SELECTION SUMMARY
도입 판단 요약
Public Health – Seattle & King County and the Hazardous Waste Management Program are providing data describing the lead content of consumer products. This data is collected from several sources, including community product testing events, in-home investigations of lead-poisoned children, and products purchased for testing for research projects. Data are presented using two types of testing methods: product screening using X-ray fluorescence (XRF) analysis and laboratory analysis . Because XRF screening can be conducted without destroying the object to be tested, this method was used to test products that could not be submitted to the laboratory for analysis. Examples of the types of products tested via XRF analysis include keys, jewelry, cookware, dishware, toys, and other essential or valuable items. However, it is important to note that XRF analysis is only a screening method that gives approximate results and may have high detection limits for some products. Although XRF analysis is very useful for identifying products that could contain relatively high lead levels, it cannot be used to compare lead results to regulatory limits or standards. Laboratory analysis is the “gold standard” for product testing. Laboratory analysis can theoretically achieve detection limits for lead in the part per billion (ppb) range, although the detection limits can be higher if not enough sample is provided for analysis and/or the sample is chemically very complex (causing “matrix interference”). Examples of the types of products tested via laboratory analysis include seasonings, cosmetics, candy, dietary supplements, and other items that can be destroyed for analysis. Laboratory results can be used to compare lead concentrations to regulatory limits or standards. Laboratory methods used to analyze consumer products for lead content include graphite furnace atomic absorption (GFAA), inductively coupled plasma mass spectrometry (ICP-MS), and inductively coupled plasma optical emission spectroscopy (ICP-OES). Technical notes: Regardless of the method used, the lead concentrations are provided in parts per million (ppm). One part per million is equivalent to 0.0001 percent. One percent is 10,000 ppm. See the Lead Limits for Consumer Products table below for how we compared the lead concentrations in the tested products to acceptable limits. Every testing method has limitations in the smallest amount of lead that can be detected in a product. For the XRF analyzer, the instrument’s limit of detection (or LOD) varies depending on the sample’s chemical composition, shininess, curvature, positioning, and operator factors. For laboratory analysis, the relevant detection limit – the limit of quantitation (or LOQ) - can also vary, depending on the chemical complexity of the sample, the amount of sample collected, how the sample is prepared, and how it is analyzed. Therefore, where results are presented with the "<" (less than) symbol, it means the lead concentration is some number less than the reported value (i.e., the LOD or LOQ). It is not possible to compare results presented as below the LOQ or LOD to lead limits. For some research projects, the median XRF result may also be represented with a qualifier if more than 50% of the measurements were below the LOD. For research projects, the XRF value presented is the median of all measurements taken on the product. For all other data sources, the XRF value presented is the maximum of all measurements taken. Disclaimer: Staff collect information as it appears on product labels or as reported to staff during community events and investigations. Factors such as language barriers and terminology variations may result in misspelling and mislabeling of some products. The amount of lead found in a consumer product can also vary greatly because of variation
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