A detailed critique is available in Issue 95 of Health Stream, a subscription service publication of Water Research Australia.
It ststes that the evidence shows that microplastics are capable of having negative effects on the food consumption, growth, reproduction and survival of a range of aquatic species, once effect thresholds (no effect levels) are exceeded. ( i.e. have an effect once the no effect level has been exceeded. This can be said of anything!). It concludes that at present there are large differences between measured environmental concentrations and predicted no-effect levels estimated from available knowledge. Therefore, it is probable that ecological risks of microplastics are currently rare, although there may be some heavily impacted locations where predicted or measured environmental levels of NMPs currently exceed the no-effect levels. However, if microplastic emissions to the environment remain the same, the ecological risks of microplastics may be widespread within a century. The lack of quantitative data on many aspects of exposure and potential health effects currently prevents any quantitative attempt at human health risk assessment in relation to nano- and microplastics.
The field of microplastics research has recently seen a robust debate about the often poor methodological quality of published research, and overstatement of the implications for ecological and human health risks in both the scientific literature and the popular media. Some have argued that the resources being devoted to microplastics research and regulation would be better directed to proven and widespread ecosystem risks such as eutrophication that require urgent action, while others contend that the pervasive and increasing nature of plastic pollution necessitates better understanding of exposures and hazards before a conclusion about risk levels can be drawn.