Large-scale spatial variation in mercury concentrations in cattle in NW Spain

Area of Science:

• Environmental Science
• Toxicology
• Ecotoxicology

Background:

• Mercury (Hg) is a toxic pollutant with significant anthropogenic contributions to atmospheric levels.
• Point sources, like coal power plants, cause localized Hg deposition and bioaccumulation.
• Understanding Hg contamination sources is crucial for environmental and health risk assessment.

Purpose of the Study:

• To assess the impact of point and diffuse mercury emission sources on biota in Galicia and Asturias, Spain.
• To quantify mercury accumulation in cattle (Bos taurus) in relation to proximity to emission sources.
• To differentiate the effects of major point sources versus diffuse sources on mercury bioaccumulation.

Main Methods:

• Analysis of renal mercury (Hg) concentrations in 284 locally reared cattle.
• Spatial correlation of Hg levels with proximity to known point (coal-fired power plants) and diffuse Hg emission sources.
• Geographical mapping of Hg deposition impact zones.

Main Results:

• Renal Hg concentrations in cattle ranged from non-detectable to 89.4 µg/kg wet weight.
• Point discharges from coal power plants in Galicia were the dominant source, explaining two-thirds of Hg variation in downwind cattle.
• Diffuse sources impacted Hg accumulation in Asturias cattle, with effects extending 140-200 km downwind from both source types.

Conclusions:

• Coal-fired power plants significantly influence mercury bioaccumulation in cattle, with regional variations observed.
• Both point and diffuse mercury sources contribute to environmental contamination and bioaccumulation in cattle up to 200 km.
• Monitoring mercury levels in livestock provides insights into the spatial impact of industrial emissions.