History of water monitoring
In 1986, a major environmental disaster occurred. In that year, fire in the Sandoz chemical plant in Basel, Switzerland, resulted in runoff that caused a massive mortality of wildlife in the river. This has sparked major concern over the Rhine River’s water quality. Government authorities started to install monitoring facilities to perform chemical control of the river. However, the shortcomings of chemical warning system started to surface. Chemical warning cannot detect all the thousands of compounds present at a practical cost. As such, the use of biological early warning systems, also known as bioassay, came into the picture. In a bioassay, a living organism serves as a detector for toxins akin to the use of canaries in coal mines to detect invisible toxic gases. Such system not only helps to determine the levels of contaminants such as acid, heavy metals, fertilizers, persistent organic pollutants etc., but also give an impression of the toxicity of all compounds under prevailing field conditions. In the past, water was monitored using fishes. Today, fishes along with other organisms are used to evaluate water conditions.

Daphnia magna
Currently, Daphnia magna, also known as freshwater water flea, is widely used as an aquatic test species for ecotoxicity testing. Often the effects of water pollutants on Daphnia magna are studied through physical approach by evaluating mortality, immobility, growth and reproduction dysfunction and appearance abnormality such as deformation and disability.

At NERI, Professor Sam Li together with his graduate students Ms. Zhang Wenlin and Ms. Lee Si Ni, adopts the metabolomics approach to predict toxicants present in water. Using the state-of-art technology such as liquid chromatography mass spectrometry and nuclear magnetic resonance spectroscopy, they were able to determine the metabolic responses of Daphnia magma to different concentrations and types of pollutants. Each class of toxicants has a unique mode of action, which elicit specific and distinct metabolic responses. Hence metabolomics can be used to predict toxicants present in water bodies through Daphnia magma. At present, the team is preparing a manuscript for their work. Please stay tune for their publication.