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.

A great deal of research has been devoted to the characterization of metal exposure due to the consumption of vegetables from urban or industrialized areas. It may seem comforting that concentrations in crops, as well as estimated exposure levels, are often found to be below permissible limits. However, we show that even a moderate increase in metal accumulation in crops may result in a significant increase in exposure. We also highlight the importance of assessing exposure levels in relation to a regional baseline. We have analyzed metal (Pb, Cd, As) concentrations in nearly 700 samples from 23 different vegetables, fruits, berries and mushrooms, collected near 21 highly contaminated industrial sites and from reference sites. Metal concentrations generally complied with permissible levels in commercial food and only Pb showed overall higher concentrations around the contaminated sites. Nevertheless, probabilistic exposure assessments revealed that the exposure to all three metals was significantly higher in the population residing around the contaminated sites, for both low-, medianand high consumers. The exposure was about twice as high for Pb and Cd, and four to six times as high for As. Since vegetable consumption alone did not result in exposure above tolerable intakes, it would have been easy to conclude that there is no risk associated with consuming vegetables grown near the contaminated sites. However, when the increase in exposure is quantified, its potential significance is harder to dismiss - especially when considering that exposure via other routes may be elevated in a similar way.

Sustainable development is an important issue for the industry in order to fulfil legislation requirements and to be able to use green marketing as a competitive advantage. The Swedish steel industry has implemented a large number of environmental improvements, for example, within energy efficiency, raw materials and recyclability. Technical improvements can help the industry decrease its environmental impact; however, in order to reach sustainable development, more factors need to be considered: an effective environmental decision-making process, for example. This process may be influenced by personal factors such as risk perception and worry, which are factors that will not contribute to an effective decision-making process. The aim of this study was to investigate if personal worry and risk perception influenced environmental decision-making within the Swedish steel industry. Thirty-eight interviews were performed at 10 Swedish steelworks using the Q-methodology. The major perceived environmental risks with the facility and personal worry were assessed, compared to the day-to-day work. It was concluded that the major perceived risks were emissions of carbon dioxide, use of non-renewable energy and emissions of particulate matter. The decision-makers were mainly worried about emissions of carbon dioxide, emissions of dioxin and use of non-renewable energy. The environmental issues that were prioritised in practice (day-to-day work) were emissions of carbon dioxide, emissions of particulate matter and emissions of metals. Even though emissions of carbon dioxide were given the highest priority in the Q-sorts, there was in general no clear relationship between risk perception and personal worry with the prioritised environmental issues at the steelworks. The quantitative analysis of the Q-sorts and the qualitative interviews both showed that the day-to-day work was unaffected by personal worry and risk.

Risk assessments of contaminated land often involve the use of generic bioconcentration factors (BCFs),which express contaminant concentrations in edible plant parts as a function of the concentration in soil,in order to assess the risks associated with consumption of homegrown vegetables. This study aimed toquantify variability in BCFs and evaluate the implications of this variability for human exposure as-sessments, focusing on cadmium (Cd) and lead (Pb) in lettuce and potatoes sampled around 22 con-taminated glassworks sites. In addition, risks associated with measured Cd and Pb concentrations in soiland vegetable samples were characterized and a probabilistic exposure assessment was conducted toestimate the likelihood of local residents exceeding tolerable daily intakes. The results show that con-centrations in vegetables were only moderately elevated despite high concentrations in soil, and mostsamples complied with applicable foodstuff legislation. Still, the daily intake of Cd (but not Pb) wasassessed to exceed toxicological thresholds for about afifth of the study population. Bioconcentrationfactors were found to vary more than indicated by previous studies, but decreasing BCFs with increasingmetal concentrations in the soil can explain why the calculated exposure is only moderately affected bythe choice of BCF value when generic soil guideline values are exceeded and the risk may be un-acceptable.