Understanding the Biological Impact of Organic Pollutants Absorbed by Nanoplastics

Many organisms are consuming food contaminated with nano- and microparticles of plastics present in the environment. Environmental plastic particles can absorb and enrich persistent organic pollutants (POPs) from the environment and act as carrier vectors by increasing bioavailability in living organisms. Recently, we established that polymethylmethacrylate (PMMA) nanoparticles are not toxic to model animals at moderate concentrations. In this study, the potential toxicity of diphenylamine (DPA) absorbed on PMMA nanoparticles was assessed using barnacle larvae as a model organism. The absorption capacity of DPA from water for virgin PMMA microparticles is relatively low (0.143 wt%). PMMA nanoparticles encapsulated with DPA (DPA-enc-PMMA) were prepared using various concentrations of DPA through a precipitation method to achieve high loading of 40 wt%. Toxicity of DPA-enc-PMMA particles were tested using freshly spawned acorn barnacle nauplii. Naupliar mortality from DPA-enc-PMMA exposure was compared to the values obtained from pure DPA exposure in water. The observed mortality of DPA-enc-PMMA exposed acorn barnacle nauplii did not exceed 50% even at a high (40%) loading of DPA inside the PMMA nanoparticles. The results suggest that POP absorbed nanoplastics do leach such components into the environment, but the slow release may not induce significant toxicity to the organism living in a dynamic environment. The impact of long-term exposure of POP absorbed nanoplastics need to be investigated in the future