In 1996, the U. S. Environmental Protection Agency (EPA) adopted a new Information Collection Rule (ICR), which provides guidelines for testing Cryptosporidium parvum, a disease-causing parasite, which has made headlines in several U.S. cities over the years. The ICR also requires testing for viruses and Giardia Lamblia, another parasite capable of causing gastrointestinal disease.
The testing effort is part of a national initiative that includes about 300 community water systems that use surface water, from lakes or rivers, and provide water to more than 100,000 people. In Minnesota, only Minneapolis and Saint Paul are part of the testing initiative.
However, despite recent improvements, current tests for Cryptosporidium in water still aren’t completely reliable. For example, if the parasite is present in the water only intermittently, a test taken at the wrong time could miss it and give people a false sense of security. Also, if the parasite is found, there is no way to tell if the organisms are viable and capable of causing disease. Moreover, it is not known at what level of contamination the organism is capable of causing illness. Thus, if Cryptosporidium is found, each situation must be assessed individually.
The testing done according to EPA guidelines, is an effort to identify the safest and most effective techniques for removing potential disease-causing contaminants from the water delivered to customers. It will help the EPA determine the optimal mix of filtration technologies and chemical disinfection methods.