Land Application of Biosolids in the USA: A Review

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 metal	Ceiling concentration limit (ppm)^a	Cumulative pollutant limit loading (kg ha^−1)	Mean (ppm)
Arsenic (As)	75	42	10
Cadmium (Cd)	85	39	7
Copper (Cu)	4300	1503	741
Lead (Pb)	840	301	134
Mercury (Hg)	57	17	5
Molybdenum (Mo)	75	—^b	9
Nickel (Ni)	420	421	43
Selenium (Se)	100	100	5
Zinc (Zn)	7500	2805	1202

^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.