Chlorhexidine residues in sludge from municipal wastewater treatment plants: analytical determination and toxicity evaluation.

Content Provider	Europe PMC
Author	Golpe, Miguel Cobo Castro, Gabriela Ramil, Maria Cela, Rafael Santos, Ysabel Rodríguez, Isaac
Abstract	In this work, a procedure for the sensitive and selective determination of chlorhexidine in sludge from municipal sewage treatment plants (STPs) based on matrix solid-phase dispersion (MSPD) and liquid chromatography coupled to tandem mass spectrometry (LC–MS/MS) was optimized and validated. Analysis of sewage sludge samples, obtained from different STPs in Northwest Spain from 2018 to 2021, showed that chlorhexidine was ubiquitous in this environmental compartment with concentrations between 0.3 and 16 µg g−1. The toxicity of this pollutant was assessed in in vitro assays considering three different model organisms: Candida albicans, Escherichia coli, and Staphylococcus aureus. C. albicans was the most sensitive of the tested microorganisms to chlorhexidine with a lethal threshold concentration of 0.1 mg L−1. Thus, the lowest observed sludge residue was 3 times higher than the acute toxicity threshold measured for C. albicans. Moreover, E. coli and S. aureus were also affected at chlorhexidine concentrations around 1.8 mg L−1 and 0.5 mg L−1, respectively. So, chlorhexidine residues might affect the population of microorganisms existing in STPs. In addition, the potential phytotoxicity of the compound was evaluated with germination experiments using different model seeds. At the evaluated dose (10 µg g−1 dried soil), chlorhexidine did not affect the germination of Sorghum saccharatum, Lepidium sativum, or Sinapis alba seeds. Thus, amending agriculture soils with chlorhexidine containing sludge is unlikely to affect the germination of plants.Supplementary InformationThe online version contains supplementary material available at 10.1007/s00216-022-04214-0.
ISSN	16182642
Journal	Analytical and Bioanalytical Chemistry
Volume Number	414
PubMed Central reference number	PMC9278323
Issue Number	22
PubMed reference number	35829768
e-ISSN	16182650
DOI	10.1007/s00216-022-04214-0
Language	English
Publisher	Springer Berlin Heidelberg
Publisher Date	2022-07-13
Publisher Place	Berlin/Heidelberg
Access Restriction	Open
Rights License	Open AccessThis article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. © The Author(s) 2022
Subject Keyword	Chlorhexidine Matrix solid-phase extraction Liquid chromatography tandem mass spectrometry Sludge Ecotoxicity
Content Type	Text
Resource Type	Article
Subject	Analytical Chemistry Biochemistry