Concentration (ng∙L−1)

Compound

*Pedras River

(lower side)

*Pedras River

(upper side)

*Parado River (upper side)

*Parado River (lower side)

Contaminated

samples (%)

Chlortetracycline

0

Demeclocycline

0

Doxycycline

0

Metacycline

0

Oxytetracycline

67

Tetracycline

0

Dapsone

0

Sulfacetamide

0

Sulfadimethoxin

0

Sulfamerazine

0

Sulfamethazine

0

Sulfamethoxazole

> MDL - 467.0

67

Sulphaquinoxaline

0

Sulfathiazole

0