Assessing the Influence of Compost and Biochar Amendments on the Mobility and Uptake of Heavy Metals by Green Leafy Vegetables.

Agnieszka Medyńska-Juraszek,Magdalena Bednik,Piotr Chohura

doi:10.3390/ijerph17217861

Abstract

Municipal green-waste compost and wheat straw biochar amendments were assessed for their assistance in regulating the mobility of Cu, Pb, Zn, Cd, Cr and Ni and the uptake of these metals by five commonly grown green leafy vegetables (radish, lettuce, dill, spinach and parsley). The amendments were applied alone or combination of both in 5% and 10% (v/w) doses to soil contaminated with heavy metals. Vegetables were grown for eight weeks under greenhouse conditions, and in collected samples plant uptake and metal speciation in soil after sequential extraction procedure (BCR) were analyzed by Microwave Plasma Atomic Emission Spectrometer (MP-AES). The results of our study show that organic amendments noticeably reduced the uptake of heavy metals by various leafy vegetables, with the best result of reduced leaf accumulation for single biochar and biochar–compost mix application at higher dose. Single application of green-waste municipal compost may have adverse effects on heavy metal uptake, increasing the risk of vegetable contamination with Zn, Pb and Cr. This study recommends careful selection of vegetables for cultivation when organic fertilizers are applied to soil with elevated contents of trace elements or co-application of compost in mix with biochar to mitigate possible negative effects and human health risk.

Highlights

Heavy metal contaminated soil has become a global concern affecting world food production [1,2,3].Excessive accumulation of trace elements in agricultural soils leads to elevated metal uptake by crops and affects food quality and safety [4,5,6]
An interesting tool for reducing the risk related to heavy metal presence in soil, especially on soil used for food production, is the use of organic amendments such as compost or biochar
One of the expected effects after incorporation of organic amendments is the improvement of soil water content

Summary

Introduction

Heavy metal contaminated soil has become a global concern affecting world food production [1,2,3]. Excessive accumulation of trace elements in agricultural soils leads to elevated metal uptake by crops and affects food quality and safety [4,5,6]. Heavy metals can be accumulated at high levels in the edible parts of plants, even when present in soil at low concentrations [7]. Trace elements contamination in soil is a challenging issue of risk management, as heavy metals do not degrade with time and remain persistent in the environment [8]. An interesting tool for reducing the risk related to heavy metal presence in soil, especially on soil used for food production, is the use of organic amendments such as compost or biochar. With the rapid development of urbanization and a large quantity of municipal solid wastes

Methods

Results

Conclusion