AgdaPkt 2007-09-10 - Laserfiche WebLink

Browse Search

7A City ofRedwood City Page 4 2007 Public Health Goal Report MCLs are set by #he U.S. Environmental Protection Agency (USEPA) or the California Department of Health Services(CDHS)as the level which is required to be met in water systems. Violations of an MCL can result in a fine, abatement order, or closure of facilities. When the USEPA, or the CDHS, adopts an MCL, they take into accour.± such factors as (1) anaIytical methodologies; (2) effectiveness of available treatrnent technologies; and (3) benefits and costs. PHGs and MCLGs are not enforceable and are not required to be met by any public water system. Water Quatity Data Reviewed for this Repor# Water quality data collected by the City of Redwood City during 2�04, 2005 and 2006 for purposes of determining compliance with drinking water standards were reviewed in order to prepare this PHG report. This data was alI summarized in our 2004, 2005, and 200b Annual Water Quality Reports {also known as Consumer Con�dence Regorts (CCRs)) that were distributed to all of our customers though direct mail. Gt�ideIines Foltowed for Preparation of this Report The Association of California Water Agencies (ACWA) formed a workgraup which prepared guidelines for water utilities to use in preparing these required reports. Tl�e AGWA guidetines were used in the preparation of this report. Best Availab�e Treatment Technology and Cast Estirnates Both USEPA and CDHS adopt Best Available Technologies {BATs), which are the best known methods of reducing contaminant levels below the MCL. While a BAT may identify a process that can reduce the presence of a contaminant,the cost of implementation can be a major factor in deciding whether or not to adopt the process. For a systern that is in compliance with MCL levels, cost considerations must be a factor. Striving to keep contaminants below PHG/MCLG levels must be evaluated with costs in mind, Costs were estimated for the implementation of BATs for each constituent exceeding a PHG or MCLG. The PHGs and MCLGs are set much lower than the MCL, and it is not always possible or feasible to determine what treatment is needed to further reduce a constituent to, or below, the PHG or MCLG. In some eases, such as when the MCLG ar PHG is set at zero,there may not he commercially available technology to reach that level. The issue is further complicated because it is often not possible to verify by analytical means that the contaminant has been totalIy eliminated. In some cases, installing a treatment technotogy to try and further reduce very low levels of ane constztuent may,in turn,have adverse effects on other aspects of water quality. This report presents the required cost estimates to implement the BATs to reduce a contaminant to a level at or beiow the PHG/MCLG. CONSTITUENTS DETECTED THAT EXCEE➢PHG OR MCLG In reviewing water quality monitoring data coIlected during 2Q04, 2005 and 2006, City of Redwood City staff have concluded that a PHG report is required that addresses the following contaminant: 1. lead The following secti.on presents a discussion of the contaminant that was detected in customer's homes at levels abave the PHG. 2