Ambient Water Quality Guidelines for Chlorophenols

Water Quality

Ambient Water Quality Guidelines for Chlorophenols

10. RECREATION

10.1 General

There are no data documenting the effects of chlorophenols on recreational uses of water. Human taste and odour thresholds for some chlorophenols in water are available, Tables 6.2.1 and 6.2.2, as are taste thresholds for some chlorophenols in fish meat, Table 8.3.1. No taste thresholds for crustacean or mollusc meat are published for the chlorophenols.

PRIMARY CONTACT RECREATION

Since swimming involves intimate contact of the face with the water, taste and odour thresholds for the chlorophenols should be met in water used for swimming. Since these thresholds are the critical factors determining drinking water guidelines, the drinking water guidelines would give adequate protection to waters used for swimming.

SECONDARY CONTACT RECREATION

The critical activity which occurs in secondary contact recreational waters is the harvest of fish, molluscs and crustaceans for human consumption. If chlorophenols are present in appreciable quantities in the water, they accumulate in the flesh of organisms and impart an objectionable taste to the meat. One needs to back-calculate from known taste thresholds in the meat, available only for fish, Table 8.3.1, and not for molluscs or crustaceans. Using the known bioconcentration factors for edible tissues one can determine water levels for chlorophenols which would not result in taste problems in the fish. Using a safety factor of 10 to allow for people with greater taste sensitivity than those on the original taste panel, the numbers generated are generally higher than the guidelines for protection of the growth and reproduction of the organism. Thus, the aquatic life guidelines would take precedence and give adequate protection against taste problems in the edible tissues. There may be some marginal taste problems with filter feeders and bottom feeding fish, and 2,4-DCP at low temperatures, using the aquatic life guidelines.

AESTHETICS

For scenic and vista uses no guidelines are necessary; for close-up aesthetic uses the odour thresholds in water are appropriate. These vary with water temperature and are a function of molecular weight and volatility. The more chlorine substituents present, the lower the volatility and higher the threshold concentration for odour detection.

10.2 Recommended Guidelines

Water used for Primary Contact Recreation should meet Drinking Water Guidelines.

Water used for Secondary Contact Recreation should meet Aquatic Life Guidelines if fishing or harvesting of crustaceans or molluscs occurs, otherwise it should meet Aesthetics Guidelines.

Water designated for Aesthetic use should not exceed 0.3 µg/L MCPs or DCPs, 11 µg/L TCPs, 600 µg/L TTCPs and 860 µg/L PCP.

10.3 Rationale

The chlorophenols have objectionable tastes and/or odours above the drinking water guidelines. Such tastes and odours would also affect swimmers who have their faces immersed in water. Fish, molluscs and crustaceans are all harvested recreationally and all accumulate and concentrate chlorophenols in their tissues. These tissues then take on an objectionable taste. Thus water levels of the chlorophenols need to be below a value which could be bioconcentrated or biomagnified to an objectionable-tasting tissue level. These water levels are, however, generally higher than the aquatic life guidelines needed to protect fish, molluscs and crustaceans from chronic harm to their growth and reproduction. Thus the aquatic life guidelines would have to apply to any waters where such recreationally harvested organisms lived and would usually give adequate protection against tainted meat.

The lowest reported odour thresholds for chlorophenols in water are 0.33 µg/L for MCPs and DCPs, 11 µg/L for TCPs, 600 µg/L for TTCPs and 857 µg/L for PCP (Table 6.2.2). These values are close to the aquatic life guidelines for the smaller, less-substituted, more volatile MCPs and DCPs, but are very much higher than the aquatic life guidelines for the larger, saturated, less volatile PCP.


	Water Quality Ambient Water Quality Guidelines for Chlorophenols 10. RECREATION 10.1 General There are no data documenting the effects of chlorophenols on recreational uses of water. Human taste and odour thresholds for some chlorophenols in water are available, Tables 6.2.1 and 6.2.2, as are taste thresholds for some chlorophenols in fish meat, Table 8.3.1. No taste thresholds for crustacean or mollusc meat are published for the chlorophenols. PRIMARY CONTACT RECREATION Since swimming involves intimate contact of the face with the water, taste and odour thresholds for the chlorophenols should be met in water used for swimming. Since these thresholds are the critical factors determining drinking water guidelines, the drinking water guidelines would give adequate protection to waters used for swimming. SECONDARY CONTACT RECREATION The critical activity which occurs in secondary contact recreational waters is the harvest of fish, molluscs and crustaceans for human consumption. If chlorophenols are present in appreciable quantities in the water, they accumulate in the flesh of organisms and impart an objectionable taste to the meat. One needs to back-calculate from known taste thresholds in the meat, available only for fish, Table 8.3.1, and not for molluscs or crustaceans. Using the known bioconcentration factors for edible tissues one can determine water levels for chlorophenols which would not result in taste problems in the fish. Using a safety factor of 10 to allow for people with greater taste sensitivity than those on the original taste panel, the numbers generated are generally higher than the guidelines for protection of the growth and reproduction of the organism. Thus, the aquatic life guidelines would take precedence and give adequate protection against taste problems in the edible tissues. There may be some marginal taste problems with filter feeders and bottom feeding fish, and 2,4-DCP at low temperatures, using the aquatic life guidelines. AESTHETICS For scenic and vista uses no guidelines are necessary; for close-up aesthetic uses the odour thresholds in water are appropriate. These vary with water temperature and are a function of molecular weight and volatility. The more chlorine substituents present, the lower the volatility and higher the threshold concentration for odour detection. 10.2 Recommended Guidelines Water used for Primary Contact Recreation should meet Drinking Water Guidelines. Water used for Secondary Contact Recreation should meet Aquatic Life Guidelines if fishing or harvesting of crustaceans or molluscs occurs, otherwise it should meet Aesthetics Guidelines. Water designated for Aesthetic use should not exceed 0.3 µg/L MCPs or DCPs, 11 µg/L TCPs, 600 µg/L TTCPs and 860 µg/L PCP. 10.3 Rationale The chlorophenols have objectionable tastes and/or odours above the drinking water guidelines. Such tastes and odours would also affect swimmers who have their faces immersed in water. Fish, molluscs and crustaceans are all harvested recreationally and all accumulate and concentrate chlorophenols in their tissues. These tissues then take on an objectionable taste. Thus water levels of the chlorophenols need to be below a value which could be bioconcentrated or biomagnified to an objectionable-tasting tissue level. These water levels are, however, generally higher than the aquatic life guidelines needed to protect fish, molluscs and crustaceans from chronic harm to their growth and reproduction. Thus the aquatic life guidelines would have to apply to any waters where such recreationally harvested organisms lived and would usually give adequate protection against tainted meat. The lowest reported odour thresholds for chlorophenols in water are 0.33 µg/L for MCPs and DCPs, 11 µg/L for TCPs, 600 µg/L for TTCPs and 857 µg/L for PCP (Table 6.2.2). These values are close to the aquatic life guidelines for the smaller, less-substituted, more volatile MCPs and DCPs, but are very much higher than the aquatic life guidelines for the larger, saturated, less volatile PCP.