Exploring the toxicity of the aged styrene-butadiene rubber microplastics to petroleum hydrocarbon-degrading bacteria under compound pollution system

As a new pollutant, microplastics have increasingly drawn public attention to its toxic behavior in the environment. The aim was to investigate the effect of styrene-butadiene-rubber microplastics (mSBR) with different degrees of aging on petroleum hydrocarbon (PHC) degrading bacteria in an environment with simultaneously existing pollutants. A series of experiments were carried out to investigate the changes in the physical and chemical properties of mSBR with aging and to examine the influence of these changes on the inhibition of PHCdegrading bacteria by mSBR in the vicinity of coexisting pollutants. The results showed that in the early stage of ultraviolet aging (10d), the particle surface shows wrinkles, but the structure is intact. After reaching the late stage of aging (20d), nano-scale fragments were generated on the surface of mSBR, the average particle size decreased from 3.074 mu m to 2.297 mu m, and the zeta potential increased from - 25.1 mV to - 33.1 mV. The inhibitory effect of bacteria is greater. At the same time, these changes in the physicochemical properties increase the adsorption effect of Cd by 20%, and also improve the stability of mSBR in solution, whereby bacterial growth is inhibited by inhibiting the LPO activity and protein concentration of PHC degrading bacteria.

Automated summary

The study found that after undergoing ultraviolet aging, microplastics exhibited wrinkles on the surface and generated nano-scale fragments; the average particle size decreased, Zeta potential increased; these changes in physicochemical properties increased the adsorption effect of Cd and improved the stability of microplastics in solution, thereby inhibiting bacterial growth by inhibiting the LPO activity and protein concentration of PHC-degrading bacteria.