Point sources for nitrates include grazing animals near surface waters, farmyard, manure/silage/fertiliser storage facilities. On livestock farms point sources may be slurry lagoons, manure depots with an inappropriate building or location or farmyards, including situations as tank-filling respectively cleaning, accidental spills or fruit washing facilities (Carter, 2000). Point sources are mainly due to misuse or inadequate management. Also small, privately owned wastewater-treatment units may have the effect of point sources.
If grazing animals have access to a small stream or lake, nitrogen and other plant nutrients may enter surface water due to animal excrements or runoff (Bohner et al., 2007).
Dense populations and discharges from point sources like septic systems or broken sewer systems contribute significantly to water pollution by nitrate in urban and suburban areas (Nemčić-Jurec et al, 2013).