Disruption of rhythms - a significant toxicant effect

Virtually all animal functions are rhythmical. If you measure a parameter, the value is different in the morning than in the evening or in the summer and in the winter. Despite this fact, the rhythmicity is seldom taken into account in considering the effects of toxicants on animals. We have earlier published an article indicating the importa

nce of disturbed rhythms in environmental responses (Prokkola and Nikinmaa Journal of Experimental Biology, 2018, 221, jeb179267). Now in Environment International (149,  106159, 2021) Zheng et al reviewed how “Environmental chemicals affect circadian rhythms: An underexplored effect influencing health and fitness in animals and humans.”

Zheng et al showed how tens of environmental toxicants including pesticides, steroids and metals can be considered circadian disrupters. Thus, the toxicants cause disturbances if normal rhythms. Considering this, the responses to toxicants will disturb the daily and seasonal rhythms of animals. Since the rhythms are an important 

aspect of animal fitness, the circadian disrupters will affect the success of animals. At the moment the rhythmical responses are further disturbed as the light-temperature relationship is altered by climate chang
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