The Kelp Gull as bioindicator of environmental chemicals in the Magellan region. A comparison with other coastal sites in Chile

Abstract

SUMMARY: During the breeding seasons 1994/5 and 1995/6 we collected Kelp Gull (Larus dominicanus) eggs from five locations in central to south Chile to study the contamination with mercury and organochlorine compounds. The sites were Algarrobo, Concepción, Maiquillahue Bay, Doña Sebastiana Island (Chalcao channel at Chiloé) and Magdalena Island (Straits of Magellan). We found differences among the sites: Kelp Gull eggs from Chiloé and Algarrobo had the greatest concentrations of mercury (about 170 ng g -1 fresh weight). Residues of DDT were greatest in eggs from Algarrobo and Maiquillahue Bay, those of PCBs (polychlorinated biphenyls) greatest at Algarrobo and Concepción. HCB had highest levels at Concepción. Considering all organochlorines, samples from Algarrobo had the highest concentrations, those from Chiloé the lowest. In consequence we found a geographical pattern from north to south, i.e., from areas with greater to lesser human impact. In comparison with other studies, the levels of environmental chemicals found in Kelp Gulls from Chile are much lower than those known to cause adverse effects on reproductive success.

Efecto de la edad y la localidad en la concentración de cadmio y cobre en el hígado de la gaviota dominicana Larus dominicanus

“…A nivel local, en playas contaminadas con relaves mineros, se determinaron altos niveles de cadmio y cobre en un grupo de 6 especies (Vermeer & Castilla 1991). A una escala espacial mayor comprendida entre Algarrobo (Región de Valparaíso, Chile central) y la Isla Magdalena (Estrecho de Magallanes, Chile austral), la concentración de compuestos organoclorados en huevos de gaviota dominicana han mostrado un patrón de variación norte-sur en el cual las mayores concentraciones se encontraron en el norte (Muñoz & Becker 1999). A una escala espacial aún mayor, desde el Parque Nacional Pan de Azúcar (Región de Atacama, norte de Chile) hasta Puerto Williams (Región de Magallanes) y el Archipiélago de Juan Fernández, la concentración de mercurio en 22 especies de aves marinas fue más baja que los niveles considerados letales y fue influenciada por la ubicación geográfica, los hábitos alimenticios y la filogenia (Ochoa-Acuña et al 2002).…”

Reviews of Environmental Contamination and Toxicology

“…PCB levels were higher by a factor of 2 in central Chile when compared to eggs collected in southern Chile, reflecting the impact of anthropogenic sources. Nevertheless, average data for six PCB congeners indicate that levels are at least 1 order of magnitude lower than those reported for gulls' eggs in the Northern Hemisphere, ranging between 53 and 245 ng/g ww, respectively (Muñoz and Becker 1999).…”

Comparison of heavy metals from resident Larus dominicanus and migratory Leucophaeus pipixcan collected in Talcahuano, Chile

“…In this study, Hg in feathers of Franklin's gulls averaged ~ 1.0 µg/kg. The remaining Chilean studies have either reported egg or liver concentrations (Vermeer and Castilla 1991, Muñoz and Becker 1999, Cifuentes et al 2003. In the early 1980's, livers from kelp and Franklin's gulls sampled from El Chañaral, Atacama (~ 900 km north of Talcahuano) from an area heavily polluted by tailings from a copper mine contained Cu and Cd concentrations ranging from 4.1 -5.5 and 1.5 -9.1 µg/g, respectively (Vermeer and Castilla 1991).…”

“…We were also interested in determining whether metal concentrations would be high enough to potentially harm these populations. This is the first study that compares heavy metal concentrations between these two gull species and one of several that have examined heavy metals in Chilean marine birds (Vermeer and Castilla 1991, Muñoz and Becker 1999, Ochoa-Acuña et al 2002, Cifuentes et al 2003, Cortés and Luna-Jorquera 2011.…”