SCERP Project Number: W-5
Principal Investigator: Milton Sommerfeld
Arizona State University
SUMMARY
Urban lakes in the arid Southwest and specifically in the Phoenix metropolitan area serve as sources for irrigation water, catchments for urban runoff, water storage, effluent distribution systems, means of recharge for groundwater aquifers, enticements for residential and commercial development, and recreational resources for fishing, boating and incidental body contact activities.
The source waters for these lakes include pumped groundwater, other surface waters, treated effluent, and urban runoff. The relative proportion and composition of these source waters ultimately determines the quality of the lake's waters, the composition of the bottom sediments, and potentially the quality of underlying aquifers. Sampling and analysis of water quality and bottom sediments of urban lakes in the Phoenix metropolitan area were performed to provide a preliminary assessment of the presence and accumulation of biohazardous substances in the lakes. Urban lakes of the Phoenix metropolitan area are diverse in morphometry, age, and watershed characteristics. Chemically, the more than 20 lakes sampled differed noticeably in surface water lead concentrations and in sediment copper, lead, zinc and petroleum hydrocarbon concentrations.
Copper, lead and zinc were the primary metallic contaminants in both surface waters and sediments. Organic priority pollutants were typically undetectable in both surface waters and sediments. Petroleum hydrocarbons, however, were present in sediments. The factors that most strongly influenced accumulation of metals and petroleum hydrocarbons in lake sediments were age of the lakes and the total impervious area of the watershed.
Analysis of stormwater runoff into the lakes revealed that runoff was a common source of metals and petroleum hydrocarbons, but rarely a source of organic priority pollutants.
Last updated 7/1/99