Arsenic in stream waters is bioaccumulated but neither biomagnified through food webs nor biodispersed to land

• Published in: Ecotoxicology and environmental safety 2017-05, Vol.139, p.132-138
• Main Authors: Hepp, Luiz U., Pratas, João A.M.S., Graça, Manuel A.S.
• Format: Article
• Language: English
• Subjects: Animals; Arsenic - metabolism; Arsenic contamination; Biomagnification; Bryophyta - drug effects; Bryophyta - metabolism; Food Chain; Insecta - drug effects; Insecta - metabolism; Invertebrates - drug effects; Invertebrates - metabolism; Isotopic approach; Macroinvertebrates; Metals - pharmacology; Mining; Spiders - drug effects; Spiders - metabolism; Water - pharmacology; Water Pollutants, Chemical - metabolism; Water quality
• ISSN: 0147-6513; 1090-2414
• DOI: 10.1016/j.ecoenv.2017.01.035

Human activities such as mining have contributed substantially to the increase of metals in aquatic environments worldwide. These metals are bioaccumulated by aquatic organisms and can be biomagnified along trophic webs. The dispersal of contaminants from water to land has been little investigated, even though most aquatic invertebrates in streams have aerial stages. We used field and laboratory approaches to investigate the effects of arsenic pollution on stream invertebrate assemblages, and its bioaccumulation, biomagnification and trophic transfer from aquatic to terrestrial environments by emergent insects. We conducted the study in an arsenic-impacted stream (40μgL–1 As at the most polluted site) and a reference stream (0.3μgL–1 As). Invertebrate abundance and richness were lowest at the most impacted site. Arsenic in biofilm and in invertebrates increased with the arsenic content in the water. The highest arsenic accumulators were bryophytes (1760μgg–1), followed by the biofilm (449μgg–1) and shredder invertebrates (313μgg–1); predators had the lowest arsenic concentration. Insects emerging from water and spiders along streambanks sampled from the reference and the impacted stream did not differ in their body arsenic concentrations. In the laboratory, the shredder Sericostoma vittatum had reduced feeding rates when exposed to water from the impacted stream in comparison with the reference stream (15.6 vs. 19.0mg leaves mg body mass–1 day–1; p