The highest level of detergents was obtained in the interior of the Santos Channely in front of Channel 6 and also in the vicinity of the Santos ocean outfall diffusor. There are thus three principal soucers of detergents in this region: a. the Cubatão industrial complex, and the Billings reservoir; b. the city of Santos (unauthorized sewage connections); c. the ocean outfall. Detergent levels obtained vary between 0.11 and 0.97 ppm ABS.