A320 First Officer reports finding the weather Radar in the 'ON' position upon entering the cockpit after completing the walk around preflight; and believes he has been irradiated.

Narrative

I met the aircraft as it parked. Some maintenance personnel went into the cockpit as passengers deplaned. While that was occurring; I did my walk around. After getting into the cockpit; I immediately found the weather Radar in the 'on' position with a ground returns showing on the Nav Display. I was irradiated. I do not know the short term or the long term health effects of this irradiation. I do not think that company procedures allow radar technicians to stand in front of an emitting radar for good reasons. It is bad for your health. The ground crew was also subject to this radiation. The company apparently has no idea what to do if their personnel have been subjected to the powerful; full strength; weather radar radiation. There is no medical support for this occurrence. I want to be clear that I do not know if I will be subject to any short term or long term health effects. As of now; 15 minutes after the incident; I do not feel dizzy or nauseous. Without any medical support available and feeling asymptomatic; I feel I must fly tonight's trip or be subject to administrative punishment procedures for using Sick List if I refuse to fly due to my fear of how I may be affected by this exposure. This is a serious lapse on many levels.