A farmer from Augusta sued the Agriculture Department after hundreds of his cows died of poisoning. Last week, he won a settlement worth $1.5 million from the city.
The interesting thing about this story is that the farmer had been spreading sewage sludge onto his land and this was what had poisoned the animals. Tests on milk from the farm showed high levels of contamination with one chemical found at 120 times the EPA safe level in drinking water.
Associate Press reports US District Judge Anthony Alaimo found:
Alaimo ordered the government to compensate dairy farmer Andy McElmurray because 1,730 acres he wanted to plant in corn and cotton to feed his herd was poisoned. The sludge contained levels of arsenic, toxic heavy metals and PCBs two to 2,500 times federal health standards.Sewage sludge is one of those things that nobody really wants to think about. We've even created a new lexicon of words for disgusting things: 'biosolids' and 'sludge cake' are technical words for human sewage, 'paunch' and 'animal byproducts' are used to describe the mix of blood and guts from an abattoir. They're full of pathogens, they're bad for the environment and they really stink. A big pile of human sewage has a disgusting clinging smell that sticks to clothing and the hair, attracts huge numbers of flies and generates nauseous wafts of ammonia.Also, data endorsed by Agriculture and EPA officials about toxic heavy metals found in the free sludge provided by Augusta's sewage treatment plant was "unreliable, incomplete, and in some cases, fudged," Alaimo wrote. -- AP
But human waste is a natural substance containing many essential plant nutrients. So why is it so toxic?
Well, the main toxins are the heavy metals. In the soil these can directly cause damage to animals and have a measurable effect on the growth of agricultural crops. There are also human microbial pathogens, such as E.coli 0157 and organic compounds (PDF) such as dioxins and PCBs. In all, it is a pretty nasty mix of substances, and it is a bit disturbing that we have it anywhere near our food.
On the other hand, we are short of options on disposal of sewage sludge. The practice of sea disposal has been fazed out in many countries, so the only real options left are disposal by incineration or by land application. Handled in a way that avoids any direct contact with food crops, sewage sludge has a valuable fertilising effect and microbial pathogens can be destroyed with fairly simple technology.
The heavy metals are a much more serious problem. As the European Environmental Agency show, metal levels in European soils are already high, so over time an increasing amount of land becomes unsuitable for sewage sludge application as metal rates reach maximum safe levels. Unless we undertake a radical redesign of our city infrastructure, separating human waste from the industrial waste which causes the metal pollution, we are polluting our soils and eventually ourselves. Maybe it is time we took a bit more interest and stop thinking that human excrement is just shit.
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