Comparative study of toxic heavy metal residues and other properties of honey from different environmental production systems

Emerging insights into the impacts of heavy metals exposure on health, reproductive and productive performance of livestock

Heavy metals, common environmental pollutants with widespread distribution hazards and several health problems linked to them are distinguished from other toxic compounds by their bioaccumulation in living organisms. They pollute the food chain and threaten the health of animals. Biologically, heavy metals exhibit both beneficial and harmful effects. Certain essential heavy metals such as Co, Mn, Se, Zn, and Mg play crucial roles in vital physiological processes in trace amounts, while others like As, Pb, Hg, Cd, and Cu are widely recognized for their toxic properties. Regardless of their physiological functions, an excess intake of all heavy metals beyond the tolerance limit can lead to toxicity. Animals face exposure to heavy metals through contaminated feed and water, primarily as a result of anthropogenic environmental pollution. After ingestion heavy metals persist in the body for an extended duration and the nature of exposure dictates whether they induce acute or chronic, clinical or subclinical, or subtle toxicities. The toxic effects of metals lead to disruption of cellular homeostasis through the generation of free radicals that develop oxidative stress. In cases of acute heavy metal poisoning, characteristic clinical symptoms may arise, potentially culminating in the death of animals with corresponding necropsy findings. Chronic toxicities manifest as a decline in overall body condition scoring and a decrease in the production potential of animals. Elevated heavy metal levels in consumable animal products raise public health concerns. Timely diagnosis, targeted antidotes, and management strategies can significantly mitigate heavy metal impact on livestock health, productivity, and reproductive performance.

Lead exposure from honey: meta-analysis and risk assessment for the Arab region

The Codex Alimentarius Commission has adopted a maximum level for lead in honey (0.1 mg/kg). Despite representing a population of more than half a billion, exposure and risk assessments for lead specific to the Arab region are lacking. The aim of this work was to collect analytical data for lead in honey available in Arab countries and to assess the risk caused by exposure to lead from these samples for local consumers. A regional mean lead concentration in honey, obtained through a meta-analysis of 57 studies, was used in deterministic risk assessments for adults (nephrotoxicity and cardiovascular effects) and young children (developmental neurotoxicity). A regional pooled mean concentration of 0.12 mg/kg [95%CI: 0.07-0.21] (0.13 mg/kg, if non-detects are considered at their highest possible value) was obtained. Margins of exposure of 363 [71-17182] and 865 [168-40909] were calculated for adults, and of 48 [9-2273] for children, indicating potential concern for the latter population subset. These values were produced using GEMS consumption data, and considering the same intake for both children and adults, potentially overestimating the risk for children. Nevertheless, food competent authorities should consider measures to reduce lead concentration in honey available for sale in the region to prevent trade constraints and to better protect vulnerable populations.

Heavy Metal Concentrations of Beeswax (Apis mellifera L.) at Different Ages

Beeswax is a naturally occurring product that worker bees produce. Beeswax is used in a variety of industries and pharmaceuticals. Humans utilize it extensively in cosmetics, medicinal formulations, and food manufacturing. Beeswax is an essential component of advanced contemporary beekeeping. Beekeepers, in particular, utilize significant amounts of beeswax to make beeswax comb foundation. In its natural condition, beeswax is white, but it becomes yellow then dark in color when it comes into touch with honey and pollen. The ongoing use of wax comb in bee activities (such as brood rearing, storage honey and bee bread), combined with environmental factors such as heavy metal and pesticide residues, resulted in a black color. Because of heavy metals can accumulate in wax for decades, beeswax can be a helpful tool for gathering data on hazardous contaminants in the environment. Because of their lipid-based chemical composition, beeswax combs act as a sink for numerous ambient pollutants as well as poisons when in the hive. The current study aims to measure nine heavy metals and important elements, including iron (Fe), chromium (Cr), zinc (Zn), copper (Cu), nickel (Ni), manganese (Mn), lead (Pb), cadmium (Cd), and cobalt (Co) in beeswax collected in the Behaira governorate region of Egypt between 2018 and 2022. Sample collection was conducted each year in triplicate. The samples were analyzed using an atomic absorption spectrophotometer. The quantity of metals in beeswax at different ages differed significantly. Depending on the wax age, Fe has the highest concentration in the range of 2.068 to 5.041 ppm, while Cd has the lowest ratio at 0.024 to 0.054 ppm from the first to fifth years old of comb age. The findings showed that as beeswax combs aged, the concentration of heavy metals rose. According to the study, it should gradually recycle beeswax combs each year and also adding new foundations.

Bees reflect better on their ecosystem health than their products

Beehives constitute a source of environmental contaminants because forager bees explore their habitat and unintentionally accumulate them while foraging for food. Therefore, this review paper investigated different bee species and products from 55 countries to identify how they can help environmental biomonitoring by giving an overview of the past 11 years. Thereby is presented in this study the beehive's use as a bioindicator for metals, analytical techniques, data analysis, environmental compartments, common inorganic contaminants, reference thresholds for some metal concentrations in bees and honey, and other factors over more than 100 references. Most authors agree that the honey bee is a suitable bioindicator to assess toxic metal contamination, and among its products, propolis, pollen, and beeswax are more suited than honey. However, in some situations, when comparing bees with their products, bees are more efficient as potential environmental biomonitors. Some factors such as the colony location, floral sources, regional effects, and activities surrounding the apiary influence the bees, and the composition of their products is reflected by alterations in their chemical profile, making them suitable bioindicators.

Microbial Community Structure among Honey Samples of Different Pollen Origin

Honey's antibacterial activity has been recently linked to the inhibitory effects of honey microbiota against a range of foodborne and human pathogens. In the current study, the microbial community structure of honey samples exerting pronounced antimicrobial activity was examined. The honey samples were obtained from different geographical locations in Greece and had diverse pollen origin (fir, cotton, fir-oak, and Arbutus unedo honeys). Identification of honey microbiota was performed by high-throughput amplicon sequencing analysis, detecting 335 distinct taxa in the analyzed samples. Regarding ecological indices, the fir and cotton honeys possessed greater diversity than the fir-oak and Arbutus unedo ones. Lactobacillus kunkeei (basionym of Apilactobacillus kun-keei) was the predominant taxon in the fir honey examined. Lactobacillus spp. appeared to be favored in honey from fir-originated pollen and nectar since lactobacilli were more pronounced in fir compared to fir-oak honey. Pseudomonas, Streptococcus, Lysobacter and Meiothermus were the predominant taxa in cotton honey, whereas Lonsdalea, the causing agent of acute oak decline, and Zymobacter, an osmotolerant facultative anaerobic fermenter, were the dominant taxa in fir-oak honey. Moreover, methylotrophic bacteria represented 1.3-3% of the total relative abundance, independently of the geographical and pollen origin, indicating that methylotrophy plays an important role in honeybee ecology and functionality. A total of 14 taxa were identified in all examined honey samples, including bacilli/anoxybacilli, paracocci, lysobacters, pseudomonads, and sphingomonads. It is concluded that microbial constituents of the honey samples examined were native gut microbiota of melliferous bees and microbiota of their flowering plants, including both beneficial bacteria, such as potential probiotic strains, and animal and plant pathogens, e.g., Staphylococcus spp. and Lonsdalea spp. Further experimentation will elucidate aspects of potential application of microbial bioindicators in identifying the authenticity of honey and honeybee-derived products.

Heavy metal in honey bees, honey, and pollen produced in rural and urban areas of Konya province in Turkey

We investigated the levels of heavy metals in honey bee, honey, and pollen samples obtained from different locations in Konya City in Turkey. Five honey bee colonies were placed in eight different locations, four of them around urban areas and four in rural areas, in the province of Konya City in Turkey. Heavy metal (Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) levels were determined in honey bee, honey, and pollen samples taken from these colonies, with a comparison between samples from urban and rural areas. The values of Cd in honey samples and those of Cd in pollen samples did not differ significantly among the locations. All heavy metal values of honey bee samples were lower in rural areas than in urban areas. Significant statistical differences were determined for Cr, Cu, Fe, Mn, Ni, Pb, and Zn values of honey and pollen samples among the locations. Heavy metal values of honey and pollen samples obtained from different locations were in agreement with the International Food Standard values.

Differentiating Wild and Apiary Honey by Elemental Profiling: a Case Study from Mangroves of Indian Sundarban

Honey is a natural substance produced by honeybees from the nectar or secretion of flowering plants. Along with the botanical and geographical origin, several environmental factors also play a major role in determining the characteristics of honey. The aim of this study is to determine and compare the elemental concentration of various macro and trace elements in apiary and wild honeys collected from different parts of Indian Sundarbans. The elemental analysis was performed in inductively coupled plasma optical emission spectroscopy preceded by microwave digestion method. The concentrations of 19 elements (Ag, Al, As, B, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Na, Ni, Pb, Se and Zn) were investigated from thirteen locations of Indian Sundarbans. This comparative study shows in wild honey samples, the concentration of K was highest followed by Ca, Mg and Na and Zn was lowest among all. In contrast, in apiary honey samples, Ca had maximum concentration followed by K, Mg and Na and Ag had minimum among all. The elemental concentration in honey from apiary was either equal or higher than their wild counterpart. The results of the factor analysis of PCA algorithm for wild and apiary honey samples were highly variable which implies that the elements are not coming from the same origin. The concentration of element was found to be highly variable across sites and across sources of honey samples.

The Occurrence of Lead in Animal Source Foods in Iran in the 2010s Decade: A Systematic Review

Lead is a toxic, non-biodegradable, and accumulative heavy metal released into the environment by natural and anthropogenic activities. Despite health concerns due to the consumption of lead-contaminated foods, no systematic and comprehensive review studies have been published about the lead occurrence in animal source foods in Iran. The present study aimed to review the papers investigating the Pb contamination in animal-based food groups (including meat, fish, milk and dairy products, egg and honey) in Iran. A comprehensive search was performed with selected keywords in databases of Scopus, Web of science, and Magiran to find articles that had been published from January 2010 to December 2019. Of 371 identified articles on Pb contaminations in foods, 60 articles were selected using PRISMA. The lead concentrations were higher than the maximum recommended limits in 3 of 9 studies on meat and meat products, 12 of 26 studies on fish and canned fish, and 5 of 18 studies on milk and dairy products. However, the Pb contamination observed in studies on honey and egg was not comparable due to the lack of national and international standards. These results represent the importance of environmental monitoring and assessment for reducing exposure of animals to Pb, resulting in an improvement of food safety.

Review of harmful chemical pollutants of environmental origin in honey and bee products

Honey is a natural food with many pro-health properties, which comprises a wide variety of valuable ingredients. It can also be the source of chemical contaminants of environmental origin, including POPs that can contribute to adverse health effects to human. Monitoring the degree of pollution of honey/bee products with hazardous chemicals is important from a nutraceutical point of view. In the present work, overview of recent literature data on chemical pollutants in honey/bee products originating from the environment was performed. Their MLs, MRLs and EDI were discussed. It can be concluded that huge amount of research concerned on the presence of TMs and pesticides in honey. Most of the studies have shown that honey/bee products sampled from urban and industrialized areas were more contaminated than these sampled from ecological and rural locations. More pollutants were usually detected in propolis and bee pollen than in honey. Based on their research and regulations, authors stated, that most of the toxic pollutants of environmental origin in honey/bee products are at levels that do not pose a threat to the health of the potential consumer. The greatest concern relates to pesticides and TMs, because in some research MLs in individual samples were highly exceeded.

Determination of the Ca, Mn, Mg and Fe in honey from multiple species of stingless bee produced in Brazil

Stingless Bees (SB) honey is a product used for different purposes, and it is worth highlighting the presence of metallic species, which can have a nutritional or toxic effect, depending on the metal present and/or the amount ingested. Therefore, the objective of this work was to quickly determine Fe, Mn, Mg and Ca in SB honey, using slurry sampling and FAAS of 88 honey samples from different regions of Brazil. The concentrations varied from < LOD to 364 µg g^-1 (Ca). The order for average concentration in the samples was Ca > Mg > Mn > Fe. Through the principal component analysis, it was verified that the SB honey analyzed in the present study has higher contents of the evaluated metals than the honey of the species Apis mellifera and SB honey from other Brazilian states. Theoretical calculation demonstrated that there is a little contribution of SB honey to human diet in relation to the metals, being more significative for Mn.

Investigation of inorganic elemental content of honey from regions of North Island, New Zealand

Determination of geographical origin of honey is important to consumers to confirm authenticity. This study investigated the elemental fingerprint of 181 honey samples collected from apiary sites in six regions of North Island, New Zealand to determine if differences were observed due to region of collection or land use surrounding the hive (e.g. agricultural, rural, urban). Using principal component analysis, soil related elements (Ca, K, Mg, Mn, Na) provided 75.2% discrimination of samples in the first two principal components. Overall, low concentrations of heavy metals were observed; lead was present in close proximity to highly trafficked roads (28.1% of samples; 9.50-76.5 µg kg^-1) and cadmium was primarily present in honey collected from agricultural land in the Waikato (<51.6 µg kg^-1). The use of an elemental fingerprint of New Zealand honey may be advantageous to determine the geographical origin compared to honey produced from other countries.

Therapeutic Potential of Bioactive Compounds in Honey for Treating Osteoarthritis

Dysregulation of joint tissue homeostasis induces articular degenerative changes and musculoskeletal diseases such as osteoarthritis. This pathology represents the first cause of motor disability in individuals over 60 years of age, impacting their quality of life and the costs of health systems. Nowadays, pharmacological treatments for cartilage disease have failed to achieve full tissue regeneration, resulting in a functional loss of the joint; therefore, joint arthroplasty is the gold standard procedure to cure this pathology in severe cases of Osteoarthritis. A different treatment is the use of anti-inflammatory drugs which mitigate pain and inflammation in some degree, but without significant inhibition of disease progression. In this sense, new therapeutic alternatives based on natural compounds have been proposed to delay osteoarthritis progression, particularly those agents that regulate articular homeostasis. Preclinical studies have shown a therapeutic application of honey and its bioactive compounds, ranging from treating wounds, coughs, skin infections, and are also used as a biological stimulant by exerting antioxidant and anti-inflammatory properties. In this article, we reviewed the current medicinal applications of honey with particular emphasis on its use regulating articular homeostasis by inhibiting inflammation and oxidative stress.