Differential uptake for dioxin-like compounds by zucchini subspecies

Abstract

The zucchini (Cucurbita pepo) cultivars 'Patty Green', 'Black Beauty', and 'Gold Rush' were cultivated on weathered dioxin-contaminated soil in pots, and concentrations of the 29 dioxin-like compounds that were assigned WHO-TEFs, three non-toxic polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs), and two non-dioxin-like polychlorinated biphenyls (PCBs) were analyzed. Toxic equivalent (TEQ) values accumulated in 'Black Beauty' and 'Gold Rush' were about 180 times higher than those in 'Patty Green'. The bioconcentration factor (BCF) based on total mass concentration of the twelve dioxin-like PCBs was higher than those of the seven PCDDs and ten PCDFs in all the cultivars. The BCFs for PCDD and PCDF congeners were negatively correlated with octanol-water partition coefficients in all the plants. No correlations were observed in PCB congeners in the high accumulators, although in 'Patty Green' the BCFs for PCB congeners were significantly correlated with octanol-water partition coefficients. Our findings suggest that the high accumulators had unknown, unique mechanisms for uptake of PCBs, whereas PCDDs and PCDFs were absorbed based on their physicochemical properties.

Model-Based Quantum-Chemical Study of the Uptake of Some Polychlorinated Pollutant Compounds by Zucchini Subspecies

“…The steps for the accumulation process of hydrophobic compounds in plants are six: exudation of compounds from the roots, desorption from soil organic matter and solubilization of hydrophobic compounds by the exuded compounds, adsorption on root surfaces, translocation from the root surface to the root stele, translocation from the roots to the aerial parts and metabolism 24,[44][45] . As we analyze the bioconcentration factors that are the final product of these six steps, in principle we have not the possibility of an a prori knowledge of the dominant step or steps.…”

“…Recently, Inui et al 24 studied the differential uptake of a group of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and dioxin-like polychlorinated biphenyls (PCBs) by zucchini (Cucurbita pepo) subspecies. They reported their results as Bioconcentration Factors (BCFs) calculated as the concentration of each compound in plants divided by its concentration in soil.…”

IN VITRO PHYTOREMEDIATION OF PERSISTENT ORGANIC POLLUTANTS BY Helianthus annuus L. PLANTS

“…32 as well as by the increased desorption resulting from the action of the root exudates. 33 Several studies have showed hydrophobic compounds found in leaves and fruits 34,35 such as polychlorinated biphenyls, [35][36][37] DDT and its metabolites, 38 chlordane, 39 hexachlorobenzene, 40 heptachlor, 41,42 and heptachlor epoxide. 43 In this work, the obtained data showed an accumulation of 15.2% of γ-HCH and 24.6% for δ-HCH in sunflower roots.…”

Effect of amending soil with organic acids on perylene uptake into <i>Cucurbita pepo</i>

“…Gold Rush accumulates 165 times the amount of dioxins and dioxin-like compounds in soil culture and 13 times the amount in hydroponic culture. 11,12) The fact that the difference between the two cultivars is lower in hydroponic culture than in soil culture suggests that Gold Rush solubilizes hydrophobic compounds from the soil more efficiently than Patty Green does and therefore that solubilization of HOPs from soil is an important determinant of the accumulation ability of a plant species.…”

“…pepo, including pumpkin and zucchini, have been shown to accumulate large amounts of HOPs. [6][7][8][9][10][11] In previous work with Cucurbita species, we found that as compared to the low-accumulation cultivar C. pepo ssp. ovifera cv.…”