Enhanced Bioaccumulation and Transfer of Monomethylmercury through Periphytic Biofilms in Benthic Food Webs of a River Affected by Run-of-River Dams.
Environ Sci Technol
; 57(49): 20792-20801, 2023 Dec 12.
Article
en En
| MEDLINE
| ID: mdl-38016692
ABSTRACT
Run-of-river (ROR) power plants impound limited terrestrial areas compared to traditional hydropower plants with large reservoirs and are assumed to have reduced impacts on mercury cycling. We conducted a study on periphyton and benthic communities from different habitats of the St. Maurice River (Québec, Canada) affected by two ROR power plants and their effect on the bioaccumulation and biomagnification of monomethylmercury (MMHg). Proportion of total mercury as MMHg reached maximum values about 2.9 times higher in flooded sites compared to unflooded sites. Impoundment by ROR would therefore provide favorable environments for the growth of periphyton, which can produce and accumulate MMHg. Periphyton MMHg concentrations significantly explained concentrations in some benthic macroinvertebrates, reflecting a local transfer. Through the analysis of δ13C and δ15N signatures, we found that flooding, creating scattered lenthic habitats, led to modifications in trophic structures by the introduction of new organic matter sources. The computed trophic magnification slopes did not show significant differences in the transfer efficiency of MMHg between sectors, while intercepts of flooded sectors were higher. Increases in MMHg concentrations in flooded areas are likely due to the impoundment, combined with watershed disturbances, and the creation of small habitats favorable to periphyton should be included in future predictive models.
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1
Base de datos:
MEDLINE
Asunto principal:
Contaminantes Químicos del Agua
/
Mercurio
/
Compuestos de Metilmercurio
Límite:
Animals
Idioma:
En
Revista:
Environ Sci Technol
Año:
2023
Tipo del documento:
Article
País de afiliación:
Canadá