Using biochemical and isotope geochemistry to understand the environmental and public health implications of lead pollution in the lower Guadiana River, Iberia: A freshwater bivalve study

• Published in: The Science of the total environment Vol. 405; no. 1; pp. 109 - 119
• Main Authors: Company, R., Serafim, A., Lopes, B., Cravo, A., Shepherd, T.J., Pearson, G., Bebianno, M.J.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 01.11.2008; [Amsterdam; New York]: Elsevier Science; Elsevier
• Subjects: ALAD; Animal, plant and microbial ecology; Animals; Applied ecology; bioaccumulation; Biological; Biological and medical sciences; Biological Assay; biomarkers; Biomarkers - metabolism; Bivalvia; clams; Corbicula - drug effects; Corbicula - enzymology; Corbicula fluminea; Correlation; Damage; Dehydration; Ecosystem; Ecosystems; Ecotoxicology, biological effects of pollution; Environmental Monitoring; Environmental pollutants toxicology; enzyme activity; Fresh water environment; Freshwater; Freshwaters; Fundamental and applied biological sciences. Psychology; indicator species; Isotopes; Lead; Lead (metal); Lead - analysis; Lead - metabolism; Lead - toxicity; Lead isotopes; Lipid peroxidation; Medical sciences; Membranes; Mining; Mining areas; Pollution; Pollution abatement; Porphobilinogen Synthase - metabolism; Portugal; Public health; Rainfall; Rivers; Rivers - chemistry; Stems; Toxic; Toxicity; Toxicology; Water; Water Pollutants, Chemical - analysis; Water Pollutants, Chemical - metabolism; Water Pollutants, Chemical - toxicity; Water pollution; Water quality; Portugal; Spain; Europe; ANE, Portugal; Europe, Iberian Peninsula, Guadiana R; Mining areas; ALAD; Corbicula fluminea; Pollution; Lead; Lead isotopes; Lipid peroxidation; Isotopic analysis; Lipids; Lyases; Freshwater environment; Health and environment; Bivalvia; Mine; Stream; Mining industry; Public health; Peroxidation; Porphobilinogen synthase; Proximity; Enzyme; Biological indicator; Rivers; Surface water; Environment; Water pollution; Invertebrata; Mollusca; Carbon-oxygen lyases; Hydro-lyases
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2008.07.016

Lead is a natural component of aquatic ecosystems with no known biological role and is highly toxic. Its toxicity stems from its ability to mimic biologically important metals and to produce membrane damage through lipid peroxidation (LPO). Most lead poisoning symptoms are thought to occur by interfering with an essential enzyme, δ-aminolevulinic acid dehydratase (ALAD), the activity of which is markedly inhibited by lead. The purpose of this work was to study the levels and effects of lead pollution (responses of ALAD and oxidative stress biomarker LPO) in the freshwater bivalve Corbicula fluminea along the lower Guadiana River (Portugal and Spain); a major river system impacted by historic mining pollution and more recent anthropogenic inputs. The results show that the enzymatic activity of ALAD is negatively correlated with the total Pb concentration of the whole tissue suggesting that ALAD has considerable potential as a biomarker of lead exposure in C. fluminea. To identify the sources of lead to which bivalves have been exposed, high precision 206Pb/ 204Pb, 207Pb/ 204Pb, 208Pb/ 204/Pb ratios for C. fluminea confirm that historical mining activities in the Iberian Pyrite Belt are the dominant source of lead pollution in the lower Guadiana River. The isotope patterns however exhibit marked seasonal and geographic variation in response to rainfall and river water management. Locally, other anthropogenic sources of lead have been detected in C. fluminea close to population centres, thus adding to its versatility as a freshwater bio-indicator. Overall, the study highlights the value of natural ecosystems as monitors of water quality and their importance for public health assessment and surveillance.