Soil–plant transfer models for metals to improve soil screening value guidelines valid for São Paulo, Brazil

Abstract

In Brazil, there is a lack of combined soil-plant data attempting to explain the influence of specific climate, soil conditions, and crop management on heavy metal uptake and accumulation by plants. As a consequence, soil-plant relationships to be used in risk assessments or for derivation of soil screening values are not available. Our objective in this study was to develop empirical soil-plant models for Cd, Cu, Pb, Ni, and Zn, in order to derive appropriate soil screening values representative of humid tropical regions such as the state of São Paulo (SP), Brazil. Soil and plant samples from 25 vegetable species in the production areas of SP were collected. The concentrations of metals found in these soil samples were relatively low. Therefore, data from temperate regions were included in our study. The soil-plant relations derived had a good performance for SP conditions for 8 out of 10 combinations of metal and vegetable species. The bioconcentration factor (BCF) values for Cd, Cu, Ni, Pb, and Zn in lettuce and for Cd, Cu, Pb, and Zn in carrot were determined under three exposure scenarios at pH 5 and 6. The application of soil-plant models and the BCFs proposed in this study can be an important tool to derive national soil quality criteria. However, this methodological approach includes data assessed under different climatic conditions and soil types and need to be carefully considered.

Prediction Models Founded on Soil Characteristics for the Estimated Uptake of Nine Metals by Okra Plant, Abelmoschus esculentus (L.) Moench., Cultivated in Agricultural Soils Modified with Varying Sewage Sludge Concentrations

“…Data from the current experiment indicate that the designed mathematical models relating to A. esculentus uptake exhibited high accuracy for the majority of the tested metals when viewed in relation to measures of model quality, i.e., R 2 , ME, MNAE and MNB. Furthermore, it was noted that all the estimated soil variables (i.e., metal, pH, and OM content) impacted the plant uptake of the metals, which was in agreement with previous studies [42,[44][45][46].…”

“…Bešter et al [44] used models to measure the impact of Cd in tomato and endive, which exhibited R 2 values of 41% and 90%, respectively. R 2 parameters in relation to Cd for Urtica dioica as well as Agrostis and Poa species were documented as 10-47% and 31-38%, respectively [42], whereas R 2 values of 45% and 47% were obtained for lettuce and carrot, respectively [45]. Some earlier publications may have demonstrated lower parameters of R 2 for several of the models (Table A2), owing to the increased replicate frequency utilised to develop the model, which also creates significant data noise that, in turn, impacts the predictive accuracy of the affected models [52].…”

Uptake prediction of ten heavy metals by Corchorus olitorius L. cultivated in soil mixed with sewage sludge

“…All the measured soil factors (HM, pH, and OM) consistently contributed to HM concentrations in shoots and roots of the studied plant. Similar findings were proposed by several investigators such as Bešter et al (2013), Boshoff et al (2014), dos Santos‐Araujo, Swartjes, Versluijs, Moreno, and Alleoni (2017), and Gan et al (2017).…”