Thirty male subjects participated in the study. Out of these, 15 were exposed to 50 Hz magnetic fields during worktime (in electrical substation) and free-time (living near the substation). The other 15 subjects had non-technical jobs and were subjected only to the normal electric and magnetic fields of daily environment.
Occurring magnetic fields were measured for each subject for one week with a wearable measurement device during normal activities. To determine the melatonin level in blood, subjects stayed in a hospital for one night. A catheter was inserted to collect blood samples hourly without waking. Additionally urine was collected to determine the 6-sulphatoxy melatonin level.
Exposure duration: 1 - 20 years
|magnetic flux density||2.6 µT||mean||measured||-||-|
|magnetic flux density||0.1 µT||mean||measured||-||-|
|magnetic flux density||0.64 µT||mean||measured||-||arithmetic mean of daytime|
|magnetic flux density||0.82 µT||mean||measured||-||arithmetic mean of nighttime|
|magnetic flux density||0.72 µT||mean||measured||-||arithmetic mean|
|magnetic flux density||0.092 µT||mean||measured||-||-|
|magnetic flux density||0.004 µT||mean||measured||-||-|
|magnetic flux density||0.04 µT||mean||measured||-||arithmetic mean of daytime|
|magnetic flux density||0.04 µT||mean||measured||-||arithmetic mean of nighttime|
|magnetic flux density||0.04 µT||mean||measured||-||arithmetic mean|
No significant differences in the melatonin level as well as in the 6-sulphatoxy melatonin level were found between exposed subjects and the control group.
The authors conclude that occupational and residential exposure to 50 Hz magnetic fields do not lead to alterations in the melatonin secretion.