Potentially Harmful Element Concentrations in the Vegetables Cultivated on Arable Soils, with Human Health-Risk Implications

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.

Human risk associated with the ingestion of artichokes grown in soils irrigated with water contaminated by potentially toxic elements, Junin, Peru

The contamination of water, air and soil with potentially toxic elements (PTE) compromises the supply of contaminant free food. Vegetables grown in contaminated soils can absorb and accumulate PTE at concentrations that are toxic to human health. In this context, the human risk associated with the intake of artichokes grown in soils irrigated with PTE contaminated water was assessed. 120 samples of surface soil and artichoke heads were collected and the concentrations of Cu, Fe, Pb, Zn and As were determined. The results showed that the concentrations of Cu, Fe and Zn in soil did not exceed the standards of the Ministry of Environment of Peru, but they did exceed those of Pb (125.45 mg kg^-1) and As (28.70 mg kg^-1). The decreasing order of mean PTE concentration in artichoke heads was Fe > Zn > Cu > Pb > As, exceeding the permissible levels of FAO/WHO CODEX Alimentarius. However, the concentrations of As comply with the maximum limits of inorganic contaminants in vegetables (0.3 mg kg^-1) established in the MERCOSUR regulations. The non-carcinogenic and carcinogenic risk of Pb and As indicated that the ingestion of artichoke heads does not represent a health risk.

Do New-Generation Recycled Phosphorus Fertilizers Increase the Content of Potentially Toxic Elements in Soil and Plants?

Phosphorus (P)-rich secondary raw materials can provide a valuable base for modern mineral fertilizers, provided that the new formulations do not load the soil–plant system with potentially toxic elements. Fertilizers from sewage sludge ash (SSA) and/or animal bones, activated by phosphorus-solubilizing bacteria (Bacillus megaterium or Acidithiobacillus ferrooxidans), were tested in field experiments in north-eastern Poland. The reference provided treatments with superphosphate and treatment without phosphorus fertilization. In one experiment, all P-fertilizers were applied at a P dose of 21 kg·ha−1, and in the other three experiments, three P doses were adopted: 17.6, 26.4, and 35.2 kg·ha−1. The effect of recycled fertilizers on the content of arsenic (As), chromium (Cr), nickel (Ni), copper (Cu), and zinc (Zn) in the soil, in wheat grain and straw (test plant), weeds, and post-harvest residues was investigated. The application of recycled fertilizers in P amounts up to 35.2 kg·ha−1 did not change the As, Cr, Ni, Cu, or Zn contents in the soil and plant biomass. The contents of these elements in soil were below the permissible levels for arable land in Poland. Their concentrations in wheat grain and straw did not exceed the permissible or suggested limits for plant material to be used for food and feed, while in the weed and post-harvest residue biomass, they usually fell within the biological plant variability ranges.

Potential Ecological and Human Health Risks of Heavy Metals in Soils in Selected Copper Mining Areas-A Case Study: The Bor Area

Surface soil samples were collected near the Open Pit Bor (S1) and Open Pit Cerovo (S2), a grassland along the Borska Reka River (S3) and an unpolluted garden near Slatina village (reference site). Spontaneous plants (dandelion, nettle, coltsfoot, and creeping buttercup) and vegetables (onion, garlic, carrot, parsley, celery, potatoes, dill, and sorrel) were obtained from the former three sites and the reference site, respectively. The samples were analyzed for Zn, Cu, Fe, Mn, and Pb via FAAS. Pollution indices indicated low-to-moderate soil contamination at sites S1, S2, and S3. Cu was the main contaminant of environmental concern, being above the maximum admitted concentration at site S1. Metal levels in spontaneous plants were below phytotoxic levels. Cu content of leafy vegetables and celery roots and Pb content of most vegetables were not safe for human consumption. Metal concentrations tended to be significantly lower in plants than in soils, with only Cu occurring at significantly elevated levels in celery roots and sorrel leaves. Non-carcinogenic risk assessment showed that consumption of carrot roots and especially celery roots grown on unpolluted soils from the Bor area might pose long-term health risks for females and males, with the main contributors being Cu and Fe.

Lead and copper-induced hormetic effect and toxicity mechanisms in lettuce (Lactuca sativa L.) grown in a contaminated soil

Lead (Pb) and copper (Cu) contamination seriously threatens agricultural production and food safety. This study aims to investigate Pb and Cu induced hormetic effect and toxicity mechanisms in lettuce (Lactuca sativa L.) and establish reliable empirical models of potentially toxic elements (PTEs) transfer in the soil-plant system. The content and distribution of Pb and Cu at subcellular levels in lettuce plants were examined using inductively coupled plasma-mass spectrometry, differential centrifugation and micro-X-ray fluorescence spectroscopy. The PTE-loaded capacity of Pb that ensures food safety was lower than that of Cu in the studied soil, but the PTE-loaded capacity of Pb that limits yield was higher than that of Cu. Lead in lettuce roots mainly accumulated in the cell wall (41%), while Cu mainly accumulated in the vacuoles (46%). The Pb and Cu were primarily distributed in the radicle of lettuce seeds under severe PTE stress, resulting in no seed development. Iron plaque formed on the root surface of lettuce seedlings and sequestered Pb and Cu via chelation. At the same concentration, lettuce was less tolerant to Cu in contaminated soil than Pb due to the higher activity of Cu ions in the soil. Lead was more phytotoxic to lettuce than Cu, however, since the radicle emerged from the seed under severe Cu levels, while it did not protrude under severe Pb levels. The potentially damaging effect of Pb in the visually healthy lettuce appeared to be higher than that of Cu under the same soil contamination level.

Human Health Risk Assessment and Potentially Harmful Element Contents in the Cereals Cultivated on Agricultural Soils

Potentially harmful element (PHE) contents were investigated in six species of cereals in southern Poland, with human health risk implications assessed afterwards. The PHE contents belonged to the following ranges (mg/kg wet weight): As below the limit of detection ( oat (HQ = 0.38) > maize (HQ = 0.02). The total non-carcinogenic risk value of the statistical daily consumption of cereals was acceptable low (HQ = 0.58). The acceptable cancer risk (CR) level of 1.0 × 10-5 investigated only for As was not exceeded under any of the intake scenarios. Concerning the mean As content in cereals consumed daily in statistical amounts the CR value was equal to 5.1 × 10-8. The health risk value according to the Pb content in cereals using the margin of exposure (MOE) approach was equal to 1.27, indicating an acceptable low risk.

Human Health Risk Assessment and Potentially Harmful Element Contents in the Fruits Cultivated in the Southern Poland

The presence of potentially harmful elements (PHEs) in popularly consumed fruits in Poland was determined by inductively coupled plasma mass spectrometry. The As, Cd, Co, Cr, Cu, Hg, Ni, Pb, Se, Sb, Tl, and Zn contents were investigated in 21 fruit species grouped as berry, pome, stone, and shell fruits. The PHE contents belonged to the following ranges (mg/kg wet weight): Cd < limit of detection (LOD)–0.116, Co < LOD–0.062, Cu < LOD–15.5, Ni < LOD–2.23, Pb < LOD–2.07, Sb < LOD–0.240, Tl < LOD–0.110, and Zn 0.37–37.7. Their concentrations exceeded the maximum allowable concentration (MAC) set by European Union regulation for Pb only. Bioconcentration coefficient (BC) values, calculated in accordance to the PHE contents in exchangeable and acid soluble forms in soil after first step of the Community Bureau of Reference (BCR) sequential extraction procedure, revealed that berry fruits had potential for accumulation of Cu, Ni, Sb, and Tl; stone fruits—Cu, Sb, and Tl; pome fruits—Cu, Ni, and Sb, and shell fruit (walnut)—Cu. Human health risk assessment associated with the intake of PHEs in fruits was evaluated in terms of daily intake rates (DIR), and carcinogenic and non-carcinogenic risk by cancer risk (CR) and hazard quotient (HQ), respectively. For Pb margin of exposure (MOE) approach was used for health risk evaluation. Daily intake rates for all PHEs were below the provisional maximum tolerable daily intake (PMTDI) values. The mean total non-carcinogenic risk values were the following: berry fruits HQ = 0.47, pome fruits HQ = 0.36, stone fruits HQ = 0.42, and shell fruits (walnut) HQ = 0.22, indicating no health hazards. The carcinogenic risk for As in walnut only under an adult intake scenario (CR = 1.98 × 10⁻⁶) was found to be above the acceptable risk level. The mean Pb health risk, according to Polish statistical intake rates, was acceptable low as the MOE value was equal to 15.7 for adults. In reference to the intake rates recommended by United States Environmental Protection Agency (USEPA), MOE values for Pb indicated acceptable low risk both for adults (MOE = 14.0) and children (MOE = 1.64). In general, the finding of this research revealed no health risk arising from PHE consumption with fruits for the population of Poland.