A symbiosis as sensitive bioindicator of arsenic pollution of drinking water

CAMPOY DÍAZ, AD; GIRAUD BILLOUD, M.; VEGA, IA

Mendoza

Simposio; 2º Simposio Internacional de Medicina Traslacional y XIV Jornadas de Investigación de la FCM; 2019

Facultad de Ciencias Médicas, Universidad Nacional de Cuyo

Frompublic and environmental health concern, arsenic (As) occupies the first placein the list of priority substances of the Agency for Toxic Substances andDiseases Registry (ATSDR) because of a high occurrence in differentenvironments, its toxicity at different organization levels, and potentialthreat for human health. In Argentine, the effects of As on environmental andhuman health are mainly associated with the entering of As in sources ofdrinking water and groundwater by leaching from geological formations andvolcanic activity. Monitoring of metals in the aquatic ecosystems can beevaluated by a combination of chemical and biological methods. However, biomonitoringhas the advantage of retaining a memory of pollutant emissions, thus overcomingthe difficulty of detecting contaminants that are irregularly emitted andquickly diluted in large volumes, for instance in lakes and streams. The modelorganism Pomacea canaliculata fulfills the requirements of a species that could be usedfor environmental monitoring studies. In addition, two types of symbioticcorpuscles have been identified within cells of the digestive gland of this snail.This work envisagedthe possibility of using this previously unrecognized association of afreshwater snail with a bacterium as a bioindicator of arsenic pollution. Ourresults showed that digestivegland showed the highest bioconcentration factor of As (BCF=426). Also, we have been surprised by the ability of both C and K symbiotic corpuscles toaccumulate arsenic (about 35 and 26 times above aquarium water). Our findingsshow that P. canaliculata is asensitive organism for biomonitoring of As in freshwater bodies since it is theentrance doorway of these elements in the trophic web.  From a toxicological view, the potential useof apple snails as a suitable substitute for protein sources will depend on theidentification of arsenic in natural aquatic ecosystems.