Monitoring N : P Ratio and Cd, Cu, Pb, and Zn Contents in Different Types of Anaerobic Digestates: A Six-Year Study Case

Figure 2

Range of contents of cadmium, copper, lead, and zinc in five digestates and cattle slurry (analyzed twice a year over six years; therefore, n = 12 (DG Mix liquid five years, n = 10). Different letters above bars mark significant differences between means (Scheffé’s test, )). Yellow boxes mark the mean values.