A recent survey found examples of water pollution with nitrates in intensive farming
areas in the Central Plain (Kanchanaburi and Suphanburi) (Greenpeace 2007) In
Kanchanaburi, the study found a clear example of heavy fertilizer use related to water
pollution with nitrates in asparagus farms: in 6 out of 11 asparagus farms, nitrates
levels in groundwater wells were above the WHO drinking water safety limit of 50
mg/l NO3
-, in some cases 2 times higher than the safety limit, and even in the other
five wells nitrate levels showed evidence of pollution. In Suphanburi, two of the five
wells sampled in farms had nitrates levels higher than the WHO safety limit. These
high levels of nitrates in drinking water could have serious health effects for the local
population, especially for children.