Uptake of Trace Elements in the Water Fern Azolla filiculoides after Short-Term Application of Chestnut Wood Distillate (Pyroligneous Acid)

Abstract

Treatments of crops with additives to increase their productivity may pose environmental risks and induce negative effects also on non-target organisms. In this study, we investigated the potential effect of chestnut wood distillate (pyroligneous acid) used in agriculture, on the accumulation of trace elements in aquatic plants. As a model species, the common water fern Azolla filiculoides Lam. was selected, being often used also in phytoremediation processes. The content of selected elements of toxicological concern (As, Ba, Cd, Cu, Fe, Mn, Ni, Pb, Zn) was assessed in the fern after short-term treatments (1–3 days) over a range of wood distillate concentrations 1:300 (3.33 mL/L), 1:500 (2.00 mL/L), 1:700 (1.43 mL/L). A statistically significant accumulation of Cd, Cu, Mn, Pb, Zn (1:700) and Pb (1:300) was recorded after three days of incubation, despite the concentrations remained overall low. Using treatment vs. control ratios, a trend of increasing temporal uptake was detected for As, Ba, Fe, Mn, Pb (1:700); Mn, Pb (1:500), and only Pb at 1:300. The results suggested that, under the experimental conditions, element uptake is positively influenced by time and negatively by increasing concentrations of wood distillate, likely due to the acidification of the medium. On the whole, the element concentrations measured in A. filiculoides were low and did not pose any toxicological concern.

Bio-Based Solutions for Agriculture: Foliar Application of Wood Distillate Alone and in Combination with Other Plant-Derived Corroborants Results in Different Effects on Lettuce (Lactuca Sativa L.)

“…From a toxicological point of view, all treatments did not alter the content of the investigated elements in lettuce leaves, confirming the results obtained by Fačkovcová et al [15,16] about the environmental safety of WD. The concentrations of Fe, Zn, and Cu of our samples were within the common ranges reported in the literature: 1.97-8.6 mg/kg for Fe [45,46], 2.1-9.4 mg/kg for Zn [45][46][47], and 0.23-1.4 mg/kg for Cu [45,47].…”

“…There is convincing evidence that WD has great potential in agriculture [4,8,9] because of its ability to act as a biostimulant for crops, to increase biomass [10,11] and fruit production (quality, size, and weight) [6,12]. Moreover, ecotoxicological studies have confirmed that this product is safe for the environment since it has been shown to have no adverse effects on either aquatic or soil organisms [13,14], as well as non-target bioindicators, i.e., lichens, mosses, and aquatic ferns [15,16]. Additionally, an investigation of the safety profile of wood distillate excluded inflammatory and cytotoxic effects at low recommended doses and short-time applications at higher doses [17].…”

“…Moreover, a second aim was to test whether the addition of 3% soy lecithin and 5% flavonoid-rich wood glycolic extract to WD has a further positive effect on the above parameters. Additionally, the potential toxicological concern regarding treatments with WD was investigated by checking the concentration of some potentially toxic elements (PTEs), namely Cd, Cu, Fe, Pb, and Zn, which may be abundant in WD [16]. Optimizing the use of WD according to crop needs may provide farmers with the most efficient use of this bio-stimulant and may increase the economic return of agricultural production.…”

Effects of wood distillate and soy lecithin on the photosynthetic performance and growth of lettuce (Lactuca sativa L.)

“…It must be emphasized that there is no correlation between natural and non-toxic as some natural compounds show a much greater toxicity than synthetic ones (i.e., botulin). Nevertheless, at routine usage doses, bio-based products have been shown to be safe, even for sensitive nontarget organisms [1,2].…”

Characterization of the Safety Profile of Sweet Chestnut Wood Distillate Employed in Agriculture

“…In recent years, evidence have been reported about the profitable use of WD extracted from different wood types, mainly owing to its antioxidant activity [12] and its derivates [13] on different soil organisms [14]. The ecotoxicology profile of WD was recently assessed on aquatic biota, excluding any risk of heavy metal accumulation in an aquatic fern model [15]. At the same time, some cytotoxic effects of natural extracts have been demonstrated, as in the case of essential oils commonly used in traditional Chinese medicine [16,17].…”