ABSTRACT
Anthropogenic activities on the land side cause microbial pollution in coastal waters. The primary culprits in changing coastal water quality are industrial effluents, urban discharges, and agricultural runoff. The current study provides a comparative overview of microbial abundance during the pre (July 2019) and post-lockdown (July 2020) periods. Microbial densities were significantly higher during July 2019. Total heterotrophic bacteria (THB) and E. coli (ECLO) like organisms were about 53 % higher during pre-lockdown, while Fecal coliform (FC) counts were approximately seven× higher than post-lockdown. FC levels surpassed the standard safe limits (100 FC/100 ml) prescribed by Central Pollution Control Board (CPCB) at many locations. Physiochemical variables are significantly high during pre-lockdown. Total suspended matter levels were higher by 40.1 %, Total nitrogen (69.2 %), Total phosphorus (7×), Biological oxygen demand (45.6 %), and pCO2 (20.4%). Although nutrients are not limiting (high TN & TP), the phytoplankton biomass (Chl-a) was relatively low in pre-lockdown due to higher TSM restricting light penetration and affecting photosynthetic activities. Significant reductions in microbial contamination during July 2020 corroborated lesser anthropogenic activities associated with the lockdown, demonstrating the positive impact of lockdown on the coastal water quality. © 2022 IEEE.
ABSTRACT
Mass gathering events commonly encounter environmental challenges that necessitate assurance of water quality and food security. The current outbreak of the coronavirus disease 2019 (COVID-19) call for maintaining safe drinking water supply and providing assessment tools of drinking water quality to avoid contamination in water sources or distribution networks. Arid environmental conditions also add more stress on supplied water to mass gathering events. Herein, we assess the quality of the water supply (desalinated 95% and groundwater 5%) in Makkah city, Saudi Arabia during a mass gathering event in 2019 (9.6 million people) for religious purposes. Fifty five samples were randomly collected from nine different districts of Makkah city, analyzed for TDS, turbidity, pH, EC, free Cl2, Al, Cd, Pb, Cr, F, major ions, coliform and E.coli bacteria and were finally used to estimate the water quality index (WQI). Major ions, trace elements and heavy metals analyses show values below permissible limits in most of the samples, while a few samples show slightly higher values. No bacterial count found in any sample. WQI values of all fifty-five samples were below 50 and were identified as "excellent water". The WQI variations could be attributed to the distribution network conditions rather than a direct impact of adding groundwater with uncontrolled chemical composition. The use of WQI to report the quality of water during mass gathering events to governmental authorities has been proved to be beneficial and should be applied for further mass gathering events worldwide.
ABSTRACT
The 2020 COVID-19 pandemic has not only resulted in immense loss of human life, but it also rampaged across the global economy and socio-cultural structure. Worldwide, countries imposed stringent mass quarantine and lockdowns to curb the transmission of the pathogen. While the efficacy of such lockdown is debatable, several reports suggest that the reduced human activities provided an inadvertent benefit by briefly improving air and water quality. India observed a 68-days long, nation-wide, stringent lockdown between 24 March and 31 May 2020. Here, we delineate the impact of the lockdown on groundwater and river sourced drinking water sustainability in the arsenic polluted Ganges river basin of India, which is regarded as one of the largest and most polluted river basins in the world. Using groundwater arsenic measurements from drinking water wells and water quality data from river monitoring stations, we have studied ~700 km stretches of the middle and lower reaches of the As (arsenic)-polluted parts of the river for pre-lockdown (January-March 2020), syn-lockdown (April-May), and post-lockdown periods (June-July). We provide the extent of As pollution-free groundwater vis-à-vis river water and examine alleviation from lockdown as an opportunity for sustainable drinking water sources. The overall decrease of biochemical oxygen demand (BOD) and chemical oxygen demand (COD) concentrations and increase of pH suggests a general improvement in Ganges water quality during the lockdown in contrast to pre-and-post lockdown periods, potentially caused by reduced effluent. We also demonstrate that land use (agricultural/industrial) and land cover (urban-periurban/rural) in the vicinity of the river reaches seems to have a strong influence on river pollutants. The observations provide a cautious optimistic scenario for potentially developing sustainable drinking water sources in the arsenic-affected Ganges river basin in the future by using these observations as the basis of proper scientifically prudent, spatially adaptive strategies, and technological interventions.