For aesthetic purposes, water shall be virtually free from substances producing objectionable color;
The source of the color should not exceed 75 color units in the standard platinum-cobalt scale for domestic water supply; and
Increased color (in combination with turbidity) should not reduce the depth of the zone of effective photosynthetic oxygen production by more than 10 percent from the seasonally established norm for aquatic life.
Water should contain sufficient dissolved oxygen to maintain aerobic conditions in the water column and, except as affected by natural phenomena, at the sediment-water interface for aesthetic purposes; and
A minimum concentration of dissolved oxygen to maintain good fish populations is 5 mg/L.
For bathing, swimming, and other body contact water recreation based on a minimum of five samples taken over 30 days, the fecal coliform bacteria should not exceed a log mean of 200 per 100 ml, nor should more than 10 percent of the total samples taken during any 30-day period exceed 400 per 100 ml; and The median fecal coliform bacteria concentration should not exceed 14 MPN (most probable number) per 100 ml with not more than 10 percent of samples exceeding 43 MPN per 100 ml for the harvesting of shellfish.
For health reasons domestic water supplies should not have nitrate nitrogen concentrations exceeding 10 mg/L (for humans).
For heath reasons domestic water supplies to be used by infants should not have nitrite nitrogen concentrations exceeding 1 mg/L.
Criteria for phosphorus from the EPA 1986 reference is explained in chapter 3 of this handbook. See 651.0302(a)(2)(ii), Effects of phosphorus in the aquatic environment.
Solids and turbidity: For freshwater fish and other aquatic life, settleable and suspended solids should not reduce the depth of the zone of photosynthetic oxygen production by more than 10 percent from the seasonally established norm.
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