Trace elements in Labrador Tea (Rhododendron groenlandicum): How predominant sources to the plants impact the chemical composition of hot water extracts

Investigation of thallium as a contaminant in dietary supplements marketed for weight loss and physical fitness

Dietary supplements are drastically growing as a category of consumer products all over the world. The abuse of supplements marketed for slimming purposes and physical fitness has been observed worldwide in recent years, which raises concerns in terms of public health. In this study, different types of dietary supplements marketed and delivered through the e-commerce were studied for the determination of thallium as a hazardous inorganic contaminant. The total content of thallium was determined by a sensitive voltammetric method after a microwave-assisted oxidative digestion of the sample. In addition, a comparative spectrometric method was applied for validation of the results in the samples. The maximum concentration found for thallium was found to be 2.89 mg kg-1, which well agree with the comparative measurement. Considering the 32 studied formulations, it can be pointed out that ∼24% of the of dietary supplements presented Tl concentrations at concentrations higher than 1 mg kg-1. The results permitted the assessment of the health risk related to thallium from contaminated samples, based on the calculation of the estimated daily intake (EDI) and the risk quotient (HQ). The highest daily intake of thallium was calculated as 82.0 µg day-1 in a protein-based supplement, which is equivalent to an EDI of 1.17 µg kg-1 day-1. This work highlights the need to develop regulations on the limits of toxic elements such as thallium in widely consumed dietary supplements, as well as an in-depth look at the adverse effects caused by this element in the human body.

Metal-free sampling methods for dust, rainwater, surface water, plants, and sediments: A selection of unique tools from the SWAMP laboratory

Contamination control remains one of the greatest challenges for the reliable determination of many trace elements in environmental samples. Here we describe a series of metal-free sampling devices and tools designed and constructed specifically to minimize the risk of contamination by trace elements during sampling of dust, rainwater, surface water, plants, and sediments. Plastic components fabricated using 3-D printing include polylactic acid (PLA), polyethylene terephthalate (PET), polyethylene terephthalate glycol (PETG), polypropylene (PP), polycarbonate (PC) and PC with carbon fibre. When additional strength is needed (e.g. supporting structural components), carbon fibre, aluminum (Al), or 316 stainless steel (SS) is used. Other plastics employed include acrylic and vinyl. Epoxy glue or SS may be used for joining components, but do not come into contact with the samples. Ceramic (zirconium dioxide) cutting blades are used where needed. Each plastic material was evaluated for contaminant trace elements by leaching with high purity nitric acid in the metal-free, ultraclean SWAMP laboratory. The devices were tested in the field to evaluate their performance and durability. When combined with appropriate cleaning procedures, the equipment enables ultraclean collection for trace element analysis of environmental media.•Plastic sampling devices were designed and constructed using 3D printing of PLA, PET, PETG or PP.•Leaching characteristics of plastic components were evaluated using high purity nitric acid in a metal-free, ultraclean laboratory.•Each sampling device was successfully field-tested in industrial settings (near open pit bitumen mines and upgraders), and in remote locations of northern Alberta, Canada.

Phytochemical Profiling and Biological Activities of Rhododendron Subsect. Ledum: Discovering the Medicinal Potential of Labrador Tea Species in the Northern Hemisphere

Rhododendron subsect. Ledum is a distinct taxonomic subdivision within the genus Rhododendron, comprising a group of evergreen shrubs and small trees. This review will comprehensively analyse the phytochemical profiles and biological properties of the Rhododendron subsect. Ledum species subsect. Ledum consists of eight plant species indigenous to temperate and subarctic regions of the Northern Hemisphere, collectively known as Labrador tea. Recent investigations have concentrated on the phytochemical constituents of these plants due to limited data, emphasizing their evergreen nature and potential industrial significance. This review summarizes their major phytochemical constituents, including flavonoids, phenolic acids, and terpenoids, and discusses their potential biological activities, such as antioxidant, anti-inflammatory, antimicrobial, antitumor, hypoglycemic, hepatoprotective, neuroprotective, and cardioprotective effects. Traditional uses of these plant species align with scientific findings, emphasizing the significance of these plants in traditional medicine. However, despite promising results, gaps exist in our understanding of specific compounds' therapeutic effects, necessitating further research for comprehensive validation. This review serves as a valuable resource for researchers, identifying current knowledge, uncertainties, and emerging trends in the study of the Rhododendron subsect. Ledum species.

Spatial variation and chemical reactivity of dusts from open-pit bitumen mining using trace elements in snow

The chemical reactivity of trace elements (TEs) in dusts from bitumen mining, upgrading and related industrial activities in the Athabasca Bituminous Sands region (ABS), Alberta, Canada, was evaluated using the acid-soluble fraction of snow. Samples were collected at 14 sites along the Athabasca River (AR) and its tributaries, and at 3 remote locations. Following metal-free, ultra-clean procedures for processing and analysis, samples were leached with nitric acid (pH < 1), filtered (<0.45 μm), and analyzed using ICP-MS. Insoluble particles (>0.45 μm) were examined using SEM-EDS. Along the river, acid-soluble concentrations of TEs varied by 6 orders of magnitude, from 1 mg/L (Al) to less than 1 ng/L (Tl). Conservative (Al, Y, La, Th) and mobile (Li, Be, Cs, Sr) lithophile elements, those enriched in bitumen (V, Ni, Mo), and potentially toxic chalcophile elements (As, Cd, Pb, Sb, Tl) showed considerable spatial variation. Normalizing the concentrations of TEs in samples collected near industry to the corresponding concentrations in snow from the reference site (UTK), resulted in enrichments of V and most of the lithophile elements. Dust reactivity, quantified as the ratio of acid-soluble to total concentrations, was less than 50% suggesting limited bioaccessibility. The large differences in behaviour between Cd and Pb versus Ni and V could be due to the occurrence of the former pair in carbonate or sulfide minerals, versus acid-insoluble petcoke particles for the latter couple. Spatial variations in the reactivity of TEs most likely reflect the range in diversity and chemical stability of dust particles, and variations in their abundance in primary source areas. The leaching conditions employed here are extreme (pH < 1) and intended to identify an upper limit of chemical reactivity, with far less dust dissolution expected when these dusts encounter natural waters of the area which range in pH from 4 to 8.

Sources of exposure to lead in Arctic and subarctic regions: a scoping review

Understanding lead exposure pathways is a priority because of its ubiquitous presence in the environment as well as the potential health risks. We aimed to identify potential lead sources and pathways of lead exposure, including long-range transport, and the magnitude of exposure in Arctic and subarctic communities. A scoping review strategy and screening approach was used to search literature from January 2000 to December 2020. A total of 228 academic and grey literature references were synthesised. The majority of these studies (54%) were from Canada. Indigenous people in Arctic and subarctic communities in Canada had higher levels of lead than the rest of Canada. The majority of studies in all Arctic countries reported at least some individuals above the level of concern. Lead levels were influenced by a number of factors including using lead ammunition to harvest traditional food and living in close proximity to mines. Lead levels in water, soil, and sediment were generally low. Literature showed the possibility of long-range transport via migratory birds. Household lead sources included lead-based paint, dust, or tap water. This literature review will help to inform management strategies for communities, researchers, and governments, with the aim of decreasing lead exposure in northern regions.

Natural enrichment of Cd and Tl in the bark of trees from a rural watershed devoid of point sources of metal contamination

To help understand the bioaccumulation of Cd and Tl in beaver tissue, we examined the enrichment of these metals in vegetation available to the animals. Bark was collected from 40 species of trees and shrubs, along with a complete soil weathering profile, within a small watershed devoid of trace metal contamination. Weathering resulted in a 5x enrichment of Cd in the soils relative to the underlying sediments, and a 6x Tl depletion: while Cd was lost from calcite and accumulates in the organic matter and oxyhydroxide fractions, Tl occurred only in the residual fraction. Soil processes alone, however, cannot explain the anomalous concentrations and enrichments of Cd in willow and poplar which contain up to 8.5 mg/kg Cd. The concentrations of Cd and Tl in the dissolved fraction (<0.45 μm) of the Wye River are similar (1.2 ± 0.4 and 1.6 ± 0.1 ng/L, respectively), and are taken to estimate their bioavailability in soil solutions. Normalizing the Cd/metal ratios in bark to the corresponding ratios in water yields the Stream Enrichment Factor: this novel approach shows that all plant species are enriched in Cd relative to Ni; 33 relative to Cu, 13 relative to Zn, and 7 relative to Mn. Thus, many plants preferentially accumulate Cd, especially willow and poplar, over these essential micronutrients. Clearly, the enrichment of Cd over Tl in bark is not a reflection of differences in bioavailability, but rather on the preferential uptake of Cd by the plants. The profound natural bioaccumulation of Cd in the bark of willow and poplar, the two favourite foods of the beaver, has ramifications for the use of these aquatic mammals as biomonitors of environmental contamination, as well as for the direct and indirect consumption of bark for traditional food and medicine.

Environmental significance of trace elements in the Athabasca Bituminous Sands: facts and misconceptions

The bituminous sands of Alberta, Canada, represent the second largest reserves of hydrocarbons on earth. Open pit bitumen mining and upgrading of the Athabasca Bituminous Sands (ABS), the largest of the deposits, began in 1967. Concerns about fugitive release of trace elements (TEs) to the environment began with studies of V, as this is the most abundant trace metal in bitumen. Recent studies, however, have extended to Ag, As, Be, Cd, Cr, Cu, Pb, Sb, and Tl, and this has led to considerable confusion about which TEs are relevant to ecosystem health. While V along with Ni, Mo, Se and Re are enriched in bitumen, Ag, As, Be, Cd, Cr, Cu, Pb, Sb and Tl are found almost exclusively in the mineral (i.e. sand) fraction of the ABS, with limited opportunity to become bioaccessible, much less bioavailable. Here, a summary is given of ten misunderstandings that have arisen regarding TEs in the environment of the ABS region. To help illustrate the significance of the misconceptions that have arisen regarding (a) air and (b) water resources, published and unpublished TE data obtained from the metal-free, ultraclean SWAMP lab is presented for: (a) snow, moss, and peat cores from bogs, and (b) the dissolved, particulate, and colloidal fractions of water from the Athabasca River (AR), as well as pristine groundwater. Natural enrichments of Ni in plants such as Rat Root (Acorus calamus) and pine (Pinus banksiana), Tl in fish (Percopsis omiscomaycus) and Cd in cranberries (Vaccinium oxycoccus), Labrador Tea (Rhododendron groenlandicum) and beaver (Castor canadensis), are also presented.

Water extract of Ferula lehmanni Boiss. prevents high-fat diet-induced overweight and liver injury by modulating the intestinal microbiota in mice

Obesity, often accompanied by hepatic steatosis, has been associated with an increased risk of health complications such as fatty liver disease and certain cancers. Ferula lehmannii Boiss., a food and medicine homologue, has been used for centuries as a seasoning showing anti-bacterial and anti-oxidant effects on digestive discomfort. In the present study, we sought to investigate whether a short-term oral administration of water extract of Ferula lehmanni Boiss. (WEFL) could prevent high-fat diet (HFD)-induced abnormal weight gain and hepatic steatosis in mice and its underlying mechanisms. WEFL reduced HFD-increased body weight, liver injury markers and inflammatory cytokines (i.e. IL-6 and IL-1β), and inhibited the elevation of AMPKα, SREBP-1c and FAS in HFD. Moreover, WEFL reconstructed the gut microbiota composition by increasing the relative abundances of beneficial bacteria, e.g. Akkermansia spp., while decreasing Desulfovibrio spp. and so on, thereby reversing the detrimental effects of HFD in mice. Removal of the gut microbiota with antibiotics partially eliminated the hepatoprotective effects of WEFL. Notably, WEFL substantially promoted the levels of short-chain fatty acids, especially butyric acid. To clarify the functional components at play in WEFL, we used UPLC-MS/MS to comprehensively detect its substance composition and found it to be a collection of polyphenol-rich compounds. Together, our findings demonstrate that WEFL prevented HFD-induced obesity and liver injury through the hepatic-microbiota axis, and such health-promoting value might be explained by the enriched abundant polyphenols.

Estimated Contributions of Rooibos Tea to the Daily Manganese and Zinc Intakes Determined in Tea Leaves and Tea Infusions by Inductively Coupled Plasma-Mass Spectrometry

Rooibos tea, scientific name Aspalathus linearis, is a popular tea grown in South Africa and consumed worldwide for its unique taste and presumed health benefits. There is a growing interest in using rooibos tea as a supplement for the deficiency of metallic nutrients in South Africa. In this study, the total concentrations of manganese (Mn) and zinc (Zn) in acid-digested tea leaves and the corresponding tea infusions were determined by inductively coupled plasma-mass spectrometry (ICP-MS) to estimate the contribution of rooibos tea consumption to the recommended daily allowance (RDA) of Mn and Zn in consumers. The accuracy of microwave-assisted acid digestion and tea infusion methods were checked by analyzing INCT-TL-1 tea leaves certified reference material (CRM) and samples spiked with standards, respectively. Both methods yielded quantitative percentage recoveries for Mn and Zn. Rooibos tea leaves and the corresponding infusions are composed of higher levels of Mn than Zn where 40.9 to 85.7 μg Mn/g and 4.15 to 12.2 μg Zn/g were found in digested tea leaves and 11.8 to 30.2 μg Mn/g and 1.51 to 4.59 μg Zn/g in tea infusions. These results indicate the contribution of about 1.0 to 3.2% Mn and 0.03 to 0.08% Zn in males approximately ≥ 9 years of age and 1.3 to 3.8% Mn and 0.04 to 0.11% Zn in females of the same age group as males of the RDA from drinking a cup of tea obtained by infusing a 2-g bag of rooibos tea.

Typical sources of Cd to paddy fields in different contaminated areas and their impacts on Cd accumulation in topsoil and rice in Changzhutan, China

Heavy metal pollution of soils has been worsening increasingly in China, which brings significant health risk to human, it is critical to investigate the sources of heavy metals in agricultural soils and explore the effects of heavy metal accumulation in crops. In this paper, the sources of cadmium (Cd) and their effects on Cd accumulation in soil and rice grown on urban farmland in Changzhutan were investigated. Among the main Cd sources (irrigation water, commercial fertilizer, and atmospheric deposition), the input flux of atmospheric deposition accounted for 76.36%-98.25% of total input flux, significantly higher than the input fluxes of irrigation water and commercial fertilizer. Manure fertilizer was also an important source of Cd in livestock breeding areas. The accumulation behaviors of Cd in soils and plants presented significant spatial variation among the study areas. Higher Cd input flux from atmospheric deposition resulted in higher Cd bioavailability in soil and more Cd accumulation in rice, and the newly deposited Cd contributed 7.35-41.23% in rice tissues. The use of manure fertilizer increased the soil pH and amount of available Cd in soil, as well as the accumulation of Cd in rice roots. Based on sequential extraction, acid-extractable Cd accounted for approximately 52.54%-61.88% of total Cd in atmospherically deposited particles in the study area, resulting in a high proportion of acid-extractable Cd in soil. This study provides useful reference data on the sources of Cd and its bioavailability in soil and rice.