Inhibition of retinoid activity by components of a paper mill effluent

A cell line stably transfected with reporter genes activated by retinoic acid was used to test a paper mill effluent for the presence of retinoids or components that interfere with retinoic acid-stimulated gene transcription. No retinoids were detected in effluent or control water. However, effluent water significantly decreased reporter activity stimulated by all-trans-retinoic acid, while activity stimulated by 9-cis-retinoic acid was unaffected. In a limited fractionation through a C-18 solid phase-exchange column the inhibitory activity was retained in the aqueous fraction, indicating that the activity was polar.