Copper toxicity on the first larval stage of Lithodes santolla

AMIN, O., COMOGLIO, L., GIARRATANO, E.

Florianópolis, Brasil

Congreso; VIII Congreso Brasileiro de Ecotoxicologia; 2004

In the last years heavy metals have been increasing along the coastal zone near Ushuaia city. Previous research has demonstrated that copper was one of the most important heavy metals found in sediments, water, mussels and algae sampled in the area. The aim of this study was evaluated the toxicity of copper on first larval stage of Lithodes santolla (Decapoda, Anomura) the most important shellfish commercially exploited in Tierra del Fuego, Argentina. Larvae were obtained from a single female maintained in the follow experimental condition: 30 ppt. salinity; 7.5°C water temperature and 12L: 12D. Short-term exposure (96 hours) was carried out in zoeae hatched during the previous night. Six copper concentrations ranged from 0.16 to 1.6 mgL-1 were used to estimate LC50-96 hr (Probit method), while lipid peroxidation ( Beuge & Aust, 1978), Oxygen consumption (polarographic electrode YSI 5100), and ammonia excretion (Strickland and Parsons, 1972), were measured at 0.08 mgL-1; 0.16 mgL-1 copper concentrations and control group. Finally O: N ratio was estimated according Taboada et al. (1998).  LC50 value obtained was 0.3 mgL-1 being more toxic than Zn, Cd and Pb (Amin et al., 2003). Oxygen consumption was no significant different (mean value: 47.9 µat O2 h-1 g-1 DW); Ammonia excretion was significantly higher at 0.08 mgL-1 (2.86 µat N h-1 g-1 DW) and no differences were detected between control and 0.16 mgL-1 . The O:N atomic ratio was lower at 0.08 mgL-1 than 0.16 mgL-1 (means values: 19.26 and 44.57 respectively). Larvae exposed to 0.16 mgL-1 of copper exhibited a significant increment lipid peroxidation. In agreement with this latter response, the O:N value obtained reflect the use of lipids in the metabolic pathway at the high concentration exposed.