January 2008:January 2008
1/21/08
9:41 PM
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Biosolids
Why biosolids applications make sense By Phil Sidhwa
here have been several media reports giving negative viewpoints on biosolids and these present misleading and confusing information. Much rhetoric has been directed at municipal and provincial governments as well as the private sector’s approach to Ontario’s biosolids land application programs. Some criticism lacked scientific studies or other findings relating to any potentially deleterious environmental and health impacts of biosolids. It is now time that biosolids’ programs be considered within a more rational context. There is plenty of evidence out there but often the evidence just doesn’t say what opponents to biosolids would like. We should all be willing to debate the issues with greater principle and discipline. The dire doomsday warnings of some activists should be kept within the context of all professional studies and history. Misguiding the public by warping scientific principles and misinterpreting available data serves no one but a few minorities. Biosolids are an important source of nitrogen, phosphorus and organic matter to farmers in Ontario. In a cash-strapped agricultural economy, farmers get a valuable no cost fertilizer equivalent, worth about $250/hectare. Moreover, municipalities can recycle biosolids in an environmentally sustainable and economically sensible way for the benefit of society. In general, this can be done by placing important carbon and organic materials back into the soil, instead of incinerating or landfilling them. Ontario farmers annually receive over $7 million worth of equivalent fertilizer value through these practices. Moreover, this practice reduces the amount of phosphorus extracted from our natural environment. It also reduces vast amounts of
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In a cash-strapped agricultural economy, farmers get a valuable no cost fertilizer equivalent, worth about $250/hectare.
fuel required to manufacture nitrogen in commercial fertilizers. Ontario has some of the strictest and safest guidelines for biosolids management in the world. These guidelines impose limits on heavy metal content, soil conditions, topographical and hydrogeological factors, separation distances to wells and water courses, waiting periods, timing of applications, volumes applied and record keeping. Municipalities enforce strict sewer use by-laws on industry to limit discharges of metals. This has resulted in a notable decrease in metals entering our sewer systems over the past 25 years. Current practices ensure that biosolids application matches farm cropping and nutrient management plans. There has been an overwhelming wealth of scientific studies conducted in North America and Europe that prove the benefit and safety of properly applied biosolids to soils, crops, human health and the environment. The safety of this program has been verified through many decades of experience and research by influential scientific bodies consisting of world-renowned soil and water scientists at the United States National Research Council, the U.S. National Academy of Sciences, Environment Canada, the University of Guelph and other academic institutions, the Ontario Ministries of Environment, Health and Agriculture, Food and Rural
Affairs and various other government institutions worldwide. Over the past 30 years, vigorous testing has been conducted on heavy metals and organic compounds in biosolids, soils and crops receiving this material. The conclusion from this extensive research, scientific evidence, expert peer review and experience, strongly demonstrates that properly applied biosolids pose negligible risk to consumers, crop production and the environment. In fact, over the past 30 years of experience in Ontario, there has never been a case where properly applied biosolids have caused a negative adverse effect on the health of humans, animals, crops or the environment. A three-year epidemiological study, conducted by Ohio State University, concluded that their general health, which included respiratory illness, digestive illness, and bacterial and viral infection levels, was the same for people living on farms that used biosolids and those living on farms that did not use biosolids as fertilizer. The University of Arizona collected more than 500 bioaerosol samples from 10 different biosolids application sites across the US to evaluate occupational and community risks from bioaerosols. The samples were measured for a number of bacteria, viruses and endotoxins. The study concluded that occupational
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