Purpose

Heavy metal contamination, i.e., cadmium (Cd) via phosphate-based fertilizers is of great concern globally due to the potential risks for human and environmental health. The present study was done to use Brassica campestris (a hyperaccumulator plant) to assess the different phosphate-based fertilizers for their Cd contamination vulnerability in agricultural soil.

Methods

Three common commercially used phosphatic-fertilizers, viz., di-ammonium phosphate (DAP), nitrophos (NP), and rock phosphate (RP) were added at 50, 60, and 70 kg ha⁻¹, and their effects on plant growth, physiology, and physico-chemical properties of soil were evaluated relative to a control (no phosphatic fertilizer added).

Results

Compared with control, the addition of RP at 70 kg ha⁻¹ increased the Cd concentrations in soil by 35%. Similarly, the Cd concentrations in roots and shoots and soil were increased by 48, 102, and 49%, respectively in soils fertilized with RP at 70 kg ha⁻¹. Relative to the control, Cd contents were most elevated in soils amended with RP which was about 27 and 34% more than when either DAP and NP amended soil, respectively. Compared to control, there was also a slight reduction in growth (24, 15, 14, and 20% decrease in shoot dry matter, root dry matter, no. of pods, and root length, respectively), and physiological (5 and 11% decrease) parameters of Brassica campestris when cropped in soil amended with RP compared to the two other fertilizers.

Conclusion

It was concluded that, compared to the other two fertilizers (DAP and NP), the use of RP as a fertilizer caused a greater amount of Cd contamination. This indicates that there is a greater chance of long-term Cd contamination in agro-ecosystems treated with RP. In order to reduce the potential of contamination, it is not advised to use RP as a fertilizer instead; alternate fertilizers with lower Cd concentration should be selected.