Exposure of metals and PAH through local foods and risk of cancer in a historically contaminated glassworks area

Abstract

Background: Production of crystal glass and colored art glassware have been going on in the south-eastern part of Sweden since the 1700s, at over 100 glassworks and smaller glass blowing facilities, resulting in environmental contamination with mainly arsenic (As), cadmium (Cd), lead (Pb) and polycyclic hydrocarbons (PAH). High levels of metals have been found in soil, and moderately elevated levels in vegetables, mushrooms and berries collected around the glassworks sites compared with reference areas. Food in general, is the major exposure source to metals, such as Cd and Pb, and PAHs. Exposure to these toxic metals and PAH has been associated with a variety of adverse health effects in humans including cancer.

Objective: The aim of the present study was to evaluate the occurrence of cancer in a cohort from the contaminated glasswork area in relation to long-term dietary intake of locally produced foods, while taking into account residential, occupational and life styles factors.

Methods: The study population was extracted from a population cohort of 34,266 individuals who, at some time between the years 1979-2004, lived within a 2 km radius of a glassworks or glass landfill. Register information on cancer incidence and questionnaire information on consumption of local foods (reflecting 30 years general eating habits), life-time residence in the area, life style factors and occupational exposure was collected. Furthermore, blood (n = 660) and urine (n = 400) samples were collected in a subsample of the population to explore associations between local food consumption frequencies, biomarker concentrations in blood (Cd, Pb, As) and urine (PAH metabolite 1-OHPy) as well as environmental and lifestyle factors. The concurrent exposure to persistent organic pollutants (POPs) from food was also considered. A case-control study was performed for evaluation of associations between intakes of local food and risk of cancer.

Results: Despite high environmental levels of Cd, Pb and As at glasswork sites and landfills, current metal exposure in the population living in the surrounding areas was similar or only moderately higher in our study population compared to the general population. Reported high consumption of certain local foods was associated with higher Cd and Pb, but not As, concentrations in blood, and 1-OHPy in urine. An increased risk of cancer was associated with smoking, family history of cancer, obesity, and residence in glasswork area before age 5 years. Also, a long-term high consumption of local foods (reflecting 30 years general eating habits), i.e. fish and meat (game, chicken, lamb), was associated with increased risk of various cancer forms.

Conclusions: The associations between consumption of local food and different types of cancer may reflect a higher contaminant exposure in the past, and thus, if consumption of local food contributes to the risk of acquiring cancer, that contribution is probably lower today than before. Furthermore, it cannot be ruled out that other contaminants in the food contribute to the increased cancer risks observed.

Keywords: Cancer; Consumption of local food; Contaminated land; Exposure; Metals; PAH.