 Waste water discharged from pulp and paper mills outside of North America may contain solids, nutrients, and dissolved organic matter that are classified as pollutants.Nutrients such as nitrogen and phosphorus can cause or exacerbate eutrophication of fresh water bodies.Printing inks and toners are very expensive and use environment-damaging volatile organic compounds, heavy metals and non-renewable oils, although standards for the amount of heavy metals in ink have been set by some regulatory bodies.