Health problems related to the environment have become a major source of concern all over the world. The health of the population depends upon good quality environmental factors including air, water, soil, food and many others. The aim of society is to establish measures that can eliminate or considerably reduce hazardous factors from the human environment to minimize the associated health risks. The ability to achieve these objectives is in great part dependent on the development of suitable experimental modelling and interpretive techniques that allow a balanced assessment of the risk involved, as well as suggest ways in which the situation can be improved. Environmental Health Risk 2009 is the Fifth International Conference in this successful series and the topics covered include Air pollution; Water and soil quality issues; Risk prevention and monitoring; Ecology and health; Food safety; Toxicology analysis; Occupational health.