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Human biomonitoring: results of the DEMOCOPHES project
In the DEMOCOPHES project, 17 European countries including Belgium (and hence Brussels) tested a common approach for biomonitoring programmes. They produced data on the distribution of specific biomarkers and related lifestyle data for a defined study population. For the first time, this led to results for exposure to outdoor and indoor pollution that are comparable on a European scale.
Humans, animals and the environment are exposed to pollutants. Human biomonitoring (HBM) is a research method that ‘measures the concentration of pollutants in the human body by means of biomarkers’. Biomarkers are organic substances which are indicators for certain biological processes. In medicine, cells, proteins and genes are used as biomarkers for forming diagnoses. These markers are detected in urine, hair, blood, saliva, breast milk, fat or (for example) sperm. The amount of a polluting substance in the body and the way in which this substance is stored or processed by the body can give an idea of the potential health effects. HBM provides a direct measurement of the amount of chemicals present in the human body that come from the external environment or the living environment. HBM is a very useful tool for detecting trends (in time and space) in levels of exposure to environmental pollutants, or for identifying priorities. This knowledge can be used to inform the population or monitor policies.
The European pilot project 'DEMOCOPHES (DEMOnstration of a study to COordinate and Perform Human biomonitoring on a European Scale), involving Belgium and 16 other countries, ran from September 2010 to November 2012. The aim of this initiative was to determine whether a harmonised and coordinated approach to biomonitoring programmes on a European scale is feasible and to compare the results of different countries, where relevant.
Each of the participating countries worked in a similar manner on the basis of a common European protocol: the same pollutants were selected and comparable procedures were laid down for recruiting and communicating with the participants, for sampling, quality control, analysis of the data and statistical processing. The selected pollutants were: mercury and cadmium (heavy metals), cotinine (cigarette smoke), phthalates (softening agents in plastics), bisphenol A (which can be released from some plastic materials) and triclosan (a preservative found in cosmetics, personal care products, textiles and plastic). The presence of these pollutants in the body does not necessarily lead to health problems. They were included in the selection because their monitoring at European level was considered important. In addition, the use of some of these products has already been restricted.
In Belgium, urine and hair samples were collected from 129 mothers (< 46 years) and 129 children (6-12 years) in order to determine the concentration of these pollutants. Half the participants lived in rural and hence sparsely populated areas of Flanders and Wallonia (areas of Brakel, Ellezelles and Frasnes-lez-Anvaing), and the other half in an urban and hence densely populated area (the Brussels-Capital Region). The children were recruited from eight rural schools and five urban schools.
To supplement the samples, the participants were given a questionnaire which asked about their living environment and indoor exposure to: 1) combustion products and plastic components, 2) diet, 3) smoking behaviour, 4) use of care products, 5) hobbies that expose to metals or plastics 6) occupation and education. The responses to these questionnaires are important for the interpretation of the chemical analyses: lifestyle factors can affect the measured pollutant levels, and consequently give some idea of how the exposure has taken place.
Results for the Belgian study population
The questionnaire revealed that 33% of the mothers and 36% of the children ate local food (from a local grower or relatives or from their own vegetable garden), and 30% of the mothers and 20% of the children consumed fish several times a week. Half (50%) of the children ate food in a canteen.
About 9% of the mothers were smokers.
The vast majority (80%) of the mothers and 5% of the children had amalgam fillings (a source of mercury). About 20% of the participants had broken an energy-saving bulb or mercury thermometer.
Most of the mothers used a lot or quite a lot of care products such as make-up, shampoo, hair products, deodorant and perfume.
25% of the mothers and 6% of the children spent an hour every day in traffic. Half of the mothers (52%) reported that their house had been redecorated or refurbished in the past two years.
The measured concentrations of pollutants in the Belgian study population were almost all below the ‘health-based guidance values’ – as far as guidance values are available.
Apart from mercury and certain phthalate metabolites, the concentrations of pollutants in the air were below the European average.
The concentrations of all measured pollutants correlated well to very well between mothers and their children. This implies that the living environment (the home) and food consumption, which is fairly similar for all family members, were responsible for a significant proportion of their exposure. The values of most pollutants, such as mercury, triclosan, diethyl phthalate (DEP) and cadmium, were higher for the mothers. The reasons for this are that heavy metals accumulate with increasing age, and beauty products are used more by mothers than by children. These products may contain triclosan and/or phthalates. On the other hand, the values of all other measured phthalates were higher for the children. The presence of the plastic component bisphenol A in urine was similar for the mothers and their children.
Cadmium levels in both mothers and children were higher in urban areas than in rural areas (Figure 1a). For cadmium levels too, the Belgian values were elow the European average (Figure 1b).
Figure 1: (a) geometric mean (± 95% confidence interval) for urinary cadmium concentrations measured in Belgian mothers and children in both rural and urban areas. (b) urinary cadmium concentrations measured in Belgian and European mothers and children (geometric mean ± 95% confidence interval) (N = number of mothers/children).
This European pilot study showed that HBM on a European scale is feasible with the use of a coordinated approach. This makes it possible to compare the results, exchange experiences on an ongoing basis and formulate common priorities and advice.
This study shows that the presence of various environment-related pollutants in children and their mothers can be explained by the requested information on lifestyle, diet and living environment. This was made possible through the use of a customised questionnaire.