Assessing heavy metal pollution by biomonitoring honeybee nectar in Córdoba (Spain).

Nectar of honeybee colonies has been used in order to identify heavy metals and establish the benefit of this type of studies as a tool for environmental management. For these goals, samples of nectar were obtained from Apis mellifera hives placed in the city of Córdoba (Spain) and its surroundings. Five stations (each with two hives) were selected and samples were collected from May to July of 2007, 2009 and 2010. Concentrations of Pb, Cr, Ni and Cd in nectar were determined by graphite furnace atomic absorption spectrophotometry. Substantial spatial and temporal differences were detected and compared with the values found in bee bodies in a previously published study based on samples obtained simultaneously with those presented in this work. Upper reference thresholds established for this investigation were surpassed frequently by the measures obtained, being Cr (21.43% of samples), stations S3 (22.22%) and S4 (11.12%) year 2009 (22.22%) and the month of July (23.68%) the metal, the locations and the periods that exceeded more times these references. Regarding the Cd, which was studied only in 2010, 33.33% of the nectar samples exceeded the upper reference thresholds. Comparing the biomonitoring of bee bodies and nectar, some coincidences were found, although they showed different results for highest worrisome values of metal, station and year. This suggests that both methods can give complementary information in the surveillance systems of atmospheric pollution.

Assessment of heavy metal pollution in Córdoba (Spain) by biomonitoring foraging honeybee.

Due to features that make them outstanding environmental bioindicator, colonies of Apis mellifera are being used to study environmental pollution. The primary objective of this research was to use honeybee colonies to identify heavy metals and determine their utility for environmental management. Five stations each with two A. mellifera hives were strategically located in urban, industrial, agricultural and forested areas within the municipality of Córdoba (Spain), and foraging bees were collected from April to December in 2007, 2009 and 2010 to analyse spatial and temporal variation in Pb, Cr, Ni and Cd pollution. Metal concentrations, in milligram per kilogram of honeybee, were determined by inductively coupled plasma-atomic emission spectrometry and graphite furnace atomic absorption spectrophotometry. Significant differences in concentrations were found among the various locations and periods. The highest number of values exceeding the upper reference thresholds proposed for this study (Pb, 0.7 mg/kg; Cr, 0.12 mg/kg; Ni, 0.3 mg/kg; and Cd, 0.1 mg/kg) was observed for Pb and Cr (6.25% respectively), station S4 (13.22%), year 2007 (20.83%) and in months of May and July (11.90% each). Regarding the Cd, which was analysed only in 2010, the highest number of values exceeding the upper reference thresholds was 40%. Biomonitoring with colonies of A. mellifera could contribute to improved surveillance and control systems for atmospheric pollution by integrating qualitative and quantitative assessments, thus facilitating prevention and readiness in the event of environmental crises.

Honeybee interference as a novel aid to reduce pollen exposure and nasal symptoms among greenhouse workers allergic to sweet bell pepper (Capsicum annuum) pollen.

BACKGROUND: In 1999, an extensive study among bell pepper growers showed a prevalence of 53.8% work-related symptoms and 35.4% sensitisation to bell pepper pollen. Experiments with bees to remove pollen from bell pepper flowers have been done for a few years. OBJECTIVES: It was the aim of this study to investigate whether bees can reduce the pollen exposure in bell pepper greenhouses and whether this reduction results in a decrease in allergic complaints in the greenhouse workers. METHODS: Eighteen greenhouses were selected for the study. In each greenhouse, pollen exposure was estimated. In 6 and 3 of the greenhouses, high, respectively low, numbers of honeybees were placed throughout the pollen season of the sweet bell pepper plant. Nine greenhouses without honeybees were used as control. At baseline, as well as after 4 and 8 months, nasal symptoms assessed with a visual analogue score and lung function parameters were used as outcome measure. RESULTS: Forty-four of the 133 employees invited reported work-related symptoms. High numbers of bees reduced the pollen amount in a dose-dependent way to 18% of the baseline exposure. A significant trend relationship between the visual analogue scale in nasal symptoms and the number of colonies of bees was seen. CONCLUSIONS: The interference of bees in bell pepper greenhouses significantly reduces the pollen amount. This reduction is associated with less work-related rhinitis symptoms in allergic greenhouse workers. This intervention study supports the hypothesis that allergic work-related complaints of greenhouse workers, sensitised to bell pepper pollen, are caused by occupational exposure to this pollen in the greenhouse.