The Water Quality at Maracas, Las Cuevas and Chaguaramas during the ‘Stay at Home’ COVID-19 Pandemic
Prepared by Sheldon Ramoutar, Microbiologist
Institute of Marine Affairs
The COVID-19 pandemic is currently changing the way we live our daily lives. No public gathering, and social distancing has been in effect since late March 2020 and has left our environment untouched. Around the world, reports have shown cleaner air quality in large cities and countries like the United Kingdom China and Spain due to the drop in carbon and nitrogen oxide emissions. There are also reports of better water quality in places like Venice and the Ganges as the watercourses are now more transparent with visible aquatic life.
In Trinidad and Tobago, numerous beaches are continuously polluted and affected by runoffs from rivers, industries, households and by beachgoers. These pollutants can vary from solid waste, 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 Institute of Marine Affairs (IMA) routinely monitors various beaches for sewage contamination using 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 United States Environmental Protection Agency (USEPA), World Health Organization (WHO) and established by the Environmental Management Agency (EMA) in the Water Pollution Rules (2019). The recommended limits are provided in the table below.
| Indicator | Single day limit | Geometric Mean Limit (Average of 5 days in a month) |
|---|---|---|
| E. coli | 235 | 126 |
| Enterococci | 104 | 35 |
Even though a beach may have levels of bacteria above the recommended limit, it does not necessarily imply you will become sick if you bathe there, but rather, you are at a greater risk of getting sick. It all depends on the individual, as the more vulnerable, high risk groups are infants, seniors and immune-compromised individuals.
Currently, all recreational beaches and rivers are closed to the public. Given the current regulations on working from home and social distancing, and to ensure the safety our colleagues, we are slowly restarting our beach monitoring. We completed a single day analysis at three beaches- Maracas, Las Cuevas and Chaguaramas to get a snap shot of bacterial levels. Further testing will continue at these beaches during May.
The 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 runoffs into bathing areas. Runoffs 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 runoffs are visible, such as by river mouths and drains that empty into the beach.
At Maracas Beach, 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 sampling event, the levels were very low. In the last couple of years, this site has never been below the recommended limit. For example, the indicator enterococci (limit 104 CFU/ 100 ml) gave a result of 50CFU/ 100 ml compared to 2018 (>183CFU/ 100 ml), 2017 (>280CFU/ 100 ml).
At Las Cuevas Beach, the bacteria levels were very low (below 30CFU/ 100ml) 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 runoffs while the western side always had good water quality. It should be noted the western side of this beach was once a certified Blue Flag Beach from 2014-2017, this was the only beach in English-speaking southern Caribbean with that status during that time interval.
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. Our sampling for geometric mean uses five sampling events with usually three to four sample days being over the limit. During this month sampling event, the bacteria levels were lower in both Williams Bay and Welcome Bay. In Williams Bay, we recorded E.coli 0- 40CFU/ 100 ml; enterococci 0 – 50CFU/ 100 ml) compared to 2019 (E.coli 100- 400CFU/ 100 ml; enterococci 20 – 300 CFU/ 100 ml). In Welcome Bay, we recorded E.coli 50- 60CFU/ 100 ml; enterococci 0 – 100 CFU/ 100 ml) compared to 2019 (E.coli 10 – >400CFU/ 100 ml; enterococci 20 – >240 CFU/ 100 ml).
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?
Extreme Dry season
Land-based runoff is the leading cause of pollutants entering the bathing areas and this usually intensifies during rainfall events. Compared to previous years, this dry season had minimal rainfall so can be a leading factor to why the levels are so low.
COVID-19 Pandemic Lockdown
At present, all the 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 seafloor 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 resuspension of sediment and bacteria, so the water looked clear and enticing on a very hot day.
It will take much more data, and more time to determine if the COVID-19 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. COVID-19 is currently affecting every aspect of human life, but it is likely having benefits to the environment. We will continue sampling and testing, and a full report will be prepared and available from the Institute of Marine Affairs.
“The Earth is what we all have in common.”
-Wendell Berry