Publication: Weekend Nation
Paper Date: Fri, Feb 16, 1996
Paper Page: 7

STRINGENT controls are needed to maintain the good quality of Barbados' drinking water supply. This is part of the preliminary findings of the Barbados Water Resource and Water Loss Study which started late last year.

Bob Dawson, of Stanley Associates of Canada, which is conducting the study, said available data showed pollutants in 25 wells. Some were just trace levels, others were increasing or high but all were considered to be acceptable, according to drinking water standards set by
the World Health Organisation (WHO).

Dawson said there was not enough data on all the pollutants to show trends but of the data that was available, there were six areas of concern, he told the public at a lecture yesterday.

Topping the list was the high or increasing levels of nitrate, especially on the west coast.

Nitrate, which comes from sewage or fertilisers, range between six and eight milligrams per litre of water (mg/l). The WHO standard is 10 mg/l. Levels above this can affect infants and result in methoglobinemia or "blue baby syndrome". More investigations are needed but Dawson said one theory was that the bulk of the nitrate pollution was coming from populations in the rural areas, upstream of underground water courses. If the theory is correct, he said there may be a need to provide water treatment in those areas or at the wellhead, which could cost about $50 million. There was also need for more efficient use of fertilisers by farmers to reduce nitrate seepage into the ground.

Bacterial contamination in drinking water wells was non-existent because of chlorination, but levels in agricultural wells were astronomical, he said, suggesting contamination, again from rural populations.

Salinity was also very high on the west coast due to high pumping rates. Possible strategies, said Dawson, was to reduce the rate of pumping, use recycled waste water for irrigation and increase the price of drinking water for agricultural use.

The pesticide atrazine, which is used widely in the sugar cane industry, is to be found in groundwater all over the island but at very miniscule levels, he explained.

However, its presence suggests a need for control of the rate of application or preferably to use a substitute, otherwise a very expensive water treatment system would have to be installed. Very low levels of ametryne, another herbicide, were recently found in two wells in the Hampton catchment.