Figure 14 shows an example of an X-ray fluorescence spectrum of the immersed carrier. Fe was the main species detected, although silicon (Si), calcium (Ca), aluminum (Al), P, sulfur (SO4), potassium (K), chlorine (Cl) were also present. Heavy metals were not detected on most of the carriers, but traces of Pb and Zn were detected in some samples (Table 2). However, they were well below regulation levels set out in the Fertilizers Regulation Act (Ministry of Agriculture, Forestry and Fisheries, 2007) and the Guidelines against Heavy Metal Accumulation in Arable Soil (Environment Agency, 1984). This was probably because the study site was in a rural area that had not been contaminated by heavy metals and also because the immersion period was too short for these metals to accumulate.

Fig. 14. X-ray fluorescence spectrum of immersed carrier