Metal burdens in surface sediments of limed and nonlimed lakes

In order to test the hypothesis, we statistically compare the areal metal and P burdens in the sediments of four groups of lakes: (1) Mainly surface limed lakes, (2) Mainly upstream/wetland limed lakes, (3) Near neutral reference lakes and, (4) Acidified reference lakes. The statistical analysis reveals that the surface limed group have significantly higher areal burdens of As, Cd, Co and Zn in the sediment compared to the acidified reference group, despite large variations within the groups. The investigation indicates that surface liming increases the areal burdens in the sediments of Cd and Pb, probably of As, Ca and Mn and possibly Co and Zn, whereas acidification decreases the areal burdens in sediments of Cd, Fe, Mn and possibly Co, P and Zn. The results of the study confirm the hypothesis.