Treated wastewater effluent increases pharmaceutical concentrations and alters benthic microbial communities in...

Area of Science:

• Environmental Science
• Environmental Chemistry
• Microbiology

Background:

• Wastewater treatment plant (WWTP) effluent is a potential source of pharmaceuticals and personal care products (PPCPs) to surface waters.
• These biologically active compounds may select for resistant traits and taxa in aquatic microbial communities.

Purpose of the Study:

• To investigate if WWTP effluent is a point source of PPCPs to urban streams.
• To determine the effect of effluent inputs on benthic microbial community composition.
• To assess if effluent inputs increase the abundance of antibiotic resistance determinants in benthic microbial communities.

Main Methods:

• Collected water and sediment from urban and rural streams in the Chicago metro area.
• Quantified concentrations of 45 common PPCPs in water samples.
• Analyzed benthic bacterial community composition and quantified the abundance of the intI1 gene.

Main Results:

• A stream with high effluent flow (80%) showed increased PPCP concentrations and shifts in bacterial communities downstream.
• Decreased abundance of photosynthetic organisms was observed in the high-effluent stream.
• intI1 gene abundance was higher in urban streams compared to rural streams, suggesting watershed-scale impacts.

Conclusions:

• WWTP effluent can be a significant source of PPCPs, driving changes in aquatic microbial communities.
• While effluent impacts were observed in high-flow scenarios, intI1 gene abundance appears more influenced by broader watershed anthropogenic impacts.
• Non-point sources also contribute to PPCP pollution in urban streams.