Wildland-urban interface fire ashes as a major source of incidental nanomaterials

Quantification of Bioaccessible and Environmentally Relevant Trace Metals in Structure Ash from a Wildland–Urban Interface Fire

“…Ash samples were significantly higher in Pb than soil samples ( p = 0.036). Pb concentrations in ash ranged between 0.4 and 142 mg/kg, aligning with median reported Pb concentrations of 350 mg/kg in structure ash . Soil Pb ranged from 1.9 to 17 mg/kg.…”

“…Differences between the ash and soil concentrations were only found for Ti. Ash samples, with an average of 424 mg/kg, have significantly higher concentrations of Ti than soil samples ( p = 5.5 × 10 –4 ), a trend reported in previous studies . Ti comprises approximately 0.2% of Colorado soils; however, we found Ti at much lower concentrations, with an average of 57 mg/kg, possibly due to incomplete acid digestion.…”

“…The concentration of Ni in ash samples was between 3.1 and 493 mg/kg, with an average of 36 mg/kg, while that in soil samples ranged from 1.4 to 13.4 mg/kg, with an average of 9.6 mg/kg. Ni in structure ash has been reported between approximately 0 and 350 mg/kg . The average Ni concentration in soil is close to the lower end of that reported for Colorado soils (9.3–19.1 mg/kg) and lower than the 19–47 mg/kg reported for the GCA…”

Improved methodology for the analysis of polydisperse engineered and natural colloids by single particle inductively coupled plasma mass spectrometry (spICP-MS)

“…As a result of this high concentration of small particles, coincidence effects will distort the PSD and PNC determined by spICP-MS, which will go undetected in a more conventional, single dilution spICP-MS approach. To demonstrate the existence of this issue, we illustrate how conclusions regarding environmental processes in our stream study can be very different when using the comprehensive multiple dilution and single-dilution spICP-MS 42–46 approaches. In our example, Al-containing NMs and colloids were sampled from Cherry Creek, Denver CO USA (5/19/22–5/23/22) where storm discharge ( Q , cfs) increased by as much as 10-fold (ESI† Fig.…”

“…The results generated by power law modeling of the PSDs using this new serial dilution approach are contrasted with a commonly used, single dilution spICP-MS data analysis. [42][43][44][45][46] To illustrate the benefits of this approach, we analyzed two types of environmentally relevant NMs: polydisperse, metal-doped NPs which were used for method development; and Al-bearing NMs and colloids (i.e., silicate minerals) sampled during a storm event in the Denver Metro Area, CO USA.…”