SU0003944 SSCRPT - Laserfiche WebLink

Home Browse Search

T -_ -7 However -as documented in several Surface and Subsurface Contamination Reportsdone for other ' - projects in San Joaquin County; the sur face and subsurface-soils that currently compose the Linn. r -- Estates project will.undergo significant clanges during the initial-phases of Project development. This-factwas also discussed ii our 1999`S SCR for the Castello Estates project:. Attached _- :photographs show the Castello Estates project presently under oin develo-ment and illustrate the' == __.. g g P 3 dramatic changes from the original "in-place" surface ods The soil cuts and f lls are substantial. A. In the street areas, the cuts_ are approximately three feet with the pads built-up two feet. Therefore it is our opinion that preliminary_sampling and analysis for adverse constituents in the soil are not warranted due to these dramatic changes in the soils that will occuf;during development of the Linne Estates project. Additionally, soil chemistry alterations caused bye } - - - _ - _ environmental factors including increases ii ultraviolet light exposure,-moisture content, aeration;. - � - all lead to-a decrease in organic matter.-Thc attached environmental fate data for DDT and its w - .. = - _ ' degradates document an affinity for organic matter.Since most of the property`has been in agricultural production, organic_matter.in these_soils would be' assumed to be higher than in non-Ar - - t agricultural soils. However, the"changes in soil chemistry brought on by the environmental factors T r specified above,will def nitely lead to an increase in sail oiganic matter decomposition and = F subsequent DDT degradation - _ _ Final concentrations of DDT and its degradates in the-play areas or garden areas of each new single P¢,family residence cannot be predicted;and`prohably Wwi11 not exist after earthwork: It must be y �after e i _ RF R emphasized that ingestion data to determine adverse health effects from.DDT, DDD, DDE'is -_ primarily basedu on a�"worst-case scenario" a€a child eating specific c volumes of soil each day. p Y gip. _ g p s. Y 4 These children and this abnormality are.called:"pica children" because of their'craving for .�s. 1 . unnaturalfood. Obviously;parents who may have children with this conditionmust prevent_ ingestion of sail by their children thus eatl reducin the risk of DDT toxicology. ' Y g v .The one-square mile Iand'area, 6r, section" bound by Valpico Road to the north, Linn' Road to the .'_ south,Chrismaii Road to the east and MacArthur Road to the westis_commonly referred to as the o _ _ - _ "Valpico Section'," -Sources contributing nitrate to the groundwater under thissection includes _ _ -. upgradient agricultural fertilizer inputs;:.septic systems (particularly.from sump and pits); - - NP lawnllandscape fertilization, indigenous soil concentrations from :.organic'inatter and-- - 9- f Factors decreasing the groundwater nitrate concentration-include denitrification; groundwaier.movement(bath vertical and horizontal); i.ell`pump- 9 and well Hydraulics, and cleaner. .w water recharge-from stormwater retention basins and the-Wastewater Treatment Plant contributing a. - dilution effect. Therefore"if each of these sources and attenuating factors could be quantified on,a mass balance basis;rtAmay be that nitrate inputas now roughly..equivalent to output,-or what could be regarded as equilibrium. Given that agricultural irrigation recharge`s the largest single contributor to } - 4 w =- - groundwater nitrate concentrations, and since the surrounding land has�been farmed for several decades, it is assumed that the riitrat oncentration5 in the underlying groundwater should be much::. E higher than those observed, if the attenuating factors were not significant. : _ - - - . _ 10 - ehavw .Cortsulti -: _ _