Prediction Model for Cadmium Transfer from Soil to Carrot (Daucus carota L.) and Its Application To Derive Soil Thresholds for Food Safety

Abstract

At present, soil quality standards used for agriculture do not fully consider the influence of soil properties on cadmium (Cd) uptake by crops. This study aimed to develop prediction models for Cd transfer from a wide range of Chinese soils to carrot (Daucus carota L.) using soil properties and the total or available soil Cd content. Path analysis showed soil pH and organic carbon (OC) content were the two most significant properties exhibiting direct effects on Cd uptake factor (ratio of Cd concentration in carrot to that in soil). Stepwise multiple linear regression analysis also showed that total soil Cd, pH, and OC were significant variables contributing to carrot Cd concentration, explaining 90% of the variance across the 21 soils. Soil thresholds for carrot (cultivar New Kuroda) cropping based on added or total Cd were then derived from the food safety standard and were presented as continuous or scenario criteria.

Cadmium and lead in vegetable and fruit produce selected from specific regional areas of the UK

“…As this survey was done across a wide range of different locations it is expected that the soil properties, which affect the availability and uptake of metals from soils, will be different at different sites. Soil pH has been identified as an important factor in cadmium accumulation in plants (Adams et al, 2004;Zheng et al, 2011;Zhao et al, 2010;Ding et al, 2013Liu et al, 2015. For example, Liu et al (2015) demonstrated that wheat varieties accumulated more cadmium in acidic soils compared to alkaline soils.…”

“…For example, Liu et al (2015) demonstrated that wheat varieties accumulated more cadmium in acidic soils compared to alkaline soils. Other important soil factors include organic carbon content, cation exchange capacity, and clay content, as well as the oxide content of Fe, Al, and Mn (Zheng et al, 2011;Zhao et al, 2010;Ding et al, 2013;). As these factors would vary across the different sampling locations, this may be a reason for the lack of correlations between soil and plant heavy metal concentration.…”

Regional accumulation characteristics of cadmium in vegetables: Influencing factors, transfer model and indication of soil threshold content

“…The direct cause-and-effect relationships between environmental factors and vegetables accumulating Cd from soil are difficult to determine because environmental factors are often correlated (Basta et al, 1993;Ding et al, 2013). By partitioning the correlation coefficient into direct and indirect effects, the path model (PA) can be used to determine the causal relationship in the agronomic studies (Shipley, 2009).…”

“…The direct effects of environmental variables on PUF are termed path coefficients and derived from multiple regression of environmental variables on PUF (Basta et al, 1993). Indirect effects are determined from the product of a simple correlation coefficient between environmental factors and the path coefficients (Ding et al, 2013). The relations between the correlation coefficient, direct effect and indirect effect are described in the following function:…”

“…This produces an inaccurate assessment of actual risks to the population (Nabulo et al, 2010;Norton et al, 2015). Predictive models factoring in environmental variables on the accumulation of Cd in crops would allow improved soil quality standards that provide a more risk-based approach to the protection of farmlands (Ding et al, 2013). Other studies established a Cd threshold for rice and vegetables using predictive models (Adams et al, 2004;Zhang et al, 2011).…”