Putting biomonitors to work: native moss as a screening tool for solid waste incineration

Area of Science:

• Environmental Science
• Biomonitoring
• Atmospheric Chemistry

Background:

• Solid waste incineration (SWI) releases air pollutants, but their geographic spread is poorly understood.
• Moss and lichens are used for biomonitoring trace elements near SWIs, yet complex emission footprints require further investigation.
• This research addresses community concerns regarding an aging incinerator in rural Oregon, USA.

Purpose of the Study:

• To develop native moss as a screening tool for SWI emissions.
• To investigate the multi-element footprint of SWI using moss biomonitoring.
• To inform community concerns about local air quality near an aging incinerator.

Main Methods:

• Collected 36 composite samples of epiphytic moss (Orthotrichum s.l.) along a 32-km transect from the SWI.
• Utilized Inductively Coupled Plasma Mass Spectrometry (ICP-MS) to analyze 40 elements, including 14 rare earth elements (REEs).
• Compared elemental signatures in moss to SWI emissions profiles and modeled element concentration vs. distance using nonparametric regression.

Main Results:

• Moss elemental signatures indicated SWI as a potential source via stack and fugitive dust emissions.
• Farther-dispersing elements like mercury and cadmium showed strong correlations with distance (xR²=0.65, 0.62), with deposition primarily within 5-10 km.
• Localized peaks of soil/dust-associated elements (arsenic, chromium) were found within 0.2 km (xR²=0.14-0.3).
• Cesium, europium, and gadolinium showed potential as novel atmospheric tracers for SWI, with gadolinium possibly indicating medical waste.

Conclusions:

• Native moss is a viable screening tool for assessing SWI air pollution.
• Specific elements can serve as effective tracers for SWI emissions and their dispersal patterns.
• Findings provide valuable data for stakeholders concerned about incinerator impacts on local air quality.