Congenital anomalies in Glasgow between 1982 and 1989 and chromium waste

BACKGROUND

The former site of a factory in Glasgow and nearby areas were found to be heavily polluted by chromium waste. This gave rise to local concern on possible health effects. As part of a wider study answering this concern, congenital malformations were investigated.

METHODS

A descriptive geographical study was carried out. A 10 km circle centred on the factory site was designated as the study area and subdivided into one circle of 2 km radius and eight 1 km wide rings. Significant differences in relative risk between the circle and rings and a decreasing trend of risk with distance from the centre would point towards a teratogenic role of the chromium waste. Relative risks by rings were obtained by Poisson regression. Relative risks by deprivation categories were also obtained, with most results adjusted by these categories.

RESULTS

Significant differences in risk appeared, with the area containing the polluted soil having the lowest risk. Aggregations of rings showed a central area with a relatively low risk, followed by an intermediate one with the highest risk and an external area with risk also high. Relative risk appeared to increase sharply between the most affluent category and the rest, then growing steadily with increasing deprivation but decreasing slightly for the most deprived.

CONCLUSIONS

Relative risk shows a significant peak in an area 2-4 km away from the pollutant, which does not point towards a possible teratogenic effect of the chromium waste. Relative risk of congenital malformations for the more affluent sector of the population appeared to be markedly lower than that for the rest.

A study of leukaemia in Glasgow in connection with chromium-contaminated land

BACKGROUND

In 1991, soil pollution was found around the site of a former chromium-processing factory in Glasgow, Scotland. Levels of chromium in soil were above limits considered as safe, although a risk assessment concluded that population exposure was likely to be below occupational levels. As an excess incidence of leukaemia has been suspected in the area, it was decided to investigate a possible relationship between the pollutant and the illness.

METHODS

The ensuing study was descriptive-geographical. In the absence of better data, levels of exposure were assumed to decrease with distance from the centre of the polluted area. Leukaemia and population figures were obtained for each of nine concentric rings by aggregation of data available at the Enumeration District level. The null study hypothesis was that relative risk (as measured by Poisson regression) would not follow a definite trend with distance from the centre. Sex, age and levels of deprivation were taken into account.

RESULTS

Relative risks by variables other than distance followed previously known patterns for leukaemia. No evident pattern by distance was found. After regroupings inside the variables, a significant excess of leukaemia was found for intermediate distances from the pollutant.

CONCLUSIONS

No evidence was found of a possible relationship between soil pollution by chromium and leukaemia in the general population. Nonetheless, the excess noticed by the study warrants further research.