Background Human Biomonitoring involves collecting tissue samples, such as urine, blood, hair, saliva or nails, from volunteers and measuring chemical uptake and effect known as biomarkers in those indicators. For a given chemical, human biomonitoring surveys can highlight spatial trends of exposure, help uncover contributing lifestyle factors, and indicate at-risk groups. With the integration of other data, biomarkers can be translated into intervention strategies or early-warning tools aimed at reducing exposure to environmental pollutants. Human biomonitoring has long been used for the medical surveillance of workers, and is increasingly used as a tool in research and environmental health policy developments. The European Environment and Health Strategy, launched in June 2003 by the European Commission as the SCALE initiative, paid particular attention to its potential. The technical working group on biomonitoring of children found that while significant resources were provided for the collection of biomarker data in environmental health within the EU, these studies were generally not using the same methodological approaches, making it difficult to compare the results. Moreover, differences in capacities and levels of expertise remained high. Some Member States already had national and regional human biomonitoring programmes embedded in their policies, while others had only carried out some dedicated studies or were still in the process of starting first studies. Objectives The main objective of the DEMOCOPHESII project was to demonstrate the feasibility of a harmonised approach to human biomonitoring in Europe by implementing a pilot study in 17 European countries, and sharing the expertise with a further four ad hoc members. The work was guided by the research project COPHES (COnsortium to Perform Human biomonitoring on a European Scale), which prepared guidelines and protocols for all tasks, trained beneficiaries, delivered preparatory materials and evaluated the process within the framework of a FP7 Concerted Action that started in December 2009. The common activities of DEMOCOPHESII and COPHES were aimed at providing results at EU, Member State and stakeholder levels to help achieve a coherent approach to human biomonitoring in Europe. Results In the LIFE DEMOCOPHESII project, 17 European countries tested a common approach for human biomonitoring surveys developed by COPHES. They produced data on the distribution of specific biomarkers and related lifestyles among defined study populations, which could be directly compared for the first time at a European scale. With the feasibility of an EU-harmonised approach being demonstrated, policy-makers could start to envisage a European human biomonitoring survey programme using the lessons learned. Teams in 17 European countries studied exposure to mercury, cadmium, tobacco smoke and some phthalates, and their possible relations to lifestyle, using biomarkers and questionnaire data. The national teams translated the European common protocol, which describes in detail how to implement the study; with small adaptations being allowed for cultural differences that did not compromise the comparability of the results. Participants were children aged 6-11 years and their mothers aged 45 years and under. Fieldworkers in the participating countries collected hair and urine samples from a total of 3 688 volunteers, half from urban areas and half from rural areas. Mothers provided details on their living environment, nutrition, smoking behaviour, and other information that could help to explain the levels of the biomarkers measured. The laboratories analysing the samples were selected through a strict quality assurance process. Statistical analysis and interpretation of the results was performed in each country as well as at EU level, with data being transferred to a central European database. The results of the demonstration study showed clear links that could be used for policy-making at national, EU and international level. Exposure to environmental stressors such as phthalates, for example, from vinyl compounds in buildings, personal care products or convenience food packaging, could be regulated if deemed necessary. Cotinine (a biomarker for nicotine) concentrations in children's and mothers' urine showed how the EU anti-smoking policy is effectively applied, with lower levels found for countries where bans on smoking in public areas have been enforced. Other environmental benefits could arise from policy-making based on human biomonitoring data relating to diet and health issues, for example, looking at mercury levels in populations consuming a fish-based diet. In the medium to long-term, the knowledge of the total exposition to chemical components in food and other products could contribute to healthier lifestyles, awareness-building, and to science-based health and environmental policy at EU Member State and European level. Human biomonitoring might become a very important tool for decision-makers looking at maximum concentration levels for certain substances, food and consumer goods safety, and other related areas. The DEMOCOPHESII project therefore succeeded in demonstrating the feasibility of human biomonitoring on a European scale, and it established links between specific consumption patterns, lifestyle or environmental conditions and the presence of certain biomarkers in the human body. Further information on the project can be found in the project's layman report and After-LIFE Communication Plan (see "Read more" section).