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} • • i ` j CCDuring the flood of 1997, there were severe boils in the northeast corner of the property. The U.S. Army Corps of Engineers imported massive amounts of gravel, cobble and boulders to shore up the levee and decrease water flow from the boils. This import material had to meet Corps regulations and would not have contained hazardous materials. CONCLUSIONS AND RECOMMENDATIONS From visual observations, there is no surface contamination. The probability of subsurface contamination from pesticides can be considered low-to-nonexistent. The surface soil type (<5 ft) is predominately silty clays, silts and sands. The biological activity of the finer soil types would be expected to be higher than in sandier soils, thus creating a favorable environment for microbial decomposition of organic molecules. The domestic well which serves the office facility and mobile home undergoes water softening and green sand filtration. In addition, bottled water is used for drinking and cooking purposes. The subject property is outside of delineated areas in which all new wells must have a grout seal to 200 feet. Although there is a significant amount of material being excavated to form the reclamation lake, consideration may be given to conducting a multi-residue pesticide screen on the infiltrated groundwater after excavation is complete. This may be especially prudent if the future lake is to be used for aquaculture. It is conceivable there may be groundwater impact from nitrate at the present time, or in the future, originating from agricultural inputs. From the orientation of the mobile home and office, it is assumed the on-site domestic well is crossgradient from the leachfield area. This assumption is based on the fact that groundwater is in all probability flowing northward toward the excavation area. As material is excavated from the reclamation lake, the hydraulics of the groundwater flow would create "recharge" from the interior limits of excavation. The well is grouted to 100 feet as illustrated on the well log. Contamination from a septic tank is usually dependent upon the age and type of tank construction material. The on-site septic system is relatively new. Since the density of septic systems in the surrounding area can be considered extremely low, it is highly unlikely there has been impact to the subject property. The density of systems is one of the prime factors for nitrate contamination of the underlying groundwater. Asbestos containing materials (ACMs) testing from any portion of the existing buildings is outside the scope of this investigation. It appears there would be no need for ACM testing since there are no existing residential structures to be demolished or remodeled. If additional raw sewage is unlawfully discharged from the referenced Mobile Home Park onto the subject property, testing should be conducted to delineate the release and determine the extent of environmental impact. 5 valley Ag Research