Metal Organic Framework materials – A new material class with limited human and environmental risk assessment relevant data

Introduction
Metal Organic Framework (MOF) cover a group of highly porous 3D networkmaterials constructed by organic - inorganic - or nanocluster ions. MOFs can be produced as nm- to µm-size particles with tailored functionalities and are characteristic by having very high specific surface areas due to their porous nature. Existing MOFs have highly diverse applications and are currently commercially available. As part of modern risk governance and responsible innovation, new materials should be thoroughly assessed to manage potential risks before they are introduced onto the market. In this work, we present results
from a scientific literature review on MOFs to understand their compositional and structural diversity, their synthesis methods, and current knowledge about their potential (eco-)toxicological risks.
Results
Approximately 20 000 MOF structures are currently known. More than 100 MOFs are commercially available and at least 15 types are available in relatively large quantities. Main existing and near-future applications appear to be gas storage, catalysts, drug delivery, environmental remediation and water treatment, food packaging, food preservatives and chemical sensors. In contrast to 27 837 papers found in Web-of-Science search ("Metal Organic Framework" NOT "in vitro" NOT "in vivo" NOT "ecotox*"), 107 papers were found searching the toxicity terms ("Metal Organic Framework" AND "in vitro" AND tox* OR "Metal Organic Framework" AND "in vivo" AND tox* OR "Metal Organic Framework" AND
"ecotox*"). Only about 20 of these scientific papers specifically study hazards of MOFs. Results suggest that the specific surface areas in addition to the type of metal ion and organic linker ions play a key role on their (eco)toxicity. No studies were found to report on human exposure and environmental release assessments.
Conclusions
It is evident that the human and environmental safety of MOFs is heavily understudied and further research is required to satisfy the modern risk innovation governance.