Barral-Fraga, Laura; Barral, María Teresa; MacNeill, Keeley; Martiñá-Prieto, Diego; Morin, Soizic; Rodríguez-Castro, María Carolina; Tuulaikhuu, Baigal-Amar; Guasch, Helena. International Journal of Environmental Research and Public Health 17 : 2331 (2020) DIGITAL CSIC
This review is focused on the biogeochemistry of arsenic in freshwaters and, especially, on the key role that benthic microalgae and prokaryotic communities from bioﬁlms play together in through speciation, distribution, and cycling. These microorganisms incorporate the dominant iAs (inorganic arsenic) form and may transform it to other arsenic forms through metabolic or detoxifying processes. These transformations have a big impact on the environmental behavior of arsenic because diﬀerent chemical forms exhibit diﬀerences in mobility and toxicity. Moreover, exposure to toxicants may alter the physiology and structure of bioﬁlms, leading to changes in ecosystem function and trophic relations. In this review we also explain how microorganisms (i.e., bioﬁlms) can inﬂuence the eﬀects of arsenic exposure on other key constituents of aquatic ecosystems such as ﬁsh. At the end, we present two real cases of ﬂuvial systems with diﬀerent origins of arsenic exposure (natural vs. anthropogenic) that have improved our comprehension of arsenic biogeochemistry and toxicity in freshwaters, the Pampean streams (Argentina) and the Anllóns River (Galicia, Spain). We ﬁnish with a brieﬂy discussion of what we consider as future research needs on this topic. This work especially contributes to the general understanding of bioﬁlms inﬂuencing arsenic biogeochemistry and highlights the strong impact of nutrient availability on arsenic toxicity for freshwater (micro) organisms.