Hygienic studies on the water in Port of Nagoya (I)

An investigation was made on the state of pollution of water in the port of Nagoya three times in summer. Samples for chemical and physical analysis were collected from the surface and the middle point of the depth at five locations in the port.The result showed the ocean water made up a double layers according to the difference of the Cl-concentration. The grade of pollution at ebb-tide was greater than that of the high-tide. It was postulated that the auto-purification of the polluted water would be to some extent made at the half depth, but not on the surface. The principal factor of the pollution of ocean water was attributed to the polluted rivers which flowed into the port. The most polluted location was found where the river Yamazaki and Horikawa flowed into, and the location into which the river Oheflowed, followed the former. The ocean water for control at the out-side of the port was more polluted than anticipated.