Biomonitoring evaluation for some toxic and trace elements in sea urchins species Lytechinus variegatus (Lamarck, 1816) in marine environment: São Paulo Northern Coast (Brazil)

Abstract

Sea urchins are marine and benthic invertebrates, many of which sessile or with reduced mobility. The species Lytechinus variegatus (Lamarck, 1816) is geographically widely distributed, from North Carolina, in the United States, to the South of Brazil. The present study analysed a mixture of gonads and gut of sea urchins (20 individuals of each site) from the north coast of São Paulo, Ilhabela, in the São Sebastião Channel (contaminated region) (23.8145 S 45.3782 W) and Praia Preta – São Sebastião (control region) (23.7745 S – 45.7132 W) to verify if this species could be used as biomonitor for the studied region. After collection, the samples were dried in a ventilated oven at 40 C until constant weight. After drying, the samples were crushed and sieved in 60 mesh (0.250 mm) granulometry. The micronutrients concentration (Ca, Fe, K, Na, Se e Zn) and trace elements (As, Ba, Br, Co, Cr, Rb, Sb e Sc) were determined by Instrumental Neutron Activation Analysis (INAA). Methodology validation was carried out by means of certified reference materials analyses such as: Oyster Tissue (NIST – 1566b), Mussel Tissue (NIST SRM – 2976), Peach Leaves (NIST SRM – 1547) and were validated by Z-Score, |Z| < 3 in 95% confidence interval (C.I.) For preliminary statistical analysis, a normality test (p > 0.05) and Grubbs test were performed for outlier detection (p < 0.05, C.I. 95%) . The preliminary results showed that the elements Cs, Cr, Sc and presented a higher concentration in the contaminated point and the elements As, Br, Co, Fe and Se, in the control point (C.I. 95%, test-t for independent samples). These are the preliminary results and Multivariate Statistical Analysis will be applied to the results.