Determination of traces of copper and zinc in honeys by the solid phase extraction pre-concentration followed by the flame atomic absorption spectrometry detection

Development of salt-induced homogeneous liquid-liquid extraction using a deep eutectic solvent performed in a narrow-bore tube for the extraction of Zn(II), Cu(II), and Cd(II) ions from honey samples

In this study, a sample preparation procedure based on salt-induced homogeneous liquid-liquid extraction performed in a narrow-bore tube was used for the preconcentration and extraction of Zn(II), Cu(II), and Cd(II) ions from honey samples. To perform the procedure, a mixture of working solution containing sodium chloride, acetonitrile, and a synthesized deep eutectic solvent (as an extraction solvent) was transferred into a narrow tube filled with solid sodium chloride up to a specific level. As the solution flowed through the tube, tiny droplets of the extraction solvent were formed at the boundary between the solution and salt layer. The droplets moved upwards in the tube and eventually collected as a distinct layer on the top of the solution. The separated phase was removed and dispersed into ionized water. After centrifugation, tiny droplets of the extraction solvent containing the analytes were sedimented at the bottom of the tube. The concentrated analytes were measured using flame atomic absorption spectrophotometry. The linear ranges and extraction recoveries were obtained in the ranges of 1.5-100 μg kg-1 and 89.6-94.8%, respectively. The detection limits ranged from 0.35 to 0.48 μg kg-1. Low relative standard deviations (C = 10 μg L-1, n = 6) of 3.1, 2.8, and 3.4% for Zn(II), Cu(II), and Cd(II), respectively, were obtained. Finally, the optimized method was successfully used in determination of concentration of the selected heavy metal ions in various honey samples.

Effects of native forest and human-modified land covers on the accumulation of toxic metals and metalloids in the tropical bee Tetragonisca angustula

The intensive shift on land cover by anthropogenic activities have led to changes in natural habitats and environmental contamination, which can ultimately impact and threat biodiversity and ecosystem services, such as pollination. The aim of this study was to evaluate the effect of native forest and human-modified land covers on the concentrations of chemical elements accumulated in the neotropical pollinator bee T. angustula. Eight landscapes, within an Ecological Corridor in the State of São Paulo, Brazil, with gradients of forest cover, spatial heterogeneity and varying land covers were used as sampling unities. Bees collected in traps or through actives searches had the concentration of 21 chemical elements determined by ICP-MS. Results show a beneficial effect of forested areas on the concentrations of some well-known toxic elements accumulated in bees, such as Hg, Cd, and Cr. Multivariate Redundancy Analysis (RDA) suggests road as the most important driver for the levels of Cr, Hg, Sb, Al, U, As, Pb and Pt and bare soil, pasture and urban areas as the landscape covers responsible for the concentrations of Zn, Cd, Mn, Mg, Ba and Sr in bees. The results reinforce the potential use of T. angustula bees as bioindicators of environmental quality and also show that these organisms are being directly affected by human land use, offering potential risks for the Neotropical ecosystem. Our study sheds light on how land covers (native forest and human-modified) can influence the levels of contaminants in insects within human-dominated landscapes. The generation of predictions of the levels of toxic metals and metalloids based on land use can both contribute to friendly farming planning as well as to support public policy development on the surrounding of protected areas and biodiversity conservation hotspots.

Hair mineral analysis in the population of students living in the Lower Silesia region (Poland) in 2019: Comparison with biomonitoring study in 2009 and literature data

The paper presents a comparative analysis of biomonitoring research results using hair mineral analysis today and 10 years ago. The aim of the present work was to examine the impact of individual factors, on the content of elements in human hair. The mineral analysis of 115 hair samples was carried out using ICP-OES and AAS technique. It was shown that calcium, barium, copper, mercury, magnesium, manganese and selenium content depend on gender and is higher for women. Statistically significant synergistic correlations were identified between the following pairs of elements: (Ca-Mg), (P-S), (Mo-Sb) and (Ba-Pb). The results of the present work were compared with the previous assessment in 2009 on students of the same age. The content of most of the heavy metals in hair was reduced significantly, which is a sign of the improving state of the local environment. The greatest decrease was recorded for silver (96.6%), arsenic (93.4%), mercury (45.1%), lead (67.7%), antimony (55.2%), thallium (10 times) and cobalt (93.7%). The level of the following elements increased: Ba: 27.3%, Cu: 28.5%, Ni: 22.4%, Ti: 191%, Zn: 11.0%. Changes in the content of most heavy metals in hair have been noted, as well as changes of reference ranges, which may indicate an improvement in the state of the environment in Wrocław, Lower Silesia (Poland) over the last 10 years. These results were confirmed by biomonitoring studies carried out with human hair, which was shown to be a reliable biomarker of human exposure to toxic elements.

Mineral Content in Honeybee Wax Combs as a Measurement of the Impact of Environmental Factors

Environmental pollution from metals needs to be constantly monitored due to their predominantly negative impacts on living organisms. As apian products stored in hives are considered useful bioindicators, the objective of this study was to: (a) investigate and compare the essential and toxic metal concentrations in freshly constructed combs (light combs, LC) and old combs (dark combs, DC) in use for two to three beekeeping seasons, and (b) compare the mineral content of beeswax combs from apiaries exposed to different levels of environmental pollution using the energy dispersive x-ray fluorescence method. Concentrations of ten elements (Cr, Pb, Cu, Ni, Fe, Zn, Mn, Sr, Rb, Ca) were determined in 18 honeybee wax comb samples from three apiaries in continental Croatia. The results showed that the influence of comb age and/or geographical origin (representing varying levels of environmental pollution exposure) on the elemental composition of beeswax was evident for the toxic elements Cr, Pb, Cu and Ni, and for the essential elements Fe, Zn, Mn and Sr, but not Rb. In addition to monitoring the environmental element content, wax combs can be used to determine contamination levels. Additionally, in-time analysis results can enable beekeepers to adjust management practices, such as moving apiaries to better positions. They can also be useful in the creation of policies on acceptable limits for toxic metal levels in particular geographical areas.

Honeybees (Apis mellifera L.) as a Potential Bioindicator for Detection of Toxic and Essential Elements in the Environment (Case Study: Markazi Province, Iran)

Honeybees, due to their wide-ranging foraging behaviour, have great potentials for monitoring environmental quality. Therefore, the purpose of this study was to use honeybees as bioindicators for the detection of toxic and essential metals (Cd, Cr, Cu, and Fe) in the environment. Totally, 180 soil, plant (including root and aerial part), honeybees, and honey samples were collected from 12 sites within the main beekeeping and honey production regions in Markazi Province, Iran in 2016. After acid digestion of samples, the metal concentrations were measured by inductively coupled plasma-optical emission spectrometers. The translocation factor (TF), and bioconcentration factor (BCF) of metals were computed. The results showed that among the analyzed bee samples, Cd (mg kg^-1) was detected in amounts ranging from 0.01 to 2.35, Cr (mg kg^-1) ranged from 0.02 to 18.10, Cu (mg kg^-1) ranged from 2.00 to 39.11, and Fe (mg kg^-1) ranged from 163 to 1695. BCF and TF values obtained showed that the Astragalus gossypinus would have a great accumulation ability for Cd and Cr. The results indicated that honeybees could be used to detect the spatial patterns of metal contaminations in the environment they dwell in.

The Relationship between the Mechanism of Zinc Oxide Crystallization and Its Antimicrobial Properties for the Surface Modification of Surgical Meshes

Surgical meshes were modified with zinc oxide (ZnO) using a chemical bath deposition method (CBD) at 50 °C, 70 °C, or 90 °C, in order to biologically activate them. Scanning electron microscopy (SEM), mass changes, and X-ray diffraction measurements revealed that at low temperatures Zn(OH)₂ was formed, and that this was converted into ZnO with a temperature increase. The antimicrobial activity without light stimulation of the ZnO modified Mersilene™ meshes was related to the species of microorganism, the incubation time, and the conditions of the experiment. Generally, cocci (S. aureus, S. epidermidis) and yeast (C. albicans) were more sensitive than Gram-negative rods (E. coli). The differences in sensitivity of the studied microorganisms to ZnO were discussed. The most active sample was that obtained at 90 °C. The mechanism of antimicrobial action of ZnO was determined by various techniques, such as zeta potential analysis, electron paramagnetic resonance (EPR) spectroscopy, SEM studies, and measurements of Zn(II) and reactive oxygen species (ROS) concentration. Our results confirmed that the generation of free radicals was crucial, which occurs on the surface of crystalline ZnO.