Fraction of Cd in oasis soil and its bioavailability to commonly grown crops in Northwest China

Heavy metals in the soil–plant system resulting from mining and wastewater irrigation have greatly threatened human health and sustainable development in Northwest China. This research used pot experiments to study the bioavailability of Cd in irrigated desert soil from the oasis regions and conducted a human health risk assessment of the Cd content in vegetables. The results show that the content of Cd associated with exchangeable and carbonate metal fractionations is not uniform in arid oasis soils cultivated with the commonly grown vegetables. These common growth vegetables are: Cole (Brassica campestris L.), Celery (Apium Graveolens L.) and carrots (Daucus carota L.). The results show that the content of Cd in the edible part of cole was significantly higher than celery and carrots in almost all of the treatments. However, cole can grow normally and keep increasing its biomass at a sustainable rate under the highest concentration of Cd added in the experiment. Cole is not a suitable vegetable to be planted for consumption in arid soil contaminated with Cd, celery planted under lower concentration of Cd will not threaten human health, and carrots are suitable to be planted in arid soil contaminated with Cd even in the highest concentration used in the experiment. According to this conclusion, stricter soil management systems should be implemented to protect arid land soil resources and to protect human health from the toxicity impacts.