Determination of extractable organic halogens in pine needles by neutron activation analysis

Pine needles were collected from four different Chinese regions and measured by instrumental neutron activation analysis (INAA) combined with organic solvent extraction method for the concentrations and distribution of extractable organohalogens (EOX), including extractable organochlorinated (EOCl), organobrominated (EOBr) and extractable organoiodinated compounds (EOI). The concentrations of EOCl, EOBr and EOI are 0.5-6.0, 0.06-0.54 and 0.013-0.4 µg/g dry weight, respectively, which are increasing in the order of EOCl >> EOBr > EOI. EOCl accounts for more than 86%, while the latter two are less than 10% and 6% of total EOX. 5-38% of EOCl exist as extractable persistent organochlorinated compounds (EPOCl) after treatment with concentrated sulfuric acid. The relative proportion of the known organochlorinated pesticides (OCPs) to total EPOCl is 3.0-19.8%.