Neutron activation analysis for organohalogen pollutants in milk and other foodstuffs

The halogen elements, when they exist as organohalide compounds (chlorinated pesticides, polychlorinated biphenyls (PCBs), dibenzo-p-dioxins/dibenzofurans, etc.), have long been known as persistent environmental pollutants. Owing to the advantageous nuclear properties of Cl, Br and I, neutron activation analysis (NAA) can easily evaluate the whole pollution status of the halogen elements, when combined with organic extraction techniques. An additional merit of instrumental neutron activation analysis (INAA) is the ease of simultaneously measuring Cl, Br and I in one sample. Since OCs (organochlorinated compounds) may accumulate in organisms through the food chain as a result of their lipophilic property, food is considered the main source of human exposure to these compounds. Milk can serve as one of the convenient indicators for measuring the extent of persistent residues that may originate from contaminated animal feed. Therefore it is recommended by the United Nations Environment Programme as an indicator of persistent organic pollutants and has been studied in recent surveys as an indicator of OCP exposure. However, there is still insufficient information on the OC concentration in milk. The nuclear analytical techniques (mainly NAA) can be applied to analyse total halogens, extractable organohalide and persistent organohalogens in milk and other foodstuffs via 37Cl(n, γ)38Cl, 79Br(n, γ)80mBr and 127I(n, γ)128I, which are short lived nuclides and are easily determined