A comparison of field portable X-ray fluorescence (FP XRF) and inductively coupled plasma atomic emission spectroscopy (ICP-AES) methods for analysis of metals on surface dust.

The traditional method for sampling for lead on surfaces uses inductively coupled plasma atomic emission spectroscopy (ICP-AES) to analyze the concentration of lead and other metals on surfaces. This type of analysis is time consuming and costly. Field portable X-ray fluorescence (FP XRF) is another analysis method that is not as accurate as traditional laboratory methods but is more cost efficient and has a turnaround time of less than an hour. The primary goal of this study is to find the best method to increase the level of agreement between the ICP-AES concentrations and the FP XRF concentrations when analyzing lead concentrations on surface wipes. Inverse regression and ratio of the means correction factors were analyzed to try to improve the prediction of ICP-AES concentrations using FP XRF results. Fifty-seven dust wipe samples were analyzed using a split-half design. Half of the samples were used to create the correction factor and the other half were used to test the level of agreement. Linear regression and Bland -Altman plots were used to determine the correction factor that provided the highest level of agreement. A ratio of the means correction factor was determined to be the most appropriate.

A comparison of field portable X-ray fluorescence (FP XRF) and inductively coupled plasma mass spectrometry (ICP-MS) for analysis of metals in the soil and ambient air.

When analyzing metal concentrations in the soil and ambient air, accurate and reliable results are essential. Inductively coupled plasma mass spectrometry (ICP-MS) is considered the benchmark analytical method for environmental soil and air filter samples containing metals. Field portable X-ray fluorescence (FP XRF) can provide more timely results with lower ongoing costs, but the results are not as accurate as ICP-MS. The primary goal of this study was to find an optimal method to maximize the level of agreement between FP XRF results and ICP-MS results when analyzing metal concentrations in soil and ambient air samples in a U.S. Superfund community. Two different correction factor methods were tested to improve the prediction of ICP-MS concentrations using FP XRF for arsenic and lead in soil and ambient air. Ninety-one residential soil samples and 42 ambient air filter samples were analyzed in a split-half design, where half the samples were used to create the correction factors and the other half to evaluate the level of agreement between the analytical methods following FP XRF correction. Paired t-tests, linear regression plots, and Bland-Altman plots were utilized to examine which correction factor provided the highest level of agreement between the two methods. Based on the results from this study, it was determined that a ratio correction factor method provided the best fit for this FP XRF analytical device.

The application of portable air cleaners in spaces occupied by vulnerable people during wildfire events.

In this study, PM2.5 concentrations were collected and documented during wildfire smoke impacted days using PurpleAir PA-II sensors at three different locations in a community located in the northwestern United States. Each location was comprised of three co-located sensors with one sensor positioned outdoors, one sensor indoors, and one sensor indoors with an air cleaner in the room. The relationship between both indoor and outdoor PM2.5 concentrations provided evidence on the effectiveness of sheltering indoors from wildfire smoke events with and without an air purification system.

Effects of Residential Environmental Screening and Perception Surveys on Superfund Environmental Health Risk Perceptions.

Residents at one of the nation's largest and longest-operating Superfund sites (Butte, Montana) have expressed environmental health risk perceptions that often diverge from those of EPA and other official stakeholders responsible for the investigation and remediation of site contamination aimed at protecting human health and the environment. A random sample of Butte residents participated in a study of how home-based environmental screening influences environmental health perceptions. Participants completed surveys measuring environmental health perceptions before and after a home site screening of soil and drinking water for lead and arsenic conducted by the research team. Local air monitoring for the same contaminants was also completed during the study period. The home-based screening intervention improved the alignment of subjective participant environmental health perceptions with objective environmental screening measures. Key features of the process that helped achieve this effect included (1) co-locating the collection of participant perceptions and individualized screening measurements; (2) sharing environmental screening results in a clear and unbiased manner; and (3) conducting this work independent of agencies and organizations with direct responsibility for Superfund-related cleanup activities. Empowering residents of a Superfund community with knowledge of the specific kinds and levels of environmental contamination in their home environment may help overcome the gap between agency conclusions regarding environmental health risk and the perceptions of community members.

Investigating the potential for microbially induced carbonate precipitation to treat mine waste.

In this study, the feasibility of promoting microbially induced carbonate precipitation (MICP) in mine waste piles by using an environmental bacterial enrichment is explored, with goals to reduce metals and acid leaching. MICP has been explored for remediation applications and stabilization of mine waste. Here, we utilize a native bacterial enrichment to promote MICP on seven mine waste samples with variability in acid production and extent of toxic metal leaching. During fifteen applications of MICP solutions and bacteria on waste rock in bench-scale columns, calcium carbonate formed on grain surfaces within all waste samples, though microscopy revealed uneven distribution of CaCO3 coating. The effluent from acid-producing wastes increased in pH during MICP treatment. MICP performance was evaluated with humidity cell and synthetic precipitation leaching procedure (SPLP) tests. Leaching tests revealed reductions in Cd, Pb and Zn concentrations in leachate of all but one sample, mixed results for Cu, and As increasing in all but one leachate sample after treatment. MICP technology has potential for coating mine waste and reducing release of acid and some metals. This study provides a laboratory assessment of MICP feasibility for stabilizing mine waste in situ and mitigating release of toxic metals into the environment.

Environmental health perceptions in a superfund community.

A disconnect between community perceptions and officially documented Superfund remedial actions and health outcomes may hinder the essential community engagement at Superfund sites. This study evaluates the extent of one such potential disconnect in Butte, Montana, which is part of the largest U.S. Superfund site in the U.S. Since the 1860s, when mining began in Butte, mine waste disposal practices in Butte and surrounding areas have left behind massive deposits that have contaminated the area's soil, sediment, groundwater and surface water with arsenic and heavy metals. Over the last four decades, a substantial amount of remediation work has been completed along with requisite community engagement and health studies at this Superfund site. The potential disconnect was evaluated using a new survey instrument that covered: (a) general environmental health perceptions, (b) mine-waste specific environmental health perceptions, (c) effectiveness of community engagement, (d) knowledge of health outcomes, and (e) demographics. The survey results demonstrated a disconnect in many instances where objective remedial improvements may not have resulted in improved environmental health perceptions in the community. The disconnect was most pronounced in the case of drinking water protection from mine waste and knowledge of health outcomes (cancer incidence rates and children's blood levels). The use of similar environmental health perception measurements may aid responsible agencies in monitoring for and addressing environmental health perception disconnects through better community engagement for the benefit of the impacted communities.