Pyrrolizidine alkaloids (PA)s are natural toxins produced by a variety of plants including ragwort. The PAs present a serious health risk to human and livestock. Although these compounds have been ...extensively studied in food and feed, little is known regarding their environmental fate. To fill this data gap, we investigated the occurrence of PAs in ragwort plants, soils and surface waters at three locations where ragwort was the dominant plant species to better understand their environmental distribution. The concentrations of PAs were quantified during the full growing season (April–November) and assessed in relation to rain events. PA concentrations ranged from 3.2–6.6 g/kg dry weight (dw) in plants, 0.8–4.0 mg/kg dw in soils, and 6.0–529 μg/L in surface waters. Maximum PA concentrations in the soil (4 mg/kg) and water (529 μg/L) were in mid-May just before flowering. The average distribution of PAs in water was approximately 5 g/10,000 L, compared to the average amounts present in ragwort (506 kg/ha), and soil (1.7 kg/ha). In general, concentrations of PAs increase in the soil and surface water following rain events.
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•Determine the potential of PAs in environmental samples: plant, soil and water•Co-relate the concentrations in soil and water with the plant growth/rain events•Scale and explain the distribution of PAs from plant into soil and water•Determine the frequency of individual PAs in all corresponded samples•Assess the risk of PAs contamination, where the plant and water sources meet
Phytotoxins are naturally produced toxins with potencies similar/higher than many anthropogenic micropollutants. Nevertheless, little is known regarding their environmental fate and off-field ...transport to streams. To fill this research gap, a network of six basins in the Midwestern United States with substantial soybean production was selected for the study. Stream water (n = 110), soybean plant tissues (n = 8), and soil samples (n = 16) were analyzed for 12 phytotoxins (5 alkaloids and 7 phytoestrogens) and 2 widely used herbicides (atrazine and metolachlor). Overall, at least 1 phytotoxin was detected in 82% of the samples, with as many as 11 phytotoxins detected in a single sample (median = 5), with a concentration range from below detection to 37 and 68 ng/L for alkaloids and phytoestrogens, respectively. In contrast, the herbicides were ubiquitously detected at substantially higher concentrations (atrazine: 99% and metolachlor: 83%; the concentrations range from below detection to 150 and 410 ng/L, respectively). There was an apparent seasonal pattern for phytotoxins, where occurrence prior to and during harvest season (September to November) and during the snow melt season (March) was higher than that in December–January. Runoff events increased phytotoxin and herbicide concentrations compared to those in base-flow conditions. Phytotoxin plant concentrations were orders of magnitude higher compared to those measured in soil and streams. These results demonstrate the potential exposure of aquatic and terrestrial organisms to soybean-derived phytotoxins.
Pyrrolizidine alkaloids (PAs) are produced in plants as defence compounds against insects. PAs present a serious health risk to humans and livestock; therefore it is necessary to have a validated ...analytical method to monitor PAs in the environment. The objective of this work is to present an UPLC-MS/MS method for quantification of PAs in environmental samples of both soil and water. A fast, reliable, and sensitive approach is developed to identify and quantify PAs in soil and water. Sample preparation was performed by clean-up and pre-concentration of the samples using MCX solid phase extraction cartridges with full optimization, and then PAs were determined by UPLC coupled with TQ-MS. In the liquid chromatography, most of the parameters were optimized and tested including gradient time, solvents, additives, and pH of the mobile phases and flow rate. In addition, the MS parameters of cone voltage, desolvation temperature, cone flows, and collision energy were optimized. The instrument limit of detection (2-7 μg L
−1
) and limit of quantification (5-9 μg L
−1
) were determined experimentally, and the method was linearity validated up to 1000 μg L
−1
. The method was applied to analyse soil and surface water samples collected in April and May 2018 in Vejle, Borup, and Holte, Denmark. In total, 15 PAs were quantified and reported for the first time in environmental samples, in a range of 3-1349 μg kg
−1
in soil and 4-270 μg L
−1
in surface water.
Pyrrolizidine alkaloids quantified in soil and water.
Plants synthesize a plethora of chemical defence compounds, which vary between evolutionary lineages. We hypothesize that plants evolved the ability to utilize defence compounds synthesized and ...released by neighbouring heterospecific plants. In two experiments, we incubated clover (Trifolium repens L.) seedlings with individual benzoxazinoid (BX) compounds (2,4-dihydroxy-1,4-benzoxazin-3-one, 2-hydroxy-1,4-benzoxazin-3-one, benzoxazolinone, and 6-methoxy- benzoxazolin-2-one), a group of bioactive compounds produced by cereals, to allow clover BX uptake. Subsequently, we transplanted the seedlings into soil and quantified BX root and shoot content and invasion of root-knot nematodes in clover roots up to 8 weeks after transplantation. We show that clover root uptake of BXs substantially enhanced clover's resistance against the root-knot nematode Meloidogyne incognita. This effect lasted up to 6 weeks after the clover roots were exposed to the BXs. BXs were absorbed by clover roots, and then translocated to the shoots. As a result of clover metabolization, we detected the parent BXs and a range of their transformation products in the roots and shoots. Based on these novel findings, we envisage that co-cultivation of crop species with complementary and transferable chemical defence systems can add to plant protection.
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•Clover roots take up and metabolize cereal benzoxazinoids (BXs).•BXs are translocated into aboveground clover tissues.•BX transformation products are a result of enzymatic reactions in clover.•BXs uptake enhanced clover's resistance against root-knot nematodes.
Background
Lupin is a promising legume crop, belongs to the
Fabaceae
(or
Leguminosae
) family. Lupin production for traditional and functional foods or animal feed is limited, due to the content of ...toxic quinolizidine (QA)s and indole alkaloids (IA)s. These compounds may not only pose a risk to humans and animals through food consumption, but may also affect soil and aquatic ecosystems. Field experiments were conducted to study the alkaloids content in both narrow-leaved or blue (
L. angustifolius
) and yellow (
L. luteus
) lupin plant tissue during a full growing season and understand the environmental fate of alkaloids in soil and water. Suction cups were used to collect soil pore water (soil solution) at four depths: 10, 25, 50 and 70 cm. A full protocol for sample preparation and UPLC–MS/MS quantification of alkaloids in plant, soil and water was developed.
Results
During the field experiments the alkaloids in the plant tissues increased, at the harvest stage the content was highest with 21.4 and 24.6 mg/kg dry weight (dw) for blue and yellow lupin, respectively. In soil, alkaloids quantified during the growing season (max concentration was 1.3 × 10
2
µg/kg dw) and even detected after harvest (0.2 µg/kg dw). In soil pore water samples, alkaloids were not detected during summer, but the concentrations increased to 9.8 × 10
2
and 1.5 × 10
3
ng/L for blue and yellow, respectively, in September when autumn precipitation began.
Conclusions
The results show the amount of alkaloids transferred from plant tissue into soil and soil pore water estimated to be on average 0.016% and 0.005% in soil and soil pore water, respectively. Alkaloids leached from topsoil to subsoil layers; the concentrations decline with soil depth. This study demonstrates that alkaloids are mobile compounds in the soil environments, thus lupin production may affect soil or aquatic ecosystems, and reduce water quality.
Metabolomic studies on root uptake and transformation of bioactive compounds, like cereal benzoxazinoids (BXs) in non-BX producing plants, are very limited. Therefore, a targeted ...mass-spectrometry-based metabolomics study was performed to elucidate the root uptake of BXs in white clover (Trifolium repens L.) and the impact of absorbed BXs on intrinsic clover secondary metabolites. Clover plants grew in a medium containing 100 μM of individual BXs (five aglycone and one glycoside BXs) for 3 weeks. Subsequently, plant tissues were analyzed by liquid chromatography–tandem mass spectrometry to quantify the BXs and clover secondary metabolite concentrations. All BXs were taken up by clover roots and translocated to the shoots. Upon uptake of 2,4-dihydroxy-1,4-benzoxazin-3-one (DIBOA), 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA), 2-hydroxy-1,4-benzoxazin-3-one (HBOA), and 2-β-d-glucopyranosyloxy-1,4-benzoxazin-3-one (HBOA-glc), the parent compounds and a range of transformation products were seen in the roots and shoots. The individual BX concentrations ranged from not detected (nd) to 469 μg/g of dry weight (dw) and from nd to 170 μg/g of dw in the roots and shoots, respectively. The root uptake of BXs altered the composition of intrinsic clover secondary metabolites. In particular, the concentration of flavonoids and the hormone abscisic acid increased substantially in comparison to control plants.
Background
Many plants contain phytotoxic alkaloids to deter herbivorous pests and grazing animals. Alkaloids include quinolizidine and indole alkaloids found in the lupin (
Lupinus
spp.), an ...ornamental flower and emerging protein crop, as well as pyrrolizidine alkaloids in the ragwort (
Senecio jacobaea
), an invasive, weed-like flower. When lupins and ragworts are present in large densities in fields, there is a concern that alkaloids may leach into freshwater environments in amounts that may affect non-target organisms, such as
Daphnia magna
. This study aimed to investigate (i) the acute toxicity of alkaloids (gramine, heliotrine, lupanine, lupinine, monocrotaline, monocrotaline N-oxide, senecionine and sparteine) in
D. magna
, (ii) the contribution of these individual alkaloids to lupin plant extract toxicity, (iii) the longer term reproductive effects of a representative alkaloid, sparteine, and conclude with (iv) a tentative risk assessment for the sum of alkaloids measured in soil and surface waters.
Results
The alkaloids exhibited toxicity, with 48 h EC
50
values in the range of 5.6 to > 100 mg/L. The 48 h EC
50
of the
Lupinus angustifolius
plant extract was 1.38 mg/L, which was far more toxic than the simulated extract where lethality was < 10% at 10 mg/L after 48 h. Hence, non-measured compounds may have contributed to the joint toxicity. Daphnid mothers exposed to > 2.5 mg/L sparteine produced significantly fewer and smaller offspring during the 21-day exposure, making chronic effects occur at concentrations approximately 10-fold lower than the 48 h EC
50
for sparteine. The risk assessment of cumulated alkaloids measured in drain, running and pond waters showed a potential risk, particularly for stagnant pond water, where concentrations were severalfold higher than in the drain and running waters.
Conclusions
The results highlight that natural toxins may contribute to poor chemical quality of natural waters, and that natural toxins from upcoming crops or invasive weeds should be considered in aquatic risk assessments.
Phytotoxins are produced in plants including agricultural crops. Lupins and other plants of the Fabaceae family produce toxic alkaloids. These alkaloids have been studied in food and feed, however, ...the environmental fate of alkaloids produced by cultivated lupins is largely unknown. Therefore, we conducted an agricultural field experiment to investigate the occurrence of indole and quinolizidine alkaloids in lupin plant tissues, soil, soil pore water and in drainage water. During the field experiment, alkaloids were regularly quantified (median concentrations) in lupin (13–8.7 × 103 ng/g dry weight (dw)), and topsoils at depth 0–5 cm (0.1–10 ng/g dw), and depth 15–30 cm (0.2–8.5 ng/g dw), soil pore water (0.2–7.5 ng/L) and drainage water samples (0.4–18 ng/L). Lupanine was the dominant alkaloid in all collected samples. Cumulative amounts of alkaloids emitted via drainage water were around 0.1–11 mg/ha for individual alkaloids over one growing season. The total cumulative amount of alkaloid in drainage water was 14 mg/ha, which is a very small amount compared to the mass of alkaloid in the lupin biomass (11 kg/ha) and soil (0.02 kg/ha). Nearly half of the alkaloids were exported in the drainage water during high flow events, indicating that alkaloids transport preferentially via macropores. These findings indicate that drainage from lupin cultivated areas contribute to surface water contamination. The environmental and ecotoxicological relevance of alkaloids as newly identified aquatic micropollutants in areas with agricultural activities have yet to be assessed.
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Heavy metal pollution in the environment has gained interest in the past few decades, as it has been found to accumulate in soil and water, as well as in the human body. Heavy metals present a ...serious health risk to humans when the concentration level and exposure time are increased. Although they have been extensively studied in the environment and food, little is known regarding their occurrence in the Kurdistan Region of northern Iraq. To fill this gap, we investigated the occurrence of some metals and heavy metals, namely aluminium (Al), barium (Ba), mercury (Hg), manganese (Mn), lead (Pb), vanadium (V) and zinc (Zn), in the blood of crude oil workers (40 men) who have worked in crude oil fields for at least 3 years—exposed group. In addition, a control group of 40 men was selected who have never worked or been close to crude oil fields. There is a significant correlation of metal concentrations between exposed and control groups, especially for Al, Ba, Hg, Mn and V (significant for all metals). Even though the correlation for Pb and Zn was weak, the concentrations were higher by 2-folds in the exposed group compared to the control group. Thus, the exposure caused an increase in the concentration of heavy metals by at least 1-fold in the blood of the exposed group compared to the control group. The environmental and ecotoxicological relevance of heavy metals in humans and the environment in areas with industrial activities have yet to be assessed.
Graphical abstract
Pyrrolizidine alkaloids (PAs) are persistent mutagenic and carcinogenic compounds produced by many common plant species. Health authorities recommend minimising human exposure via food and medicinal ...products to ensure consumer health and safety. However, there is little awareness that PAs can contaminate water resources. Therefore, no regulations exist to limit PAs in drinking water. This study measured a PA base concentration of ~ 70 ng/L in stream water adjacent to an invasive PA-producing plant Petasites hybridus (Asteraceae). After intense rain the PA concentration increased tenfold. In addition, PAs measured up to 230 ng/L in seepage water from groundwater wells. The dominant PAs in both water types corresponded to the most abundant PAs in the plants (senkirkine, senecionine, senecionine N-oxide). The study presents the first discovery of persistent plant toxins in well water and their associated risks. In addition, it for the first time reports monocrotaline and monocrotaline N-oxide in Petasites sp.
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