Wis. Admin. Code Department of Agriculture, Trade and Consumer Protection, ATCP 20-54, ch. ATCP 40, subch. VI, app C
NON-NUTRIENT METALS; PROHIBITED CONCENTRATIONS
Products Derived from Organic Sources
If a soil or plant additive is derived from materials that are at least 80% organic matter on a dry weight basis, the concentration of arsenic, cadmium, lead, mercury, nickel or selenium in that product may not exceed the maximum concentration specified for that metal in 40 CFR 503.
Soil or Plant Additive Less than 80% Organic
If a soil or plant additive is derived from materials that are less than 80% organic matter on a dry weight basis, the product may not contain any metal shown in Table C-1 in a concentration that exceeds the maximum concentration shown in Table C-1:
Table C-1
METAL CONTAMINATION LIMITS FOR SOIL OR PLANT ADDITIVES
DERIVED FROM SOURCE LESS THAN 80% ORGANIC
Wis. Admin. Code Department of Agriculture, Trade and Consumer Protection, ATCP 20-54, ch. ATCP 40, subch. VI, app C