Fri | Sep 30, 2022

Influx of algae may be behind 'reddish-pink' St Mary river - NEPA

Published:Monday | July 29, 2019 | 4:03 PM
A section of the discoloured Outram River, Port Maria, St Mary - Contributed photo

The National Environment and Planning Agency (NEPA) is reporting that the 'reddish-pink' discolouration of the Outram River in St Mary may be as a result of an algal bloom known as 'red tide'.

​An algal bloom or algae bloom is a rapid increase in the population of algae in freshwater or marine water systems and causes the discolouration in the water from their pigments.

NEPA says it is awaiting the outcome of laboratory analysis for confirmation.

It says a joint site visit was conducted by a team from the agency, the St Mary Municipal Corporation and the St Mary Health Department last week Thursday to investigate the possible sources of the discolouration.

NEPA added that it completed ‘ground thruthing’ activities along the corridors of the river aimed at identifying possible anthropogenic (man-made) influences on the river.

Richard Nelson, Senior Manager, Environmental Management, NEPA explained that, “during the investigation it was noted that the mouth of the river was blocked off from the sea and that there was very little flow of water in the upper sections of the river."

He added, “a ‘reddish-pink’ discolouration containing suspended matter was observed. This discolouration had a distinct odour of hydrogen sulphide. In addition, on-site water quality measurements were taken and samples collected and sent for laboratory analysis at two laboratories. Based on the on-site measurements, the strong odour of hydrogen sulphide and the ‘reddish-pink’ colouration of the water, the agency’s tentative conclusion is that the discolouration is due to an algal bloom known as ‘red tide’.”

NEPA says it will continue to work with the St Mary Municipal Corporation and the Water Resources Authority should corrective measures, based on the results of the analysis, becomes necessary.

We want to hear from you! Send us a message on WhatsApp at 1-876-499-0169, email us at or