Investigating the estrogenic risk along the river Po and its intermediate section

Area of Science:

• Environmental Chemistry
• Ecotoxicology
• Ichthyology

Background:

• Estrogenic risk assessment in the middle River Po is crucial due to potential contamination.
• Previous findings indicated intersex conditions in barbel, necessitating further investigation.

Purpose of the Study:

• To investigate the occurrence and sources of estrogenic risk in the middle River Po.
• To correlate chemical contamination with observed biological effects in fish.

Main Methods:

• In vitro yeast assay for estrogenic activity detection.
• Chemical analysis of water, fish bile, bed sediments, and macroinvertebrates for eight estrogenic compounds.
• Histologic examination of barbel gonads for intersex conditions.

Main Results:

• Recombinant yeast assay detected limited estrogenic activity, except in one carp near the River Lambro.
• Diffuse contamination by eight estrogenic chemicals found in the middle River Po, with River Lambro identified as a major source.
• Higher concentrations of natural steroids and xenoestrogens detected in downstream sediments and macroinvertebrates.
• Histologic analysis confirmed intersex gonads exclusively in barbel from the downstream stretch.

Conclusions:

• The middle River Po exhibits estrogenic disrupting conditions.
• The River Lambro tributary contributes significantly to the estrogenic contamination of the River Po.
• A cause-effect relationship between estrogenic contamination and intersex conditions in barbel is suggested.