Table 1: Pollutant ceiling concentrations and cumulative loading amounts for biosolids (adapted from [6]) and mean concentrations measured in biosolids from the National Sewage Sludge Survey [7].

Trace metalCeiling concentration limit (ppm)aCumulative pollutant limit loading (kg ha−1)Mean (ppm)

Arsenic (As)754210
Cadmium (Cd)85397
Copper (Cu)43001503741
Lead (Pb)840301134
Mercury (Hg)57175
Molybdenum (Mo)75b9
Nickel (Ni)42042143
Selenium (Se)1001005
Zinc (Zn)750028051202

aDry weight basis.
bThe February 25, 1994 Part 503 Rule amendment deleted the molybdenum cumulative limit loading for sewage sludge applied to agricultural land but retained the molybdenum ceiling concentration.