Fig. 3.

Effect sizes of 8 metals during 2010–2021 normalized to the background (1990) levels. X-axis means the response ratio of heavy metal amount of past 12 years: background in a natural log scale. Values are effect sizes with 95% confidence intervals (CIs). A ratio of 0 (or CIs overlapped with 0) means statistically no significant difference between the 12-year data and the background levels. A ratio larger than 0 (marked in red) indicates an increase of a pollutant compare with the background levels, and whereas a ratio smaller than 0 (green) indicates a decrease.