Isotopic biomonitoring of N pollution in rivers embedded in complex human landscapes.
Sci Total Environ
; 706: 136081, 2020 Mar 01.
Article
em En
| MEDLINE
| ID: mdl-31862596
The dynamic and hierarchical structure of rivers, together with disruption of the natural river continuum by human activities, makes it difficult to identify and locate sources of nutrient pollution affecting receiving waters and observe its dispersion, thus impairing monitoring efforts. The identification of reliable indicators of anthropogenic nitrogen inputs in catchments is therefore key to achieving effective management of polluted rivers. We tested the capacity of N isotopic signatures (δ15N) of epilithon and snails to provide useful indications of organic and inorganic anthropogenic N inputs in three Mediterranean rivers differing in terms of surrounding land use and physicochemical conditions. We used a combined approach based on (i) analysis of nutrient concentrations in water, (ii) CORINE land cover classification and drainage patterns in catchments and (iii) isotopic analysis of river biota to verify whether isotopic variations were indicative of anthropic activities in the watershed, the associated alteration of water quality, and the consequent impact on snail abundance and diversity. Variation in the δ15N of epilithon within and between rivers reflected localised and diffuse N inputs from inorganic and organic sources. Negative epilithon δ15N values (<0) indicated inorganic pollution from agriculture. Values between 4 and 8 and those above 8 respectively indicated moderate organic pollution from urban areas, and high organic pollution, mostly from waste waters. The diversity and abundance of snails decreased with increasing water pollution. While their isotopic variations reflected between-river differences, they failed to indicate within-river variations in anthropogenic N inputs, since the proportion of epilithon in their diet varied along the rivers. Concluding, epilithon was a reliable indicator of anthropogenic N sources across a wide range of nutrient concentrations and anthropogenic inputs, and the proposed approach allowed us to determine the nature of nitrogen pollutants, their sources, location and dispersion along rivers embedded in complex human landscapes.
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Contexto em Saúde:
12_ODS3_hazardous_contamination
/
2_ODS3
Base de dados:
MEDLINE
Assunto principal:
Rios
/
Monitoramento Biológico
Limite:
Humans
Idioma:
En
Revista:
Sci Total Environ
Ano de publicação:
2020
Tipo de documento:
Article