parameters were prepared using the kriging method in ArcGIS 10.3. Drinking water quality index, sodium adsorption ratio (SAR), percentage sodium (Na%), residual sodium carbonate (RSC), and permeability index (PI) were considered for drinking and irrigation suitability assessment. Comparison of the hydrochemical results with the World Health Organization (WHO) and Ethiopian drinking water standards (ES) and various classifications revealed that the current status of the groundwaters is suitable for drinking and irrigation purposes except for a few sites at the northwestern part of the study area. The WQI results revealed that 7% and 64% of samples fall from excellent to good classes for drinking categories. Irrigation indices also demonstrated that 80% of samples fall in good classes for irrigation purposes. About 75 percent of samples belong to Ca–Mg-HCO
3
facies, and the reaming samples belong to Ca–Mg–Cl facies. The results of the study concluded that the proposed approach is reliable and efficient for the groundwater pollution status evaluation and can also be applied in decision making for effective groundwater resources monitoring in the study area.
Evaluation of the hydrogeochemical processes governing the heavy metal distribution and the associated health risk is important in managing and protecting the health of freshwater resources. This ...study mainly focused on the health impacts due to the heavy metals pollution in a known Cretaceous-Tertiary (K/T) contact region (Tiruchinopoly, Tamilnadu) of peninsular India, using various pollution indices, statistical, and geochemical analyses. A total of 63 samples were collected from the hard rock aquifers and sedimentary formations during southwest monsoon and analysed for heavy metals, such as Li, Be, Al, Rb, Sr, Cs, Ba, pb, Mn, Fe, Cr, Zn, Ga, Cu, As, Ni, and Co. Ba was the dominant element that ranged from 441 to 42,638 μg/l in hard rock aquifers, whereas Zn was the major element in sedimentary formations, with concentrations that ranged from 44 to 118,281 μg/l. The concentrations of Fe, Ni, Cr, Al, Cr, and Ni fell above the permissible limit in both of the formations. However, the calculated heavy metal evaluation index (HEI), heavy metal pollution index (HPI), and the degree of contamination (
C
d
) parameters were higher in the sedimentary formation along the contact zone of the K/T boundary. Excessive health risks from consumption of contaminated groundwater were mostly confined to populations in the northern and southwestern regions of the study area. Carcinogenic risk assessment suggests that there are elevated risks of cancer due to prolonged consumption of untreated groundwater. Ba, Sr, and Zn were found to be geochemically highly mobile due to the partitioning between the rock matrix and groundwater, aided by the formation of soluble carbonato-complexes. Factor analysis indicates that the metals are mainly derived from the host rocks and anthropogenic inputs are relatively insignificant. Overall, this study indicated that groundwater in K/T contact zones is vulnerable to contamination because of the favorable geochemical factors. Long-term monitoring of such contact zones is required to avert the potential health hazards associated with consumption of the contaminated groundwater.
This research was carried out using the open-source database system along with the continuous air quality monitoring station results from global data sets during the COVID-19 pandemic lockdown in ...India and the global. Our purpose of this research is to study the improvement of air quality and human mortality rates in countries worldwide during the COVID-19 pandemic lockdown. Worldwide air quality data were collected from > 12,000 continuous air quality monitoring stations on six continents covering 1000 major cities from over 100 countries. Here, we discussed the implementation of the open-source data set of basic air pollutants such as PM 2.5, NO
2
, temperature, relative humidity, and Air Quality Index variation during the pre-lockdown and lockdown pandemic COVID-19 in India and described the global aspect. An average concentration of PM 2.5 (145.51 μg/m
3
), NO
2
(21.64 μg/m
3
), and AQI index (55.58) continuously decreased. The variation of PM 2.5, NO
2
, normally shows more than 25 μg/m
3
every year, but during the COVID-19 lockdown period (April 2020) continuously decreased below 20 μg/m
3
. Similarly, the AQI index and meteorological factors such as temperature, relative humidity, and wind speed variation decreased significantly in the many countries in the world. In Asian countries, air quality improved during the national lockdown especially in the most polluted cities globally such as Beijing, Delhi, and Nanjing and also in developed cities like Madrid, New York, Paris, Seoul, Sydney, Tokyo. Furthermore, the reduction of particulate matter was in about 46%, and other gaseous pollutants during the lockdown period were observed in a 54% reduction. We are witnessing pollution reductions which add significantly to improvements in air quality. This is due to the massive decrease in the use of fossil fuel, which in turn reduces production and traffic in general. People nowadays are now willing to see a comparatively healthier world with bleached skies and natural ecosystems. This research finding demonstrates potential safety benefits associated with improving air quality and mortality rates during the COVID-19 pandemic, resulting in decreases in mortality rates in India and around the world.
Estuaries are highly dynamic zones. They are confluence of sea, river, tributaries, effluents, and runoff water that modify constantly their physical conditions and affect growth, productivity, and ...survival of inhabiting biota. In the current study, we investigated the extent to which estuarine sediment fractions explain variation of grain size parameters (mean size: Mz, standard deviation: σI, skewness: Ski and kurtosis: KG), fish diversity, and phytoplankton richness in estuaries. We applied series of multivariate regression models and controlled for the effect of sediment origin, season, and measurement method. The models output showed that sand fraction explained consistently variation of all the four grain size parameters. However, silt fraction was significantly associated with Mz, Ski, and KG but not σI. We couldn't detect any significant relationship between sand or silt fraction with fish diversity. In contrast, we found that high richness in phytoplankton species was associated with low sand and low silt conditions. We therefore conclude that it is possible to reliably estimate Mz, σI, Ski, KG, and phytoplankton richness from sand and silt fractions. Moreover, managing sand and silt fractions ejected in estuaries may be an alternative of protecting and restoring estuarine biodiversity.
This study aims to explore the state-wise assessment of SARS-CoV-2 (COVID-19) pandemic spread in Malaysia with focus on influence of meteorological parameters and air quality. In this study, ...state-wise COVID-19 data, meteorological parameters and air quality index (AQI) were collected from March 13 to April 30, 2020, which encompass three movement control order (MCO) periods in the country. Overall, total infected cases were observed to be higher in MCO phase 1 and 2 and significantly reduced in MCO phase 3. Due to the variation in the spatial interval of population density and individual immunity, the relationship of these parameters to pandemic spread could not be achieved. The study infers that temperature (T) between 23 and 25 °C and relative humidity (RH) (70–80%) triggered the pandemic spread by increase in the infected cases in northern and central Peninsular Malaysia. Selangor, WP Kuala Lumpur and WP Putrajaya show significantly high infected cases and a definite trend was not observed with respect to a particular meteorological factor. It is identified that high precipitation (PPT), RH and good air quality have reduced the spread in East Malaysia. A negative correlation of T and AQI and positive correlation of RH with total infected cases were found during MCO phase 3. Principal component analysis (PCA) indicated that T, RH, PPT, dew point (DP) and AQI are the main controlling factors for the spread across the country apart from social distancing. Vulnerability zones were identified based on the spatial analysis of T, RH, PPT and AQI with reference to total infected cases. Based on time series analysis, it was determined that higher RH and T in Peninsular Malaysia and high amount of PPT, RH and good air quality in East Malaysia have controlled the spreading during MCO phase 3. The predominance of D614 mutant was observed prior to March and decreases at the end of March, coinciding with the fluctuation of meteorological factors and air quality. The outcome of this study gives a general awareness to the public on COVID-19 and the influence of meteorological factors. It will also help the policymakers to enhance the management plans against the pandemic spreading apart from social distancing in the next wave of COVID-19.
Estuaries are prone to degradation due to incessant environmental changes encircling them. In the current study, we tested the effect of agricultural land use, tidal range and estuary length on ...estuary sediment texture (sand, silt, and clay), and grain size parameters (mean size,
Mz
; standard deviation,
σ
I
; skewness,
Ski
; and kurtosis,
K
G
). We analyzed a compiled dataset of 500 samples by using multiple linear regression models fitted with agricultural land use, tidal range and estuary length as predictors, sediment texture and grain size parameters as response variables, and seasons as control variable. For each model, we checked and assured that assumptions, stability and collinearity thresholds are not violated. Overall, models output showed a significant effect of agricultural land use, tidal range and estuary length on estuary sediment texture, and grain size parameters except
K
G
. More specifically, estuarine sediments from countries using more than 60% of their land for agriculture had highest sand content (66.48 ± 32.44%), lowest clay content (11.89 ± 11.49%), smallest
Mz
(2.84 ± 1.70), lowest
σ
I
(1.78 ± 1.98), and highest
Ski
(1.06 ± 2.39). Sediments from microtidal estuaries had highest sand content (62.53 ± 32.45%), lowest silt content (14.13 ± 18.94%), lowest clay (23.60 ± 26.78%), and lowest
Mz
(4.82 ± 2.99). Sediments from short sized estuaries had highest sand content (74.32 ± 19.99%), lowest clay content (10.41 ± 9.81%), smallest
Mz
(2.29 ± 1.13), smallest
σ
I
(0.98 ± 0.32), and smallest
Ski
(0.03 ± 0.24). Taken together, these results point out that environmental pressure on estuaries is real and operating significant changes on estuaries sediments. Therefore, the authors lend voice to worldwide calls for responsible land use and conservation measures adapted to each type of estuaries.
Graphical abstract
Mercury is a pollutant that is used everywhere, is harmful, and has a global impact. The ambient Total Gaseous Mercury (TGM) concentrations in the Chennai metropolis areas were measured in this ...study. Because of various anthropogenic source pollutants, studies of atmospheric mercury in this city are extremely significant. The measurement was conducted using a high-resolution mercury vapor analyzer (Tekran 2537B) instrument in February and March 2016. The annual mean concentration of TGM in the Chennai metropolis was 8.89 mg m
−3
and 8.01 mg m
−3
, respectively. The extreme aggregate recurrence between the directions is WNW to NNW and NNE to ENE, and TGM was released about 39% in this region, according to this research. We performed statistical studies, and the results of the principal component analysis and conditional probability function suggest that mercury sources are equivalent to other atmospheric pollutants such as SO
2
, CO, NO
2
, and PM2.5, which are predominantly emitted by urban and industrial combustion plants. The meteorological parameters and TGM concentration have a direct relationship, according to continuous measurements of TGM in the air and dendrogram maps, and they have been essentially controlled by sunlight-based radiation. Some estimates of atmospheric mercury focuses have been conducted in the urban region; however, as far as we know, our findings are the essentials that unveiled concerning environmental aggregate vaporous mercury observed in a necessary industrialized metropolitan zone in India. This research will aid in the development of more effective management measures to reduce the effects of atmospheric mercury in the urban environment and public safety in a megacity, as well as those who may be harmed by the long-distance transit of TGM. The assessment of mercury emissions and the effectiveness of Chennai’s mercury control policies is warranted by long-term observations of mercury in the city—and background regions in Chennai.
Hydrofracturing process was developed during the 1940s for improving the yield from oil and gas wells. Later this technique was adopted for water well development. The hydrofracturing process ...consists of pumping test before and after fracturing a well. The pre-fracturing and post-fracturing pumping test results are analysed and correlated to estimate the yield improvement realized due to fracturing. An attempt was made to improve the groundwater yield from a borewell in hard rock formation in Thachchur Village of Cuddalore District, Tamil Nadu, India. The pre-pumping static water level was 4.25 m below measuring point (bmp), and the safe yield was 5 litres per minute (lpm)/16 m drawdown/8 h of pumping per day. Hydrofracturing was carried out using a single packer assembly system, and two fracture zones lying at the depth of 15 m and 45 m were treated. After fracturing treatment, pumping test was carried out. Post-fracturing pumping test results revealed that the safe yield was 80 lpm/16 m drawdown/8 h of pumping per day. The yield improvement from 5 to 80 lpm substantiated the success of hydrofracturing in the hard rock borewell. The groundwater yield improvement in the borewell is due to the enlargement of fissures and cracks in and around the borewell by hydrofracturing.
Surface water pollution is a global problem and has been evident for a long period of time. Hence, the aim of the study was to evaluate the hydro-geochemical characteristics of Selamko farm reservoir ...water quality and its suitability for multipurpose uses using GIS-based water quality indices. The water sampling sites and parameters were selected systematically based on the land use, land cover, and anthropogenic activities around Selamko reservoir watershed in Debre Tabor, Ethiopia. Water samples were collected from 11 sampling stations from July 2019 to March 2020 using the composite sampling method and examined using standard procedures. The suitability of the reservoir's water quality for multipurpose use was investigated using drinking and irrigation water quality indices, and other tools. The spatial distribution maps of water quality parameters were prepared using the kriging method in ArcGIS 10.5. The results of the geospatial analysis indicated that the reservoir water quality parameters had spatial variation, which was caused by industrial and household wastewater inflow across the reservoir's watershed. Based on WHO and ES standards, the computed drinking water quality index results revealed that 81.81% and 18.18% of the reservoir's water quality fall into the poor to very poor classes, which indicates that the water in the reservoir is not fit for drinking. However, a Wilcox diagram, irrigation indices, and USEPA regulations revealed that the reservoir water quality is found to be safe and suitable for irrigation, fishing, and livestock purposes. The study concluded that Selamko reservoir's water quality is suitable for irrigation, fishing, and livestock watering with proper management accordingly.
To understand the sub-surface lithology variation and identify possible groundwater potential zones, multi-electrode resistivity scanning was carried out at 7 locations in the part of Chittar ...sub-basin, Tirunelveli District, South India. Physiographically, the selected study area is a plain and falls under the semi-arid climatic type. Archaean crystalline of hornblende biotite gneiss and charnockite are the major rock types, pediments and buried pediments are the major geomorphological units. A length of 100 m was scanned using 50 electrodes with interspacing of 2 m by SSR-MP-AT-ME model resistivity meter and analysed in IPI 2WIN software. The data obtained from resistivity showed huge resistivity variations in areas where Narikudi, Rastha, Therkkupatti and Vagaikulam locations represented ≤ 1000 Ohm m and Alagiyapandiapuram, Muthamalpuram and Nilethanallur locations represented < 1000 to > 9000 Ohm m. To validate the scanning interpretation, constructed geoelectric layers were correlated to existing lithology of the region and it showed an appreciable match. Considering the resistivity range of 50 to 120 Ohm m and bore well lithology, Narikudi and Muthamalpuram locations have been identified as potential groundwater zones while Nilethanallur, Rastha, Therkkupatti, Alagiyapandiapuram and Vagaikulam locations were also identified as low to moderate groundwater zones.
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