Piaractus mesopotamicus juveniles (total length 12 AE 0.5 mm) were exposed to different concentrations of ammonia-N (un-ionized plus ionized ammonia as nitrogen), using the static renewal method at different temperature levels (15, 20 and 25°C) at pH 7. The 24, 48, 72, 96 h LC 50 values of ammonia-N in P. mesopotamicus juveniles were 5.32, 4.19, 3.79 and 2.85 mg L À1 at 15°C; 4.81, 3.97, 3.25 and 2.50 mg L À1 at 20°C; and 4.16, 3.79, 2.58 and 1.97 mg L À1 at 25°C respectively. The 24, 48, 72, 96 h LC 50 values of NH 3 -N (un-ionized ammonia as nitrogen) were 0.018, 0.014, 0.013, 0.009 mg L À1 at 15°C temperature; 0.023, 0.019, 0.016 and 0.012 mg L À1 at 20°C; 0.029, 0.026, 0.018 and 0.014 mg L À1 at 25°C. The temperature increase from 15 to 25°C caused an increase of ammonia-N susceptibility by 21.80%, 9.55%, 31.92% and 30.87%, after 24, 48, 72 and 96 h exposure respectively. Furthermore, we found that exposure of fish to ammonia-N caused an elevation in total haemoglobin and blood glucose with an increase of 2 mg L À1 concentration. Ammonia levels tolerated, especially in different temperatures levels, have important implications for the management of aquaculture.

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In Brazil, pink shrimp (Farfantepenaeus paulensis) is an important commercially exploited species and is an ideal animal for studying the impairment caused by the effects of heavy metals that are often detected in coastal areas. The main purpose of the present study was to detect the acute toxicity of cadmium and zinc to F. paulensis and investigate their effects on oxygen consumption and ammonium excretion, investigations that have not been carried out in this species before. First, the acute toxicity of zinc and cadmium to F. paulensis for 24, 48, 72, and 96 h--medium lethal concentration was examined, which resulted in the following values: 9.39, 6.00, 4.88, and 3.31 mg/l for zinc and 2.35, 1.67, 1.26, and 0.83 mg/l for cadmium. Furthermore, we also found that exposure of shrimp to zinc and cadmium caused an inhibition in oxygen consumption of 25 and 32.4%, respectively, relative to the control. In addition, after separate exposure to cadmium and zinc, elevations in ammonium excretion were obtained, which were 42.85 and 51.85% higher than the control, respectively.

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Cd, Co, Cr, Cu, Mn, Ni, Zn, and Pb were measured in feather samples of adult, subadult, and juvenile of Larus dominicanus, sampled in the Florianólis, SC, in the south of Brazil in December 2005, by flame atomic absorption spectrophotometry. The average of the distribution of Cd concentration in adult feathers (0.072 microg g(-1)) was significantly different than that found in juvenile feathers (0.021 microg g(-1)). Cu concentration averages were not significantly different between adults (13.30 microg g(-1)), subadults (9.67 microg g(-1)), and juveniles (13.76 microg g(-1)). For adults and juveniles there was significant difference in feather concentrations for Cd, Co, Cr, Ni, and Pb. The distribution of Mn concentration averages in feathers differs between adults (11.36 microg g(-1)) and juveniles (1.184 microg g(-1)). Ni concentration averages of adults (5.92 microg g(-1)) were significantly higher than those of juveniles (2.23 microg g(-1)). For Pb, concentration averages were significantly higher in adults (7.53 microg g(-1)) than in juveniles (1.47 microg g(-1)). The concentration of Co and Cr in juvenile and subadults are statistically different when compared with the adults. In the present study, levels of Cd, Co, Cr, Mn, Ni, Zn, and Pb increased with age. The concentrations of essential trace elements in L. dominicanus were generally comparable to values reported in other studies. With non-essential metals (Cd, Pb, and Ni), in our study, L. dominicanus had lower values than those reported for their northern Atlantic counterparts.

Penaeid shrimps are important resources for worldwide fisheries and aquaculture. In Brazil, Litopenaeus schmitti (L. schmitti) is a important commercially exploited species and is an ideal animal for studying the impairment caused by the effects of heavy metals that are often detected in coastal areas. The main purpose of the present study was to detect the acute toxicity of cadmium and zinc to L. schmitti and investigate their effects on oxygen consumption and ammonium excretion, investigations that have not been carried out in this species before. First, the acute toxicity of cadmium and zinc to L. schmitti 24, 48, 72, and 96-hour medium lethal concentration was examined, which resulted in the following values: 0.98, 0.54, 0.32, and 0.18 mg/L for cadmium and 1.64, 1.22, 0.86, and 0.31 mg/L for zinc. Furthermore, we also found that exposure of shrimp to cadmium and zinc caused an inhibition in oxygen consumption of 55.92 and 44.09%, respectively, relative to the control. However, after separate exposure to cadmium and zinc, elevations in ammonium excretion were obtained, which were 174.28 and 162.5% higher than the control, respectively. Water Environ. Res., 79, 641 (2007).

Thirty specimens (15 adults and 15 juveniles) of Chelonia mydas found in the Cananéia estuary in the state of São Paulo on the southeastern Brazilian coast between January 2005 and September 2006, were analyzed The concentrations of Cd, Cu, Pb, Mn and Ni in liver and kidney samples of adult and juvenile green turtles were determined by Flame Atomic Absorption Spectrophotometry.The average Cd concentration found in adult livers (0.57µg.g-1) was significantly higher than that in juveniles (0.279µg.g-1). Cu concentrations were significantly higher in the liver than in the kidney, and significantly higher in adults (39.9µg.g-1) than in juveniles (20.7µg.g-1) Average Mn concentrations in liver and kidney did not differ between adults (4.32 and 4.17µg.g-1) and juveniles (4.81 and 3.82µg.g-1), whereas Ni concentrations in adults (0.28 and 0.19µg.g-1, respectively) were significantly higher than in juveniles (0.13 and 0.089µg.g-1, respectively). Pb concentrations in liver were significantly higher in adults (0.37µg.g-1) than in juveniles (0.06µg.g-1). The concentrations of essential trace elements in Chelonia mydas were generally comparable to values reported in other, similar studies. With respect to non-essential metals (Cd, Pb and Ni), Chelonia mydas presented lower values than those reported for their northern Atlantic counterparts.
Analisou-se 30 espécimes (15 adultos e 15 juvenis) de Chelonia mydas encontradas no estuário de Cananéia, Estado de São Paulo, região sudeste, durante o período de janeiro de 2005 a setembro de 2006. Foram determinados no fígado e rins de adultos e juvenis de C. mydas os seguintes metais: Cd, Cu, Pb, Mn e Ni, através de Espectrofotometria de Absorção Atômica. Verificou-se que as concentrações médias de Cd no fígado de adultos (0,957µg.g-1) foram significativamente diferentes em relação a dos juvenis (0,279µg.g-1). As concentrações médias de Cu no fígado de C. mydas foram diferentes em relação ao rim. Houve diferença também entre os fígados de adultos (39,9µg.g-1) e juvenis (20,7µg.g-1). Os valores médios de Mn encontrados no fígado e rim não diferiram entre adultos (4,32 e 4,17µg.g-1) e juvenis (4,81 e 3,82µg.g-1). Já as médias das concentrações de Ni no fígado e rins de adultos (0,28 e 0,19µg.g-1) foram diferentes das dos juvenis (0,13 e 0,089µg.g-1). Entretanto, as concentrações de Pb no fígado foram significativamente mais altas em adultos (0,37µg.g-1) do que nos juvenis (0,06µg.g-1). As concentrações dos elementos traços essenciais em C. mydas foram comparáveis aos valores registrados em outros estudos. Quanto aos metais não essenciais (Cd, Pb e Ni), C. mydas apresentou uma menor concentração em relação às registradas para o Atlântico Norte