Cadmium accumulation, translocation factor, and health risk potential in a wastewater-irrigated soil-wheat (Triticum aestivum L.) system

Abstract

The accumulation of trace elements in wastewater-irrigated soils may introduce them to the food chain and therefore can threaten human health. The present study investigated the accumulation, translocation factor, and health risk potential of cadmium (Cd) in a soil-wheat system irrigated with treated wastewater compared with a reference soil (irrigated with fresh water). All treated wastewater-irrigated soils showed significantly higher levels of electrical conductivity (EC) than that of reference soil by 75–143%. Irrigation with treated wastewater increased both available and total Cd content in soil by 2–4 times. In all irrigated sites, Cd content was about twice as great as the maximum acceptable rate. Bioconcentration factor (BCF) and translocation factor (TF) indicated that Cd was mainly accumulated in the roots (BCF = 2.2–3.1), while little mobilization from roots to stems and grains was noted (TFshoot/root = 0.07–0.21; TFgrain/root = 0.18–0.24). The average hazard quotient (HQ) for different age groups of the population varied in the range of 0.1–1.0, implying low non-carcinogenic health risk of Cd to local wheat-consuming residents. The risk of Cd to cause carcinogenic health risk (CR) was in the range of 1 × 10-5 to 1 × 10-4, indicating low to moderate potential risk. CR for different age groups was in the order: individuals above 18 years old > individuals 7–18 years old > individuals 0–6 years old. For reducing potential health risks to local people, it is imperative to continuously monitor heavy metal levels in the wheat-soil system and urgently adopt more efficient managerial strategies to reduce Cd contamination.