The importance of time of exposure to harmful anthropogenic factors as an element of cancer risk assessment in children.

This study attempted to verify whether the time of exposure to harmful factors is important for the increased risk of developing cancer. A statistical analysis of all cases of cancer in children in the period from 1995 to 2004 in the province of Silesia (Poland) was conducted, and their spatial distribution was then presented using cartographic and GIS methods. The data were then juxtaposed with the developed assessment of the degree of anthropogenic pressure in the province of Silesia with regard to: population density, the volume of produced waste and the density of road networks. The anthropogenization index, which was determined by taking into account the selected factors and the degree of impact on human health, was presented as values from 0 to 1, where 0 represents no anthropogenic pressure and 1 represents its maximum level. In the province of Silesia, the estimated values of the anthropogenization index range from 0.2 to 0.67. The study revealed significant variation in the incidence rates in certain age groups, sexes and districts. It also showed a change in incidence rate values in 2004 compared to 1995, with the largest increase (over 9-fold) occurring in boys. In girls, a decrease (almost 5-fold) in incidence rates was recorded in most cancer groups. The correlation coefficient which was determined indicates a diverse relationship between exposure time and the number of cases of cancer, but in only a few districts it is statistically significant.

The effects of changes in cadmium and lead air pollution on cancer incidence in children.

This article presents the results of research on the effects of air pollution on cancer incidence in children in the region of Silesia (Poland), which has undergone one of the most profound anthropogenic transformations in Europe. The main objective of the research was to specify the impact of changes in cadmium and lead pollution in the years 1990-2005 on the incidence of cancers reported in children. Lead concentration ranged from 0 to 1490 x 10(-9) G m(-2)/year, and cadmium concentration ranged from 0 to 33.7 x 10(-9) G m(-2)/year. There was no strong significant correlation (max 0.3) between air pollution and incidence rate (IR) in the general population of children in any particular year. Alongside the cartographic presentation of dependences, correlation coefficients between the variables in question were calculated. This made it possible to determine the relationship between the pollution levels and incidence rates in the area. There was a significant reduction in the level of pollution during the investigated period. The study of the relationship between the number of cancers reported and the condition of the natural environment revealed increased sensitivity to toxins in boys (correlation coefficient 0.3). In addition, the spatial distribution of the number of cases reported in boys suggests a correlation with the spatial distribution of the coefficients for the entire group of children included in the study. The yearly average IR of childhood cancer in specific districts ranged from 0 to 61.48/100,000 children under 18 years of age during the 1995-2004 period.