Determination of ultra trace amounts of cobalt in fish by graphite furnace Zeeman effect atomic absorption spectrometry.

A method is described for determining stable cobalt concentrations in fish flesh and bone using polarized Zeeman effect graphite furnace atomic absorption spectrometry (ZAAS). Cobalt analysis on freshwater fish flesh samples (10 g dry weight) required predigestion and wet-ashing at 70-80 degrees C. Cobalt is chelated with ammonium pyrrolidine dithiocarbamate (APDC) extracted with methyl isobutyl ketone (MIBK) and analysed by ZAAS. The mean cobalt content calculated from the standard additions method using three replicate fish flesh samples was 4.23 +/- 1.0 microgram Co. Kg-1 (dry weight). Analyses were also carried out on flesh and bone samples from similar sized fish, of the same species, taken from three area lakes.

Changing risks in tuberculosis.

Past and present experience with tuberculosis in New York State exclusive of New York City is presented. TB has been on the decline since the turn of the century and reached an all-time low in 1974 with only 844 new active cases and 137 deaths reported. Although incidence rates are highest among the poor, the bulk of cases come from middle and upper socioeconomic levels. Cohort analysis shows an individual's risk of developing pulmonary or miliary TB is greatest at age 20-24, whereas the greatest risk of dying from TB is before age 5. Projections based on past experience indicate a male born in 1970-74 will have a lifetime risk of developing pulmonary or miliary TB of 80/100,000 and of dying from TB of 4/100,000. For females the respective risks are 40/100,000 and 6/100,000.