ABSTRACT
This chapter discusses health risks related to agriculture and aquaculture. The health risk associated with waste use depends on the degree of treatment which has been provided and the nature of the process involved. Sewage, nightsoil, organic refuse and sludge from sewage treatment can be put to use in most situations. In China, the use of human excreta in agriculture is an ancient practice and may provide the main source of fertiliser for the fields. Sewage and nightsoil are often used in agriculture, sometimes in an organised way but often informally, illegally or clandestinely. Aerobic ponds containing sewage or nightsoil typically support large growths of algae. These may be used to support populations of fish, which can be harvested for consumption. Storage of the wastes before adding them to ponds is an effective treatment measure. Removal of aquatic vegetation from the banks of a pond makes it more likely that it will not harbour snails.
