Among the major consequences of uncontrolled urbanisation, is deforestation as well as water and soil contamination due to pesticides, nitrogen, phosphorus and raw organic matter containing undesirable residues such as heavy metals. Doubts have therefore sometimes been raised about the contribution of urban and periurban agriculture to a city's environmental sustainability. Indeed, basic resources (water, soil) needed for agricultural production are in competition with other priority urban needs (drinking and industrial water use, housing and infrastructure, etc.). Much depends on how successful farmers and urban officials are at exploiting the potential environmental benefits, minimizing the problems, and finding ways to secure farmers access to land.
Diseases and veterinary public health issues can arise from intensive livestock production in urban and peri urban areas when space, facilities and equipment are inadequate. Also, food can be contaminated by numerous causes during production, handling, storage or when in markets. During production and storage, contamination can take place because of the incorrect use of chemical products or the use of untreated or improperly treated sewage water. In markets, food can be contaminated because of garbage, stagnant water, or inadequate facilities for personal hygiene.