The effect of triclosan on microbial community structure in three soils

• Published in: Chemosphere (Oxford) Vol. 89; no. 1; pp. 1 - 9
• Main Authors: Butler, E., Whelan, M.J., Ritz, K., Sakrabani, R., van Egmond, R.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.09.2012; Elsevier
• Subjects: Analysis of Variance; Animal, plant and microbial ecology; Applied ecology; Bacteria - drug effects; Bacteria - growth & development; Biological and medical sciences; Ecotoxicology, biological effects of pollution; Fatty Acids - analysis; Fundamental and applied biological sciences. Psychology; Fungi - drug effects; Fungi - growth & development; General aspects; Microbial; Microbial ecology; Phospholipids - chemistry; PLFA; Principal Component Analysis; Sludge; Soil; Soil - analysis; Soil Microbiology; Soil Pollutants - pharmacology; Toxicity; Triclosan; Triclosan - pharmacology; Various environments (extraatmospheric space, air, water); Soil; PLFA; Microbial; Triclosan; Sludge; Toxicity; Community structure; Phospholipid; Fatty acids; Sewage sludge; Soils; Microorganism; Microbial community; Organic compounds
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2012.04.002

► The effects triclosan on microbial community structure was explored using PLFAs. ► Community structure changes were complex. ► Soil type and time were the most important explanatory factors. ► There was a significant increase in the fungal:bacterial ratio with triclosan dose. The application of sewage sludge to land can expose soils to a range of associated chemical toxicants. In this paper we explore the effects of the broad spectrum anti-microbial compound triclosan on the phenotypic composition of the microbial communities of three soils of contrasting texture (loamy sand, sandy loam and clay) using phospholipid fatty-acid (PLFA) analysis. Each soil type was dosed and subsequently re-dosed 6weeks later with triclosan at five nominal concentrations in microcosms (10, 100, 500, 1000mgkg−1 and a zero-dose control). PLFA profiles were analysed using multivariate statistics focussing on changes in the soil phenotypic community structure. Additionally, ratios of fungal:bacterial PLFA indicators and cyclo:mono-unsaturated PLFAs (a common stress indicator) were calculated. It was hypothesised that triclosan addition would alter the community structure in each soil with a particular effect on the fungal:bacterial ratio, since bacteria are likely to be more susceptible to triclosan than fungi. It was also hypothesised that the PLFA response to re-dosing would be suppressed due to acclimation. Although the microbial community structure changed over the course of the experiment, the response was complex. Soil type and time emerged as the most important explanatory factors. Principal component analysis was used to detect phenotypic responses to different doses of triclosan in each soil. As expected, there was a significant increase in the fungal:bacterial ratio with triclosan dose especially in treatments with the highest nominal concentrations. Furthermore, the PLFA response to re-dosing was negligible in all soils confirming the acclimation hypothesis.