Pesticide Contamination in Central Kentucky Urban Honey: A Pilot Study.

Author:Sheldon, Mary
Position:ADVANCEMENT OF THE SCIENCE - Report - Cover story


Honey has increased in popularity among shoppers at chain and local marketplaces. The increased popularity has led to small-scale urban beekeeping becoming an attractive practice, coinciding with the local food movement and concern over the decreasing honeybee population (Peters, 2012). Concerning to the producers of honey, and ultimately the end market, are the potential contaminants that can result in a toxic hive product or hive collapse. During foraging, honeybees are exposed to pollutants deposited on plants and from systemic pesticides. Most honeybees and their food are contaminated by spray applications that bees fly through or by residual pesticide left on foliage or floral parts (especially pollen).

Honeybees can bring these pollutants into their hive via collected nectar or pollutants that attach to the pollen-collecting hairs on their body; the aforementioned modes of pollutant transport yields the possibility of pesticide contamination in honey and other bee products, including the honeycomb (Mussen & Brandi, 2010). Pesticide contamination could weaken the beneficial properties of honey and, if present in hazardous amounts, pose a threat to human health (Peters, 2012).

Assessment of environmental diffusion of pesticides can be accomplished via matrix analyses of hive products, such as beeswax or honey (Chauzat et al., 2006). Monitoring pesticide residues in honey is also critical for assessing potential risk to consumer health and health of the hive, and can provide information on the pesticide treatments that have been used in areas surrounding hives (Peters, 2012). Researchers have used bees and bee products as biomonitoring agents for environmental contamination (Badiou-Beneteau et al., 2013; Barganska, Slebioda, & Namiesnik, 2016; Chauzat et al., 2011; de Oliveira, Queiroz, da Luz, Porto, & Rath, 2016; Malhat, Haggag, Loutfy, Osman, & Ahmed, 2015; Perez et al., 2016), to assess heavy metal environmental contamination (Giglio et al., 2017; Matin, Kargar, & Buyukisik, 2016), and to analytically document chemicals used in agricultural settings (Irungu et al., 2016; Niell et al., 2015). Monitoring research suggests that urban bees are exposed to even higher levels of pesticides than rural bees. Approved pesticide-use levels often are much higher for home and garden use than the levels permitted in commercial agriculture (Peters, 2012).

Pesticide Applications

The rising fear of potential diseases transmitted via mosquito bites has sparked increased mosquito abatement through commercial pesticide application, homeowner pesticide application, and public health programming. Pyrethroids are an extensively used class of insecticides with acute toxicity to insects governed by toxicological actions upon the central nervous system. Humans are less sensitive to pyrethroids than are insects, due to a combination of faster metabolic disposal, higher body temperature, and an inherently lower sensitivity of the similar human ion channel target sites. These features led to pyrethroids becoming the major pesticide class for agricultural and public health applications (Ray & Fry, 2006). As an insecticide with both repellent and killing functions, pyrethroids are the mainstay of current mosquito management. Insecticide use in the U.S. accounted for 40% of total world use by volume in 2006, and at least 9% or 70 million pounds of these insecticides were applied in urban settings (Zhu et al., 2016).

Due to extensive use of pesticides on food, escalated commercial pesticide use, and easy unsupervised access to pesticides by the general public, the public likely is facing higher risks from pesticide exposure than currently acknowledged. Unfortunately, the Food and Drug Administration has no regulations or definition for honey, so approximately 70% of the honey on U.S. grocery store shelves is adulterated. Adulterated honey can contain cheaper sweeteners, illegally trafficked honey, and/or chemicals. U.S. honey companies can dilute honey with other sweeteners to save money. Some companies receive imported honey, which can come from countries with negligent environmental safety regulations (The Honeybee Conservancy, 2017).

The best way to avoid adulterated honey is to buy local honey from a source that you can trust such as from farmers markets, coops, or local apiaries. The Kentucky State Beekeepers Association (2018) launched the Kentucky Certified Honey Program in summer 2018 as a new marketing program. This certification signifies that the producers' beehives are being managed within the state, the bees have collected nectar and pollen within the area immediately surrounding their beehives, and the honey is processed and bottled in Kentucky.

Organochlorine Pesticides and Heavy Metals

Organochlorine pesticides are chlorinated hydrocarbons used extensively from the 1940s through the 1960s in agriculture and mosquito control. These compounds are lipophilic pesticides known for their high toxicity, slow degradation, and bioaccumulation in lipid-rich tissue such as body fat. As a result, most living organisms now contain organochlorine residues, with the highest concentrations generally occurring in carnivorous species. These chemicals belong to the class of persistent organic pollutants, with high persistence in the environment through large reservoirs that remain in soils, sediments, and other environmental compartments (Huang et al., 2018).

Among environmental contaminants found on honeybees and in bee products, the most commonly studied are heavy metals. Honeybees are good biological indicators of anthropogenic pollution because they can indicate the chemical damage of their environment through high bee mortality and the residues present on their bodies or in beehive products. Honeybees sample most environmental sectors (i.e., soil, vegetation, water, air) through foraging (Abrol, 2013).

Ecosystem pollution from chemicals and heavy metals have greatly accelerated during the last few decades due to mining, smelting, manufacturing, use of agricultural fertilizers, pesticides, municipal wastes, traffic emissions, industrial emissions, and industrial chemicals (Bogdanov, 2006). The primary characteristic that distinguishes heavy metals from other pollutants, such as pesticides, is their introduction into an area and their environmental outcome. Pesticides are scattered both in time and space and deteriorate by means of various...

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