Ambient Water Quality Guidelines for Chlorophenols

Water Quality

Ambient Water Quality Guidelines for Chlorophenols

1. INTRODUCTION

1.1 Preamble

BC Environment (now called Water, Land and Air Protection) is developing province-wide ambient water quality guidelines for variables that are important in the surface waters of British Columbia. This work has the following goals:

to provide guidelines for the evaluation of data on water, sediment, and biota;
to provide guidelines for the establishment of site-specific ambient water quality objectives.

The ambient water quality objectives for specific waterbodies are based on the guidelines, as well as on present and future water uses, waste discharges, hydrology, limnology, oceanography, and existing background water quality. The process for establishing water quality objectives is more fully outlined in Principles for Preparing Water Quality Objectives in British Columbia, copies of which are available from the Water Quality Branch, Water Management Division.

Neither guidelines, nor the objectives which are derived from them, have any legal standing. The objectives can be used in calculating the limits to be allowed in waste discharges. These limits are set out in waste management permits which do have legal standing. The objectives are not usually incorporated as conditions of the permit.

The definition adopted for guideline is: "A maximum and/or a minimum value for a physical, chemical or biological characteristic of water, sediment or biota, which should not be exceeded to prevent specified detrimental effects from occurring to a water use, including aquatic life, under specified environmental conditions."

The guidelines are applied province-wide, but are use-specific, and are being developed for the following water uses:

Drinking, public water supply, and food processing
Aquatic life and wildlife
Agriculture (livestock watering and irrigation)
Recreation and aesthetics
Industrial (water supplies)

The guidelines apply to the ambient raw water source before it is diverted or treated for domestic use. The Ministry of Health regulates the quality of water for domestic use after it is treated and delivered by a water purveyor. Guidelines relating to public health at bathing beaches will be the same as those used by the Ministry of Health which regulates their use.

The guidelines are set after considering the scientific literature, guidelines from other jurisdictions, and general conditions in British Columbia. The scientific literature gives information on the effects of toxicants on various life forms. This information is not always conclusive because it is usually based on laboratory work which, at best, only approximates actual field conditions. To compensate for this uncertainty, guidelines have built-in safety factors which are conservative but reflect natural background conditions in the province.

Given this procedure for setting guidelines, the objectives will, in most cases, be the same as the guidelines. However, in some cases, such as when natural background levels exceed the guidelines, the objectives could be less stringent than the guidelines. In relatively rare instances, for example if the resource is unusually valuable or of special provincial significance, the safety factor could be increased by using objectives which are more stringent than the guidelines. Another approach in such special cases would be to develop site-specific guidelines by carrying out toxicity experiments in the field. However, this approach is costly and time-consuming and therefore seldom used. The guidelines will be subject to review and revision as new information becomes available, existing data is proven unreliable or as other circumstances dictate.

1.2 Literature Reviews

A major literature review on the effects of various chemicals, including chlorophenols, on microorganisms, was carried out by Walker in 1988 (241). Other major reviews on chlorophenols were done by Jones in 1981 (8), Jones in 1984 (91), McKee et al. in 1984 (220), IJC in 1980 (258), Krijgsheld et al. in 1986 (335), EPA in 1979 (257), EPS in 1988 (289),Ware in 1988 (405) and NRCC in 1982 (321).

The following computerized data bases were, at least in part, also consulted in carrying out this literature review: PROPERTIES (428), CESARS (422), LOG P (420), ACQUIRE (419), RTECS (418) and ENVIROFATE (459). Many references were consulted through these data bases and the original papers were not read.

The large number of references cited in this report is not by any means exhaustive in this field. The literature on chlorophenols is enormous and has only been sampled. The literature is also selective. Of the chlorophenol congeners, pentachlorophenol (PCP) is by far the most studied. Several of the dichlorophenols (DCPs) and trichlorophenols (TCPs) are virtually ignored.
The pharmacokinetics of chlorophenols in rats and mice have been studied in detail. The effects of chlorophenols on freshwater fish have been well documented, but effects on other groups of organisms, such as amphibians, which appear to be quite sensitive, are poorly understood. Many subjects dealt with in this report, such as recreation, industrial use and irrigation, are virtually ignored by the literature.

1.3 Chlorophenols

There are 19 different chlorophenols (CPs) depending upon the number and arrangement of chlorine atoms on the parent phenol ring; only eight are of major commercial significance. As a group, all the chlorophenols are referred to as different congeners; those with the same number of chlorine atoms are isomers of each other.

Many commercial products contain chlorophenols, often in complex mixtures, and have often been contaminated with the more toxic dioxins and other organic compounds. It may be difficult in some cases to determine whether the observed toxicity results from the chlorophenols or from the contaminants.

Chlorophenols are used as broad-spectrum pesticides, and all act by uncoupling oxidative phosphorylation from respiration. This affects all aerobic, eukaryotic life in essentially the same way, and permits extrapolation of experimental data to organisms not specifically tested. The main reason for different LC50 values in various groups of organisms is the variable efficiency of net uptake, accumulation, and transfer to the mitochondria, which are the sites of chlorophenol action.

Chlorination of phenol greatly increases the toxicity of the resulting molecules relative to phenol. Generally, molecules with more chlorines are more toxic, due mainly to higher fat solubility as indicated by higher octanol/water coefficients ( K o/w ) values, resulting in greater uptake by organisms.

Table 1.3 gives the relative toxicity of many chlorophenols, in several biological test systems, relative to PCP being assigned a value of 1000. These values have been back-calculated from published LC50, IC50, LD50 and EC50 values, which indicate the dose or concentration of a chemical at which one half the test organisms were affected. Inspection of this table shows how much variability there is in the toxicity of any compound to different organisms, and how different end-point measures affect the magnitude of the numbers generated. A brief description of the test systems, A to P follows:

A is 24-h IC₅₀ data for Daphnia magna
B is 96-h LC₅₀ data for Poecilia reticulata
C is EC₅₀ data for Chlorella pyrenoidosa
D is 48-h LC₅₀ data for Daphnia magna
E is EC₅₀ data for Lemna minor
F is 24-h LC₅₀ data for Carassius auratus
G is EC₅₀ data for rat liver enzymes
H is LD₅₀ data for rat intraperitoneal injections
I is LC₅₀ data for Pimephales promelas
J is EC₅₀ data for Tetrahymena pyriformis
K is EC₅₀ data for Trichoderma viride
L is EC₅₀ data for Raphanus sativus
M is EC₅₀ data for Sorghum sudanense
N is 96-h LC₅₀ data for Palaemonetes pugio (intermolt)
O is 96-h LC₅₀ data for Palaemonetes pugio (molt)
P is 24-h LC₅₀ data for Salmo trutta

1.4 Registration

A British Columbia Ministry of Environment News Release (Aug. 30, 1989:109) reported that an August 24, 1989 Antisapstain Chemical Waste Control Regulation restricted levels in water discharged from lumber storage areas, to 6 µg/L (404). Revisions adopted on August 30, 1990 maintained these restrictions. Holland suspended the use of chlorophenols for indoor wood treatment. Canada, Denmark, Germany and Japan have suspended or restricted agricultural uses. Sweden banned all uses of chlorophenols in 1977 and Germany followed in 1987 (199). On August 1, 1990 Agriculture Canada terminated all sapstain control uses of TTCP and PCP effective December 31, 1990. Heavy duty wood preservation for outdoor use using chlorophenols is the only registered use and is presently being re-evaluated in Canada.

The United States cancelled registration of chlorophenols for herbicidal and anti-microbial uses, and for the preservation of wood in contact with food, feed, animals and livestock. Only certified applicators may use the product. Registration has been cancelled for use as a biocide in the wet end of paper production, and most other uses have also been proposed for cancellation. Even uses for lumber preservation and anti-sapstain fungal treatments are being, or have been, phased out as replacement preservatives are found. Only heavy timber and pole uses are being considered for retention.


	Water Quality Ambient Water Quality Guidelines for Chlorophenols 1. INTRODUCTION 1.1 Preamble BC Environment (now called Water, Land and Air Protection) is developing province-wide ambient water quality guidelines for variables that are important in the surface waters of British Columbia. This work has the following goals: to provide guidelines for the evaluation of data on water, sediment, and biota; to provide guidelines for the establishment of site-specific ambient water quality objectives. The ambient water quality objectives for specific waterbodies are based on the guidelines, as well as on present and future water uses, waste discharges, hydrology, limnology, oceanography, and existing background water quality. The process for establishing water quality objectives is more fully outlined in *Principles for Preparing Water Quality Objectives in British Columbia, copies of which are available from the Water Quality Branch, Water Management Division. Neither guidelines, nor the objectives which are derived from them, have any legal standing. The objectives can be used in calculating the limits to be allowed in waste discharges. These limits are set out in waste management permits which do have legal standing. The objectives are not usually incorporated as conditions of the permit. The definition adopted for guideline is: "A maximum and/or a minimum value for a physical, chemical or biological characteristic of water, sediment or biota, which should not be exceeded to prevent specified detrimental effects from occurring to a water use, including aquatic life, under specified environmental conditions." The guidelines are applied province-wide, but are use-specific, and are being developed for the following water uses: Drinking, public water supply, and food processing Aquatic life and wildlife Agriculture (livestock watering and irrigation) Recreation and aesthetics Industrial (water supplies) The guidelines apply to the ambient raw water source before it is diverted or treated for domestic use. The Ministry of Health regulates the quality of water for domestic use after it is treated and delivered by a water purveyor. Guidelines relating to public health at bathing beaches will be the same as those used by the Ministry of Health which regulates their use. The guidelines are set after considering the scientific literature, guidelines from other jurisdictions, and general conditions in British Columbia. The scientific literature gives information on the effects of toxicants on various life forms. This information is not always conclusive because it is usually based on laboratory work which, at best, only approximates actual field conditions. To compensate for this uncertainty, guidelines have built-in safety factors which are conservative but reflect natural background conditions in the province. Given this procedure for setting guidelines, the objectives will, in most cases, be the same as the guidelines. However, in some cases, such as when natural background levels exceed the guidelines, the objectives could be less stringent than the guidelines. In relatively rare instances, for example if the resource is unusually valuable or of special provincial significance, the safety factor could be increased by using objectives which are more stringent than the guidelines. Another approach in such special cases would be to develop site-specific guidelines by carrying out toxicity experiments in the field. However, this approach is costly and time-consuming and therefore seldom used. The guidelines will be subject to review and revision as new information becomes available, existing data is proven unreliable or as other circumstances dictate. 1.2 Literature Reviews* A major literature review on the effects of various chemicals, including chlorophenols, on microorganisms, was carried out by Walker in 1988 (241). Other major reviews on chlorophenols were done by Jones in 1981 (8), Jones in 1984 (91), McKee et al. in 1984 (220), IJC in 1980 (258), Krijgsheld et al. in 1986 (335), EPA in 1979 (257), EPS in 1988 (289),Ware in 1988 (405) and NRCC in 1982 (321). The following computerized data bases were, at least in part, also consulted in carrying out this literature review: PROPERTIES (428), CESARS (422), LOG P (420), ACQUIRE (419), RTECS (418) and ENVIROFATE (459). Many references were consulted through these data bases and the original papers were not read. The large number of references cited in this report is not by any means exhaustive in this field. The literature on chlorophenols is enormous and has only been sampled. The literature is also selective. Of the chlorophenol congeners, pentachlorophenol (PCP) is by far the most studied. Several of the dichlorophenols (DCPs) and trichlorophenols (TCPs) are virtually ignored. The pharmacokinetics of chlorophenols in rats and mice have been studied in detail. The effects of chlorophenols on freshwater fish have been well documented, but effects on other groups of organisms, such as amphibians, which appear to be quite sensitive, are poorly understood. Many subjects dealt with in this report, such as recreation, industrial use and irrigation, are virtually ignored by the literature. 1.3 Chlorophenols There are 19 different chlorophenols (CPs) depending upon the number and arrangement of chlorine atoms on the parent phenol ring; only eight are of major commercial significance. As a group, all the chlorophenols are referred to as different congeners; those with the same number of chlorine atoms are isomers of each other. Many commercial products contain chlorophenols, often in complex mixtures, and have often been contaminated with the more toxic dioxins and other organic compounds. It may be difficult in some cases to determine whether the observed toxicity results from the chlorophenols or from the contaminants. Chlorophenols are used as broad-spectrum pesticides, and all act by uncoupling oxidative phosphorylation from respiration. This affects all aerobic, eukaryotic life in essentially the same way, and permits extrapolation of experimental data to organisms not specifically tested. The main reason for different LC50 values in various groups of organisms is the variable efficiency of net uptake, accumulation, and transfer to the mitochondria, which are the sites of chlorophenol action. Chlorination of phenol greatly increases the toxicity of the resulting molecules relative to phenol. Generally, molecules with more chlorines are more toxic, due mainly to higher fat solubility as indicated by higher octanol/water coefficients ( K o/w ) values, resulting in greater uptake by organisms. Table 1.3 gives the relative toxicity of many chlorophenols, in several biological test systems, relative to PCP being assigned a value of 1000. These values have been back-calculated from published LC50, IC50, LD50 and EC50 values, which indicate the dose or concentration of a chemical at which one half the test organisms were affected. Inspection of this table shows how much variability there is in the toxicity of any compound to different organisms, and how different end-point measures affect the magnitude of the numbers generated. A brief description of the test systems, A to P follows: A is 24-h IC₅₀ data for Daphnia magna B is 96-h LC₅₀ data for Poecilia reticulata C is EC₅₀ data for Chlorella pyrenoidosa D is 48-h LC₅₀ data for Daphnia magna E is EC₅₀ data for Lemna minor F is 24-h LC₅₀ data for Carassius auratus G is EC₅₀ data for rat liver enzymes H is LD₅₀ data for rat intraperitoneal injections I is LC₅₀ data for Pimephales promelas J is EC₅₀ data for Tetrahymena pyriformis K is EC₅₀ data for Trichoderma viride L is EC₅₀ data for Raphanus sativus M is EC₅₀ data for Sorghum sudanense N is 96-h LC₅₀ data for Palaemonetes pugio (intermolt) O is 96-h LC₅₀ data for Palaemonetes pugio (molt) P is 24-h LC₅₀ data for Salmo trutta *1.4 Registration* A British Columbia Ministry of Environment News Release (Aug. 30, 1989:109) reported that an August 24, 1989 Antisapstain Chemical Waste Control Regulation restricted levels in water discharged from lumber storage areas, to 6 µg/L (404). Revisions adopted on August 30, 1990 maintained these restrictions. Holland suspended the use of chlorophenols for indoor wood treatment. Canada, Denmark, Germany and Japan have suspended or restricted agricultural uses. Sweden banned all uses of chlorophenols in 1977 and Germany followed in 1987 (199). On August 1, 1990 Agriculture Canada terminated all sapstain control uses of TTCP and PCP effective December 31, 1990. Heavy duty wood preservation for outdoor use using chlorophenols is the only registered use and is presently being re-evaluated in Canada. The United States cancelled registration of chlorophenols for herbicidal and anti-microbial uses, and for the preservation of wood in contact with food, feed, animals and livestock. Only certified applicators may use the product. Registration has been cancelled for use as a biocide in the wet end of paper production, and most other uses have also been proposed for cancellation. Even uses for lumber preservation and anti-sapstain fungal treatments are being, or have been, phased out as replacement preservatives are found. Only heavy timber and pole uses are being considered for retention.