Cadmium accumulation in soils from long‐continued applications of superphosphate

Abstract

A simple, sensitive method developed for the analysis of geostandards was used to measure the accumulation of Cd in soils from superphosphate applied annually to grassland and arable soils for many years. Rates of application were equivalent to 33 kg P and 5 g Cd ha-' yr-' for 95 yr in three experiments in England and to 37 kgP and 20gCdha-'yr-' for 30 yr in one experiment in New Zealand. Very little Cd accumulated in the surface horizons (0-22.5cm) of either of the arable soils from England; about one-quarter of the applied Cd was detected in the sub-soil (22.5-45.0 cm) of one experiment (Broadbalk) but none in the second (Barnfield). About one-half of the applied Cd was retained in the CL22.5 cm horizon of grassland soils from both England tnd New Zealand. The light ( <2.2 g C I T -~) organic-rich fraction of Park Grass soil from England contained about three times as much Cd as the heavier, mineral-rich fraction. This suggests that when Cd is incorporated into organic matter its mobility is decreased and soil pH then has smaller effects on its mobility. Uptake of Cd by grass-clover pasture in New Zealand averaged only 0.4 g Cd ha-' yr-' or 2% of the amount applied.

Absorption and distribution of cadmium of three maize hybrids in three environments

“…On the contrary, another factor that would explain low Cd accumulation in Chillán for grain, stem, and root could be due to greater competition between the H + and Cd +2 cations in the uptake sites on the root surface (Larsson and Asp, 2013). A directly proportional response was found between the applied Cd rate and root Cd concentration ( Figure 2b); results were similar to those reported by Liu et al (2013), and values corresponded to an increase equivalent to 3.5 and 4.5 times compared with the control when applying 1 and 2 mg kg (Rothbaum et al, 1986;Quezada-Hinojosa et al, 2015) (Figures 3a, 3b, 3c), and also similar to those cited by Segura et al (2006) for different soils in…”

“…However, concentrations and the magnitude of the differences were lower (Figures 3a, 3b). This effect could be attributable to the characteristics of this element in the soil, which is mainly located at the surface (Rothbaum et al, 1986). When comparing the environments, the Cd concentration was higher in Los…”

“…Cadmium is one of the heavy metals that is usually found in low concentrations in the soil (Rothbaum et al 1986;Quezada-Hinojosa et al, 2015;Seshadri et al, 2015). It is toxic for living organisms and carcinogenic for human beings (Liu et al, 2015;Seshadri et al, 2015).…”

Cadmium status of soils, plants, and grazing animals in New Zealand

“…One such farming practice that is a likely source of Cd is the application of phosphatic fertilisers. Reports in the literature (Williams & David 1973;Williams & David 1976;Rothbaum et al 1986) have shown that soil Cd concentration and the amount of superphosphate added were strongly related. Mortvedt (1987) has shown that accumulation of Cd in soils was negligible when Cd in the fertiliser was less than 10 (ig/g, whereas Andersson (1976) calculated that if Cd concentration in fertiliser exceeded 8 (lg/g, topsoil Cd levels were likely to increase.…”

“…Mortvedt (1987) has shown that accumulation of Cd in soils was negligible when Cd in the fertiliser was less than 10 (ig/g, whereas Andersson (1976) calculated that if Cd concentration in fertiliser exceeded 8 (lg/g, topsoil Cd levels were likely to increase. Australian superphosphate has been shown to contain, on average, 33 jig Cd/g (range 6-68 ng/g) (Hilliard et al 1988) whereas New Zealand superphosphate contained, on average, 48 ug Cd/g (range 34-69 ug/g) (Rothbaum et al 1986). The Cd in superphosphate arises primarily from the phosphorite used as the raw material, although Cd content varies considerably with origin of the phosphorite (Syers et al 1986).…”