PANAJI
The pollution level of River Mandovi has decreased and the water quality showed significant improvement during the Covid-19 lockdown in 2020, according to a study by the National Institute of Oceanography. This will have a positive effect on the marine life in the estuary.
The steep reduction in human activity is the main reason attributed to this improvement in water quality.
The study revealed that the midstream sections of the river that usually show a high proportion of Coloured Dissolved Organic Matter (CDOM) were found to be clearer by almost two folds.
The NIO has been monitoring CDOM levels in the Mandovi Estuary since 2014.
Usually, high CDOM absorption was observed during summer (especially in the midstream region) due to an increase in anthropogenic activities. In 2020, following the government of India imposed the Covid lockdown (March 24 - June 8), a significant decrease of CDOM by almost two folds was observed in the midstream region, the study revealed.
“The Sentinel-2 satellite data showed similar variations of CDOM absorption with low values during 2020. Apart from this, the concentration of dissolved nutrients in 2020 was also low compared to the previous reports. There was a complete standstill of anthropogenic activities such as operating pleasure cruises, water transport systems like barges, shipbuilding activities, and commercial establishments following the government-imposed lockdown, which might have reduced the CDOM in the estuary,” the study adds.
The Sentinel-2 satellite data also showed similar variations of CDOM absorption with low values during 2020. Apart from this, the concentration of dissolved nutrients in 2020 was also low compared to the previous reports.
A fraction of this organic carbon absorbs light and imparts colour to the water and hence known as coloured dissolved organic matter (CDOM). The origin of CDOM can be either natural or anthropogenic sources. CDOM absorbs light highly in the UV and blue regions of the solar spectrum and hence can have a positive or negative impact on the ecosystem.
