Microplastics and Emerging Concern Microparticles in Sediments from Buenos Aires Aquatic Environments: All in the Same Microplastics Analysis Bag?

DÍAZ JARAMILLO, M.; ISLAS, M.S.; GONZALEZ, M.

Montevideo

Congreso; SETAC Latin America 15th Biennial Meeting; 2023

SETAC LA

Coastal sediments are affected by contaminants from in situ and ex situ sources, including microplastic particles (MPs) derived from land-based and marine productive activities. However, due to the complexity of the matrix and the time-consuming/expensive methods available, there is little information on the MPs levels in this environmental compartment. In addition, the presence of emerging concern microparticles, such as paints/coatings and black rubbery particles commonly referred to as tire wear particles (TWPs), pose challenges for recovery due to their reported higher density and chemical complexity. Analysis of MPs, including paints and TWPs, in subtidal and riverine sediments from urban, peri-urban, and rural areas located in densely populated regions such as Buenos Aires Province revealed their occurrence. Paints and TWPs were found mainly at sites associated with stormwater runoff, bridges of major and minor roads/highways. Also it revealed its high contribution in the total MPs stock from low to impacted areas ( Paints 0-36% and TWPs 0-90%). In addition to the complexity of chemical characterization, current separation methods rely on the use of dense floating solutions to separate MPs from sediment components. Many commonly used floating solutions result in underestimation of these emerging particles. Floating solutions that achieve higher densities are expensive or pose a risk to humans and the environment due to their toxicity. In addition, interactions with the matrix and biogenic aggregations can compromise the efficiency of density-floating methods. Based on methodology proposed for the analysis of high-density microparticles such as paints/coatings, we compared the use of two extraction methods for subtidal sediments impacted by stormwater discharges. Our preliminary results showed differences between density-based and non-density-based methods in MP abundance averaging 255% and 310% for paints and TWPs, respectively. Our preliminary approach to analyzing classic and emerging concern microparticles from impacted and non-impacted sediments demonstrated their contribution and the need to properly identify these microparticle groups. In addition, non-floating extraction techniques could provide a nonexpensive, affordable, and more green friendly technology for microparticle assessment in environmentally relevant but complex matrices.