WASHINGTON -- In response to the Environmental Protection Agency's (EPA) request, the National Academy of Sciences has agreed to review the science and methodology behind its standards for municipal biosolids.
EPA asked the academy to step in and check the process after a debate arose July 13 in a USA TODAY article on the dangers of land-applied biosolids. The EPA seeks to show that government standards for land application of municipal biosolids are protective of human health and the environment. It has also asked the academy to recommend any new practices that will strengthen the sludge program.
The U.S. Centers for Disease Control (CDC) and the National Institutes of Occupational Safety and Health (NIOSH) have agreed to work with EPA and NAS on the review. The participation of CDC and NIOSH may help allay worries that biosolids represent a threat to the public, a concern that has come up several times in USA Today articles.
In a July 13 article, "CDC Sounds an Alarm on the Risks of Sludge," the author stated that sewage sludge converted into fertilizer can carry a potential health risk of E. coli, salmonella, hepatitis B, and other bacteria and viruses, especially for workers who are around the sludge.
According to the article, the CDC is recommending that all sludge be cleaned to Class A standards because of the risk that diseases could be transmitted through Class B sludge. It discussed the deaths of two boys whose mothers said that pathogens from the Class B biosolids applied on nearby land are to blame.
The report from NIOSH, upon which the USA Today article was based, also discussed ways to minimize the risks associated with working around Class B biosolids, including providing hand-washing stations, mixing the biosolids into the soil, wearing personal protective equipment if there is a possibility of contact with the biosolids, and using heavy equipment with a properly sealed and filtered cab.
Although it agreed with the potential benefits of studying EPA's biosolids rules, the Water Environment Federation (WEF) in a letter to the USA Today said that the newspaper had misinterpreted the draft document from the NIOSH (which develops recommendations for worker safety) as a Center for Disease Control "alarm" for the general public.
"Further, the story fails to mention the vast majority of scientific opinion and research which proves that properly treated sludge (biosolids) is perfectly safe for public health and the environment when managed according to federal standards," wrote Albert Gray, Deputy Executive Director of Technical Programs.
"There has not been a single fatality attributed to biosolids exposure in all the years that thousands of wastewater workers around the country have worked with the material. In terms of the general public, the two unfortunate deaths mentioned have been extensively investigated by the responsible health agencies of both states and found to have absolutely no relationship to biosolids."
Less than one percent of the nation's agricultural land is fertilized with sludge. However, EPA requires that both the water leaving the plant, as well as the sludge wastes, meet health and environmental standards.
For more information, visit EPA's section on biosolids, http://www.epa.gov/owm/bio.htm. Also, visit the National Biosolids Partnership web site at http://www.biosolids.org.
To view the Europe viewpoint from the Institute for Prospective Technological Studies (IPTS) of the Joint Research Centre (JRC) of the European Commission, visit http://www.jrc.es/iptsreport/vol18/english/ENV1E186.htm
