Spreading Sludge on Farmland

Assumptions behind The Environmental Protection Agency sludge policy.

1. 'Sludge contains useful nutrients such as Phosphorous and Nitrogen, which are taken out of the soil and need to be replaced'.
   While sludges may contain useful nutients, they also contain contaminants, such as heavy metals and persistant organic toxins, that build up in the soil and are eventually taken up by plants and animals.
   If Vitamin C (which is good for us) is mixed with cyanide (which will kill us) the resulting mixture is bad for us.
   
2. Soils seem to be able to tolerate high concentrations of certain metals before damage occurs to micro-organisms, crops and those consuming those crops
   This assumption is based on some particular metals in isolation: sludge contains large numbers of metals that are altered into forms and combinations. that are extremely variable. We have little understanding of the consequences of increasing the concentration of this mixture of metals and organic chemicals in soils. Current regulations are not based on a sustainable agricutural practice. Even if these regulations were closely enforced (which they are not -- the EPA inspector general concedes that the agency has no capability to ensure the publics safety), it may result in heavy metal loadings in the soil within a few decades.
   The land application of sludge results for example in the release of mercury into the atmosphere. The mercury comes from many sources including hospitals and dental offices. This mercury then falls to earth and adds to the toxification of lakes and rivers. The build up of mercury in fish has resulted in government programs to limit the consumption of sport fish throughout the United States and Canada.
    
3. Sludge can be monitored to prevent harmful substances from reaching the land
   Sludge monitoring is very costly--and is more expensive the more things we attempt to "monitor." Measuring the content of a few metals and chemicals in some batches of sludge has virtually no meaning. Over time there will be thousands of other potentially toxic substances that are not detected and thus are bound to slip through onto farmland and vegetable gardens, only to manifest themselves in statistics of increased cancer rates, allergies and birth-defects not to mention increases in infectious diseases resulting from generally lowered immune defenses.
   
4. By regulating the land-application process we are better off than if sludge were just dumped on the land.
   We need to explore different ways to manage waste. Using drinking water to flush domestic and industrial waste is a massive misuse of several resources.
   If we must build a source-separating resource recovery system, let us begin now. We are deeply into the error of combining waste materials. We must begin a pollution prevention program aimed at limiting the contaminants released from industry and homes, as well as exploring alternatives to sewering new communities.
   
5. Sewage treatment plant sludge can be made "safe" by curtailing input from certain industries
   Sewers are open systems. There is no way to stop harmful substances from entering the sewer system even with well drafted and enforced legislation. Some contaminants come from industry (mercury from dental offices, heavy metals from plating companies) some from homes (surfactants from cleaning products, broken thermometers, paint, etc). The sludge batches vary widely and no tests are done on specific loads before they are trucked out to the fields.
   The danger is that the policy of allowing sludge on food-producing land is cumulative. Since this is a non sustainable practice, we must find alternative methods of getting rid of sludges. The concern is that we may continue to dispose of sludge on farmland until the toxicity is irremediable.