Animal manure pits

One common indirect source of xenobiotics into the environment is the passing of antibiotics, anaesthetics and growth hormones by farm animals in urine and manure. This is often stored in large pits before being pumped and applied to fields as fertilizers, where many of the chemicals can be washed away by rainfall into lakes and rivers. This pollution is then widely spread, and dealing with it may require the cooperation of scientists in different countries that share a common water system. Other common environmental xenobiotics include pesticides and fungicides (from farming), and a variety of other chemicals mainly from the chemical industry. 

Compost is a cheap organic manure containing appreciable amounts of nitrogen and phosphorus. It is easily prepared by the tanners on the farm by burying waste plants, leaves and animal dung in pits and covering them with soil, where anaerobic decay takes place. 

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