Laserfiche WebLink
W� <br /> TO : R . Gwilvm .�� � <br /> FROM: K . Hagelstein <br /> Lgk <br /> DATE : July 27 , 1993 <br /> RE : Health Implicati ns of Lead in the Groundwater- <br /> Quarterly Groundwater MOnitoring , <br /> Diamond Lumber Retail Facility <br /> Lodi , CA <br /> The following discussion focuses on the human health impact of lead <br /> in the groundwater at Lodi . The chemistry , fate , and transport of <br /> lead will be discussed with respect to its potential movement into <br /> the groundwater supplies. The health effects and symptoms of <br /> ' chronic lead poisoning will be explained . The regulated and <br /> recommended standards for drinking water and general exposures to <br /> lead in U . S . drinking water supplies will be documented . <br /> 1 <br /> BACKGROUND GROUNDWATER LEAD CONCENTRATIONS <br /> The concentrations of lead in the groundwater at Lodi are found in <br /> Table 2 . Five sampling rounds in the three monitoring wells <br /> indicated that the EPA Maximum Contaminant Level ( MCL ) of 0 . 015 <br /> mg/l was exceeded in eight ( ranging from 0.018 to . 260 mg/1 ) of the <br /> fifteen samples over the period between November 1991 and June <br /> 1993 . All three wells showed MCL exceedances, but SRK/MW 2 had the <br /> highest concentration and exceeded the standard in the last <br /> sampling round of June 28 , 1993 . The dissolved lead concentrations <br /> taken in the last sampling round were less than 0.001 mg/l . <br /> ' The general trend in these lead concentrations is decreasing over <br /> time . The mechanisms for lead entering the groundwater system is <br /> complicated by the chemistry of the soils, groundwater , and sources <br /> of lead - <br /> ENVIRONMENTAL <br /> ead _ENVIRONMENTAL FATE , TRANSPORT , AND CHEMISTRY OF LEAD <br /> ' Lead is a heavy metal that exists in one of three oxidation states . <br /> Although lead generally has a low solubility in water , some <br /> industrially produced lead compounds are readily soluble . Metallic <br /> 1 lead and the common lead minerals are generally insoluble in water . <br /> Natural compounds of lead are not usually mobile in normal surface <br /> water or groundwater because the lead leached from the ores is <br /> adsorbed by ferric hydroxide or combines with carbonate or sulfate <br /> ions to form insoluble compounds . <br /> Sorption processes appear to exert a dominant effect on the <br /> distribution of lead in the environment . Adsorption to inorganic <br /> solids, organic materials and hydrous iron and managanese oxides <br /> usually controls the mobility of lead and results in a strong <br /> partitioning of lead to the bed sediments in aquatic systems. The <br /> sorption mechanism most important in a particular system varies <br /> with geological setting , pH , Eh , availability of ligands , dissolved <br /> and particulate ion concentrations, salinity , and chemical <br />