Septic systems as hot-spots of pollutants in the environment: Fate and mass balance of micropollutants in septic drainfields.
Septic systems, a common type of onsite wastewater treatment systems, can be an important source of micropollutants in the environment. We investigated the fate and mass balance of 17 micropollutants, including wastewater markers, hormones, pharmaceuticals and personal care products (PPCPs) in the drainfield of a septic system. Drainfields were replicated in lysimeters (1.5m length, 0.9m width, 0.9m height) and managed similar to the field practice. In each lysimeter, a drip line dispersed 9L of septic tank effluent (STE) per day (equivalent to 32.29L/m(2) per day). Fourteen micropollutants in the STE and 12 in the leachate from drainfields were detected over eight months. Concentrations of most micropollutants in the leachate were low (<200ng/L) when compared to STE because >85% of the added micropollutants except for sucralose were attenuated in the drainfield. We discovered that sorption was the key mechanism for retention of carbamazepine and partially for sulfamethoxazole, whereas microbial degradation likely attenuated acetaminophen in the drainfield. This data suggests that sorption and microbial degradation limited transport of micropollutants from the drainfields. However, the leaching of small amounts of micropollutants indicate that septic systems are hot-spots of micropollutants in the environment and a better understanding of micropollutants in septic systems is needed to protect groundwater quality.
Soil and Water Quality Laboratory, Gulf Coast Research and Education Center, University of Florida, 14625 CR 672, Wimauma, FL 33598, USA.
Yun-Ya
YY
Yang
Soil and Water Quality Laboratory, Gulf Coast Research and Education Center, University of Florida, 14625 CR 672, Wimauma, FL 33598, USA. Electronic address: gstoor@ufl.edu.
Gurpal S
GS
Toor
Environmental Chemistry and Toxicology Laboratory, University of Florida, Soil and Water Science Department, 110290, Gainesville, FL 32611, USA.
P Chris
PC
Wilson
USDA-ARS, US Arid Land Agricultural Research Center, 21881 N. Cardon Ln, Maricopa, AZ 85239, USA.
Clinton F
CF
Williams
D004784:Environmental Monitoring; D005431:Florida; D060587:Groundwater / Q000032:analysis*; D014865:Waste Disposal, Fluid / Q000379:methods*; D062065:Wastewater / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis*
D062065:Wastewater; D014874:Water Pollutants, Chemical
Degradation; Drainfields; Leaching; Micropollutants; Septic systems; Sorption