Total organically-bound chlorine and bromine in Lake Ontario herring gull eggs, 1977, by instrumental neutron activation and chromatographic methods

Abstract

In order to determine the extent to which orginically-bound chlorine in Herring Gull eggs from Lake Ontario can be accounted for by gas chromatographic analysis, comparison was made with values obtained for total chlorine using instrumental neutron activation analysis (INAA). Total chlorine and bromine (mg/kg fresh weight of egg) was determined by INAA on crude extract (Cl, 65 ± 35; Br, 1/03 ± 1.00), Florisil-chromatography treated extracts (Cl, 46 ± 10; Br, 0.93 ± 0.82) and H 2SO 4-treated extracts (Cl, 43 ± 11; Br, 0.44 ± 0.22) of eggs collected from seven colonies around Lake Ontario in 1977. Levels of chlorine were also determined by gas chromatography using the Hall electrolytic conductivity detector (51 ±11 mg/kg) and estimated by conversion of levels of individual residues determined by electron-capture gas chromatography (61 ±12 mg/kg). The agreement between the various determinations indicated that PCBs, DDE, mirex and photomirex accounted for most of the orginically-bound chlorine. Two colonies had total chlorine levels in crude extracts 2–4 times higher than could be accounted for by known compounds. The “excess” chlorine was removed by H 2SO 4-treatment or Florisil clean-up. The same two samples had abnormally high bromine levels, possibly indicating the presence of compounds formed during aqueous chlorination processes.