Differential bioconcentration of Cadmium in tissues and endosymbionts of the sentinel organism

CAMPOY DIAZ, DANIELA; CANIZO, BRENDA; WUILLOUD, RODOLFO G.; VEGA, ISRAEL A.

Mendoza

Congreso; XXXIV REUNIÓN CIENTÍFICA DE LA SOCIEDAD DE BIOLOGÍA DE CUYO; 2016

Two morphs of an endosymbiont (identified as C and K corpuscles) are found within cells of the digestive gland in P. canaliculata. Since previous evidence suggested that cadmium produced a decrease frequency of copulation and the number of egg masses, and an increase of unembryonated egg in this snail, experiments were launched to measure cadmium concentrations in both isolated morphs, as well as in samples of digestive gland, kidney, uterine gland, and testicle. Snails were cultured in reconstituted water (prepared with American Society for Testing and Materials type I water) and then exposed to different concentrations of cadmium in the aquarium´s water (50, 250, and 500 ug/L) for 28 days. Graphite furnace atomic absorption spectroscopy (instrumental detection limit = 0.03 ug/L) was used to determine cadmium. This element was detected in all tissues and endosymbionts of all exposed snails. High levels of cadmium were found in the digestive gland (50 µg/L) and kidney (250 and 500 µg/L) while were lower in testicle and uterine gland. The bioaccumulation in the digestive gland was at expenses to both morphs of the endosymbiont. These observations indicate that cadmium, when ingress to the snail, is distributed preferentially in the digestive gland (which includes the endocytobiont) and kidney of P. canaliculata. Bioaccumulation of cadmium in testicle and uterine gland (which was much lower) could explain the deleterious effects in reproductive functions. Together, these results indicate that this freshwater snail may be used as a bioindicator of cadmium pollution in limnic environments.