higher than that of the suburbs, and the number of hours exceeding $ 30^{\circ} $ C increases during the summer. Waste heat from air conditioning and other systems brings about a temperature rise, and has various environmental impacts such as the creation of a vicious circle, causing further waste heat from air conditioning.

According to the “Outline of the Policy Framework to Reduce Urban Heat Island Effects.” the ministry has promoted four major pillars of countermeasures against the heat island phenomenon; reduction of anthropogenic heat emissions, improvement of the urban surface, improvement of urban structures, and improvement of lifestyles. The Inter-Ministry Coordination Committee to Mitigate Urban Heat Island Effects has also been launched to revise the “Outline of the Policy Framework to Reduce Urban Heat Island Effects.”

The ministry has continuously implemented research and observations on heat island phenomenon and impacts on the environment, and has provided information and monitoring for preventing heat stroke, as related to the research.

## (3) Current status of the Water Environment

Regarding the EQS for the protection of human health from substances in the EQS for Water (Health Items), the achievement level for public water areas in FY2007 was 99.1%. Among the conservation of the living environment (Living Environment Items), the achievement level of the EQS for Biochemical Oxygen Demand (BOD) or Chemical Oxygen Demand (COD), a typical water quality indicator for organic contamination, was 85.8% in FY2007. By water areas, the achievement levels were 90.0% for rivers, 50.3% for lakes and 78.7% for seas, and the achievement level of lakes and reservoirs still remained low (Figure2-8, Figure2-9).

The achievement rates of EQS in enclosed water areas, in terms of COD were 63.2% for Tokyo Bay, 56.3% for Ise Bay, 66.7% for Osaka Bay and 78.0% for the Seto Inland Sea excluding Osaka Bay.

Results of the general monitoring survey of groundwater quality in FY2007 saw 7.0% (325 wells) out of the 4,631 wells tested exceed EQS limits (Figure2-10). EQS limits were most exceeded by nitrate-nitrogen or nitrite-nitrogen, an excess of 4.1%, caused by farmland fertilization, livestock excreta and domestic wastewater, and countermeasures against them have become an urgent issue.

## (4) Current status of the soil environment

Regarding soil contamination in urban areas, research and measures based on the Soil Contamination Countermeasures Act (Act No.53 of 2002) have been progressing. In recent years, more soil contamination cases have been identified, resulting from an increase in the number of companies that conduct independent pollution surveys, continuous monitoring system development for groundwater in local governments and the development of ordinances on soil contamination measures (Figure2-11).

Under these circumstances, the ministry adopted the

## Figure2-10 Changes in the Percentages of the Groundwater Exceeded the EQS (General Monitoring Survey)

Note 1: Different sets of wells are monitored every year. (i.e. Not necessarily the same wells are monitored for the data every year.)

2: Until the EQSs for groundwater were established in 1997, the Assessment Standards had been used to evaluate groundwater quality. (The Assessment Standard for Arsenic was revised from 0.05 mg/L or less to "0.01 mg/L or less" and that for Lead was revised from "0.1 mg/L or less" to "0.01 mg/L or less" in 1993.)

The EQS for nitrate/nitrite nitrogen, fluorine and boron were added to the EQS in 1999.

The data contained in the chart is limited to those of the substances with relatively high rate of the data that exceeded the EQS.

Source: Ministry of the Environment, FY2007 Results of Monitoring Survey of Groundwater

“Bill Partially Amending the Soil Contamination Countermeasures Act” at a Cabinet meeting in March 2009 and submitted to the Diet (promulgated in April 2009) after debates in the Central Environment Council’s subcommittee on the future system for soil environmental protection measures in December 2008.

## (5) Current status of the ground subsidence

Excessive pumping of groundwater for industrial, residential and agricultural uses lowers the level of groundwater followed by a shrinking of the clay layer due to water content reduction, causing ground subsidence. As of FY2007, 60 areas in 37 prefectures suffered ground subsidence.

Measures such as restrictions on the pumping of groundwater have slowed down or almost stopped the ground subsidence in Tokyo’s 23 wards, Osaka City and Nagoya City, where remarkable ground subsidence have occurred in the past. However some parts of Japan still show ground subsidence, including snow-covered areas that use groundwater for snow melting and areas pumping brine water from natural gas wells.

In addition to this, there are many areas faced with potential risks from natural disasters due to flood, high tide and tsunami within ground subsidence areas that are at or below sea level.