Determination of the Bioavailable Fraction of Cu and Zn in Soils Amended with Biosolids as Determined by Diffusive Gradients in Thin Films (DGT), BCR Sequential Extraction, and Ryegrass Plant

Abstract

This study assessed the effect of biosolids applied at rates, 0, 30, 45, and 60 Mg ha −1 on the chemical associations and bioavailability of Cu and Zn in soils from an important agricultural zone of the Metropolitan Region in Central Chile. Three methods were used to determine the bioavailability of Cu and Zn in soils: ryegrass (Lolium perenne) plants, diffusive gradients in thin films (DGT) technique, and Community Bureau of Reference (BCR) sequential extraction. The DGT effective concentration (C E ) and sequential extract acid soluble fraction of the BCR extraction (most labile fraction of the soils, normally associated with bioavailability) were compared with total metal concentration in ryegrass plants as a means to compare the chemical and biological measures of bioavailability. Total Zn was higher in comparison to Cu for all treatments. Concentrations were within the limits set by the Chilean regulations for land-applied biosolids. Metals in the control soil were primarily found in the residual fraction of soils. Biosolids application generally decreased this fraction, with a subsequent increase observed mainly in the acid soluble fraction. The contents of Cu and Zn in ryegrass plants increased with increasing rates of biosolids. Comparison of the Cu and Zn content in ryegrass plants with C E , showed a good correlation for Zn. However, the C E for soil Cu was only related to plant Cu for some of the soils studied. Correlation between Zn in ryegrass plants and the labile fraction of Zn as measured by the sequential extraction was excellent, with correlation coefficients >0.9, while for Cu, correlation coefficients were lower.

Assessment of metals bioavailability to vegetables under field conditions using DGT, single extractions and multivariate statistics

“…Also, the lack of correlation among the pseudo-total and acid extractable Zn contents with Zn accumulation in plants was observed. The strong positive correlations between C E and plants uptake of Zn observed in our study is confirmed by previous pot experiment studies [4,12,36,37]. …”

“…Our results are consistent with those reported by Wang et al [31] who found positive correlation between soil OC and Cu accumulation in plant roots. In addition, our results confirm the lab-scale studies that found positive correlations between available Cu content assessed by DGT and plants uptake [10,11,35,36], although there are other studies indicated that DGT is less effective in Cu bioavailability prediction [4]. …”

“…In addition to their toxicity, metals persist in soil for long times and have the capacity to be transferred into the food chain [1,2] thus the assessment of their content in soil and the estimation of their transfer rates to vegetation are of great interest [3]. The soil quality guidelines are usually based on total metal content, although it is generally accepted that total metal content include both bioavailable and non-bioavailable fractions [4]. The estimation of bioavailable metal fractions is, generally, based on single or sequential extraction procedures [5,6], but these provide only a classification of metal fractions in the soil compartments.…”

Can washing-pretreatment eliminate the health risk of municipal solid waste incineration fly ash reuse?

“…Considering the cost and time, most researchers preferred to do in-vitro methods, such as the physiologically based extraction test (PBET) (Juhasz et al, 2010(Juhasz et al, , 2011, to evaluate the bioaccessibility of pollutions from matrix such as soils and dust, when assess the actual health risk of heavy metals by ingestion (Hu et al, 2013;Luo et al, 2012;Vasiluk et al, 2011). However, a wealth of studies demonstrated a strong linear relationship between bioaccessibility and exchangeable and soluble fraction, reducible fraction extracted by BCR method (Ahumada et al, 2011;Akkajit and Tongcumpou, 2010;Alvarenga et al, 2009;Baig et al, 2009;Dabek-Zlotorzynska et al, 2005;De La Calle et al, 2013;Karadaş and Kara, 2012;Poggio et al, 2009;USEPA, 2003USEPA, , 2007. Hence, we used modified four-step BCR method to evaluate the oral bioaccessible fraction (bioaccessibility) in MSWI fly ash.…”

Heavy metal accumulation in wheat and barley: The effects of soil presence and liquid manure amendment

“…As described in the literature, the mobility of metals in soil can also be influenced by the application of different natural or synthetic additives such as lime, phosphates, organic matter residues, zeolites, beringite and aluminium, manganese and iron oxides (Bolan & Duraisamy 2003;Abbasi & Yousra 2012). According to Ahumada et al (2011), biosolids application reduced the metal content of the residual fraction, with a subsequent increase observed in the acidsoluble fraction which is phytoavailable. Also, Businelli et al (2009) investigated the long-term distribution, mobility and phytoavailability of heavy metals by collecting soil samples at different depths subsequent to the amendment of the top layer of a landfill covering soil with municipal waste compost.…”