Estrogen pollution in a highly productive ecosystem off central-south Chile

► We measured steroid estrogen levels in 54 coastal sediments receiving sewage waste. ► Estrogen pollution appears pervasive along the coast of central-south Chile. ► High levels of the very potent synthetic estrogen 17α-ethinylestradiol are detected. ► Estrogenic loads are linked to the human population size served by sewage plants. ► 17α-ethinylestradiol in marine systems may cause environmental and health damages.