Radioisotopes

Unstable atomic variants that decay with characteristic emissions, prized as tracers in research. Food and agricultural scientists have followed carbon-14 through photosynthesis into crops, phosphorus-32 through fertilizer into plants, and labeled pesticides through soil and food chains, mapping pathways invisible to ordinary chemistry. Their analytical power comes with strict licensing, shielding, and waste rules that confine their use to authorized laboratories. Stable-isotope tracers increasingly substitute for them where radioactivity is unwelcome. Strict licensing governs every laboratory authorized to handle radioactive tracers.