Massachusetts officials will hold hearings across the state to get public input on proposed regulations for medical marijuana. The Department of Public Health issued draft regulations last month. Three public hearings are scheduled Friday at 10 a.m. at the Public Health Department’s headquarters in Boston, Plymouth Memorial Hall in Plymouth, and Look Park Garden House in Northampton. Speakers are asked to provide a copy of their testimony. People may e-mail testimony to Reg.Testimony@state.ma. The proposed regulations require operators of marijuana dispensaries to test their products for contaminants and to adopt inventory control measures. The Public Health Council is scheduled to vote on the regulations May 8.