A common pattern can be seen in the emergence of contaminants that affect human health and the environment, according to new research.

Rolf Halden, Ph.D., a researcher at Arizona State University's Biodesign Institute, examined the trajectory of chemicals appearing as emergent threats to human or environmental health. He identified patters in substances emerging from obscurity to peak concern and eventual decline, over a period of 30 years.

The study reveals that it takes around 14 years from initial safety concerns being expressed about a given chemical until the height of concern is reached and appropriate action is taken. During that period a large number of people are exposed to these "chemicals of emerging concern" (CECs).

The research suggests that it's possible to forecast the rise and fall in concern for CECs of recent interest. For example, rising concern over the safety of nanomaterials is expected to peak no later than 2016, while concern over microplastics is anticipated to reach a peak in 2022, if current trends continue.

Halden hopes that the data will support future efforts to safeguard human and environmental health. Improvements that could be made include shortening the time between CEC emergence and regulatory action being taken, and developing new chemical and engineering methods that would offer an alternative to harmful chemicals.

"My hope is that the 'law of pollutant emergence' uncovered here will not endure for another 60 years. Green chemistry — the design of inherently safe chemicals — points the way to a future of fewer risks and a healthier planet," Halden commented.

The findings of the study have been published in the current issue of the Journal of Hazardous Materials.