Serum concentrations of chlorinated dibenzo-p-dioxins, furans and PCBs, among former phenoxy herbicide production workers and firefighters in New Zealand.

PURPOSE: To quantify serum concentrations of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and dioxin-like compounds in former phenoxy herbicide production plant workers and firefighters, 20 years after 2,4,5-T production ceased. METHODS: Of 1025 workers employed any time during 1969-1984, 430 were randomly selected and invited to take part in a morbidity survey and provide a blood sample; 244 (57%) participated. Firefighters stationed in close proximity of the plant and/or engaged in call-outs to the plant between 1962 and 1987 also participated (39 of 70 invited). Reported here are the serum concentrations of TCDD and other chlorinated dibenzo-dioxins, dibenzofurans, and polychlorinated biphenyls (PCBs). Determinants of the serum concentrations were assessed using linear regression. RESULTS: The 60 men who had worked in the phenoxy/TCP production area had a mean TCDD serum concentration of 19.1 pg/g lipid, three times the mean concentration of the 141 men and 43 women employed in other parts of the plant (6.3 and 6.0 pg/g respectively), and more than 10 times the mean for the firefighters (1.6 pg/g). Duration of employment in phenoxy herbicide synthesis, maintenance work, and work as a boilerman, chemist, and packer were associated with increased serum concentrations of TCDD and 1,2,3,4,7-pentachlorodibenzo-p-dioxin (PeCDD). Employment as a boilerman was also associated with elevated serum concentrations of PCBs. CONCLUSIONS: Occupations in the plant associated with phenoxy herbicide synthesis had elevated levels of TCDD and PeCDD. Most other people working within the plant, and the local firefighters, had serum concentrations of dioxin-like compounds comparable to those of the general population.

Cancer incidence and mortality in a New Zealand community potentially exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin from 2,4,5-trichlorophenoxyacetic acid manufacture.

OBJECTIVE: To investigate whether the rates of all cancers and four cancers (soft tissue sarcoma, non-Hodgkin's lymphoma, Hodgkin's disease and chronic lymphocytic leukaemia) associated with dioxin exposure are higher in New Plymouth, the site of a former 2,4,5-T manufacturing plant, than for the rest of New Zealand. METHODS: Analysis of 1970-2001 cancer data from the New Zealand Cancer Registry was undertaken for New Plymouth and the rest of New Zealand. RESULTS: There is no evidence of an increased cancer risk apart from one period (1970-74), which falls partly outside the 1962-1987 manufacturing period if 10-year latency is assumed. For 1970-74, there was an elevated risk for all cancer incidence (SIR = 111, 95% CI 104-119), and for two of the four specific cancers that are associated with dioxin exposure (non-Hodgkin's lymphoma SIR = 175, 95% CI 121-246 and chronic lymphocytic leukaemia SIR = 251, 95% CI 144-408). CONCLUSIONS AND IMPLICATIONS: The results do not suggest an increased cancer risk among the New Plymouth population related to the period of 2,4,5-T manufacture, although the study's limitations mean the possibility of an undetectable small elevation in cancer risk cannot be excluded. Although TCDD exposure in the first few years of 2,4,5-T manufacture may have contributed to cancer incidence in 1970-74, unknown exposure(s) before the start of 2,4,5-T manufacture and chance are also possible explanations.

Bioavailability of dioxin in soil from a 2,4,5-T manufacturing site.

Dioxin (2,3,7,8-tetrachlorodibenzo-p-dioxin, TCDD) is a highly toxic contaminant produced in the manufacture of phenoxy herbicides. Despite its high TCDD content, soil from a contaminated area associated with a 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) manufacturing site in Newark, New Jersey, did not induce acute toxicity when administered to guinea pigs (the most sensitive species) by gavage. Analysis of liver samples demonstrated low bioavailability of TCDD from this soil. A comparative analysis of soils showed that Soxhlet extraction was necessary for the determination of TCDD on Newark soil, whereas solvent extraction was sufficient for soil from Times Beach, Missouri. The difference in the bioavailability of TCDD from these soils is correlated with TCDD extractability and may be related to the different compositions of the soils.