[ There are two other abstracts below this title study]
Knox E ORGA: E.G.Knox@btinternet.com
mindfully.org note: this study lasted 27 years.
See complete paper
BACKGROUND: In all, 70 municipal incinerators, 307 hospital incinerators and 460 toxic-waste landfill sites in Great Britain were examined for evidence of effluents causing childhood cancers. Municipal incinerators had previously shown significant excesses of adult cancers within 7.5 and 3.0 km. The relative risks for adults had been marginal and an analysis of childhood cancers seemed to offer a more sensitive approach. METHODS: A newly developed technique of analysis compares distances from suspect sources to the birth addresses and to the death addresses of cancer-children who had moved house. A localized hazard, effective at only one of these times, must be preferentially associated with the corresponding address. This creates an asymmetry of migrations towards or away from age-restricted effective sources. RESULTS: The child-cancer/leukaemia data showed no systematic migration-asymmetries around toxic-waste landfill sites; but showed highly significant excesses of migrations away from birthplaces close to municipal incinerators. Relative risks within 5.0 km of these sites were about 2:1. Hospital incinerators gave analogous results. The ratios greatly exceed findings around 'non-combustion' urban sites. CONCLUSIONS: Because of their locations, the specific effects of the municipal incinerators could not be separated clearly from those of adjacent industrial sources of combustion-effluents. Both were probably carcinogenic. Landfill waste sites showed no such effect.
Elliott P, Shaddick G, Kleinschmidt I, Jolley D, Walls P, Beresford J, Grundy C
Small Area Health Statistics Unit, Department of Public Health and Policy, London School of Hygiene and Tropical Medicine, UK.
By use of the postcoded database held by the Small Area Health Statistic Unit, cancer incidence of over 14 million people living near 72 municipal solid waste incinerators in Great Britain was examined from 1974-86 (England), 1974-84 (Wales) and 1975-87 (Scotland). Numbers of observed cases were compared with expected numbers calculated from national rates (regionally adjusted) after stratification by a deprivation index based on 1981 census small area statistics. Observed-expected ratios were tested for decline in risk with distance up to 7.5 km. The study was conducted in two stages: the first involved a stratified random sample of 20 incinerators; the second the remaining 52 incinerators. Over the two stages of the study was a statistically significant (P<0.05) decline in risk with distance from incinerators for all cancers combined, stomach, colorectal, liver and lung cancer. Among these cancers in the second stage, the excess from 0 to 1 km ranged from 37% for liver cancer (0.95) excess cases 10(-5) per year to 5% for colorectal cancer. There was evidence of residual confounding near the incinerators, which seems to be a likely explanation of the finding for all cancers, stomach and lung, and also to explain at least part of the excess of liver cancer. For this reason and because of a substantial level of misdiagnosis (mainly secondary tumours) found among registrations and death certificates for liver cancer, further investigation, including histological review of the cases, is to be done to help determine whether or not there is an increase in primary liver cancer in the vicinity of incinerators.
As part of an environmental epidemiological study on potential exposure to a toxic waste incineration we investigated whether children in an area with a toxic waste incinerator (TWI) have different levels of thyroid hormones than children in two comparative regions. The TWI region is situated in the Rhine valley (about 30 km across) with low mountains on both sides. Other industries such as a chemical plant are nearby, and several municipalities are located in the environment of these. One comparative area 20 km north is also industrially and agriculturally used, but has no incinerator (Rhine Valley comparison group, RVC group). South- East of the incinerator region in an area of low mountains (about 400 m high) we investigated the second comparison group (Odenwald comparison group, OWC group). Altogether 671 children from 18 municipalities participated in 1994/95 (participation 61.5%). Blood samples were taken from 341 children, aged 7 to 10 years, living in non-smoking households or in households with only light smokers. Serum levels of thyrotropin stimulating hormone (TSH), free thyroxine (FT4), and free triiodothyronine ( FT3) were analysed. In a self- administered questionnaire for the parents, which was checked during the medical examination, we gathered information on age, gender, passive smoking, consumption of fish, as well as use of wood preservatives and pesticides at home. By means of adjusted regression analysis the first step was to check whether the TWI group had means of TSH, FT4 and FT3 that differed from the OWC group and the RVC group. If differences were at least marginally significant, the second step was to analyse whether children from different municipalities had statistically different mean values and if the pattern of these municipalities fitted into the three regions. For the latter, children from a town in the Odenwald served as comparison group. The TWI group had statistically significantly (p < or = 0.05) reduced FT3 and FT4 values with a higher prevalence of FT3 values below clinical references (TWI group: 7.7%, RVC group: 3.2%, OWC group: 1.2%). Children from four out of nine TWI municipalities showed statistically significantly lower FT3 means than children from the reference town, and one of the seven municipalities from the comparative areas. The mean FT4 was significantly lower in four municipalities of the TWI area and in one of the two other areas. The mean TSH was only marginally different, mainly influenced by gender differences with boys having higher TSH levels. Comparison of the municipalities did not reveal a consistent pattern. Industrial pollution might influence the regulatory system of the pituitary thyroid axis. Reduced peripheral thyroid hormones associated with exposure to polychlorinated biphenyls ( PCB) and dioxins/furans (PCDD/F) were found in previous studies. Our results suggest that children exposed to toxic waste incineration in their environment have lower thyroxine and triiodothyronine levels.
If you have come to this page from an outside location click here to get back to mindfully.org