Mercury in Fertilizer

International norms that are applied to soil amendments such as fertilizer and sewage sludge (bio-solids obtained from municipal biological treatment systems) were examined. Important to these regulations are background levels of mercury in soils and mercury concentrations in commonly applied fertilizers. The regulations that apply to permissible limits of heavy metal additions to soil (or to crops by foliar application) are structured to limit metal additions that would drastically increase the naturally present background levels of metals in soils.

Table 1 - Background Levels of Mercury in Soil (1)

Country	Mean Mercury Concentration ppb	Range ppb
USA	60 (g) 90 (a)	10 - 4,600
Canada	60 (a)	5 - 1,000
China	40 (g) 60 (a)

(a) arithmetic mean (g) geometric mean

MTS analyzed the risk of adding petroleum by-products to soil as fertilizer.