Indicator Chemicals
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| Contaminant | Health Effect * | MCL | Potency Factor |
| | | | (Carcinogens |
| | | mg/L | Only) |
| | | | |
| | | | (mg/kg-day-1) |
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| Arsenic | Dermal and nervous | 0.05 | 1.8 |
| | system toxicity; Class A | | |
| | carcinogen | | |
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| Benzene | Class A carcinogen | 0.005 | 2.9 x 10-2 |
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| Chromium | Liver and kidney damage; | 0.10 | Not available for |
| | Class A carcinogen. | | oral ingestion. |
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| DBCP | B2 carcinogen | 0.0002 | 1.4 |
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| EDB | B2 carcinogen | 0.00005 | 85 |
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| Lead | Nervous system damage, | No MCL; action | Not applicable |
| | including reduced IQ and | limit of 0.015 | |
| | behavioral disorders in | mg/L adopted | |
| | children; kidney damage | in 1995. | |
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| Mercury | Nervous system | 0.002 | N/A |
| | disorders; kidney effects; | | |
| | Class D cancer risk. | | |
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| Nitrate | Methemoglobinemia (blue- | 10 | N/A |
| | baby syndrome) | | |
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| Trichloroethylene | Class B2 carcinogen | 0.005 | 1.1 x 10-2 |
| (TCE) | | | |
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| Trihalomethanes | Class B2 carcinogens | 0.100 | Vary |
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| * Carcinogens are ranked by the degree of evidence of carcinogenicity. | | | |
| | | | |
| Class A = known human carcinogen | | | |
| | | | |
| Class B1 = probable human carcinogen with limited epidemiological evidence | | | |
| | | | |
| Class B2 = probable human carcinogen with inadequate human data but | | | |
| sufficient evidence of carcinogenicity in animals | | | |
| | | | |
| Class C = possible human carcinogens | | | |
| | | | |
| Class D = not classifiable as human carcinogens. | | | |
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