A participating municipality’s secretary and treasurer are assigned to those same duties for Port District business within the participating municipality. Their respective municipal offices’ constitutional oaths and corporate sureties shall serve as the same for the conduct of work related to the Port District within the participating municipality. Whatever penal sum may be directed by the participating municipality’s city council conditioned upon the faithful performance of the duties of the office and the payment of all money received by him or her according to law shall be the same for work related to the Port District within the participating municipality’s corporate limits. The city council may, at any time, require a new bond from the treasurer in a penal sum determined by the city council within the municipality’s existing ordinances. The obligation of the sureties shall not extend to any loss sustained by the insolvency, failure, or closing of any savings or loan association or national or State bank where the treasurer has deposited funds if the bank or savings and loan association has been approved by the city council as a depositary for these funds. The oaths and corporate sureties shall be filed in the principal office of the participating municipality.