Increases in organic matter on these access ways will generally cause temporary deterioration in the productivity of the underlying soil. Impacts on Water Impacts which greenhouse growers may cause on the water environment vary with the type of irrigation system used, the technology employed and the specific hydrology of the site. Items that cause water pollution and where they come from are discussed below. Because it is soluble, it does not attach to soil particles as ammonium nitrogen does, and so is easily leached from the soil. Once past the root zone, nitrates can continue moving downwards to the groundwater and into drinking water supplies.
Nitrates can cause a disease in infants known as blue-baby syndrome.
Nitrates in groundwater are considered to be an early warning sign to further contamination. Spills, leakages and exposure of supplies to weather may result in nitrates, other fertilizers, pesticides and disinfectants being introduced into surface water or groundwater. Excessive application of irrigation water is also a cause of nutrients entering surface or groundwater. The use of biological filters, such as wetlands to clean runoff, and volumes of greenhouse discharge in relation to drainage flow also affect the pollution potential. The potential threat to groundwater is strongly influenced by the properties of the chemicals used in greenhouse operations.