Blood lead levels, δ-ALAD inhibition, and hemoglobin content in blood of giant toad (Rhinella marina) to asses lead exposure in three areas surrounding an industrial complex in Coatzacoalcos, Veracruz, Mexico - via Herp Digest

Environmental Monitoring and Assessment 

Volume 185, Issue 2 , pp 1685-1698

César Arturo Ilizaliturri-Hernández  (1)

Donaji Josefina González-Mille (1)

Jesús Mejía-Saavedra (1)

Guillermo Espinosa-Reyes (1)

Arturo Torres-Dosal (2)

Iván Pérez-Maldonado (1)

Author Affiliations

1. Departamento Toxicología Ambiental, Facultad de Medicina, Universidad Autónoma de San Luis Potosí, Avenida Venustiano Carranza 2405, CP 78210, San Luis Potosí, SLP, México

2. El Colegio de la Frontera Sur (ECOSUR), Unidad San Cristóbal, Carretera Panamericana y Periférico Sur s/n, CP 29290, San Cristobal de Las Casas, Chiapas, México

Abstract

The Coatzacoalcos Region in Veracruz, Mexico houses one of the most important industrial complexes in Mexico and Latin America. Lead is an ubiquitous environmental pollutant which represents a great risk to human health and ecosystems. Amphibian populations have been recognized as biomonitors of changes in environmental conditions. The purpose of this research is to measure exposure to lead and evaluate hematological and biochemical effects in specimens of giant toads (Rhinella marina) taken from three areas surrounding an industrial complex in the Coatzacoalcos River downstream. Lead levels in toads' blood are between 10.8 and 70.6 μg/dL and are significantly higher in industrial sites. We have found a significant decrease in the delta-aminolevulinic acid dehydratase (δ-ALAD) activity in blood from 35.3 to 78 % for the urban–industrial and industrial sites, respectively. In addition, we have identified a strong inverse relationship between the δ-ALAD activity and the blood lead levels (r = −0.84, p  < 0.001). Hemoglobin and mean corpuscular hemoglobin levels, as well as the condition factor, are found to be lower at industrial sites compared with the reference sites. Our results suggest that the R. marina can be considered a good biomonitor of the δ-ALAD activity inhibition and hematological alterations at low lead concentrations.