Evaluation of metal aerosols in four communities adjacent to metal recyclers in Houston, Texas, USA

Abstract

The metal recycling industry provides jobs, generates revenue in local communities and conserves energy and resources. Nonetheless, possible negative impacts of metal recyclers (MRs) include the potential for emissions of metal aerosols and other dusts, noise, traffic and fire during operations. In Houston, Texas, there were more than 180 resident complaints about air quality related to MRs from 2006 to 2011 that were reported to the city's 311 call system. As a part of a communitybased participatory research study, Metal Air Pollution Partnership Solutions (MAPPS), we evaluated the impact of metal emissions from MRs on air quality over two years in four environmental justice communities. We simultaneously collected samples of inhalable particles (aerodynamic particle size less than 10 µm, PM 10) using a sampling strategy to capture emissions from the MRs while they were in operation at four locations within each community: an upwind location, the fence line of MR and two downwind locations and analyzed the samples for 10 metals. The highest values of iron (Fe), manganese (Mn), nickel (Ni), lead (Pb), arsenic (As) and chromium (Cr) were detected at the fence lines of MRs. The normalized ratios of these metals at near and far neighborhood locations were 0.01 to 0.64 and 0.01 to 0.34, respectively, as compared with the metals at the fence line. The concentrations of metals rapidly decreased by 57-70% within 100 meters and reached similar levels at upwind (background) locations at approximately 600 meters. After adjusting the measured data for wind direction, rain and operating hours, we calculated non-carcinogenic hazard index values and carcinogenic risks for adult residents from breathing metals emitted from the facilities. Estimated inhalation cancer risks ranged from 0.12 case to 24 cases in 1 million people and the hazard index values ranged from 0.04 to 11. Implications: In Houston, Texas, residents complained about air quality related to metal recyclers from 2006 to 2011. Using a community-based participatory research method, metal emissions were characterized at four environmental justice communities. The results indicate that metal concentrations were the highest at the fence line and decreased by 57-70% within 100 meters and reached similar levels of background at 600 meters. After adjusting the measured data for meteorological parameters and operating hours, estimated inhalation cancer risks ranged from 0.12 cases to 24 cases in 1 million people and hazard index values ranged from 0.04 to 11.

Identification of Legacy and Active Sources of Metal Contamination in Soils in Brooklyn, NY

“…A study conducted in Houston, TX observed increased concentrations of Fe, nickel (Ni), chromium (Cr), Mn and Pb particulates in the vicinity of metal recyclers. 51 In our analysis, Fe was associated with scrap yards in the crude association but not after adjusting for other potential sources of metals while Pb was not signi cantly associated with scrap yards in the crude or unadjusted associations; however, our data was non-speci c and did not take into account the type of metals processed at the facility or wind direction.…”

Applying Social Science to Bring Resident Stakeholders into Pollution Governance: A Rural Environmental Justice Public Health Case Study

“…In time, we hope to build a community-academic-government-industry collaboration to develop a public health action plan capable of improving environmental conditions and residents’ health in a manner similar to what the Air Alliance Houston has achieved in four neighborhoods in Houston, Texas (Symanski et al 2020). Although metal recyclers operating within neighborhoods provide jobs for local communities, increase revenues for local businesses, and conserve resources and energy by recycling metals, they also generate metal aerosol dust, odor, fume, noise, and traffic, and expose residents to explosions and/or fires that may increase their cancer risk (Han et al 2020). In Houston, some initial studies were conducted and findings were reported in Houston’s daily newspapers.…”

“…However, some of the companies, such as Allied Alloys, took a proactive approach to voluntarily limit emissions (Lobet 2012; Symanski et al 2020). In response to ongoing resident complaints, a task force was eventually created and a CBPR approach was taken to address the air pollution coming from some of the metal recycling facilities (Han et al 2020). Despite the failure of governance efforts to regulate pollution, Houston successfully developed a community-academic-government-industry partnership that secured funding from the National Institute of Environmental Health Sciences to conduct a 20-month air monitoring public health campaign.…”

“…They gathered information about stakeholder’s views and concerns about their neighborhood and environmental health and worked with the Houston Health Department to conduct community air monitoring in four selected neighborhoods that focused on public health. They detected increases in health risks associated with carcinogenic metal emission concentrations at several of the metal recycling facilities even though the facilities were operating within legal limits (Han et al 2020). Although the collaboration partners were unable to agree whether or not to include policy initiatives to regulate the metal recycling industry as part of the public health action plan, they did include voluntary actions on the part of the recycling industry partners to change practices, processes, or conditions in the scrapyard to minimize emissions from metal recycling facilities and improve communication with residents.…”

Polluting under the Radar: Emissions, Inequality, and Concrete Batch Plants in Houston

“…Existing research has demonstrated that small industrial emissions sources can diminish nearby air quality and increase adverse health risks. Researchers for example, have studied metal recycling facilities, − urban oil wells, , dry cleaners, and restaurants. − In most studies, researchers use either stationary or mobile sensors to measure ambient concentrations of pollutants at different distances from the point sources of emissions, often focusing on race- and income-based disparities in exposure. ,, Related work takes a “hot spots” approach whereby researchers identify areas of high pollution concentration, which can then be attributed to sources . In general, however, work in this area remains sparse compared with studies of larger industrial emissions sources for which data are more plentiful.…”