Potential microbial toxicity and non-target impact of different concentrations of glyphosate-containing herbicide (GCH) in a model Pervious Paving System.
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 0.0484 m(2) 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 (7200 mg L(-1)), medium (720 mg L(-1)) and low (72 mg L(-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 7200 mg L(-1) glyphosate-containing herbicides yielded the highest fungal growth whilst those with a concentration of 720 mg L(-1) glyphosate-containing herbicides applied yielded the highest bacterial growth. In the case of protists, doses of glyphosate-containing herbicides above 72 mg L(-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 (72 mg L(-1)), biodegradation processes may not be affected as all trophic levels required for optimum biodegradation of contaminants were present.
Sustainable Drainage Applied Research Group, Coventry University, Coventry CV1 5FB, United Kingdom. Electronic address: mbanasof@uni.coventry.ac.uk.
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Mbanaso
Sustainable Drainage Applied Research Group, Coventry University, Coventry CV1 5FB, United Kingdom.
S J
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Coupe
Sustainable Drainage Applied Research Group, Coventry University, Coventry CV1 5FB, United Kingdom.
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Charlesworth
Sustainable Drainage Applied Research Group, Coventry University, Coventry CV1 5FB, United Kingdom.
E O
EO
Nnadi
Sustainable Drainage Applied Research Group, Coventry University, Coventry CV1 5FB, United Kingdom.
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AO
Ifelebuegu
D001419:Bacteria / Q000187:drug effects* / Q000378:metabolism; D001673:Biodegradation, Environmental; D002245:Carbon Dioxide / Q000737:chemistry; D016798:Ciliophora / Q000187:drug effects; D003247:Conservation of Natural Resources; D004305:Dose-Response Relationship, Drug; D004323:Drainage, Sanitary / Q000379:methods*; D004785:Environmental Pollutants / Q000737:chemistry / Q000378:metabolism / Q000633:toxicity*; D005658:Fungi / Q000187:drug effects* / Q000378:metabolism; D005998:Glycine / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism / Q000633:toxicity; D006540:Herbicides / Q000737:chemistry / Q000378:metabolism / Q000633:toxicity*; D006838:Hydrocarbons / Q000032:analysis; D006863:Hydrogen-Ion Concentration; D013997:Time Factors; D000097797:Glyphosate
D002245:Carbon Dioxide; D004785:Environmental Pollutants; D005998:Glycine; D006540:Herbicides; D006838:Hydrocarbons; D000097797:Glyphosate
Biofilm; Eutrophication; Glyphosate-containing herbicide; Heavy metals; Microbiology; Pervious paving