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Heavy Metal Poisoning and Its Impacts on the Conservation of Amazonian Parrots: An Interdisciplinary Review
by
,
Marina Sette Camara Benarrós
†
,
Ketelen Ayumi Corrêa Sakata
†, 
Brenda Juliane Silva dos Santos
and
Felipe Masiero Salvarani
*
Instituto de Medicina Veterinária, Universidade Federal do Pará, Castanhal 68740-970, PA, Brazil
*
Author to whom correspondence should be addressed.
†
These authors contributed equally to this work.
Biology 2025, 14(6), 660; https://doi.org/10.3390/biology14060660
Submission received: 8 May 2025
/
Revised: 4 June 2025
/
Accepted: 5 June 2025
/
Published: 6 June 2025
(This article belongs to the Special Issue Progress in Wildlife Conservation, Management and Biological Research)
Simple Summary
Parrots are among the most iconic and threatened birds in the Amazon. Among other threats they face, their survival is increasingly at risk due to exposure to heavy metals such as lead, mercury, and cadmium. These toxic substances can be released into the environment through mining, deforestation, and pollution from cities and agriculture. In this review, we explore how exposure and poisoning can occur when these metals enter the food chain and affect the health, behavior, and reproduction of Amazonian parrots. We also highlight how poisoning can go unnoticed, especially in wild populations, and the urgent need for more studies and monitoring. This work brings together findings from biology, toxicology, conservation, and veterinary medicine to understand the full impact of this threat. Our results show that heavy metal contamination can lead to neurological damage, impaired development, and even death in parrots, contributing to population declines. By drawing attention to this often-overlooked issue, we hope to support actions that reduce environmental contamination and promote the conservation of these vital birds. Protecting parrots also helps preserve the balance of the Amazon ecosystem, where they play key roles in seed dispersal and forest regeneration.
Abstract
Amazonian parrots (Psittacidae) are essential to ecosystem balance. Already vulnerable to habitat fragmentation and weak environmental regulations, they are now increasingly threatened by heavy metal contamination. This review synthesizes evidence on the sources, transgenerational bioaccumulation, and physiological impacts of metals such as mercury (Hg), lead (Pb), cadmium (Cd), zinc (Zn), and arsenic (As) in these birds. Anthropogenic activities, including illegal gold mining, agricultural intensification, and urban expansion, release metals that biomagnify along food webs. Parrots, as long-lived, high-trophic consumers, accumulate metals in vital tissues, leading to severe neurotoxic effects, immunosuppression, reproductive failure, and reduced survival. Furthermore, maternal transfer of contaminants to eggs exacerbates genetic erosion and threatens population viability. While biomonitoring tools and habitat restoration have been proposed, current strategies are insufficient against the synergistic pressures of pollution and climate change. Addressing heavy metal exposure is critical to conserving Amazonian biodiversity and safe-guarding ecosystem services. Future efforts should prioritize multidisciplinary predictive models, bioremediation actions, and the strengthening of international environmental governance to ensure the survival of these sentinel species.
Keywords:
psittacid; mercury; cadmium; arsenic; conservation; One Health; ecotoxicology; sentinel; anthropogenic
