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There is a relatively large amount of aquatic toxicity data available for LCCPs. Aquatic toxicity testing is problematic due to the very low water solubility of LCCPs. In many instances it is uncertain whether saturated test solutions contained undissolved test substance.It is likely that themethods used in some tests (e.g., water accommodated fraction) to prepare test solutions may result in the more soluble components (ie those with shorter chainlengths) present in the commercial LCCP being preferentially represented in the resultant solution. These, and the fact that any effects observed were near the limit of water solubility, complicate interpretation of test results. The substances in the category generally show little or no toxicity at concentrations well in excess of their water solubility in acute tests. Available acute test results are as follows.

 

C18-20LCCPs

Fish (96h): no effects at limit of solubility

Daphnia magna(48-h): no effects at solubility limit in one of two studies; 15% immobilisation in another study in a saturated solution (400500 ug/l, measured). (However these effectsare likely to be physical effects rather than direct toxicity of the substance itself).

C20 -30liquid LCCPs

Fish (96-h): no effects at limit of solubility

Daphnia magna(48h): no effects at limit of solubility

C20-30solid LCCPs

Fish (96-h): no effects at limit of solubility

  

No study is available for C20-30solid LCCPs, but no effects are expected given no effects were seen with C20-30liquid LCCPs. No valid algal study exists for any of the LCCPs, but data from related chlorinated paraffins (SCCPs and MCCPS) suggest that LCCPs would show no effects on algae. The overall toxicity profile of these substances (SCCP, MCCP, LCCPs) suggest that filling this data gap is not critical for the environmental assessment. 

 

Chronic studies in fish are available for C20-30liquid and solid LCCPs. No effects were seen in the tests (NOECs equating to the highest concentrations tested were reported: 4 mg/l nominal and 3.8 mg/l nominal). The results may be read across to C18-20LCCPs.

Daphnia magna has been identified as the most sensitive species for chlorinated paraffins as a substance class. Two studies are available which investigated chronic toxicity toDaphnia magnafrom C18-20LCCPs. One showed no effects at a saturation limit of 2 ug/L (measured) and the other, which followed a water-accommodated fraction technique, showed effects at 58‑65 µg/L and no effects at 29 – 32 ug/L (measured). Based on these data, the worst case assumption is that the NOEC for C18 -20LCCPs for Daphnia magna is 29 μg/L (which is above many estimates of water solubility for LCCPs). Available chronic studies with C20-30 liquid LCCPs in Daphnia magnaindicate no effects are observed below the limit of water solubility; the same conclusion can be read across to C20-30solid LCCPs.