Testing the World's Drinking Water

While in most parts of Canada, safe drinking water is as close as a turn of the tap, more than 2.5 billion people the world over are without access to this basic resource. The problem is particularly severe in developing countries, where regulations governing waste disposal and the use of toxic chemicals are lax. The dangers this poses to human health are exacerbated by the fact that water quality testing is simply too costly for many communities to carry out.

or the past two years, Environment Canada scientists in Burlington and Montréal have been working to help transfer simple, cost-effective water toxicity testing technologies to scientists in developing countries so they can identify grossly contaminated water sources. Their efforts--an integral component of the International Development Research Centre's (IDRC) WaterTox program--include developing and refining bioassays, training scientists, providing technical support to lesser developed laboratories, preparing contaminated water samples, assessing results, and producing a resource manual.

The first challenge faced by the scientists was to find tests that could be carried out using basic equipment and readily available supplies. Six bioassays--tests that involve exposing small, living organisms to liquid samples and measuring the effects--were chosen from a list of more than 25. In two of these tests--the lettuce seed germination test and onion root inhibition test--toxicity is indicated by slowed plant growth. In the Daphnia magna acute toxicity test, 96-hour hydra test and nematode toxicity and growth inhibition test, the mortality rate of tiny invertebrates serves as an indicator. All are easily visible and unambiguous indicators of toxic contamination.

Normally shaped like a tiny tree trunk with tentacles, the hydra is a highly visible indicator of chemical contamination because it changes shape when it dies.

Scientists from institutions in Costa Rica, Colombia, Mexico, Argentina, Chile, Turkey, India, the Ukraine and Canada attended a two-week workshop in Cornwall, Ontario, to learn how to perform these bioassays, and were given supplies and test organisms to take back to their labs. As an initial training exercise, they were then sent a set of 24 samples containing metals, organics and pesticides for analysis, and asked to return the results for examination.

These results revealed large discrepancies in quality control and reproducibility among the participating labs. Some problems were caused by the lack of full-time staff devoted to bioassay testing, while others were localized problems, such as lack of air-controlled growth facilities, the variability of distilled water supplies, and the closure of labs due to civil disruptions. Lack of proper facilities affected the seed and onion tests, which tended to sprout or rot during storage.

To standardize and calibrate these tests, the process has recently been repeated using fewer samples and bioassays. After the second round of results has been collated this spring, the labs will begin analyzing natural environmental samples. In the meantime, university scientists in Bogota, Colombia, are working to develop simple methods for concentrating natural samples, so contaminants will be detectable within the parts-per-million range--the limit for most bioassays.

One of the results of this project will be to produce a resource manual for interested laboratories that documents testing protocols and quality control procedures, and interprets results for the core battery of bioassays. It is hoped that the institutions currently involved in WaterTox will eventually transfer their newly acquired technologies to other labs in their home countries.

Boys washing dishes in a lake near their home. Contaminated water is the norm rather than the exception in developing countries.

IDRC recently applied some of the WaterTox technologies, along with simple bacteriological procedures, to its new AQUAtox 2000 program--which began in February of this year. Under the program, dozens of public and high schools in Canada and around the world are carrying out environmental tests for bacterial pollution and the presence of toxics. By providing people with the tools to measure water quality, these programs are raising international awareness of the hazards of contaminated water, and enabling citizens to make more informed decisions about their health.

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