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Ecotoxicological information

Toxicity to soil macroorganisms except arthropods

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Administrative data

Endpoint:
toxicity to soil macroorganisms except arthropods: long-term
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Secondary source; data review and critical evaluation, acceptable for assessment

Data source

Reference
Reference Type:
review article or handbook
Title:
Unnamed
Year:
2008

Materials and methods

Principles of method if other than guideline:
Determination of terrestrial toxicity of single polycyclic aromatic hydrocarbons (PAH) towards various soil-dwelling organisms: No toxicity values of pitch itself in soil are available. The exclusive consideration of PAH data is justified as follows:
1. Coal-tar pitch is a UVCB substance consisting of polycyclic aromatic structures, some 10 % of which can be identified as PAH by GC
2. Pitch is water insoluble and thus not bioavailable or only to very limited extent.
3. Direct and indirect environmental exposure by pitch is very unlikely.
4. Environmental exposure may occur only through release of PAHs during application.
GLP compliance:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Type:
Constituent
Details on test material:
Main components in coal-tar pitch identifyable and quantifiable by GC:
CAS-No. Concentration [%w/w] *
=====================================
Phenanthrene 85-01-8 0.25 - 0.30
Anthracene 120-12-7 ~ 0.06
Fluoranthene 206-44-0 0.7 - 0.85
Pyrene 129-00-0 0.6 - 0.75
Benz(a)anthracene 56-55-3 0.6 - 0.7
Chrysene 218-01-9 0.8 - 0.85
Benzo(a)pyrene 50-32-8 0.8- 1.1
=====================================
* Concentrations in coal-tar pitch CS08 (GC analysis)

Sampling and analysis

Details on sampling:
not applicable: Analytical monitoring depending on each investigation

Test substrate

Details on preparation and application of test substrate:
not applicable: study specific

Test organisms

Test organisms (species):
other: Eisenia sp.; Enchytraeus sp.; Folsomia sp.; Oniscus and Porcellio sp.
Animal group:
other: annelida, collembola; crustacea
Details on test organisms:
--

Study design

Study type:
laboratory study
Substrate type:
other: study-specific
Limit test:
no
Remarks:
not applicable: study-specific
Post exposure observation period:
--

Test conditions

Details on test conditions:
not applicable: study-specific
Nominal and measured concentrations:
not applicable: study specific

Results and discussion

Details on results:
Results are summarised under the EP summary "Terrestrial toxicity"
Reported statistics and error estimates:
not applicable

Applicant's summary and conclusion

Conclusions:
Calculation of Predicted No Effect Concentration (PNEC)
The EC10 of 0.53 mg/kgdw for growth efficiency of the isopod Porcellio scaber is used as endpoint for the PNEC. Because chronic toxicity data are available for annelids, crustaceans, and collembola, an assessment factor of 10 can be applied. The PNEC thus becomes 0.053 mg/kgdw. In view of the high extrapolation factor, this PNEC might be overconservative.
Executive summary:

Excerpt from EU 2008: Risk Assessment Report on Coa-Tar Pitch, final draft [R323_0805_ENV_FINAL_ECB.DOC]

3.2.2.1.4 Benzo(a)pyrene

Chronic toxicity studies with B(a)P are available for 2 species each of terrestrial annelids, crustaceans, and collembola. No effects were found for the studies with Folsomia species (Sverdrup et al., 2002; Bleeker et al., 2003 , Droge et al., 2006). For annelids, effects were observed in one study only, with Eisenia fetida being slightly more sensitive than Enchytraeus crypticus (Achazi et al., 1995). The NOECs for reproduction are 2.6 and 8.7 mg/kgdw respectively, recalculated to a soil with 2% organic carbon. For the crustaceans Oniscus asellus and Porcellio scaber effects were observed in tests that were conducted in contaminated food with a organic matter content of more than 90% (Van Straalen & Verweij, 1991; Van Brummelen & Stuijfzand, 1992; Van Brummelen et al., 1996). This way of exposure introduces a large extrapolation to a soil with 3.4% organic matter (2% organic carbon). No significant effects on growth of Oniscus assellus were observed in a 47-w study up to concentrations of 12 mg/kgdw, recalculated to a soil with 2% organic carbon (Van Brummelen et al., 1996). In a 9-w study, however, effects were observed (Van Brummelen & Stuijfzand, 1992). The NOEC for weight and length is 1.2 mg/kgdw and for mortality 3.8 mg/kgdw in standard soil. The EC10s derived from the presented data for wet and dry weight, and length vary from 2.8 to 4.2 mg/kgdw. For Porcellio scaber too no significant effects on growth were observed in a 47-w study up to concentrations of 12 mg/kgdw, recalculated to a soil with 2% organic carbon (Van Brummelen et al., 1996). Also in this case in the 9-w study effects were observed (Van Brummelen & Stuijfzand, 1992). The NOEC for weight is 1.2 mg/kgdw but for length no significant effects were observed at concentrations of up to 12 mg/kgdw, recalculated to a soil with 2% organic carbon. Although in this case no firm dose-response relationships could be derived from the presented data, a decrease in fresh weight, length, and dry weight of more than 10% appears from these data at concentrations higher than 0.12 mg/kgdw, recalculated to a soil with 2% organic carbon. At higher concentrations these parameters remain more or less constant. The absence of a clear dose-response curve might be the result of the limited solubility of B(a)P. If it is assumed that uptake of the compounds occurs via the aqueous phase, the further uptake and hence more effect can be limited by the aqueous solubility of B(a)P of 1.2-1.8 μg/l (Mackay et al., 2000). In a third study, the growth efficiency was studied during 4 weeks (Van Straalen & Verweij, 1991). Growth efficiency was expressed as increase of dry weight divided by the difference between the consumption of food and defecation. Because the consumption of food and the assimilation efficiency were more or less constant for both male and female isopods, the growth efficiency mainly represents the increase in dry weight. The NOEC for growth efficiency of male isopods is 0.94 mg/kgdw, extrapolated to 2% organic carbon. A clear dose-response curve is presented. From the presented figure an EC10 of 0.53 mg/kgdw in standard soil is estimated with a log-logistic model. For female isopods no significant effects were observed at the highest concentration of 4.7 mg/kgdw recalculated to standard soil. However, for females a strong increase is observed for the growth efficiency at the two lowest concentrations. In comparison with these concentrations the growth efficiency declines strongly after 0.2 mg/kgdw in standard soil. Due to the initial increase in growth efficiency the fit of the log-logistic dose-response curve is not as good as for male isopods. However, similar values are obtained for the EC50 and EC10. The EC10 for growth efficiency of male isopods of 0.53 mg/kgdw is comparable with the concentrations at which 10% effect or more was observed in the study by Van Brummelen & Stuijfzand (1992). In this study by Van Straalen & Verweij (1991) the food was refreshed once a week. The concentrations were expressed as nominal concentrations. Initial concentrations were more than 90% of the nominal concentrations.