Methodology for the analysis of selected pharmaceuticals and drugs of abuse in sediments and sludge

March 2010

Background to research

Pharmaceuticals are potentially of concern in the environment as certain drugs are ubiquitous, persistent and biologically active compounds with recognised endocrine disrupting functions. Even low concentrations of these compounds may lead to unwanted effects in the environment. Currently very little data exist on the levels of pharmaceuticals in the Scottish environment. In addition to pharmaceuticals, illicit drugs and personal care products have also been reported as being common in samples analysed from wastewater treatment works. The widespread use of human pharmaceuticals, illicit drugs and certain personal care products suggests a number of these compounds could be discharged into the environment. It is possible that certain pharmaceuticals may partition to sediment and sludge and subsequently accumulate in sediments and soils (following the disposal of sludge to land). The aim of this project was to identify, based on prescription and physico-chemical data, which human pharmaceuticals may be present in Scottish sewage sludge and freshwater sediments along with selected illicit drugs and bactericides in personal care products, and then to develop a suitable analytical technique for establishing which compounds may be present in a suite of validation samples.

Objectives of research
The objectives of the research were to:

  1. Identify a list of target compounds based on sales and chemical properties e.g. the likelihood of products or metabolites to partition into sludge and sediment and accumulate and/or bio-accumulate.
  2. Conduct a literature review to ascertain the likelihood of the preliminary list of compounds being present in sludge and freshwater sediment.
  3. Develop a suitable analytical and extraction method for the determination of the selected pharmaceuticals and drugs of abuse in sewage sludge and freshwater sediment.
  4. Perform a pilot screening study as part of the method validation process to determine if the developed technique(s) can detect the target compounds in sludge from three different sewage treatments works and the respective upstream and downstream river sediments.

Key findings and recommendations
The key outcome of this report is a robust and validated analytical method for the analysis of a selection of pharmaceutical compounds, illicit drugs and personal care product bactericides in sediments and sludges. The method was suitable for the analysis of the selected illicit drugs amphetamine, benzoylecgonine, cocaine, and methamphetamine, the pharmaceuticals atenolol, bendroflumethiazide, carbamazepine, citalopram, diclofenac, fluoxetine, ibuprofen, salbutamol and the bactericides triclosan and triclocarban. The method provided an overall recovery of between 56 and 128%, RSDs of between 2 and 19% and LODs of between 1 and 50 ng/g. The illicit drugs cocaine, its metabolite benzoylecgonine, amphetamine and methamphetamine were not detected in any of the samples analysed. Triclosan and triclocarban were present at the highest concentrations and frequency of detection. These compounds were detected in all but one sample and showing a pattern of co-occurrence in both sludge and sediment samples. A key recommendation of this project is to apply the methods developed to a greater number of samples in order to get a more detailed understanding of the level of pharmaceuticals, personal care products and illicit drugs in the Scottish environment.

Key words: Pharmaceuticals, drugs of abuse, triclosan, triclocarban, sediments, sewage sludge

Copies of this report are available from the Foundation, in electronic format on CDRom at 20.00 + VAT or hard copy at 25.00, less 20% to FWR members.

N.B. The report is available for download from the SNIFFER Website