Review Articles
Chemicals Regulation Assessment
Chemicals Regulation A s s e s s m e n t
Environmental Hazard - Assessment of Chemicals and Products Part Ill: T h e Limits to Single C o m p o u n d Assessment
Walter Kl6pffer C. A. U. GmbH, Daimlerstrafle 23, D-63303 Dreieich/Frankfurt, Germany
Abstract Part III: The Limits to Single Compound Assessment The principles and basic assumptions of single compound assessment are briefly reviewed. Limitations to this approach are shown, especially with regard to complex mixtures of similar substances, substitution products, and complicated (final) products containing chemicals and materials produced by the chemical industry. A new thinking in product lines and life cycles is emerging, leading to new assessment methods. In some cases, substitution has not improved the environmental performance of products, since very similar chemicals were used as substitutes.
1
Introduction
Ten to twenty years ago, at the time when the Chemicals Laws were prepared and enacted in most industrialized nations, single compound assessment (SCA) was a considerable progress compared to the older practice of judging organic pollutants by sum-parameters. Although SCA has been very useful in identifying potentially dangerous chemicals and still is indispensable in regulating pesticides and all other substances, there are also limits to this method requiring the improvement of the established hazard assessment approach beyond the status reached [ 1 - 3]. It is the purpose of this paper to shortly review the basic principles of environmental SCA, based on results obtained by the OECD Hazard Assessment Programme [4] (-~ Section 2). Furthermore, a few case studies will be presented which demonstrate the shortcomings of SCA (-~ Section 3). Finally, suggestions will be presented how to improve the hazard assessment of chemicals in accordance with the requirements of modern environmental and chemistry policy ("Chemiepolitik") [1, 5, 6]. The latter aspect also belongs to the tasks of the Enquete Commission of the German Parliament (Bundestag) [33]. This commission is attempting to disentangle the complicated network of substance flows which are not only due to the activities of the chemical industry, but also to other activities within the technosphere such as traffic, energy supply, building, clothing, food production, leisure-time activities etc.. All these substance-related human activities occur against a background of natural chemical flows which partly overlap with the flows of synthetic chemicals. In this paper, which continues earlier articles [2, 3], only problems connected with synthetic (organic) chemicals are discussed. ESPR-Environ. Sci. & Pollut. Res. 1 (3) 179-184 (1994) 9 ecomed publishers, D-86899 Landsberg, Germany
2 2.1
Principles of Single C o m p o u n d Assessment (SCA) The hazard potential of chemicals
The SCA of chemicals with regard to environmental hazards rests on three basic assumptions: 1) The individual compounds are distributed in the environment independently from each other. 2) The compounds act on potential targets independently from each other. 3) The hazard posed by a substance can be estimated with the help of compound-related data on environmental exposure and (noxious) effects.
On the basis of assumptions 1 and 2, which are mostly accepted tacitly, a "Hazard" is attributed to single chemical compounds, which indicates the potential of a substance to harm the environment [2, 3, 7, 8]. Since this hazard can be derived from simple physical-chemical data and a few data on noxious effects, it is considered to be a kind of substance property [10]. According to OECD [4], hazard is defined as a function of (environmental) exposure and (noxious) effects (see also [2]). With regard to the effects it is essential that not only noxious effects toward living systems are considered, but also harmful effects toward inanimate systems [2, 4, 7]. This is also the view of a working party of the Society of German Chemists (GDCh) on environmental chemistry and ecotoxicity [9]. According to the same working group and in full agreement with principles layed down by OECD [4], exposure means distribution over all environmental compartments (transfer processes), taking into account biotic as well as abiotic degradation [9]. In order to estimate the hazard posed by a substance, exposure [14] and effects [15] have to be measured (if possible) or estimated. If the information thus obtained is sufficient to calculate a quantitative probability of occurrence for actual damages, this exercise may be called "Risk Assessment" in a strict sense [2, 7]. In the general case, however, this is not possible, so that only the potential of a substance to harm the environment (hazard) can be estimated. General criteria and methods of hazard assessment were discussed in Part I of this series [2], followed by a more detailed presentation of the central criterium in Part II [3], i.e. Persistence. A more advanced and comprehensive method of hazard assessment for single compounds is discussed in principle in the next section.
179
Chemicals Regulation Assessment 2.2
Review Articles
Comprehensive SCA
Ideally, a comprehensive SCA should be performed for each anthropogenic chemical. Given the great and increasing number of chemicals in commerce (more than 100 000), this approach is not feasible. Therefore, priority schemes for selecting potentially dangerous "existing" substances (the contrary of existing substances are "new" substances) were developed in several countries. The German exercise [16] has been followed by extensive data collection ("BUA-Reports", now available for 100 substances, i.e. roughly 1 % of the "existing" chemicals). For new substances, comprehensive SCA is required in the higher levels (1 + 2) of chemical testing and notification, but not for the base set or zero-level information. As an example of a comprehensive SCA, a small segment of the one developed by RlVVENet al. [11] for the German environmental agency, Berlin (UBA) is shown in Fig. 1. It shows that part of the scheme which is related to the compartment water
Discharge-pattern AI
Waste water
i
I J
p oducts?
I
li l
,, A1
r
( H +~'0.04)?
A ;Tts
W2
r
Amounts and I
t
Transformation-
concentrationsj
products?
- - ~ W2 if volatile b LI.1
a) Seawater
b) Freshwater W2"1
I
9 LH
I
Volatile? 9 L1.1
1
Transformationproducts ? ~ 9 W2 I
if vo~ati~e,, LH I
Iconcentrations a) S e a w a t e r I b) FreshWater
I
w~;2 I
H igher concentration a)Seawater b)Freshwater I Ecotoxic e f f e c t s ~ E f f e c t
a) Seawater b)Freshwater
J |
J
The segment shown in Fig. I includes the sub-compartments waste water (essentially a part of the technosphere [13]) and surface water (environment). The amounts and potential concentrations of the substance considered have to be calculated for the two sub-compartments. There are questions to be answered related to the following items: - possible transformation products - transfer to soil (B) and sediment (S), which are treated in separate schemes - volatility from sewage treatment plants and from surface waters into the atmosphere (treated in a separate scheme).
The concentrations of the substance in sea- and freshwater have to be estimated or measured, if feasible. These exposurerelated data are used for comparing with the effect data in this case toxic effects toward aquatic test-species (e.g. LCsodata for daphi~ia, fish, algae etc., as required by the Chemical Law). F!nally, the safety margins between the calculated (or measured) concentrations and the effect-related concentrations are determined. If these are smaller than 1 000, harm to aquatic organisms cannot be excluded according to this assessment (which is a tentative one). This is essentially the method recently adopted by the EU in an update of the European chemical legislation. Here, the hazard is expressed as the quotient PEC/NEC where PEC = Predicted Environmental Concentration and NEC = No Effect Concentration (or, if calculated PNEC = Predicted No Effect Concentration). Depending on the data available for the determination of NEC or PNEC (acute, chronic, number of species tested), the safety factor is variable, being highest if only acute data for one species are available and lowest if there are long-term observations on several species [15].
Surface water
Wl
ITransf~176
~F-g-1
accidental formation in the environment etc.; the discharge pattern has to be known, at least approximately, for the compartments water, soil, and air (the compartment sediment is in general reached only indirectly via water).
I
For reasons given in Part II [3], no safe limit can be given due to the general shortcomings of the single species testing approach. The data material necessary for comprehensive hazard assessment is presently available only for a few substances [2].
I
levels water
Chemicals Regulation Assessment
Chemicals Regulation A s s e s s m e n t
Environmental Hazard - Assessment of Chemicals and Products Part Ill: T h e Limits to Single C o m p o u n d Assessment
Walter Kl6pffer C. A. U. GmbH, Daimlerstrafle 23, D-63303 Dreieich/Frankfurt, Germany
Abstract Part III: The Limits to Single Compound Assessment The principles and basic assumptions of single compound assessment are briefly reviewed. Limitations to this approach are shown, especially with regard to complex mixtures of similar substances, substitution products, and complicated (final) products containing chemicals and materials produced by the chemical industry. A new thinking in product lines and life cycles is emerging, leading to new assessment methods. In some cases, substitution has not improved the environmental performance of products, since very similar chemicals were used as substitutes.
1
Introduction
Ten to twenty years ago, at the time when the Chemicals Laws were prepared and enacted in most industrialized nations, single compound assessment (SCA) was a considerable progress compared to the older practice of judging organic pollutants by sum-parameters. Although SCA has been very useful in identifying potentially dangerous chemicals and still is indispensable in regulating pesticides and all other substances, there are also limits to this method requiring the improvement of the established hazard assessment approach beyond the status reached [ 1 - 3]. It is the purpose of this paper to shortly review the basic principles of environmental SCA, based on results obtained by the OECD Hazard Assessment Programme [4] (-~ Section 2). Furthermore, a few case studies will be presented which demonstrate the shortcomings of SCA (-~ Section 3). Finally, suggestions will be presented how to improve the hazard assessment of chemicals in accordance with the requirements of modern environmental and chemistry policy ("Chemiepolitik") [1, 5, 6]. The latter aspect also belongs to the tasks of the Enquete Commission of the German Parliament (Bundestag) [33]. This commission is attempting to disentangle the complicated network of substance flows which are not only due to the activities of the chemical industry, but also to other activities within the technosphere such as traffic, energy supply, building, clothing, food production, leisure-time activities etc.. All these substance-related human activities occur against a background of natural chemical flows which partly overlap with the flows of synthetic chemicals. In this paper, which continues earlier articles [2, 3], only problems connected with synthetic (organic) chemicals are discussed. ESPR-Environ. Sci. & Pollut. Res. 1 (3) 179-184 (1994) 9 ecomed publishers, D-86899 Landsberg, Germany
2 2.1
Principles of Single C o m p o u n d Assessment (SCA) The hazard potential of chemicals
The SCA of chemicals with regard to environmental hazards rests on three basic assumptions: 1) The individual compounds are distributed in the environment independently from each other. 2) The compounds act on potential targets independently from each other. 3) The hazard posed by a substance can be estimated with the help of compound-related data on environmental exposure and (noxious) effects.
On the basis of assumptions 1 and 2, which are mostly accepted tacitly, a "Hazard" is attributed to single chemical compounds, which indicates the potential of a substance to harm the environment [2, 3, 7, 8]. Since this hazard can be derived from simple physical-chemical data and a few data on noxious effects, it is considered to be a kind of substance property [10]. According to OECD [4], hazard is defined as a function of (environmental) exposure and (noxious) effects (see also [2]). With regard to the effects it is essential that not only noxious effects toward living systems are considered, but also harmful effects toward inanimate systems [2, 4, 7]. This is also the view of a working party of the Society of German Chemists (GDCh) on environmental chemistry and ecotoxicity [9]. According to the same working group and in full agreement with principles layed down by OECD [4], exposure means distribution over all environmental compartments (transfer processes), taking into account biotic as well as abiotic degradation [9]. In order to estimate the hazard posed by a substance, exposure [14] and effects [15] have to be measured (if possible) or estimated. If the information thus obtained is sufficient to calculate a quantitative probability of occurrence for actual damages, this exercise may be called "Risk Assessment" in a strict sense [2, 7]. In the general case, however, this is not possible, so that only the potential of a substance to harm the environment (hazard) can be estimated. General criteria and methods of hazard assessment were discussed in Part I of this series [2], followed by a more detailed presentation of the central criterium in Part II [3], i.e. Persistence. A more advanced and comprehensive method of hazard assessment for single compounds is discussed in principle in the next section.
179
Chemicals Regulation Assessment 2.2
Review Articles
Comprehensive SCA
Ideally, a comprehensive SCA should be performed for each anthropogenic chemical. Given the great and increasing number of chemicals in commerce (more than 100 000), this approach is not feasible. Therefore, priority schemes for selecting potentially dangerous "existing" substances (the contrary of existing substances are "new" substances) were developed in several countries. The German exercise [16] has been followed by extensive data collection ("BUA-Reports", now available for 100 substances, i.e. roughly 1 % of the "existing" chemicals). For new substances, comprehensive SCA is required in the higher levels (1 + 2) of chemical testing and notification, but not for the base set or zero-level information. As an example of a comprehensive SCA, a small segment of the one developed by RlVVENet al. [11] for the German environmental agency, Berlin (UBA) is shown in Fig. 1. It shows that part of the scheme which is related to the compartment water
Discharge-pattern AI
Waste water
i
I J
p oducts?
I
li l
,, A1
r
( H +~'0.04)?
A ;Tts
W2
r
Amounts and I
t
Transformation-
concentrationsj
products?
- - ~ W2 if volatile b LI.1
a) Seawater
b) Freshwater W2"1
I
9 LH
I
Volatile? 9 L1.1
1
Transformationproducts ? ~ 9 W2 I
if vo~ati~e,, LH I
Iconcentrations a) S e a w a t e r I b) FreshWater
I
w~;2 I
H igher concentration a)Seawater b)Freshwater I Ecotoxic e f f e c t s ~ E f f e c t
a) Seawater b)Freshwater
J |
J
The segment shown in Fig. I includes the sub-compartments waste water (essentially a part of the technosphere [13]) and surface water (environment). The amounts and potential concentrations of the substance considered have to be calculated for the two sub-compartments. There are questions to be answered related to the following items: - possible transformation products - transfer to soil (B) and sediment (S), which are treated in separate schemes - volatility from sewage treatment plants and from surface waters into the atmosphere (treated in a separate scheme).
The concentrations of the substance in sea- and freshwater have to be estimated or measured, if feasible. These exposurerelated data are used for comparing with the effect data in this case toxic effects toward aquatic test-species (e.g. LCsodata for daphi~ia, fish, algae etc., as required by the Chemical Law). F!nally, the safety margins between the calculated (or measured) concentrations and the effect-related concentrations are determined. If these are smaller than 1 000, harm to aquatic organisms cannot be excluded according to this assessment (which is a tentative one). This is essentially the method recently adopted by the EU in an update of the European chemical legislation. Here, the hazard is expressed as the quotient PEC/NEC where PEC = Predicted Environmental Concentration and NEC = No Effect Concentration (or, if calculated PNEC = Predicted No Effect Concentration). Depending on the data available for the determination of NEC or PNEC (acute, chronic, number of species tested), the safety factor is variable, being highest if only acute data for one species are available and lowest if there are long-term observations on several species [15].
Surface water
Wl
ITransf~176
~F-g-1
accidental formation in the environment etc.; the discharge pattern has to be known, at least approximately, for the compartments water, soil, and air (the compartment sediment is in general reached only indirectly via water).
I
For reasons given in Part II [3], no safe limit can be given due to the general shortcomings of the single species testing approach. The data material necessary for comprehensive hazard assessment is presently available only for a few substances [2].
I
levels water
