Copper and Zinc Concentrations from an Artificial Turf Field

This study reports copper and zinc concentrations in stormwater runoff from a third-generation artificial turf field. Comparison is made between two different stormwater flow paths and metal concentrations. Third-generation turf fields are different from previous generation fields because crumb rubber is used as a shock absorber. Crumb rubber is typically sourced from recycled vehicle tyres and has been identified as a potential source of metals and organic contaminants. Contaminants are introduced during the tyre manufacturing process as plasticisers, vulcanisers and antioxidants. Two recent meta-reviews reported that there had been few studies of crumb rubber washoff in the field. This study set-out to monitor heavy metal concentrations in runoff from a newly installed third generation artificial turf field.

Automatic flow monitoring and water quality sampling equipment was installed in April 2013 and maintained for a 28-month period. The sampler was positioned to collect samples from a combination of surface runoff from the field and surrounding concrete path (hereafter ‘runoff’ flow) and subsurface field drainage (‘infiltration’ flow). Flow weighted samples were taken during storm events. The water samples were collected and transported to an accredited laboratory where they were analysed for total copper and zinc.

Over the monitoring period copper concentrations exceeded ANZECC 80% survival thresholds for 87% of samples and zinc thresholds for 26% of samples (sample n = 561). Zinc showed greater intra-event variability in concentration. Copper and zinc yield from the artificial turf field for the first three months was comparable to a heavily trafficked road (>20,000 vpd). Thirty-four events were sampled for Mass First Flush (MFF). Both metals demonstrated a range of MFF values, with zinc having a stronger overall response than copper. High MFF was observed when peak flow was high and the peak one-hour rainfall intensity was high. High rainfall intensity, high peak flows and high pollutant concentrations were linked to runoff. Infiltration flow had lower concentrations. Thus, redesign of the artificial turf field to reduce runoff flow could reduce pollutant yield.