(a) The proceeds from the sale of any bonds issued under authority of this article may be applied only for the purpose for which the bonds were issued: Provided, That any accrued interest received in any sale shall be applied to the payment of the principal of or the interest on the bonds sold. If for any reason any portion of the proceeds are not needed for the purpose for which the bonds were issued, then the unneeded portion of the proceeds shall be applied to the purchase of bonds for cancellation or payment of the principal of or the interest on the bonds or held in reserve for the payment thereof.

(b) The costs of any public project shall be considered to include the following:

(1) Capital costs, including, but not limited to, the actual costs of the construction of public works or improvements, capital improvements and facilities, new buildings, structures and fixtures, the demolition, alteration, remodeling, repair or reconstruction of existing buildings, structures and fixtures, the removal or containment of, or the restoration of soil or groundwater affected by environmental pollution, environmental remediation, the acquisition of equipment and site clearing, grading and preparation;

(2) Financing costs, including, but not limited to, any interest paid to holders of evidences of indebtedness issued to pay for project costs, all costs of issuance and any redemption premiums, credit enhancement or other related costs;

(3) Real property acquisition costs;

(4) Professional service costs, including, but not limited to, those costs incurred for architectural planning, engineering and legal advice and services;

(5) Imputed administrative costs, including, but not limited to, reasonable charges for time spent by governmental body employees in connection with the implementation of a project;

(6) Relocation costs, including, but not limited to, those relocation payments made following condemnation and job training and retraining and costs for utility relocation; and

(7) Organizational costs, including, but not limited to, the costs of conducting environmental impact and other studies and the costs of informing the public with respect to the implementation of project plans.