Rotenone

Rotenone has been used for centuries by indigenous peoples in South America and Asia — they would pound the roots of Derris and Lonchocarpus plants into rivers to stun fish for collection [1]. Western science isolated the active compound in 1902, and rotenone became commercially available as an insecticide in the 1930s. Its botanical origin gave it a "natural" reputation that made it popular in organic and integrated pest management — it was widely used in organic gardening, on organic vegetables, and in fish management programs [2]. EPA data shows that fish kills carried out by wildlife management agencies used enormous amounts of rotenone to clear invasive species from lakes before restocking. The Parkinson's connection became scientifically prominent when University of Pittsburgh researcher William Langston (who had also characterized MPTP-induced Parkinsonism) published work showing that rats infused with rotenone developed Parkinson's-like pathology — the first reliable animal model of the disease [3].

Agricultural workers who apply rotenone — and workers in organic farming who use it as an approved organic pesticide — face the most significant occupational exposures through inhalation and dermal contact [1]. Consumers who use rotenone-based organic garden insecticides (dusts or sprays) in home gardens face lower but non-trivial exposures. Fish management crews and wildlife managers who use rotenone for lake and stream treatment face high occupational exposures [2]. The Iowa Pesticide Applicators Study and other epidemiological studies have captured the farmworker exposure data that showed elevated Parkinson's risk [3].

Rotenone is a highly specific inhibitor of mitochondrial Complex I, the first step in the electron transport chain [1]. This is the same cellular pathway implicated in the dopaminergic neuron death that underlies Parkinson's disease. In animal models, chronic rotenone infusion reproduces not just the motor features of Parkinson's but also the pathological hallmarks — alpha-synuclein accumulation (Lewy bodies) in dopamine-producing neurons [2]. The Iowa Pesticide Applicators Study found a 2.5-fold increase in Parkinson's disease in rotenone-exposed farm applicators compared to unexposed workers. Combined with paraquat exposure, the risk synergizes further [3].

Agricultural workers who apply rotenone, organic farmers who use it as an approved pesticide, and fish management workers face the highest occupational exposures [1]. Home gardeners who use rotenone-based organic pesticide products without respiratory protection have meaningful exposures. People in fishing communities where rotenone is used for lake management have short-term high exposures during treatment operations [2]. People with relevant genetic polymorphisms in DJ-1, PINK1, or Parkin genes — genes associated with familial Parkinson's — may be more susceptible to rotenone's neurotoxic effects [3].

If you use organic garden pesticides, read labels carefully — rotenone is often listed as "derris" or "cube root" — and use respiratory protection (N95 or better) during application [1]. Choose alternative organic pest control strategies where possible: neem oil, insecticidal soap, and beneficial insects provide pest control with lower neurotoxicity risk [2]. Wash hands and change clothes after any pesticide application. For fish management workers: wear respiratory protection during rotenone application, do not enter treated waterways without waterproof waders and gloves [3]. If you have significant rotenone exposure history and notice early signs of Parkinson's disease (reduced sense of smell, constipation, REM sleep behavior disorder), consult a neurologist and mention your exposure history.