Analysis and quantification of microplastic particles in the digestory system of workers of Apis mellifera (Hymenoptera: Apidae)

Abstract

Microplastics are plastic particles that come from the production process and inadequate disposal of plastic objects in the environment, which are fragmented to particles smaller than 5 mm due to the physical-chemical degradation processes to which they are subjected in nature. The production of plastic nanoparticles in the pharmaceutical, beauty and personal hygiene industries has enhanced the dispersion and quantity of these particles to worrying proportions, being present in almost every terrestrial and aquatic ecosystems. The deleterious effects of microplastics on biota are still being investigated, however such contaminants may release the toxicant Bisphenol A (2,2-bis (4-hydroxyphenyl) -propane), reduce the absorption of nutrients in the gut and enhance the carrying of persistent organic pollutants (POPs), such as trace metals, pesticides and drugs. Although bees are the main agents of pollination services and their increasing population decline, with many species threatened with extinction, there are not studies on the presence of microplastics in their guts, nor are there studies on the impact of microplastics on their health, despite the several records point to the presence of these contaminants in the honey and pollen stored in the colony. Therefore, the aim of the present study is to evaluate whether there are microplastics in the digestive system of workers from Africanized Apis mellifera. For this, 70 individuals will be collected in the field. Twenty bees collected will have their guts exclusively for weighing fresh and dry mass to supply the average volume of the gut, since this value will be necessary to calculate the estimated amount of microplastics per gut volume. The remaining fifty worker bees will have their guts dissected for organic digestion with a solution of potassium hydroxide and hydrogen peroxide. Finally, these samples will be filtered and used for the quantification step of microplastics per digestive tube, through a Neubauer chamber. Fractions of the same samples will be stained with Nile Red for analysis under fluorescence microscopy, using a green filter. In this step, the aim will be to identify and photograph, in a randomized way, 1000 microplastic particles to estimate the chemical profile of the microplastics found by estimating through fluorescence index the prevalence of the types of microplastics present in the guts of these bees: polar (nylon, PET) and hydrophobic (PE, PP, PS), according to the methodology employed by Maes et al. (2017).