General methodology:

Chemicals present in the water samples were analyzed using a variety of techniques capable of detecting a very large range of compounds. Analytical results were screened for a long list of potential cancer-causing agents and chemicals that may disrupt endocrine function. Sophisticated data analysis approaches were applied to discover compounds that were associated with observed endocrine disrupting activity. Significant differences between chemical profiles and endocrine activity in drinking water were compared between areas with different breast cancer rates, areas relying on different types of source water and treatment technology, neighborhoods with different poverty rates, and across seasons.