Short- and long-duration exposures to cell-phone radiofrequency waves produce dichotomous effects on phototactic response and circadian characteristics of locomotor activity rhythm in zebrafish, Danio rerio

ABSTRACT

We examined the effects of short- and long-duration exposure to cell phone radiation (CPR) on phototactic response (PR) and circadian characteristics of locomotor-activity rhythm, respectively, in zebrafish. We exposed four groups (10 in each) randomly selected fish to CPR emitted by a 2300 MHz 4G cell phone for 0.5 h, 1 h, 2 h, 3 h, and 4 h duration at two different time points of a day, i.e. morning and evening, to assess the PR. We also studied the effects of 1 week CPR exposure on circadian rhythm in locomotor activity pattern in eight singly housed zebrafish. We had eight singly housed sham-exposed zebrafish as the control. Results of two-way ANOVA revealed statistically significant effects of the factors exposure time and exposure duration on the PR of zebrafish. Fish exhibited photo-positive response till 2 h following morning exposure, and thereafter, showed photo-negative response with increased duration of exposure. During evening exposure, the fish were mostly photo-negative. However, 1 week exposure to CPR did not produce any significant effects on the circadian characteristics of locomotor activity rhythm. It is concluded that the CPR might alter phototaxis, but not the parameters of circadian rhythm in locomotor activity pattern of zebrafish.

KEYWORDS:

• Cell-phone radiofrequency waves
• short- and long-duration exposure
• phototactic response (PR)
• locomotor activity
• zebrafish

Acknowledgments

The authors are thankful to the University Grants Commission, New Delhi, for the research grants received through its DRS-SAP (Phase-III) scheme sanctioned to the School of Studies in Life Science, Pandit Ravishankar Shukla University (PRSU) in the thrust area – Chronobiology. The logistic support received from the Center for Translational Chronobiology at the SoS in Life Science, PRSU, Raipur, is gratefully acknowledged. We are also thankful to an anonymous reviewer for offering us with valuable suggestions for the improvement of the manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.