The U.S. Environmental Protection Agency (EPA) runs a biosolids program that aggressively promotes the use of treated human sewage as a safe fertiliser for cropland. But due to public concern and significant media attention, a debate about the safety of using human sewage on cropland has escalated. Most recently, internal U.S. EPA documents obtained by Insight Magazine indicate that the agency’s public confidence about the safety of its sludge policy may not square with results its own experts are reporting internally.
The controversy has spread beyond the David-and-Goliath battle between a suspicious public and municipalities that have to somehow dispose of their sludge. Throughout the United States the sludge industry is being hit with anti-sludge lawsuits and sludge bans. Deaths and disease are alleged, and the first wrongful-death lawsuit implicating the land application of sewage sludge has ended with a settlement by the sludgers, although the settlement did not attribute sludge as the cause of death.
In January 2002, Joanne and Thomas Marshall, the parents of Shayne Conner, a 26-year-old New Hampshire man who died of a respiratory infection after sludge was dumped in his neighbourhood, settled for an undisclosed amount with sludge hauler Synagro Inc. The original complaint was filed against the parent company of Maryland-based Bio-Gro Inc., which Synagro acquired in 2000 as these problems began to surface. As a condition of the settlement, the family has agreed to say nothing further about it.
As if to reassure the public, on its web site, the EPA claims that “Biosolids recycling is safe, and the food corps grown on land fertilized with biosolids are safe to eat.”
But according to internal EPA documents, even as agency officials publicly defend “biosolids” science, it privately acknowledges that there are information gaps in the research on which the policy is based, calling it incomplete.
Notes from a June 2001 workshop co-sponsored by the EPA and the U.S. Department of Agriculture on emerging infectious disease agents associated with animal manure, biosolids and related products confirm official concern that additional research might be needed. The participating experts were charged with assessing the extent to which sludge treatment technologies and practices currently in use adequately reduce or destroy infectious disease agents.
EPA officials noted that certain high infectious disease rates have been emerging and re-emerging in the U.S., and acknowledged that there is little data documenting the fate of many of the offending organisms in biosolids treatment processes and land application programs.
According to another workshop expert on soil, water and environment science, “We actually know surprisingly little about the occurrence of enteric [intestinal tract] viruses and their removal by biosolid-treatment processes. Most of our knowledge comes from work done before 1990 and is generally limited to the enteroviruses [which also can include respiratory ailments, meningitis and neurological disorders]. Enteroviruses may represent a small fraction of all the viruses present in biosolids. Previous cell-culture techniques were very limited in their ability to detect viruses in wastewater.”
Sludge from wastewater treatment plants used for land application is but one aspect of the EPA’s “beneficial use” of treated human waste that has gone on for nearly a decade without significant study.
According to workshop notes, “There have been no health studies conducted to examine theoretical risks to users of distributed or marketed biosolids products for home use,” either. None.
Written by Sheila Cherry, a writer with Insight Magazine & Insight Online, based in Washington, D.C. Adapted from an article already published on Insight Online on March 4, 2002.