Toxicity of Biocide Formulations in the Soil to the Gut Community in Balloniscus selowii Brandt, 1983 (Crustacea: Isopoda: Oniscidea)

Abstract

Soil contamination by pharmaceutical and personal care products (PPCPs) has attracted the attention of many researchers. Continued release of these products into the environment can compromise the health of non-target organisms as well as interfere in ecological interactions between species. We hypothesized that contamination of the soil by these products affects the gut microbiota of macrodecomposers that live in symbiosis with these microorganisms and therefore interferes with the assimilation of nutrients by these animals. Therefore, this study aims to evaluate the effects of soil contaminated by triclosan (TCS) and chlorhexidine (CHX) by analyzing changes in nutrient assimilation and in the assimilation pattern of carbon sources from the Balloniscus selowii gut microbiota. The food consumption rate in B. selowii was not altered by biocides, and assimilation rate as well as assimilation efficiency (%) decreased under triclosan treatment. Based on the results obtained, the soil and gut microbiota demonstrated similar response to each study treatment when compared to other treatments. However, there were no significant differences in the diversity, evenness, and richness values. Dehydrogenase activity showed no significant differences between TCS and CHX exposure and control. In this study, exposure to TCS and CHX biocides changed the metabolic profile of the soil microbiota and consequently of the B. selowii digestive tract. With TCS exposure, this change was enough to affect the assimilation of nutrients by B. selowii. The continuous release of antimicrobials such as chlorhexidine and triclosan into the environment may compromise the health of non-target organisms and interfere with symbiotic relationships.