From the late 1960s to the 1970s, the production of caustic soda accounted for more than half of the mercury consumption. The shift from mercury process to non-mercury processes in the caustic soda production had the most significant effect on the reduction of the demand for mercury.
Implementation Situation of Mercury Monitoring and Results
The nationwide monitoring of air and water is being conducted throughout Japan to check the state of achievement of the environmental quality standards or guideline values for mercury in the general environment. The latest monitoring results indicate that the environmental quality standards are exceeded in groundwater and soil at some locations but that all of the standards or guideline values are met in public water areas and air at every single monitoring point. In the case of public water areas, the relevant environmental quality standards have never been exceeded since FY 1997 at all of the monitoring points. In regard to air, none of the guideline values have been exceeded since FY 1998 when the full-scale monitoring of air started (see Table 8).