Through modern chemistry, we live better. However, as researchers continue to recognize the environmental and health risks associated with the mass production, use and disposal of complex synthetic molecules, a need for safer and more sustainable chemicals has become clear. In this special issue of Science, "Chemistry for Tomorrow's Earth," four Reviews, a Perspective and a related feature from Science's news department chart a path towards a cleaner and greener future for the chemical industry on which we all rely, while reckoning with the hazardous legacy left in its wake. To introduce the issue, Science editors Michael Funk and Caroline Ash ask: "How can we continue to develop molecules that address the challenges we face today while ensuring we understand the effects of the complex and ubiquitous chemicals we produce on our health and the environment? ... Our health, and that of ecosystems around the world, depend on our commitment to gathering this information and taking action accordingly."
Nearly 140,000 different industrial chemicals are currently used worldwide, and their complexity presents a challenge to developing the circular economy needed to make the chemical industry sustainable - one aimed at eliminating waste by circulating and recycling chemical products. In a Perspective, Klaus Kümmerer and colleagues argue that achieving a circular economy for chemicals requires a rethinking of chemistry, involving efforts like keeping molecular complexity to a minimum when designing new compounds and designing products with recycling in mind. In a Review, Julie Beth Zimmerman and colleagues argue that the important inherent properties of new molecules need to be considered at the early stages of chemical design. To avoid the pitfalls of the past, Zimmerman et al. suggest that chemical performance should not only be evaluated by functionality, but also by if compounds are non-depleting, non-toxic and non-persistent. In another Review, Andrew Johnson and colleagues emphasize that the sheer diversity of chemical compounds used today puts the ability to assess their total risks beyond our reach. However, our past experience with environmental chemicals may be used in modeling hazards and gauging relative risk, they say. In a third Review, Beate Escher and colleagues discuss the detection and characterization of chemical mixtures in indoor and outdoor environments. Currently, tracking groups of chemicals and the toxicological effects of the products they inadvertently create when combined is a great challenge. To address this, Escher et al. propose a new approach, which combines chemical analysis with bioassays to identify potentially harmful mixtures in the environment. A final Review, by Roel Vermeulen and colleagues, discusses the "exposome" concept conceived in 2005 as a way of understanding the non-genetic factors associated with disease and health related to chemical exposures. The authors review several recently developed technologies for measuring multiple chemical exposures in high-throughput analyses, similar to genome-wide association studies.
Lastly, in a news Feature, Science contributing correspondent Warren Cornwall reports on how one chemical company is teaming up with some unlikely allies. Many food and beverage cans are lined with BPA, a chemical that has long been the focus of health concerns. Chemical company Sherwin-Williams has taken an unusual approach to finding an alternative: joining up with some of BPA's fiercest critics.