(The following message is posted on the Lakewood Water District website regarding concern over lead and copper levels in other communities)
Due to recent events in Flint Michigan and the growing public concern over the level of lead and copper content in potable water, Lakewood Water District has re-examined its historical data and methodology for complying with the Lead and Copper Rule (LCR) to be sure it is taking all necessary steps to ensure the health and wellbeing of its customers.
The primary issue facing Flint and many east coast cities is the corrosiveness of water and the potential for leaching toxic metals, including lead and copper, into the water system. Corrosion will occur anywhere a galvanic cell or field can be established. To establish the field, all that is needed is two dissimilar metals that are connected directly or indirectly by an electrolyte such as water. The degree of corrosion in a potable water system is determined by the water’s chemical make-up. The basic rule of thumb is the lower the pH, the more corrosive or “aggressive” the water. Hardness (as measured by the amount of Calcium Carbonate CaCo3) and temperature are also possible indicators of the aggressive potential of water.
The District’s sole source of water is ground water from thirty (30) active wells. The District is fortunate to be able to draw from four different aquifers underlying its service boundary area. Therefore, water in any given water storage facility or portion of the distribution system or an individual customer’s residence at any given time can be a blend from several different wells from up to four different aquifers. The overall degree of blending is dependent upon time of day, time of year, system demand, and source availability. The District has installed continuous chlorine and pH analyzers at all storage and treatment facilities as well as several booster station facilities. The analyzers combined with the District’s SCADA system provide real-time water quality monitoring capability.
Due to the blended nature of the water, the District calculates the average Hardness to be on the low end of the “moderately hard” scale with a system average of 70 mg/L. The District’s pH averages between 7.0 and 7.4 which is slightly alkaline. This combination of pH and Hardness does not constitute aggressive or highly corrosive water, validating the fact the District’s water has not historically had issues with extensive lead or copper corrosion. In fact, evidence from sampling data and the infrastructure Replacement and Rehabilitation (R&R) program suggests the pH and Hardness combination stimulates the generation of a biofilm lining of pipes thereby directly inhibiting any corrosive conductivity of the water.
Since the advent of the LCR, the District has been diligent in following its customer tap lead and copper sampling protocol. Since 2001, the highest lead test result from a customer tap is 0.004 mg/L (parts per million) or 4 µg/L (parts per billion) with the sample average <0.002 mg/L. The present Action Level for lead under the LCR is 0.015 mg/L or 15 µg/L. The highest copper test result from a customer tap is 0.72 mg/L. The Action Level for copper is presently set at 1.3 mg/L. June 2014 test results show a copper sample average of 0.16 mg/L. The District employs an independent laboratory (Water Management in Tacoma) to process all its reporting samples. The lab sends the sample results directly to the Washington State Department of Health, thereby eliminating any potential possibility of tampering with or falsifying data by District personnel. Once the District receives the test results, it immediately sends the results to all customers who willingly participated in the program. The District regularly conducts before-treatment Inorganic Compound (IOC) tests on its source wells. Lead and copper levels in the raw water are two of the twenty-nine elements sampled for in the IOC test. The average system-wide well source lead test results equal 0.002 mg/L, well below the LCR 0.015 mg/L Action Level. The highest result for copper in the test data equals 0.03 mg/L with the system average of <0.02 mg/L. Can what happened in Flint happen in Lakewood? Unlikely…very unlikely; State law specifically prohibits the District from changing its source water without conducting extensive testing to absolutely ensure there are no negative effects on the District’s customer base. The District has always been and will continue to be committed to provide the highest quality water possible.
NOTE: We understand this writing is long and quite technical, but we felt it was important to give you this level of detail in light of the importance of the matter.Print This Post