Pollution is only one way humans are altering our planet. There’s climate change, sea level rise, biodiversity loss, and much more. Earth system scientists, including biological oceanographer Katherine Richardson, developed the nine planetary boundaries, a framework to understand what Earth systems are critical for life, and what will happen if human-caused changes to our planet continue. Katherine unpacks these boundaries, revealing how chemistry sits at the heart of both the problems and solutions to the equilibrium of many of these critical systems. It’s a sobering yet hopeful look at humanity’s future on a finite planet.

Transcripts and episode sources at acs.org/chainreaction

Water and air pollution may capture the headlines, but there’s another threat looming beneath our feet: soil. We farm on it, build cities on it, and pull water from it. But pollutants from industrial waste, mining, and trash settle in soil, wreaking havoc on existing ecosystems and threatening our food and water supply. Soil and environmental chemist Owen Duckworth shares how chemists study soil, the unique qualities of soil pollutants, and the role chemists play in protecting public health.

After understanding what’s polluting our soil, then comes the difficult task of cleaning up those pollutants. Biogeochemist William Burgos discusses the little known world of soil remediation, including storing waste in landfills or allowing adaptable microbes to slowly remediate pollutants on their own. This episode transports you to the Superfund sites, old mining caves, and acid pits where waste hides away, and reveals chemistry’s role in understanding — and fixing — soil pollution.

Transcripts and episode sources at acs.org/chainreaction

We live in a watery world; 71% of Earth is covered in water. But humans have polluted Earth’s water for decades with pollutants like plastic, oil, and drugs. Marine chemist Chris Reddy guides us through what happens to the ocean during human-caused spills – from the Deepwater Horizon oil spill to the X-Press Pearl plastic spill – and how the ocean recovers.

But our oceans aren’t the only waters at risk of human-caused pollution. Analytical chemist Carrie McDonough transports us to the water in our taps and the ‘forever chemicals’ lurking in them. She demystifies PFAS chemicals, explaining where they come from, where they end up, and the dangers they pose to our environment and human health. This episode is a whirling adventure through the world of water, including the analytical tools chemists use to study it and the looming public health threat of polluted water.

Transcripts and episode sources at acs.org/chainreaction