A Better Test for Water Quality
A new tool for determining water quality criteria (WQC) for toxic metals in both fresh and marine waters and under differing temperatures, has been developed by Professor Kenneth Leung of the School of Biological Sciences and Professor Wu Fengchang of Chinese Research Academy of Environmental Sciences.
The current WQC have been derived from testing in fixed laboratory conditions, which may not be protective to marine ecosystems because conditions such as temperature and salinity vary across different geographic regions and even seasonally within the same region. These changes can substantially influence the toxicities of metals to marine organisms.
Professor Leung and Professor Wu overcame that limitation by developing a model that takes account of variable temperature and salinity levels. They then tested it with real-time environmental data of sea surface temperature and salinity from different parts of the world to derive provisional site-specific WQC for more than 30 metals and metalloids. The results indicated metal toxicities to marine organisms generally increase with warmer seawater temperature and when the salinity increases or decreases from the optimum level. Professor Leung noted that their method had other benefits, too “We can reduce the number of toxicity tests, use less chemicals in the tests, kill fewer animals, and greatly save money and time involved in testing,” he said.