Laboratory-based experiments to determine the impact of application of glyphosate-containing herbicides (GCH) on the water quality role of pervious paving systems (PPS).

Sue Charlesworth, Fredrick Mbanaso, Steve Coupe, Ernest Okwudiri Nnadi

Research output: Contribution to conferencePaperpeer-review

Abstract

Laboratory-based experiments using test pervious paving (PPS) rigs were used to determine the effect of glyphosate-containing herbicides (GCH) on the PPS’s pollutant retention performance. The pollutant used was used engine oil and results found that GCH disrupted the ability of the PPS to retain hydrocarbons (HC) since they were released in increasing concentrations over time in the rig effluents. Background concentrations were below the limits of detection, but rigs with both oil and GCH added reached over 70 mg l-1 HC whilst those with just GCH applied reached 25 mg l-1 HC. Cloudiness observed in the effluents from rigs with GCH added were confirmed by turbidity monitoring whereby the higher the concentration of GCH added, the higher the turbidity. Measurement of pH declined with time, particularly in the GCH rigs. Both pH and turbidity were thought to be involved in the release of heavy metals, particularly Pb and Zn, which were of concern as they were close to WHO 2011 potable water guidelines. It is concluded that the surfactant in the GCH formulation may be forming an
emulsion with the oil, which is shown to contain high levels of metals, and this is then pushed through the geotextile, which is where biodegradation of oil usually takes place, and washes out through the PPS base layer. This study has raised concerns regarding the impact commonly used GCH formulations may have on receiving water quality, particularly with the introduction of legislation recently in the UK which encourages the use of sustainable drainage systems and therefore PPS.
Original languageEnglish
Publication statusPublished - 2013
Event8th International Conference NOVATECH: Planning & technologies for sustainable urban water management - Lyon, France, Lyon, France
Duration: 23 Jun 201327 Jun 2013

Conference

Conference8th International Conference NOVATECH
Abbreviated titleNOVATECH 2013
Country/TerritoryFrance
CityLyon
Period23/06/1327/06/13

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