Colchicine: toxicity and safe handling practice.

Colchicine is a potent alkaloid used in genetics to double the chromosome number in plants. It is also an extremely toxic substance: the lethal dose for a human is only 7–65 mg, and the solution is absorbed even through intact skin.

Personal protective equipment.

• Respiratory: a P3 / FFP3 respirator, ideally a laboratory fume hood.
• Eyes and face: chemical goggles with indirect ventilation, or a face shield.
• Hands: nitrile gloves only — colchicine passes through latex quickly.
• Clothing: a heavy chemical-resistant apron and a change of long-sleeved clothing.

The most dangerous stage is weighing the dry powder, because it generates an aerosol.

Seed treatment, step by step.

1. Soaking: 0.05–0.2 % concentration, 2–24 hours, in a hermetically sealed vessel.
2. Work in gloves only; after loading, wash the outer walls of the vessel with soap.
3. Drain the solution into a dedicated toxic-waste jar, never into the sink.
4. Rinse three times with cold running water inside the closed vessel; the rinse water goes into the jar as well.
5. Sow with tweezers while gloved, never touching the seeds by hand; then discard the gloves and wipe the tweezers with alcohol.
6. Water without splashing: colchicine can leach into the soil and accumulate there, which is dangerous for animals.

After the work — mandatory.

• No food, drink, smoking or phone in the treatment area.
• Soak all equipment for 30 minutes in 10 % sodium thiosulfate, then rinse.
• Solutions, wipes and gloves go into a sealed bag and are handed over as chemical waste — never down the toilet or into a water body.

What result to expect.

The goal is for almost all seeds to die, but not all: roughly 97–98 % perish and 2–3 % survive. Among the survivors, true tetraploids are under 1 % — no more than 10 out of 1000 seeds. Most survivors turn out to be chimeras or aneuploids.