That was why collected human wastes were often dumped in the surrounding sea areas, but according to an international treaty the dumping of human wastes at sea was banned and the measures such as the improvement of bounty system for the maintenance of sewage lines or the installation of septic tanks have been promoted.
そのため、汲み取ったし尿は周辺の海域に投棄されることが多かったが、国際条約によってし尿の海洋投棄が禁止されることになり、下水道の整備や浄化槽の設置に対する補助金制度の拡充などの施策が進められている。