The impact of algal toxicity on life-cycle impact assessment of plastic additives and the potential of using QSAR predictions to fill the algae data gap

Abstract: Purpose There is a need to find a quick way to assess the impacts of the growing amount of globally manufactured and emitted chemical substances. This paper evaluates the use of Quantitative Structure Activity Relationships (QSAR) for predicting environmental effects of plastic additives in Life Cycle Impact Assessment (LCIA). It also evaluates the impact on so called Characterization Factors (CF) when including toxicity on algae as opposed to only chordate and arthropod. Method A review concluded that few (39) toxicity data for algae (experimental and QSAR predicted) were available for the 159 plastic additives of concern. To fill the data gap, a QSAR for algal toxicity was constructed that was able to predict toxicity for 54 substances. CFs were calculated and assessed based on; 1. QSAR predicted data for arthropod and chordate, 2. QSAR predicted data for arthropod, chordate and algae and 3. Experimental data for all three phyla. Results and discussion CFs could be calculated considering algal toxicity for totally 97 out of the 159 substances. Algae were overall less sensitive to the substances leading to lower CFs when it was included. The correlation between the effect data of algae and the other two phyla was very small resulting in an altered internal rank when algal data was included. Conclusions & recommendations - The sensitivity of the species varied both between phyla and between substances. - The inclusion of algal effect data did alter the internal rank of the resulting CFs although not extensively. - Algae generally exhibited lower sensitivity to the additives. Not including algae in LCIA studies might therefore result in more conservative CFs.