Results of the second quarter of air testing in Midlothian by the Texas Commission on Environmental Quality are in with no alarming results reported.
The Texas Commission on Environmental Quality (TCEQ), in cooperation with the City of Midlothian, launched a year-long four-phase air quality study in the Fall of 2008. The study involves the collection of air samples from at least eight sites within and around the City of Midlothian - four fixed and four rotating locations.
“The second sampling quarter was held from Feb. 26 to March 2, 2009 and the TCEQ recently released the results,” said Tracie Phillips, Ph.D., TCEQ’s Toxicology Division. “The initial results may be reassuring to many: all toxic compounds tested in the study measured well within the state’s established levels for safe exposure.”
The second quarter sampled each of the four stationary sites as well as Mountain Peak Elementary School for the mobile site. The mobile sites are set up and measure air quality 24-hours a day for five days. The fixed sites measure air quality constantly during the study period.
Ambient air concentrations of volatile organic compounds, aldehydes, and carbonyls (VOCs) were measured at four of the five second quarter sampling sites: CAMS 52 collection at Old Fort Worth Road, Jaycee Park, Midlothian Water Treatment Plant and Mountain Peak Elementary School.
Ambient air concentrations of metals were measured at all five of the second quarter sampling sites: Wyatt Road, CAMS 52, Jaycee Park, Water Treatment Plant, and Mountain Peak Elementary School. These metals, called PM10 metals in the report, basically include a variety of heavy metals, specifically aluminum, chromium and manganese.
“For the purposes of this evaluation, only five compounds will be highlighted: aluminum, total chromium, hexavalent chromium, manganese, and benzene,” said Phillips. “These four metals represent the ones which citizens appear to be the most concerned about based on public inquiry, while benzene is a good benchmark chemical for all VOCs.
“It is important to note that field blanks, field duplicates and laboratory blanks indicate some level of metals are inherently present on the filters, which may bias all metals results high,” Phillips added. “However, all metals results are well below TCEQ health-based comparison values; therefore, any bias this may introduce is not relevant to this evaluation.”
The report railed at a USA Today newspaper article that brought political heat on TCEQ to gather its most recent data on air quality in Midlothian.
“As the state’s environmental protection agency, the TCEQ takes its role in protecting public health very seriously, and knows of no schools in Texas where ambient concentrations of air toxics are unsafe,” said Phillips.
“Based on the TD’s preliminary evaluation, some concerns about the methodology utilized by USA Today have been identified,” Phillips said. “The rankings of Texas schools by USA Today are based on theoretical modeling results of emissions data, not on a health effects evaluation of actual measured ambient air concentrations from air monitors.”
Ambient air concentrations of 60 VOCs were measured at four of the five, second quarter sampling sites and the report stated all measured concentrations of VOCs were well below their respective appropriate short-term comparison levels.
The report did indicate it made one measurement of acrolein at an elevated number.
At the CAMS 52 monitor on Feb. 26, acrolein had a measurement of 2.47-parts-per-billion (ppb). The short-term level for acrolein is 1 ppb.
Acrolein is a very reactive component of ambient air that is formed from the breakdown of other organic chemicals. It can be emitted by several different types of sources (automobiles, power plants, natural and manmade fires, cigarettes) and due to its reactivity is very difficult to reliably measure in ambient air.
TECQ’s report said second quarter data for aluminum, chromium, and manganese all appear similar to historical data collected by the state in previous studies.
“The historical February-March data appear to be similar to the second quarter data, which indicate that these values are typical for this time of year,” said Phillips
“Overall, the highest concentrations were measured at the Wyatt Rd site, with the CAMS 52 collocated and Jaycee Park sites being the second highest when winds were such that those sites were positioned downwind of nearby industry,” Phillips said. “For the Wyatt Rd and CAMS 52 sites the highest measurements were observed on sampling day one, while the highest measurement was observed on sampling day three for the Jaycee Park site.
“As with the day comparisons, the TD concludes that the monitors are sited at locations which allow TCEQ to monitor potential emissions from nearby industry with favorable wind conditions,” Phillips said in the report. “Overall, it appears that nearby industry does have a measurable impact on the levels of PM10 metals detected in air in the Midlothian area. However, the levels detected are low, well below the TCEQ health-based screening values, and are not of health concern. Therefore, we would not expect to see a health impact from the observed levels of PM10 metals.”
Air pollution has garnered its share of headlines across the Metroplex over the past five years as the state tries to implement green standards and EPA air quality requirements.
The state gathered a group of area residents, including those who have long opposed heavy industry emissions in Midlothian and asked them what chemicals and compounds they wanted to have measured. One of the compounds was chromium, the type of element made famous in the movie “Erin Brockovich,” who visited Midlothian several years ago at the request of a local friend to complain about pollution.
Metroplex elected officials have repeatedly pointed to Midlothian’s three cement kilns and steel recycling mill as the source or air pollution in Dallas and Fort Worth, despite the fact there are an estimated 800,000 cars and hundreds of factories in the area.
Both the City of Midlothian and Midlothian Independent School District officials have said they want the data collected in the TCEQ report – good or bad – to be made public.
The complete report can be viewed at the City of Midlothian’s website at www.midlothian.tx.us/DocumentView.aspx?DID=767
TECQ’s Tracie Phillips can be reached by e-mailing firstname.lastname@example.org or calling 512-239-2269.