Certain ecosystems have been affected by the continuous exposure to environmental pollution. The effects of certain pollutants on organisms are not always obvious, and they are often disguised. To isolate the effects and quantify damage, scientists of the Universidad de Granada have analysed mineralized tissue samples of organisms using them as markers of the level of environmental pollution.
The scientists have provided themselves with bones and eggshells of different birds affected by a pollution source in their habitat. According to the supervisor of the project, Alejandro Rodríguez Navarro, of the Department of Mineralogy and Petrology of the Universidad de Granada, the nature of the samples allows to study how pollution affects the formation of the mineralized tissues of the organisms, as certain pollutants affect calcium metabolism. According to Alejandro Rodríguez, we need develop analytical techniques to detect subtle changes in bone composition and conformation, as well as micro-structural modifications: crystals´ size and variations in eggshells´ thickness.
This way, they have found out that certain chemical compounds are related with damages in bird populations.
One of the species studied, in collaboration with the Estación Biológica de Doñana (Doñana Biological Station), has been a population of Egyptian vultures in Lanzarote. This migratory vulture feeds on carrion. However, these birds have incorporated into their diet lead pellets of hunting, as they confuse them with seeds.
In order to discover a direct relation between lead concentrations present in Egyptian vultures and the apparent damages, they have compared the results obtained with a population of non-affected vultures. On the one hand, the population of polluted birds shows broken wings and foot more frequently. According to scientists, this fact is due to deficiencies in tissue mineralization. According to Alejandro Rodríguez, lead interferes in calcium metabolism. In addition, they have determined an increase on lead concentration in older vultures. According to Alejandro Rodríguez, it is because this metal accumulates in the bones of the affected organisms.
Besides heavy metals, other chemical compounds studied are the organochlorates, considered as hormonal disruptors. Once incorporated to organism, they influence the hormonal balance affecting bone composition and mineralization in the affected birds.
Reference:
Prof Alejandro Rodríguez Navarro
Department of Mineralogy and Petrology
Phone number.: 958 240 059.
E-mail: anava@ugr.es
