It should be examined if the increased occurrence of cataract in calves on a farm in Switzerland was related to the exposure to a 1800 MHz electromagnetic field of a GSM base station.
The base station was erected at a distance of 20 m to the cow stable and it was active from mid-1999 to mid-2006 with short breaks (3 and 2 months). In the beginning, the increased occurrence of cataract was observed by the farmer himself. The first author, who examined the animals during a general check for cataract and took blood samples, was engaged in mid-2002. Beginning with May 2004 and until the end of the examination in June 2009, ophthalmic examinations of the animals were conducted on a regular basis. 196 animals were examined in total, of which 154 were examined in an ophthalmic manner (42 cows, 112 calves).
Exposure duration: continuous
|Setup||mobile phone base station with 5 mobile channels serving 3 sectors at a height of 15.4 m was erected at a distance of 20 m to the stable; the stable was located between two main beams of the antenna|
|electric field strength||0.17 V/m||maximum||measured||-||in the stable; based on measurement from 9/12/2002|
|electric field strength||0.5 V/m||maximum||measured||-||on the farm square; based on measurement from 9/12/2002|
According to the farmer's records, the occurrence of cataract increased after the erection of the base station with a latency of 12 months and decreased again after its deconstruction. In fact, new born calves showed a 3.5 times higher risk for heavy cataract compared to Swiss average in the time from 19-5-2004 to 20-6-2009.
Moreover, an increased number of eosinophils was found in 2 of 5 cattle, which indicated a reaction of the immune system, possibly due to a parasite infestation. The animals were underfed and the mold content in the food, as well as the heavy metal content, lay at the upper border of the norm. However, infections and intoxications could be excluded.
The authors conclude that there is indeed a time-based correlation of the increased occurrence of cataract in the calves and the presence of the GSM base station. However, no causal relation can be derived from that. Hence, the actual reason for the increased occurrence of cataract remains unknown and a genetic component could be involved.