Mo. Rev. Stat. § 644.545

All funds paid into the water pollution control bond and interest fund shall be and stand appropriated without legislative action to the payment of principal and interest of the bonds, there to remain until paid out in discharge of the principal of the bonds and interest accruing thereon, and no part of such funds shall be used for any other purpose so long as any of the principal of the bonds and the interest thereon shall be unpaid.