As part of the ongoing investigation to identify and address sources of hexavalent chromium in the City of Paramount, the South Coast Air Quality Management District (SCAQMD), with assistance from the California Air Resources Board (CARB), is conducting air sampling for this metal at schools in Paramount. The objective of this sampling effort is to assess whether elevated levels of hexavalent chromium (found in some industrial areas) may also be found at the local schools.
SCAQMD has published an updated assessment of the monitoring data from the school sites. The previous reports (from February 22, 2017 and April 12, 2017) can be found on the aqmd.gov website.
Sampling began on December 23, 2016 at six Paramount area schools. Sampling is conducted over a 24-hour period every third day (one 24-hour sample every third day, or 1-in-3 day sampling schedule). At each Paramount school site, a minimum of seven valid results are used in the assessment. With this sampling schedule, seven data points represent a minimum of two-and-a-half weeks of monitoring, and is a reasonably balanced assessment of the levels at that location during this time period. Sometimes, a sample is determined to be “invalid” due to loss of power in the sampler, equipment malfunction, or other reasons. To ensure high quality data, invalid samples are not part of this assessment.
To date, this sampling effort resulted in the collection of at least seven valid samples from each of the 12 Paramount area schools surveyed by SCAQMD and CARB.
The overall sampling results from that school will be compared to “background” or typical hexavalent chromium levels found elsewhere in the South Coast Air Basin. If the levels at a school are relatively consistent with levels at MATES IV monitoring sites near Paramount, then no further investigation at that location is needed. Because it is long-term exposure to Cr6 that is associated with increased cancer risk, the key comparison is for the average levels of Cr6, although the range of measured levels is also part of the assessment.
The full report can be viewed on SCAQMD’s website, following this link.
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