Visakhapatnam: A number of volunteers came forward to donate blood at a camp organised by PVS Helping Hands in association with Rotary Blood Bank at Sriharipuram on Thursday. As many as 510 units of blood were collected at the camp held as part of the 68th Republic Day celebrations. Chairman of Rotary Blood Bank B.K. Rai said that there was a need to dispel misconceptions associated with blood donation so that more volunteers can contribute to the cause.