Mercury Levels in Hair of Domestic and Wild Animals

TL;DR

This study measures mercury levels in the hair of domestic and wild animals in Brazil to assess environmental contamination and its impact on ecosystems and food security.

Contribution

The study provides new regional data on mercury bioaccumulation in diverse animal species across Brazil, highlighting ecological exposure patterns.

Findings

Wild animals in the Pantanal region had the highest mercury levels (274.93 µg/kg), indicating significant environmental exposure.

Confinement-raised animals had lower mercury levels compared to wild animals, suggesting bioaccumulation is influenced by environmental contact.

Lactating sows showed greater mercury sensitivity than piglets, indicating animal category affects metal absorption.

Abstract

Studying the effects of mercury on swine and wild animal populations is crucial, as the latter, being free-ranging, have a greater potential for exposure to environmental contaminants such as mercury. The bioaccumulation of this metal in hair tissue indicates the degree of environmental contamination, reflecting risks to animals and the public. Assessing mercury levels in different species enables the understanding of regional and ecological patterns of exposure, which is essential for mitigation and environmental management strategies. This monitoring strengthens biodiversity conservation and food security.

This study quantified mercury (Hg) levels in the body hair of domestic and wild animals in four Brazilian states, Paraná, Mato Grosso do Sul, Goiás, and Minas Gerais, by analyzing 169 samples from sows, piglets, free-range pigs, and wild animals. The highest mean Hg concentration (274.93 ± 48.14 µg/kg) was found in wild animals in the Pantanal (MSSilvestre, Mato Grosso do Sul), followed by Minas Gerais (245.09 ± 40.27 µg/kg) and Paraná (193.0 ± 42.45 µg/kg). Levels at the GO, MGM, MSLiv, and PRV sites were significantly lower (p ≤ 0.05), according to the Scott–Knott test. Statistical analysis using ANOVA indicated significant variation in Hg levels between locations (F = 2.36; p ≤ 0.05), with homogeneity of variance (Levene’s test, p = 0.1772). Animals raised in confinement had lower levels than wild animals, which, due to extensive movement and contact with diverse environments, exhibited greater bioaccumulation. Lactating sows showed greater sensitivity than piglets, demonstrating an effect of animal category on metal absorption. The main sources of mercury are anthropogenic activities, such as mining and industrial processes, responsible for the environmental release of the metal. Although the detected levels do not pose an immediate risk to animal health or meat quality, they highlight the need for continuous monitoring, given mercury’s ability to bioaccumulate and affect ecosystems and food security. This work contributes to the understanding of environmental exposure to mercury in Brazil, reinforcing the urgency of effective mitigation strategies to preserve biodiversity and public health.

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