Epidemiological study (observational study)

No effects of power line frequency extremely low frequency electromagnetic field exposure on selected neurobehavior tests of workers inspecting transformers and distribution line stations versus controls epidem.

By: Li L, Xiong DF, Liu JW, Li ZX, Zeng GC, Li HL

Published in: Australas Phys Eng Sci Med 2014; 37 (1): 37-44

Aim of study (acc. to author)

A study was conducted in China to investigate the association between power line frequency extremely low frequency electromagnetic field exposure on selected neurobehavioral tests of workers inspecting transformers and distribution line stations.

Further details

The participants performed computer-based neurobehavioral tests (e.g., mental arithmetic, visual retention, auditory digit span, simple visual reaction time and pursuit aiming), which mainly assessed memory recognition accuracy, visual discrimination, short-term memory and cognitive performance.

Endpoint/type of risk estimation

neurobehavior: memory recognition accuracy, visual discrimination, short-term memory, cognitive performance

Type of risk estimation:

prevalence

Exposure

- 50/60 Hz
- magnetic field
- power transmission line
- electrical substation
- occupational

Assessment

measurement: spot measurements of electric field intensity and magnetic flux density outdoor in the 500 kV and 220 kV areas of voltage transformers and distribution power lines respectively located in the routes where workers regularly perform tour-inspections

Exposure groups

Group	Description
Reference group 1	administrative staff and logistical personnel who were not authorized to enter the 500 kV and 220 kV zone
Group 2	workers who performed tour-inspection close to voltage transformers and distribution power lines

Population

Group:
- men
- women
Age: 23–50 years
Observation period: not stated
Study location: China
Exclusion criteria: subjects with CNS diseases like epilepsy, cerebritis, severe brain trauma history, visual and auditory disturbance, upper limb dyskinesia

Study size

Type	Value
Total	710
Evaluable	610

Statistical analysis method:

ANOVA

Results (acc. to author)

In 500 kV areas, electric field intensity at 72.0% of total measured 590 spots was above 5 kV/m (national occupational standard), while in 220 kV areas electric field intensity at 15.7% of total 701 spots was above 5 kV/m. Magnetic field flux density at all the spots was below 1,000 µT (ICNIRP occupational standard).
The neurobehavioral score changes showed no statistical significance between unexposed workers (group 1) and exposed workers (group 2). No significant changes in neurobehavioral tests were found among different age and seniority groups.
The authors concluded that in the present study no neurobehavioral changes were observed among workers with daily repeated exposure to extremely low frequency electric and magnetic fields.

Study funded by

Guangdong Power Grid Corporation, Guangzhou, China

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