²¹⁰Po and ²¹⁰Pb in fish and shellfish from Guanabara Bay, Brazil

¹ Dep. of Chemistry, Pontificia Universidade Catolica, R. Marquês de S. Vicente 225, CEP 22453-900, Rio de Janeiro, Brazil
² IRD, Comissao Nacional de Energia Nuclear, CP. 37750, Barra da Tijuca, Rio de Janeiro, Brazil

Abstract

Muscles of forty-four fish of two different species, Mugil spp and Micropogonia furnieri, and six composite samples of the shellfish Perna perna, collected in Guanabara Bay, a tropical estuary, were analysed for ²¹⁰Po and ²¹⁰Pb contents. The method for ²¹⁰Po determination consisted of spontaneous deposition on copper disks, followed by alfa counting. The method for ²¹⁰Pb determination was mineralization followed by leaching, ion-exchange separation, precipitation and, finally, beta counting. The average values found for concentration of ²¹⁰Po in fish was 2.6 Bq.kg^-1, wet basis, while for shellfish the values were higher, reaching 43.8 Bq.kg^-1, wet basis. For ²¹⁰Pb, concentrations were very low, frequently below the detection limit for fish samples. For shellfish this was higher, reaching 1.8 Bq.kg^-1, wet basis.