Assessment of Water Quality Along the Southeast Coast of India During COVID-19 Lockdown

Abstract

The COVID-19 pandemic has affected the entire world and has had a devastating impact on both lives and livelihoods in India. The only way to defeat the rapid spread of COVID-19, is to shut down socio-economic activities and to maintain minimal human interaction with the implementation of a lockdown. Such lockdowns have manifested in a pollution curtailment in almost all spheres of the planet, including in marine pollution. Quantifying this decrease in pollution levels enables the scientific community to assess the contribution of anthropogenic (especially non-essential) activities to global/regional pollution levels. This paper aims to study the impact of the stringent lockdown period (phase 1 and 2) on coastal water quality along the Chennai coast of India, by analyzing suspended matter concentration (SPM), a key element of water quality and diffuse attenuation coefficient, Kd(490), using LANDSAT-8 Operational Land Imager (OLI) data. LANDSAT-8/OLI, L1TP scenes were subjected to radiometric calibration and atmospheric correction to derive surface reflectance values from raw digital numbers using ACOLITE software and a brief insight has been given for the Dark Spectrum Fitting algorithm used in ACOLITE. SPM concentration decreased by 15.48 and 37.50% in the Chennai and Ennore ports, respectively, due to minimal vessel movement and cargo handling. The stringent lockdown led to the operation of fewer thermal plant units, thus less fly ash was emanated, resulting in a 28.05% reduction in SPM levels over Ennore creek. As industrial and commercial activities subsided, the city’s water bodies became clearer than they were just a fortnight prior to the lockdown, with a reduction of 22.26% of SPM in Adyar and 33.97% in Cooum riverine estuaries. Decrease in Kd(490) showed a positive relationship with SPM and thus improved coastal water quality because of the reduction of SPM during this period. The variations in PM2.5 and PM10 concentrations were studied using National Air Quality Monitoring Programme (NAMP) data and reduced levels in particulate matter concentration (PM2.5 and PM10) for the Adyar residential area (24.38 and 28.43%) and for the Nungampakkam commercial area (36.09 and 67.18%) were observed. A significant reduction in PM2.5 concentration (45.63%) was observed in the Ennore-Manali Industrial region.

COVID-19 Impacts on Beaches and Coastal Water Pollution at Selected Sites in Ecuador, and Management Proposals Post-pandemic

“…For the first occasion in modern times, most of the coastline studied has developed features of marine protected areas. Recent reports from the southeast coast of India (Prakash et al, 2021) and in Brazil (Pereira et al, 2021) contain similar findings to those here.…”

Effect of COVID-19 Lockdown on Metal Concentration in the Water Column of Asia’s Largest Coastal Lagoon

“…Coastal ecosystems receive a large influx of anthropogenic contaminants through riverine input and these contaminants are reflected in the water, sediment, and associated biodiversity of these ecosystems (Nazneen et al, 2019;Vijay Prakash et al, 2021;Lotliker et al, 2021). Our results suggest a similar phenomenon, where the COVID-19 induced lockdown has halted various industries and human activities and resulted in the reduction of various metals in the water samples of the Chilika lagoon.…”

“…Various researchers in India used this opportunity to assess the air and water pollution status under the influence of the imposed lockdown and observed a reduction in various pollutants in the natural ecosystems (Garg et al, 2020;Lokhandwala and Gautam, 2020;Mishra et al, 2020;Patel et al, 2020). As major river systems discharge various anthropogenic derived pollutants to the coastal ecosystems of India, the lockdown also led to a reduction in coastal pollution (Mishra et al, 2020;Lotliker et al, 2021;Vijay Prakash et al, 2021). However, this lockdown resulted in a decline of phytoplankton biomass in the Bay of Bengal due to reduced input of nutrients (Mishra et al, 2020), whereas reduction in pollutants improved the surface water quality along both the east and the west coast of India (Vijay Prakash et al, 2021;Lotliker et al, 2021).…”

“…As major river systems discharge various anthropogenic derived pollutants to the coastal ecosystems of India, the lockdown also led to a reduction in coastal pollution (Mishra et al, 2020;Lotliker et al, 2021;Vijay Prakash et al, 2021). However, this lockdown resulted in a decline of phytoplankton biomass in the Bay of Bengal due to reduced input of nutrients (Mishra et al, 2020), whereas reduction in pollutants improved the surface water quality along both the east and the west coast of India (Vijay Prakash et al, 2021;Lotliker et al, 2021). However, these studies did not quantify the concentration of various metals in the coastal water column, which also plays an important role in maintaining water quality (Richir and Gobert, 2014).…”

“…The coastal areas of India are dynamic ecosystems where there is a confluence of fresh and marine water. Being at the interface of land and marine systems these ecosystems receive river discharges, dredging, waste dumping, industrial effluents, domestic sewage disposal, and various other pollutants (Gopal et al, 2018;Vijay Prakash et al, 2021). This continuous input of anthropogenic pollutants exerts a significant impact on the coastal environments (Häder et al, 2020).…”