Colloids as a sink for certain pharmaceuticals in the aquatic environment
1School of Life Sciences, University of Sussex, Falmer, Brighton, BN1 9QG, UK.
Environmental Science and Pollution Research International
|December 22, 2009
Summary
Pharmaceuticals are present in aquatic environments, with colloids acting as significant sinks. This highlights the need to consider colloids in water quality models for accurate risk assessment.
Area of Science:
- Environmental Chemistry
- Environmental Science
- Analytical Chemistry
Background:
- Pharmaceuticals in aquatic environments are an emerging concern.
- Limited data exists on pharmaceutical concentrations in particulate phases.
- Current monitoring methods do not differentiate between soluble and colloidal phases, impacting bioavailability assessments.
Purpose of the Study:
- To investigate the concentrations and phase association (soluble, colloidal, SPM) of selected pharmaceuticals in UK river water, STW effluents, and groundwater.
- To understand the role of different phases in the environmental fate of pharmaceuticals.
Main Methods:
- Selected pharmaceuticals were analyzed in river water, sewage treatment works (STW) effluent, and groundwater.
- Colloids were isolated using cross-flow ultrafiltration (CFUF).
- Samples were extracted using solid-phase extraction (SPE) and microwave digestion, followed by LC-MS/MS analysis.
Main Results:
- Five pharmaceuticals (propranolol, sulfamethoxazole, carbamazepine, indomethacine, diclofenac) were detected in all sample types, with carbamazepine showing the highest concentrations.
- STW effluents were identified as a key source of these pharmaceuticals.
- Calculated partition coefficients indicated that aquatic colloids are more powerful sorbents for pharmaceuticals than sediments.
- Mass balance calculations revealed significant fractions of pharmaceuticals present in the colloidal phase (23-70% for propranolol, 17-62% for sulfamethoxazole, 7-58% for carbamazepine, 19-84% for indomethacine, and 9-74% for diclofenac).
Conclusions:
- Sorption to aquatic colloids is a major sink for pharmaceuticals in the aquatic environment.
- Strong pharmaceutical-colloid interactions can increase pharmaceutical persistence and reduce bioavailability.
- A holistic approach, including colloids, is crucial for future environmental fate investigations and water quality modeling of pharmaceuticals.
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