Some residents near land-application sites blame the infectious pathogens and heavy metals that sewage sludge sometimes contain for high incidences of cancer in their communities. Hearl thinks it would take more than 10 to 15 years before researchers would expect to find cancer from exposure to sewer sludge. He acknowledges that sludge can contain carcinogens, including arsenic, cadmium and nickel. The EPA, however, insisted that sludge use had been tracked and researched for 25 to 30 years. The point was corroborated in a December 1999 online correspondence, obtained by Insight, by Alan Rubin, Ph.D., senior scientist for the EPA s Health and Ecological Criteria Division.
Proponents insist there is no documented evidence that sludge negatively affects health.
But in response to a Freedom of Information Act re-quest made to Rubin s EPA online address, it was explained that the main classes of pathogenic organisms found in waste are bacteria such as salmonella, viruses such as polio, protozoa such as giardia and helminths such as ascaris. This information clearly indicates that if humans and other living species are exposed to these materials at sufficient doses and over sufficient periods of time, there is a potential for adverse effects to be observed. It would be very difficult if not impossible to copy and send you all of this material. It would probably fill many file cabinets. The point, however, is not that these pollutants are in the environment or in biosolids or manures.