The combinatory effects of microplastics and emerging contaminant on the model green alga Chlamydomonas reinhardtii

In our oceans today, there is much concern about the effects of microplastics (MPs) and other emerging contaminants (ECs). Here, we investigate the combinatory effects of microplastics Polyvinyl Chloride (PVC) and Acrylates/C10-30 Alkyl Acrylates crosspolymer (AC) (which are commonly found in face wash), together with 2-phenoxyethanol (an EC commonly used in soaps). The model photosynthetic unicellular alga Chlamydomonas reinhardtii, was used to study the potential of these pollutants to initiate algal blooms. We showed that AC alone resulted in a greater decline in algal biomass as compared to PVC in the short term (14 days). While algal cultures exposed to PVC registered the highest increase in concentrations of Chlorophyll a pigment, it was the combinatory effects of each MP and 2-phenoxyethanol that were most pronounced in terms of the large increase in algal biomass and the formation of extracellular polymeric substances (EPS). Proliferative growths of C. reinhardtii after prolonged exposure to AC-EC contaminants show potential for initiating algal blooms in aquatic environments. Hence, AC should be considered for regulation of wastewater removal into water bodies while other combinations of MPs and ECs should also be investigated.