Potential microbial toxicity and non-target impact of different concentrations of glyphosate-containing herbicide (GCH) in a model pervious paving system

• Published in: Chemosphere (Oxford) 2014-04, Vol.100, p.34-41
• Main Authors: Mbanaso, F.U., Coupe, S.J., Charlesworth, S.M., Nnadi, E.O., Ifelebuegu, A.O.
• Format: Article
• Language: English
• Subjects: Bacteria - drug effects; Bacteria - metabolism; Biodegradation, Environmental; Biofilm; Biological and medical sciences; Carbon Dioxide - chemistry; Ciliophora - drug effects; Conservation of Natural Resources; Dose-Response Relationship, Drug; Drainage, Sanitary - methods; Environmental Pollutants - chemistry; Environmental Pollutants - metabolism; Environmental Pollutants - toxicity; Eutrophication; Fundamental and applied biological sciences. Psychology; Fungi - drug effects; Fungi - metabolism; General aspects; Glycine - analogs & derivatives; Glycine - chemistry; Glycine - metabolism; Glycine - toxicity; Glyphosate; Glyphosate-containing herbicide; Heavy metals; Herbicides - chemistry; Herbicides - metabolism; Herbicides - toxicity; Hydrocarbons - analysis; Hydrogen-Ion Concentration; Microbiology; Pervious paving; Time Factors
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2013.12.091

[Display omitted] •GCH concentration influences species richness of protists.•GCH concentration above 72mgL−1 was fatal to the protists.•GCH concentration above 720mgL−1 had adverse effect on the bacteria community.•Colpoda cucullus and Colpoda steinii may be used as biomarkers of GCH-polluted environment.•At GCH concentration of 72mgL−1, biodegradation processes may not be affected. Pervious Pavement Systems are Sustainable Drainage devices that meet the three-fold SUDS functions of stormwater quantity reduction, quality improvement and amenity benefits. This paper reports on a study to determine the impact of different concentrations of glyphosate-containing herbicides on non-target microorganisms and on the pollutant retention performance of PPS. The experiment was conducted using 0.0484m2 test rigs based on a four-layered design. Previous studies have shown that PPS can trap up to 98.7% of applied hydrocarbons, but results of this study show that application of glyphosate-containing herbicides affected this capability as 15%, 9% and 5% of added hydrocarbons were released by high (7200mgL−1), medium (720mgL−1) and low (72mgL−1) glyphosate-containing herbicides concentrations respectively. The concentrations of nutrients released also indicate a potential for eutrophication if these effluents were to infiltrate into aquifers or be released into surface waters. The effect of glyphosate-containing herbicides application on the bacterial and fungal communities was slightly different; fungi exhibited a “top-down” trend as doses of 7200mgL−1 glyphosate-containing herbicides yielded the highest fungal growth whilst those with a concentration of 720mgL−1 glyphosate-containing herbicides applied yielded the highest bacterial growth. In the case of protists, doses of glyphosate-containing herbicides above 72mgL−1 were fatal, but they survived at the lower concentration, especially the ciliates Colpoda cucullus and Colpoda steinii thus indicating potential for their use as biomarkers of herbicide-polluted environments. Data also showed that at the lowest concentration of glyphosate-containing herbicides (72mgL−1), biodegradation processes may not be affected as all trophic levels required for optimum biodegradation of contaminants were present.