Section 23. The commissioner of environmental protection shall make an annual report, including the results of the examination of main outlets of sewers and drainage of towns and the effect of sewage disposal, with such recommendations for the preservation of the interest of persons and property and for the prevention of offensive odors and objectionable conditions as he considers expedient, together with recommendations for the prevention of the pollution of waters used for ice or water supply and for the removal of polluting substances, in order to protect and develop the rights and property of the commonwealth therein and protect public health; and he may recommend any legislation or plans for systems of main sewers necessary for the preservation of the public health and for the purification and prevention of pollution of ponds, streams and inland waters of the commonwealth. The commissioner of environmental protection shall include in his annual report the number of prosecutions by the department of environmental protection and an itemized account of the money expended by it in enforcement actions.