Res 2011-037 (2) - Laserfiche WebLink

Home Browse Search

In addition, herbicides and insecticides typically purchased for residential use contain compounds that are commonly classified as suspected or known endocrine disruptors. Following application, these compounds may bind to soil particles or subsequently runoff into water systems during rain events. The Paso Robles Best Management Practices state that only organic herbicides and insecticides are to be used on the golf course. Residential lawns will be subject to guidelines concerning yard care as well, but there is still the possibility that common commercial herbicides and insecticides may be present. A further source of contamination concerning the development of Paso Robles could lie within the construction processes. Polycyclic aromatic hydrocarbons may be formed during the incomplete burning of oil, coal, or gas. In addition, these potentially carcinogenic compounds can be found in construction materials, such as asphalt (Barrett et al., 1995). The aquifer may also be exposed to volatile and semi -volatile organic compounds, which can be associated with products such as gasoline, paints, adhesives, and plastics. Many of these compounds are known or suspected carcinogens, and may enter the Edwards Aquifer through pathways such as urban runoff following rain events and exhaust from gasoline engines (Moran, Hamilton, Zogorski, 2006). Both organic and inorganic water soluble compounds will move with the water within an aquifer. Organic compounds which are less dense than water and are slightly soluble, such as petroleum hydrocarbons, will float on the water and often accumulate behind obstructions within the conduit systems. Organic compounds that are slightly soluble but denser than water, such as chlorinated hydrocarbons, often sink to the bottom of an aquifer and may even adhere to sediments. Over years, these compounds may degrade and once again rise into the moving water (Ford, Williams, 2007). It is thus imperative that water analysis be conducted in order to aid in the early detection and prevention of contamination to groundwater. It should be noted that existing developments, many of which currently contain septic tanks, are present in the surrounding area of the future Paso Robles site location. These developments could potentially be sources of contamination for some compounds analyzed in this study. In addition, Paso Robles will be located down gradient of industrial activity on Hunter Road (FM 2439), such as Texas Industries, Inc (TXI). This operation specializes in the production of cement, concrete, concrete products, and steel. In addition, coal piles have been observed on the property of TXI, which could potentially be a source of polycyclic aromatic hydrocarbons in the surrounding environment. Objective The purpose of this study is to: 1. Establish a baseline understanding of the water quality for the immediate region of the future Paso Robles development and associated golf course prior to construction. This will be done through the analysis of water samples from wells chosen based on an inferred likelihood of hydraulic connectivity to this site, both up gradient and down gradient from Paso Robles. 2. Monitor the quality of groundwater and that obtained from surface runoff following significant rain events during development to assess the effects of local construction, effluent applied to the golf course, the use of insecticides and herbicides, and general changes in water chemistry. The resulting data can then be used to analyze for a correlation between changes in groundwater quality and surface activity over the extremely permeable and structurally altered Edwards Aquifer recharge zone and associated up gradient contributing zone. -6-