Biosolids--Grounded in Sound Science
Around the world, applying biosolids to agricultural land for crop production has been a common practice for decades. Long-term scientific studies over the years have consistently demonstrated that biosolids recycling is both safe and beneficial. This research strongly supports the finding of the U.S. Environmental Protection Agency that "In fact, in all the years that properly treated biosolids have been applied to the land, we have been unable to find one documented case of illness or disease that resulted." (Martha Prothro, former Deputy Assistant Administrator for Water, U.S. EPA, 9/1/ 1992).
Many studies attest to the safety and efficacy of biosolids recycling:
Finding: There were no observed differences between disease occurrence in domestic animals on farms using biosolids and on control farms. Similarly, there was no significant difference in the presence of adverse effects to residents of either farms using biosolids or the control farms. Biosolids were also found to be effective in increasing crop yields.
Source: Comprehensive health effects study comparing the health status of residents living on 47 Ohio farms using biosolids with those on 46 control farms. The 1985, study sponsored by the Environmental Protection Agency, was conducted jointly by Ohio State University and the Ohio Farm Bureau Federation.
Finding: Biosolids are extremely safe when used in agriculture as a nutrient source and soil conditioner. They can be used in ways that do not endanger the environment or the food chain.
Source: Article for the October 1990 issue of BioCycle; Rufus L. Chaney discussed the impact of biosolids on the human diet and took an updated look at biosolids management regulations. Chaney is with the Soil-Microbial Systems Laboratory of Agricultural Research Service, U.S. Department of Agriculture.
Finding: Biosolids provide nutrients and organic matter that can be used beneficially for growing crops. They can supply appreciable amounts of nitrogen and phosphorus. The return of organic solids to the soil will contribute to the maintenance of organic matter levels. Some biosolids also help neutralize acidity in soils (similar to the function played by agricultural limestone) so as to help maintain the proper soil pH for crop growth.
Source: Lee W. Jacobs reviewed the agricultural application of biosolids for a recent book on biosolids. Jacobs is associate professor in the Department of Crop and Soil Sciences of Michigan State University.
Finding: Runoff from pastures receiving a surface application of biosolids exhibited the least overall potential for pollution when compared with pastureland that received applications of dairy and poultry manure or to commercial fertilizer.
Source: One of the conclusions from a 1984 article in the Journal of Environmental Quality by R.V. McLeod and R.O. Hegg.
Finding: Research into the application of biosolids to agricultural land for over 20 years indicates that properly applied, high quality biosolids can be safely utilized on crop and forest lands, for reclamation of disturbed lands, and on urban and residential turf grass and ornamental plantings.
Source: The Water Environment Research Foundation (WERF) documented long-term experience of biosolids land application programs in a report issued in 1993.
Finding: In recent years, crop yields on biosolids-improved farm land in Yuma, Arizona, have been 10 to 85 percent higher than crop yields on soils receiving commercial fertilizers. In addition, no significant increase in metal concentrations in plant tissues was observed.
Source: WERF Report, 1993 citing biosolids application in Yuma, AZ, begun in 1980.
Finding: Groundwater and surface water monitoring data from the Hampton Roads, Virginia, biosolids management program shows no environmental degradation. The site was monitored more extensively than any other site surveyed.
Source: WERF Report, 1993. The Hampton Roads Sanitation District operates the Progress Farm using biosolids applications. The District gathered comprehensive data on soil, groundwater and surface water quality for two years before using biosolids. This data has provided a long-term scientific baseline to study the effects of biosolids.
Finding: Soils act as extremely tight binders for organic and most inorganic pollutants, and this significantly reduces the ability of these pollutants to enter the environment and be exposed to humans, plants, and animals.
Source: "How Toxic are Toxic Chemicals in Soil," by Martin Alexander, Environmental Science and Technology, Vol. 29, No. 11, November 1995.
Copyright @1996 Water Environment Federation
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Adapted by: Philadelphia Water Department,
Biosolids Management Unit, 215-685-6248