Scope
The loaded rows cover land-application pollutant concentration limits in 40 CFR 503.13 Table 1 and Table 3 for sewage sludge and derived bulk material. Loading-rate tables are not loaded because their units are kg/ha rather than product concentration.
Exact limit and units
| Metal | Matrix | Limit | Unit | Basis |
|---|---|---|---|---|
| total arsenic (tAs) | Table 1 ceiling concentration | 75 | mg/kg | dry weight basis |
| cadmium (Cd) | Table 1 ceiling concentration | 85 | mg/kg | dry weight basis |
| lead (Pb) | Table 1 ceiling concentration | 840 | mg/kg | dry weight basis |
| total mercury (tHg) | Table 1 ceiling concentration | 57 | mg/kg | dry weight basis |
| nickel (Ni) | Table 1 ceiling concentration | 420 | mg/kg | dry weight basis |
| total arsenic (tAs) | Table 3 pollutant concentration | 41 | mg/kg | dry weight basis |
| cadmium (Cd) | Table 3 pollutant concentration | 39 | mg/kg | dry weight basis |
| lead (Pb) | Table 3 pollutant concentration | 300 | mg/kg | dry weight basis |
| total mercury (tHg) | Table 3 pollutant concentration | 17 | mg/kg | dry weight basis |
| nickel (Ni) | Table 3 pollutant concentration | 420 | mg/kg | dry weight basis |
How tested
Part 503 references inorganic-pollutant test methods elsewhere in the rule and states the pollutant tables on a dry-weight basis.
Enforcement posture
No person may apply sewage sludge to land except in accordance with Part 503. The regulation imposes ceiling concentration, pollutant concentration, and loading-rate conditions depending on the land-application scenario.
History of changes
Part 503 was promulgated in 1993, with later amendments. The local copy is the 7-1-2025 edition of 40 CFR Chapter I.
How it compares
Table 3 pollutant concentrations are lower than Table 1 ceiling concentrations for arsenic, cadmium, lead, and mercury; nickel is 420 mg/kg in both tables.
Sources
Update history
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