Ground and surface waters. Agricultural runoff from fertilizer application and animal waste results in NO 3 -concentrations above levels safe for human consumption , but two to three orders of magnitude lower than that in industrial and nuclear waste water. These water streams are circumneutral and often have a similar amount of PO 4 3-and NO 3 -, which can compete for surface sites and provide some level of buffering. Ground water can also contain similar amounts of CO 3