Dissolved organic matter (DOM) is known to influence the chemical speciation, biogeochemical transformations, and mobilization of trace metals and mineral colloids in the aquatic environment. Dr. George Aiken, the DOM whisperer, has been a central contributor to scientific discoveries that elucidated the relevant chemical properties of DOM for trace metal cycling. More recent work includes DOM interactions with nanoparticles, both naturally occurring and engineered nanomaterials. This presentation will provide an overview of lessons learned in the study of DOM-nanoparticle interactions with specific attention to the interplay of particle solubility, aggregation, surface composition, and metal chelation and how these processes work in concert to control particle/metal mobility and bioavailability. Examples include the role of organic matter in controlling aggregation and crystallization states of newly formed mercury sulfides and subsequent bioavailability to anaerobic bacteria. Likewise, the molecular structure of DOM could be used in elucidating effects on solubility, aggregation, and bioavailability of soluble metal oxide nanomaterials (CuO and ZnO). These examples highlight the complexity of DOM interactions with nanoparticles and the need to develop empirically- or mechanistically-based functional assays of metal reactivity that can guide models for nanomaterial and pollutant metal fate and risk in the environment.

Nanoscale metal-organic matter interactions

253rd National Meeting (2017)

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