**1. Introduction**

Honey, due to its high nutritional value and numerous health-promoting properties, is a valuable component of the daily diet. The chemical composition of honey is varied and depends mainly on the region where it is produced, the soil conditions, and the water and air quality, which affect the quality of the food sources for bees, including the presence and level of chemical pollutants [1]. The health risks associated with honey consumption stem from the presence of pesticide residues (including active substances and their metabolites), antibacterial substances (including antibiotics), and heavy metals. Another source of risk in honey is microbial contaminants [2]. These substances come mainly from the environment, whose cleanliness depends largely on human activity. Antibacterial substances are used to prevent and fight diseases in broods and bees, and pesticides are meant to protect crop plants against fungi (fungicides), insects (insecticides), and weeds (herbicides). The use of pesticides in agriculture is essential to obtaining high yields, but results in the contamination of the soil, water, air, and also the flowers from which bees collect nectar and pollen, the natural components of honey [3]. These agents negatively affect both bees and people, causing changes in the endocrine and nervous systems [4]. Detailed information on the potential sources of the contamination of honeys (e.g., heavy metals, airborne particulate matter, and agrochemical pesticides) was provided by Cunningham et al. [5].

**Citation:** K ˛edzierska-Matysek, M.; Teter, A.; Skałecki, P.; Topyła, B.; Domaradzki, P.; Poleszak, E.; Florek, M. Residues of Pesticides and Heavy Metals in Polish Varietal Honey. *Foods* **2022**, *11*, 2362. https:// doi.org/10.3390/foods11152362

Academic Editors: Dapeng Peng and Yongzhong Qian

Received: 4 July 2022 Accepted: 4 August 2022 Published: 6 August 2022

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**Copyright:** © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).

Therefore, the monitoring of their levels in food products is crucial for ensuring consumer health safety.

Colony collapse disorder (CCD) threatens the health of beehives worldwide, but scientists still struggle to identify the specific causes. In view of the important ecological and economic value of bees, there is a need to monitor and maintain healthy bee stocks. In the framework of the Farm to Fork Strategy, one of the main priorities of the European Commission is the 50% reduction of the overall use of (and risk from) chemical pesticides by 2030, especially for the most hazardous ones. In addition, the EU Pollinators Initiative objectives state that by 2030, the scientific knowledge about the magnitude, causes, and consequences of the insect pollinator decline will have improved, that the main known causes of this decline will be addressed and managed, and that the societal awareness and collaboration amongst stakeholders will have strengthened [6]. In response to a mandate from the European Parliament's Committee for the Environment, Public Health, and Food Safety (ENVI), The European Food Safety Authority (EFSA) devised an integrated framework for the environmental risk assessment (ERA) of multiple stressors in honey bees (MUST-B). These stressors range from chemicals such as plant protection products, other types of chemicals (e.g., biocides), biological agents (e.g., *Varroa*, *Nosema*), and other elements (e.g., food availability, weather conditions, and beekeeping management practices) in managed honey bees [7].

Among the compounds recognized as toxic for pollinating insects, an important group is the neonicotinoid insecticides, widely used in agriculture and with a share of about one third of the global insecticide market. Neonicotinoids act on nicotinic acetylcholine receptors (nAChRs) in the central nervous system of the honeybee and other pollinating insects, which impairs their learning and memory functions, causing them to not look for food [8] and thus leading to their elimination [9]. The most commonly used insecticides are imidacloprid and acetamiprid [10].

The Agency for Toxic Substances and Disease Registry [11] lists polychlorinated biphenyls, dimethoate, and metals such as lead, mercury, cadmium, zinc, and copper as harmful substances. Fakhri et al. [12], based on a meta-analysis of the results of 45 studies, estimated the overall rank order of nine potentially toxic elements (PTE) according to their concentrations in honey (Fe > Mn > Pb > Cr > Cu > Ni > Cd > As > Hg) as well as their rank according to their hazard quotient (HQ: Pb > Cd > Mn > Fe >Ni > As > Cu > Hg > Cr). Lead (Pb) and cadmium (Cd), due to their carcinogenic and cytotoxic properties, are regarded as the most toxic heavy metals. Lead, mainly from car exhaust, is not transported by plants, but can pollute the air and subsequently nectar and honeydew. Cadmium from the metallurgical industry and combustion plants is transferred from the soil to plants; thus, it can contaminate nectar and honeydew [13]. The predominant source of lead, cadmium, mercury, and arsenic is industrial contamination, i.e., exhaust gases and fumes, as well as pesticides and synthetic fertilizers. Oroian et al. [14] showed that information on the level of heavy metals in honey can be used to determine its botanical origin, with an about 81% accuracy, and its geographic origin, but with only a 21% accuracy.

One of the effects of human activity on the environment may be the presence of unacceptable chemical residues and drugs in the honey made by bees. The presence of these compounds is a significant challenge in monitoring the quality of honey. Taking into account human exposure to the effects of active substances and their potential cumulative and synergistic effects, maximum residue levels (MRL) have been established. Foodstuffs, including honey, are safe for human health or life if their content of these compounds does not exceed the acceptable limits [15]. The maximum residue levels of pesticides in food are regulated by Regulation (EC) No 396/2005 of the European Parliament and of the Council [16], and the levels of veterinary agents by Regulation (EC) No 37/2010 [17]. In Poland, honey is monitored in accordance with the Regulation of the Minister of Agriculture and Rural Development [18]. Specifically, it is tested for the presence of antibacterial substances, including sulphonamides and quinolones; medicinal products (carbamates and pyrethroids); chemical pollutants such as organochlorine pesticides, polychlorinated

biphenyls (PCB), and organophosphate pesticides; and toxic elements. Changing hazards, however, make it necessary to study new unsafe chemical compounds as they appear.

Testing for the presence of chemical contaminants in honey can provide important data on the presence of these contaminants in the environment. The honey bee (*Apis mellifera* L.) and its products are currently also used as bioindicators of environmental contamination. These insects fly around nectar plants growing up to 4 km away from the hive, but they can cover distances even up to 12 km, accumulating pollutants present in the air, soil, and water [19]. For this reason, honey can serve as an indicator material for evaluating the contamination of the environment from which bees have collected nectar for making honey.

The aim of the study was to assess the safety of honey from southeastern Poland based on the levels of residues of pesticides, including organochlorine and organophosphate insecticides, herbicides, and fungicides; plant growth regulators; acaricides; and others, as well as the content of copper and zinc and the presence of these toxic heavy metals: lead, cadmium, and mercury.
