Contaminants of Concern in Reclaimed Water & Biosolids Amended Turf
Grass
By Dana Devin-Clarke, University of Washington
A study was conducted to determine the fate of estrogens, triclosan (an antimicrobial) and ibuprofen in
turf grass soils amended with biosolids. The study was conducted with turf collected from the Foster Links golf course in Tukwila,
WA.
This course may be one of the first to use reclaimed water from the King County South Wastewater Treatment Plant. The study was done to
document turf
response to reclaimed water as well as the fate of these Contaminants of Concern (COCs) in the soils irrigated with reclaimed water or amended with
biosolids. The study
was conducted in a greenhouse at the University of Washington. Biosolids were added to the surface of the turfgrass at 38 Mt ha. Grasses
were grown for 6 months. Leachate water was collected periodically during the study. At the end of the study, soils from each pot as well
as plant samples were analyzed for total concentrations of each of these compounds.
For both the leachate water and the soil samples, Ibuprofen was below the detection limit for all
sampling intervals. This result is in line with what has been seen in the literature - Ibuprofen does not persist in soils, although effective
for headaches, it is not a concern for soil systems.
Triclosan also degraded rapidly in the soils. Although still above detection limits, the soil
concentration of triclosan at the end of the study was over one order of magnitude lower than the calculated concentration (biosolids concentration x
application rate/ volume of soil) from what was initially added to the soil system. The initial concentration of triclosan in the
biosolids was about 35 ppm. The soil concentration at the start of the study was 0.6 ppm. By the end of the study, total concentration of
triclosan had decreased to 0.035 ppm.
A full report on the study will be finished this summer and results will be presented at the NBMA's 2008
Biosolids Management Conference.
