GENETICS AND P LANT P HYSIOLOGY – 2012, VOLUME 2 (1–2), PP . 64–72 ©2012 Published by the Institute of Plant Physiology and Genetics – Bulgarian Academy of Sciences Available online at http://www.ifrg-bg.com CONTENT OF HEAVY METALS AND ARSENIC IN MEDICINAL PLANTS FROM RECREATIONAL AREAS IN BULGARKA NATURE PARK Bezlova D.*, E. Tsvetkova, D. Karatoteva, L. Malinova University of Forestry, 10 Kl. Ohridski Blvd., Sofi a, Bulgaria Received: 20 September 2012 Accepted: 01 November 2012 Summary. Medicinal plants collected from grassland landscapes in Bulgarka Nature Park were analyzed for lead (Pb), cadmium (Cd), arsenic (As) and mercury (Hg) content. Contamination with Pb, Cd and As was found, Pb being the main contaminant. Urtica dioica, Mentha pulegium, Geranium macrorrhizum, Viola tricolor, Fragaria vesca, Primula veris and Plantago major were the plant species that accumulated Pb in concentrations more than 5 times the regulation limits. Cd was accumulated to a lesser extent compared with Pb. The exceedances were 1.5 to 3.1 times the limit and concerned Rubus idaeus (leaves), Viola dacica and Viola tricolor . Plants that accumulated As were Primula veris and Thymus sp. with maximum measured content exceeding 1.6 times the limit. The average Hg content in most of the analyzed plant samples varied within the range of 0.006-0.020 mg kg -1 FW, with the exception of Primula veris (0.035 mg kg -1 FW) and Carum carvi and Geranium phaeum (0.028 mg kg -1 FW). Key words: arsenic; cadmium; lead; mercury; medicinal plants; nature park. INTRODUCTION As, Cd, Pb and Hg are among the measures to reduce the presence of Pb in most toxic for the living organisms heavy food as much as possible. Greater efforts metals. The UNECE Protocol on Heavy are needed to reduce dietary exposure to Metals, Article 6, encourages parties inter Cd since foodstuffs are the main source of alia to develop “an effects-based approach Cd intake by man. … for the purpose of formulating future The mobility of Cd, Pb, Hg and As in optimized control strategies …”, primarily soils and the ability of these heavy metals focusing on Cd, Pb and Hg. to migrate from soil to other environmental In the framework of Directive 93/5/ components, including medicinal plants EEC a project on the “Assessment of the represent a signifi cant health risk to dietary exposure to arsenic, cadmium, humans and animals. Existing studies lead and mercury of the population of the prove bioaccumulation of heavy metals EU Member States” was implemented and arsenic in different above- and in 2004 (DGHCP, 2004). The results underground plant parts (Kabata-Pendias, showed that the Community needs 2001). *Corresponding author: [email protected] Heavy metals and arsenic in medicinal plants in Bulgarka Nature Park 65 According to the World Health 2009). Organization (WHO, 1981) natural Contamination of some landscape concentrations of As range between components of Bulgarka Nature Park 0.023 and 0.25 ppm in plants. Arsenic have been studied by Malinova (2010) and content in above-ground plant organs on Malinova et al. (2010). In some key areas contaminated soils varies and in most cases high levels of As, Pb and Zn in soils and the values are low (Anawar et al., 2006; plants were found, indicating a possible Madejon and Lepp, 2007; Dominguez et risk to the environment and humans. The al., 2008), which corresponds to its low measured values of As in soils exceeded mobility (Moreno-Jimenez et al., 2008). the maximum permitted levels but the The majority of plant species preferentially presence of the element was considered store As in the roots rather than in the natural. Among the observed plant species above-ground organs (Moreno-Jimenez higher accumulation of As was found in et al. 2008), except for hiperaccumulating Origanum vulgare and Galium odoratum. plant species (Zhang et al., 2002). The aim of the present study was to Pb is also characterized by weak analyze and assess the content of Pb, Cd, translocation in plants, which leads to As and Hg in herbaceous plants widely accumulation mainly in roots (Kabata- used as tea, decoction and spices in Pendias, 2001; Pahlsson, 1989). grassland landscapes of Bulgarka Nature Unlike As and Pb, Cd is mobile and Park. easily taken up by plants changing its location in various organs (Adriano, 1986; MATERIALS AND METHODS Kabata-Pendias, 2001). Hg is a specifi c element since the Sampling sites and plant material major toxicant is not its ionic form, as is Bulgarka Nature Park is a protected the case with most heavy metals, but the area according to the Protected Area Act elementary Hg. It is taken up by plants of Bulgaria and a Natura 2000 site under easier in alkaline media and located in both Directives – the Birds Directive and various organs including seeds and fruits. the Habitats Directive. Bulgarka Nature Apart from soil, plants can absorb it from Park was established in 2002 with the air as vapours. main purpose to preserve the natural In natural conditions, heavy metals beech forests in the central part of the and metalloids exist in various chemical Balkan mountains. The park covers an forms and their toxicity can vary area of 22 000 hectares and supports more considerably (WHO, 2006). In nature, than 1800 plant species. About 70% of the the accumulation of heavy metals and offi cially recognized as medicinal plants metalloids in medicinal plants largely in Bulgaria are found in the park (http:// depends on their individual features and www.ppbulgarka.net). the concentration of the elements in soils, Sampling sites and species were air and water. Since heavy metals are a defi ned on the basis of a preliminary expert health hazard to humans, their content in assessment. According to the experts of plants used for consumption or for medical the Directorate of Bulgarka Natural Park purposes should be limited (Gasser et al., and local companies for buying medicinal GENETICS & PLANT P HYSIOLOGY 2012 VOL. 2 (1–2) 66 Bezlova et al. plants and fruits, the most commonly licensed Central Laboratory for Chemical used medicinal plants in the area are: Testing and Control of the Ministry of wild mint (Mentha pulegium), wild Agriculture and Food in compliance with pansy (Viola tricolor ), thyme (Thymus Bulgarian State Standards EN 14084:2003 sp.), caraway (Carum carvi), crosswort and EN 13806:2003. The results were (Cruciata laevipes), St. John‘s wort calculated on a fresh weight (FW) basis (Hypericum perforatum), nettle (Urtica and compared to the limits defi ned in dioica), common chicory (Cichorium Ordinance № 31/29.07.2006 for maximal intybus), dropwort (Filipendula vulgaris), admissible contaminants’ concentrations wild raspberry (Rubus idaeus) geranium in food (State Gazette 88 / 8.10.2004, alt. (Geranium macrorrhizum), cowslip State Gazette 51/23.06.2006) as follows: (Primula veris) wild strawberry ( Fragaria 0.500 mg kg -1 FW, 0.200 mg kg -1 FW vesca), yarrow (Achillea millefolium), and 0.200 mg kg -1 FW for As, Pb and Cd, common plantain (Plantago major). respectively. Samples for analysis were collected from the above plant species. Statistics Preferred areas for gathering Statistical analysis was done using medicinal plants and wild fruits are the One-sample t-tests. sites of Uzana, Gabrovo hut, Malusha, Mount Ispolin and the vicinities of the RESULTS AND DISCUSSION settlements. Samples for analysis were collected from these sites and near two The studied grassland landscapes were villages, Potok and Ezeroto as well as near divided into two groups: natural grassland Voditsi holiday village. landscapes and grassland landscapes near Sampling sites were determined by settlements. means of GIS, using a database for relief The landscape-ecological analysis of and soil conditions (Malinova, 2007). the park showed that most favorable for recreation and gathering of medicinal Sample analysis plants were the natural grassland Sampling was carried out in late June landscapes in the ridge parts of the park (2011) which is the preferred time for occupying altitudinal range between 700 picking medicinal plants. Mixed samples m and 1350 m: Malusha, Mount Ispolin, of the specifi c medicinal plant species in Uzana and Gabrovo hut (Fig. 1). The each site were collected. Dry weight was areas near the settlements of Ezeroto, measured after oven drying at 40 oC until Potok and Voditsi were situated at lower constant weight. For decomposition of altitudes and had very steep slopes (Fig. the samples closed microwave digestion 2). Grassland landscapes there occupied with HNO3 + H 2O2 was used. The small scattered areas and not all of them content of Cd and Pb was determined were accessible. Nevertheless, these areas by Graphite furnace atomic absorption also have potential for picking medicinal spectrophotometry (GFAAS) whereas a plants. hydride system was applied for As and In the region of Malusha site all Hg. Analyses were conducted by the analyzed plants contained Pb above GENETICS & PLANT P HYSIOLOGY 2012 VOL. 2 (1–2) Heavy metals and arsenic in medicinal plants in Bulgarka Nature Park 67 Figure 1. Natural grassland landscapes in Bulgarka Nature Park. Figure 2. Grassland landscapes near Potok and Ezeroto villages. GENETICS & PLANT P HYSIOLOGY 2012 VOL. 2 (1–2) 68 Bezlova et al. the limits determined in Ordinance are no regulations concerning limits for № 31 (2006). Primula veris, Viola the content of Hg in plants, the assessment tricolor and Mentha pulegium showed was based on comparison between plants. high accumulation of Pb (Fig. 3). High Most of the measured concentrations concentrations of Cd were measured only varied within the range of 0.011-0.018 mg in Viola tricolor , exceeding 6.8 times the kg -1 FW. Higher values were registered limit. Exceedances for As were measured in Carum carvi (0.028 mg kg -1 FW) and in two species, Thymus sp.