Biosolids found to pose negligible risk

Today, thousands of municipalities are land applying or otherwise recycling biosolids. Those communities are producing an estimated 8 million dry tons a year of biosolids that are managed according to federal and state standards. Nevertheless, the beneficial use of biosolids, as described in EPA’s Title 40, Part 503 regulation, has been the focus of contentious debate over the past few years.

Local government officials in California, New England, Pennsylvania, Virginia and other areas of the country who must decide whether to allow biosolids facilities in their communities have fielded a number of complaints from critics. A prominent court case, bans and restrictive ordinances have generated a rash of media attention, much of it deemed by the biosolids industry, EPA and the Alexandria, Va.-based Water Environment Federation (WEF) to be fraught with scientific inaccuracy.

At issue are the potential health effects of exposure to biosolids facilities and operations. Some detractors have alleged that biosolids exposure potentially causes illness among humans and can lead to respiratory, gastrointestinal and other health effects. Some also have alleged that deaths can be linked to the land application of biosolids.

To validate the safety of biosolids, local officials need the best information available on the science of those materials and safe management practices for land application and other uses. The settlement in January of a court case in New Hampshire and results of an investigation by the Pennsylvania departments of Environmental Protection and Health provide evidence that claims of adverse health effects from biosolids exposure lack a scientific basis.

In New Hampshire, a lawsuit was filed on behalf of Shayne Conner, who died in 1995 after Class B biosolids were applied to a field near his home. The plaintiff’s key expert, David Lewis, an EPA microbiologist, alleged that the individual’s death was linked with airborne exposure to an unidentified pathogen.

In Pennsylvaina, Tony Behun died in 1994 after allegedly traveling through a field on which biosolids had been applied. Lewis theorized that biosolids exposure led to an infection that resulted in Behun’s death.

In both cases, biosolids were vindicated. Though the court was unable to pinpoint the cause of Conner’s death, the New Hampshire Acting Chief Medical Examiner ruled out biosolids as a factor. As part of the case’s settlement, the plaintiffs stated that the science Lewis used failed to show that the land-applied biosolids caused or contributed to the fatality.

The Pennsylvania departments of Environmental Protection and Health investigated Behun’s death and confirmed that Behun died of an infection caused by a pathogen common in the environment but not known to be found in biosolids. Officials also ruled out a link between the pathogen and the field where biosolids had been applied.

In addition to the court cases, the National Institute of Occupational Safety and Health (NIOSH) issued the Hazard ID (HID-10) report on July 28, 2000. It raised concerns that biosolids posed a risk to wastewater treatment plant workers in LeSourdesville, Ohio, exposed to pathogens from contact and through the air. Some of the workers at the plant claimed symptoms of gastroenteritis, which are similar to those associated with infections caused by common bacteria. However, NIOSH stated it was unable to attribute those symptoms to biosolids exposure. The Atlanta-based Centers for Disease Control and Prevention and NIOSH are re-evaluating HID-10.

Regulations governing biosolids management have been revised and modified to ensure the information is up to date. Development of risk-based rules included a precedent-setting review of extensive university and field data by scientists independent of EPA. At EPA’s request, the Washington, D.C.-based National Academy of Science (NAS) is reviewing current biosolids management practices to determine any need to update or otherwise revisit the 503 regulations. An earlier NAS-National Research Council evaluation in 1996 found that the use of biosolids on food crops posed “negligible risk” to human health.

While the debate continues, EPA and WEF make a compelling case for biosolids recycling. Biosolids help local governments meet the challenge of managing wastewater treatment residuals while providing a nutrient-rich fertilizer. Other benefits include cost savings to communities; increased crop yields; strip mine reclamation uses; and reduced erosion and leaching of treated soils.

This article was written by Robert O’Dette, vice president, government relations, compliance and technical services, for Houston-based Synagro Technologies. He also is a member of the steering committee of the National Biosolids Partnership. The Alexandria, Va.-based National Biosolids Partnership (NBP) has developed an environmental management system (EMS) that provides local governments with voluntary procedures for demonstrating environmental performance and best management practices. For more on the EMS, visit the NBP’s Web site atwww.biosolids.org.