THE Institute of Marine Affairs (IMA) has found that pollution levels at three popular beaches in Trinidad – deserted for several weeks because of covid19 restrictions – are below the normal annual average for this time of the year.
A report compiled by microbiologist Sheldon Ramoutar, contained in a press release sent by the institute stated that further analysis must be done before it can conclusively say if human absence, because of covid19 restrictions, an extremely harsh dry season or a combination of both, are behind the drop in marine pollution levels.
Local beaches and rivers are continuously polluted by run-off of pollutants from industries, households and by beachgoers, the IMA said. These pollutants can vary from solid waste and chemicals to biological agents such as bacteria from sewage. These biological agents enter through skin contact or ingestion can cause minor irritations to skin, eye, ear and even gastro-intestinal illnesses.
The IMA said it uses specific bacterial indicators such as Escherichia coli (E.coli), enterococci and faecal coliform, which, if over a recommended limit, indicates sewage pollution. These indicators are used by the US Environmental Protection Agency (EPA) and the World Health Organization (WHO) and have been established locally by the Environmental Management Agency (EMA) in the Water Pollution Rules (2019).
The IMA recently completed a single-day analysis at three beaches – Maracas Bay, Las Cuevas and Chaguaramas – to get a snap shot of bacterial levels. Further testing will continue at these beaches in the coming weeks.
Initial results showed that the bacteria levels were much lower than recorded in previous years during dry season. Generally, water quality is always better in the dry season due to less land-based run-off into bathing areas. Run-off from rainfall transports debris and pollutants from inland to the coastline.
The public should always avoid bathing after a heavy rainfall event, especially areas where run-offs are visible, such as by river mouths and drains that empty into the beach.
At Maracas Bay, in the dry season, the Maracas River is usually the only location heavily polluted with extremely high bacteria levels, above the recommended limit. During this month’s sampling event, the levels were very low. In the last couple of years, this site has never been below the recommended limit.
At Las Cuevas beach, the bacteria levels were also very low indicating excellent bathing beach water quality at both the western and eastern ends.
In previous years, the eastern side of the bay near the fishing facility had poor water quality due to land-based run-off while the western side always had good water quality.
It should be noted the western side of this beach was certified Blue Flag Beach from 2014-2017, the only beach in English-speaking southern Caribbean with that status during that time interval. The Blue Flag rating is one of the world’s most recognised voluntary eco-labels awarded to beaches, marinas, and sustainable boating tourism operators.
At Chaguaramas Bay, the water quality varies tremendously as rain, outflows, and current movements affect it in the dry season. The Chaguaramas Peninsula has become industrialised with many outflows from businesses making its way into the waters. The water quality has always been slightly over the established limit.
IMA sampling in May showed bacteria levels were lower in both Williams Bay and Welcome Bay. Overall, in the initial testing at the three beaches, the bacteria levels were the lowest recorded compared to daily values from previous years. Therefore, what can be the reason for the low bacteria levels at the beaches?
At present, all beaches are closed to the public and during sampling there was little to no trash and the facilities (toilets, food establishments) were not in use.
The sediments on the sea floor that is capable of holding bacteria are usually disturbed by bathers, outflows and boats, and this can result in re-suspension of bacteria into the water column. With no bathers present, there is little to no re-suspension of sediment and bacteria.
The IMA said it will take much more data, and more time to determine if the covid19 lockdown contributed to improved bathing beach water quality, but physically being on the beach and seeing no signs of garbage and very clear waters, one will have to believe it did.