Analysis of Mercury Concentration in Honey from the Point of View of Human Body Exposure

Comprehensive assessment of mercury contamination in bees, bee products and moss and lichen bags

Twenty-eight beekeepers around Slovakia were included in the research to evaluate the presence of mercury in honeybee bodies and selected bee-related products: bee pollen and honey. The samples were collected in May, June, and July (honeybee bodies only in May and June). During this period, moss and lichen bags for air quality assessment were exposed around the beehives and relative accumulation factor (RAF) was used for its evaluation. Mercury content in evaluated bioindicators was determined using AMA 254 analyser. Percentage of provisional tolerable intake (%PTWI) and target hazard quotient (THQ) were used to determine health risks related to bee pollen and honey consumption. Around the beehives the proportion of landscape structure elements was determined for each sampling locality, using a geographical informational system QGIS. The aim of the study was a comprehensive evaluation of the mercury content in the environment around beehives using several bioindicators and an assessment of the relationship between the presence of mercury pollution and the proportion of landscape structure elements in the vicinity of the beehives. The study also aimed to evaluate the transfer of contaminants between bee bodies and bee-related products and the health risks resulting from their consumption.

Isolation and characterization of mercury and multidrug-resistant Citrobacter freundii strains from tannery effluents in Kolkata, India

Mercury (Hg) is one of the most potent toxic heavy metals that distresses livestock, humans, and ecological health. Owing to uncontrolled exposure to untreated tannery industrial effluents, metals such as Hg are increasing in nature and are, therefore, becoming a global concern. As a result, understanding the thriving microflora in that severe condition and their characteristics becomes immensely important. During the course of this study, two Hg-resistant bacteria were isolated from tannery wastewater effluents from leather factories in Kolkata, India, which were able to tolerate 2.211 × 10- 3 M (600 µg/ml) Hg. 16 S rDNA analysis revealed strong sequence homology with Citrobacter freundii, were named as BNC22A and BNC22C for this study. In addition they showed high tolerance to nickel (Ni) and Chromium (Cr) at 6.31 × 10- 3 M (1500 µg/ml) and 6.792 × 10- 3 M (2000 µg/ml) respectively. However, both the isolates were sensitive to arsenic (As) and cadmium (Cd). Furthermore, their antibiotic sensitivity profiles reveal a concerning trend towards resistance to multiple drugs. Overuse and misuse of antibiotics in healthcare systems and agriculture has been identified as two of the main reasons for the decline in efficacy of antibiotics. Though their ability to produce lipase makes them industrially potent organisms, their competence to resist several antibiotics and metals that are toxic makes this study immensely relevant. In addition, their ability to negate heavy metal toxicity makes them potential candidates for bioremediation. Finally, the green mung bean seed germination test showed a significant favourable effect of BNC22A and BNC22C against Hg-stimulated toxicity.

Elevated Metal Levels in U.S. Honeys: Is There a Concern for Human Health?

Honey is a bioactive food used for millennia to improve health and treat diseases. More recently, researchers employ honey as a tool to assess local environmental pollution. Honeybees effectively 'sample' their environment within a ~ 7 km radius, actively collecting nectar, pollen, and water to bring to their hive. Foraging honeybees also sample the air as dust particles accumulate on their pubescence, adding to the hive's contaminant load. Many studies from around the world report elevated metal levels in honey, with the most reports from Iran, Italy, and Turkey, but only two reports have measured metal levels in honey from the United States (U.S.). We report levels of 20 metals from 28 honeys collected from 15 U.S. states between 2022-2023. We then focus on four toxic metals recognized as hazards in foodstuffs when the concentrations are above safety recommendations - lead, cadmium, arsenic, and mercury. Two of these metals (lead and mercury) are regulated in honey by the European Union (EU), though the U.S. currently lacks defined regulations for metal levels in honey. We consider the levels of these toxic metals by state, then compare the U.S. mean honey level for these metals against the provisional tolerable weekly intake (PTWI). Our results suggest U.S. honey have levels metal that exceed the PWTI and EU regulations and may be hazardous to human health. Further research is needed to determine if the effects of these toxic metal at measured levels outweigh the health benefits from consumption of honey.

Mercury in honey from the Marche region (central Italy). Risk assessment from human consumption and its use as bioindicator of environmental pollution

Honey is a natural product made by honeybees (Apis mellifera) from nectar or honeydew. It is a very popular and appreciated product all over the world as it represents a rapidly available energy source and exerts several beneficial properties for humans. However, it has been demonstrated that honey can be contaminated by potentially toxic elements (PTEs) of natural or anthropogenic origin. Among them, mercury (Hg) represents one of the most dangerous for its toxicity and its capacity to biomagnify along the trophic web. In the present study, 100 honey samples from the Marche Region (Central Italy) produced in the year 2021, were analyzed by thermal decomposition amalgamation atomic absorption spectrometry to determine the Hg content. The overall mean concentration was 0.2 ± 0.2 μg kg-1. The results showed that no statistically significant differences were found in Hg content among honey from different pollen origin, but honeydew had a significantly higher Hg content with respect to all other honey samples (0.6 ± 0.3 μg kg-1). The Hg content in honey depends mainly on local pollution, while geographical origin did not play a key role. Furthermore, considering the regulatory limits and provisional tolerable weekly intake (PTWIs) identified by FAO/WHO, the Hg Hazard Quotient (HQ) measurement revealed that this product is safe for human consumption.