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Ecotoxicological information

Ecotoxicological Summary

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Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:
no data: aquatic toxicity unlikely

Marine water

Hazard assessment conclusion:
no data: aquatic toxicity unlikely

STP

Hazard assessment conclusion:
no data: aquatic toxicity unlikely

Sediment (freshwater)

Hazard assessment conclusion:
no exposure of sediment expected

Sediment (marine water)

Hazard assessment conclusion:
no exposure of sediment expected

Hazard for air

Air

Hazard assessment conclusion:
no hazard identified

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:
no exposure of soil expected

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:
PNEC oral
PNEC value:
70 mg/kg food
Assessment factor:
90

Additional information

Aquatic toxicity is unlikey because the expected concentrations are insignificant. The production of Resin 835A and its uses by downstream users do not require water and therefore the release of Resin 835A into the effluent is minimal. For the production of Resin 835A a waste water volume of <5 l/day was estimated. Considering a water solubility of <1 mg/l, <5 mg Resin 835A per day would be released by waste water.

The substance is inherently degradable. 54 % are biodegraded (to CO2) within 28 d in a test for ready biodegradability under its strict conditions, so that it can be assumed that Resin 835A is completely mineralized in a WWTP by adapted microorganisms and only a negligible concentration is expected in the effluent and thereby in the receiving river.

But even if no or an ineffective WWTP would be assumed, a concentration of 5 mg/18000 m3 corresponding to 2.8.10-7mg/l is calculated for the receiving water, that is according to EUSES a small ditch having by default a flow of 18000 m3/d. This concentration in the receiving river again is considered to be negligible.

Using more realistic flow rates of receiving rivers at industrial sites and an effective WWTP would results in a concentration in fresh water of probably far below 10-10 mg/l.

The logPow of Resin 835A is high if the Resin is in the undissociated state. The dissociation constant was calculated to 5.1 so that at environmentally relevant pH in the neutral range the sparingly dissoluted substance will be in the dissociated state, which would result in a much lower logPow. Although formally a candidate for a bioaccumulative substance it is under realistic conditions probably not bioaccumulative.

This matches with the determined relatively low adsorption coefficient of logKoc of >0.9 to <2 at pH 6.5 (an environmentally relevant pH). The adsorption coefficient points to a ca. 10 to 100 times higher concentration in sediment and soil than in water, so that the concentrations in soil and sediment are still very low and are also considered to be insignificant.

Resin 835A has a vapour pressure of ≤0.0001 Pa at 25 °C. A relevant evaporation and a transport of the substance by air is therefore considered to be not relevant.

As Resin 835A is a sticky substance produced and used as flakes, no dust and no transfer of dust by air is expected.

Solid wastes are also not expected from experience. Possibly occuring solid wastes will be incinerated and will not be released to the environment.

One short term test result (and on long term for algae) is available for each of the three trophic levels. Daphnia: EC50;48h: 3.2 mg/L; Algae: EC50;72h: >15.9 mg/L; Fish: LC50;96h: 60.3 mg/L. Each of the EC50s is above the solubility limit of Resin 835A of <1 mg/L, which raises doubts on the validity of the test results for Resin 835A and its relevance for risk assessment purposes.

Conclusion on classification

One short term (respective long term for algae) test result is available for each of the three trophic levels.
Daphnia EC50,48h: 3.2 mg/L; Algae EC50,72h: >15.94 mg/L; Fish LC50,96h: 60.3 mg/L.
Each of the aquatic EC50s is above the solubility limit of Resin 835A of <1 mg/L, which raises doubts on the validity of the test results for classification and risk assessment purposes and therefore a clear cut classification is not possible.

According to the CLP regulation Resin 835A could - at first sight - be classified in the Safety Net classification Chronic Category 4 (and not in Category 2), because of the criteria of Category 4, i.e. "no acute toxicity is recorded at levels up to the water solubility" for "poorly soluble substances" (water solubility <1 mg/l), and the substance is "not rapidly degradable and have an experimentally determined BCF ≥ 500 (or, if absent, a log Kow ≥ 4)".

"No acute toxicity is recorded at levels up to the water solubility":This applies to Resin 835A, see above.

"Not rapidly degradable" also applies as the substance is biodegraded in a test for ready biodegradability to 54 % within 28 days. Although, there are papers available that for such an UVCB-substance, and also for closely related substances such as Rosin, other criteria should be applied because the degradation of the single substances included in the UVCB substance are degraded one after the other under the strict conditions of the ready biodegradability tests and therefore need more time for degradation (expressed by the 54 % for Resin 835A just not reaching the threshold of 60 %) compared to environmental conditions or even more to conditions in a sewage treatment plant.

"log Kow ≥ 4": The logPow of Resin 835A is high (≤6.5) if Resin 835A is in the undissociated state. The dissociation constant was calculated to 5.1 so that at environmentally relevant pH in the neutral range the sparingly dissoluted substance will be in the dissociated state, which would result in a much lower logPow. This is endorsed from experimental determinations of the adsorption coefficient soil/water of Resin 835A resulting in the relatively low logKoc >0.9 to <2 at pH 6.5, which is an environmentally relevant pH. This low logKoc would not be expected only considering the log Pow of ≤6.5. Although formally a candidate for a bioaccumulative substance, Resine 835A is under realistic conditions probably not bioaccumulative.

Taking the last considerations into account it is now - in a second sight - not so clear that a classification Chronic Category 4 is justified and even more that Category 2 is justified.

Further arguments stated in the classification criteria in the CLP regulation are now used in a third sight of this weight of evidence approach:

Substances "will be classified in this category(4)unless other scientific evidence exists showing classification to be unnecessary. Such evidence includes chronic toxicity NOECs > water solubility or > 1 mg/l, or evidence of rapid degradation in the environment."
There is a chronic toxicity NOEC of ≥15.94 mg/l available from the algae study, which is clearly above the water solubility of Resin 835A and clearly above 1 mg/L, thereby fulfilling the criterium.
And there are also indications that Resin 835A will be rapidly degraded in the environment (compared to the not sufficiently rapid degradation under the strict conditions of a laboratory experiment for ready biodegradation).

Altogether, on a weight of evidence basis, it is considered not to classify Resin 835A according to its aquatic toxicity.