Assessment of cancer risk from ethylene oxide residues in spices imported into New Zealand

Quantitative estimates of cancer risks from ethylene oxide (ETO) residues were constructed based on 200 retail samples of various spices in New Zealand. Two samples of cinnamon contained detectable ETO. The highest value encountered was 15 ppm. ETO was not detected in the remaining 198 samples. However, 31 samples had detectable levels of ethylene chlorohydrin (ECH) and/or ethylene bromohydrin (EBH). A conservative estimate of ETO intake, based on average spice consumption, was 3.4×10−6 mg/kg/day. Cancer potency factors for ETO ranging from 0.29 to 0.55 (mg/kg/day)−1 were used to form cancer risk estimates. The resulting estimates of average lifetime excess cancer risk was 0.8×10−6 to 1.7×10−6. The US 97.5 percentile value for spice consumption (2.8 kg spices per year), gave an extreme upper-end estimate of lifetime cancer risk of approximately 1.4×10−5. These risks are practically negligible considering the conservative assumptions used in estimating exposure to ETO. The exposures to ECH and EBH are 200–300-fold higher than to ETO. These compounds are of lesser potency to ETO in terms of mutagenicity or carcinogenicity in studies to date. However, the precise contribution of these compounds to the cancer risk estimate is uncertain due to large toxicological data gaps, including the absence of a 2-year cancer bioassay by the oral route.