Q2-3 Consultation on Water Pollution

When washed water containing paint (painting) or concrete (mortar) is washed away, even a small amount will cover the water surface and become cloudy. In Yokohama City, we conduct on-site surveys to determine whether there are any dangers such as hazards, and arrange for collection of pollutants as necessary. In addition, we will provide guidance on identifying the cause and appropriate drainage methods.
The cause may be subject to penalties imposed by laws and regulations or charged for recovery costs.

＊Flyer I would like appropriate treatment of paint and oil waste liquid so as not to pollute rivers and the sea (PDF: 781KB)
Road gutters allow rainwater on the road to flow quickly into rainwater pipes. If paint is poured into road gutters, river pollution will adversely affect fish and other creatures and the river environment. For this reason, do not pour paint into road gutters.

In addition, the river may turn brown as a natural phenomenon. Kanakemizu, commonly found in river revetments, is caused by the melting of iron contained in the soil and oxidized by bacteria.
In addition, the sea and rivers may turn red due to the red tide.

(River manager: Public Works Office, Yokohama Kawasaki flood control office (outside site), Keihin river office (outside site))
(Water and Soil Environment Division, Water Quality Section, Phone number: 045-671-4244)

River turbidity

White turbidity in rice fields

• White turbidity

Water containing paint flowed into rivers and rice fields.

[Natural phenomena] Water in rivers

• Metal water (iron rust)

It's a natural phenomenon.
The iron contained in the soil is oxidized by bacteria and springs out as iron rust.

[Natural phenomena] Red tide in the sea area

• Red tide

It's a natural phenomenon.
It is a phenomenon in which seawater discolors reddish brown, orange, and sometimes blue-green due to abnormal breeding of plankton.
The river also discolors from the tide.

※ As of April 2024, a phenomenon that seems to be red tide is occurring! (External Site)

When waste oil or fuel oil is washed away, even a small amount covers the surface of the water and becomes an oil slick. In Yokohama City, we conduct on-site surveys to determine whether there is any danger such as ignition, and arrange oil collection work as necessary. In addition, we will provide guidance on identifying the cause and appropriate drainage methods.
The cause may be subject to penalties imposed by laws and regulations or charged for recovery costs.

＊Flyer I would like appropriate treatment of paint and oil waste liquid so as not to pollute rivers and the sea (PDF: 781KB)
Road gutters allow rainwater on the road to flow quickly into rainwater pipes. Flowing oil etc. into road gutters can adversely affect fish and other creatures and the river environment due to river pollution. For this reason, do not allow oil to flow into road gutters.

(In case of emergency such as flammable oils and fats, police: 110, fire department: 119, Japan Coast Guard: 118)
(River manager: Public Works Office, Yokohama Kawasaki flood control office (outside site), Keihin river office (outside site))
(Port manager: Port and Harbor Bureau)
(Water and Soil Environment Division, Water Quality Section, Phone number: 045-671-4244)

In order to investigate the cause of the death of the fish, Yokohama City conducts water quality tests and fish inspections according to the situation. If harmful substances are detected, we will investigate the cause and investigate the impact on the surrounding area, and take necessary measures in cooperation with related organizations.
Dischargers of harmful substances, etc. may be subject to penalties under laws and regulations, and may be charged for restoration costs.

In addition, it has been confirmed that carp herpes is the cause of death in carp death. In this case, take measures such as prohibiting the movement of fish to prevent transmission to other waters.
About carp herpes, please see information (outside site) about carp herpes virus disease of Ministry of Agriculture, Forestry and Fisheries.

(In case of emergency, police: 110, fire: 119, Japan Coast Guard: 118)
(River manager: Public Works Office, Yokohama Kawasaki flood control office (outside site), Keihin river office (outside site))
(Port manager: Port and Harbor Bureau)
(Water and Soil Environment Division, Water Quality Section, Phone number: 045-671-4244)

Fish floating accident

Please see the list of water quality accidents that occurred in the city.

As of July 27, 2023, the pond of Tomioka General Park and the area of Minamidai River were designated within the range of water prohibited carp taking out based on the instructions of the Kanagawa Prefectural Water Surface Fisheries Management Committee.
For more information, please refer to the following website.

About carp herpes virus (KHV) disease (Kanagawa Prefecture) (outside site)
About range of water system pertaining to prohibition of taking out carp (Kanagawa Prefecture) (outside site)