| dc.description.abstract | Plastic pollution is a global problem, with numerous studies focusing on the effects of
microplastics (1- 1000 μm). Cosmetic products like exfoliators have been identified as an
important source of primary microplastics. After abundant reports on the hazards caused by
microplastics, subsequent banning or voluntary removal from cosmetics is going on, causing them
to be replaced by the non- plastic alternative particles. However, the replacement by so- called
natural particles seems to be just a marketing strategy and lacks enough research verifying if they
are actually safer than microplastics.
The present study investigated the chemical and particle toxicity of eight exfoliators containing
microplastics and alternative particles used in Nepal. This was addressed by means of two in vitro
and one in vivo assay. The bioluminescent bacteria Photobacterium leiognathi was exposed to 2-
300 μg product and particles extracts and luminescence inhibition was measured. The recombinant
yeast strain Saccharomyces cerevisiae containing a gene coding for human estrogen receptor alpha
was exposed to 500 μg product and particle extract and estrogenicity was measured. Daphnia
magna neonates (< 24 h old) were exposed to 2- 45 μm microplastic and alternative particles at
0.8 – 500 mg/L for 21-days and survival and reproduction was examined.
The chemical toxicity from products was higher than the particle toxicity for bacteria with no
significant differences among microplastic and alternative particles. Most of the ingredients in the
products were unknown and thus the observed toxicity could not be attributed to any specific
chemical. In the YES, only one sample that contained parabens was estrogenic in the product
extract but not the particle extract. Both types of particles did not show any adsorbance. From in
vivo assay, the alternative particles had stronger effects in the lethality of D. magna whereas
microplastics caused higher reproductive effects.
Based on the findings of this study, alternative particles cannot be considered safer than
microplastics and with regards to products from Nepal, chemicals used in the cosmetics seem to
be of more concern. Since this study analyzed only exfoliators, study on effects of other classes of
cosmetics using environmentally relevant concentrations and other bioassays needs to be done in
the future. | |