There shall be a board of health which shall consist of five (5) members elected for terms of three years each, so arranged that the term of office of as nearly an equal number of members as is possible shall expire each year. The board of health shall be responsible for the formulation and enforcement of rules and regulations affecting the environment and the public health, and shall have all of the powers and duties which are given to boards of health under the constitution and laws of the Commonwealth of Massachusetts, and such additional powers and duties as may be authorized by the charter, by by-law or by other vote of the town meeting.