Bioindication of atmospheric trace metals--with special references to megacities

Assessment of lettuces grown in urban areas for human consumption and as bioindicators of atmospheric pollution

This study proposes using the network of urban gardens to grow vegetables and to monitor air quality, and it also evaluates whether food grown on a clean substrate in an urban environment is safe for consumption. For this purpose, lettuces were exposed to different degrees of air pollution in five locations in the city of Copenhagen, plus a reference site. Six specimens were placed at each site and, after the exposure period, half of each sample was washed. Subsamples were then digested by a total extraction method and a bioaccessible extraction method, and the concentration of 23 elements subsequently measured by ICP-MS. The results showed that exposed samples in areas of higher atmospheric pollution accumulated a larger amount of trace elements associated with typical urban sources. They also highlighted the importance of washing food to remove particles that adhere to their surface. However, bioaccessibility testing demonstrated the importance of including bioaccessibility in risk analyses and how this factor varies depending on the type of matrix. In this case, bioaccessibility was higher for plant tissue than for particulate matter. Lastly, metal concentrations in lettuce were compared with legal values and an analysis of daily intake showed that the levels in Copenhagen were within limits for the protection of human health.

Bioaccumulation of heavy metals air pollutants by urban trees

Leaf and bark of trees are tools for assessing the effects of the heavy metals pollution and monitoring the environmental air quality. In this study, the possibility of using leaves and bark of two urban trees, namely, Ficus nitida and Eucalyptus globulus as a bioindicator of atmospheric pollution was evaluated by determining the composition of heavy elements in the tree leaves, bark, soil, and the atmospheric dust. Two common tree species, namely, F. nitida and E. globulus were selected in the heavily industrial zone of surrounding Minya governorate, Upper Egypt. Two urban areas with heavy traffic load (sites 1 and 2), three industrial zones (sites 3, 4, and 5) and an uncontaminated area as a control were selected (site 6). Sampling from leaf, bark, soil, deposited dust of trees was carried out in winter and summer seasons (from November 2016 to March 2017). The concentrations of heavy metals in dust, soil, leaves, and bark possess the same trend: Pb>Cu>Cd. The highest concentration of cadmium, lead, and copper was found in the leaf of F. nitida and E. globulus higher than bark samples of the studied species, supporting the idea suggesting that tree leaves can be used as a good indicator of heavy metals accumulation. A high and statistically significant correlation (p < .05) was found between Pb concentrations in the atmospheric dust and those in the leaves of both species throughout the two growing seasons, confirming that the main source of incorporated Pb is the atmospheric dust. Otherwise, the obtained results showed that F. nitida tree does not seem to be a good accumulator of Cu. According to the obtained results, F. nitida and E. globulus trees are more likely to capture cadmium and lead from air, so planting these trees in industrial areas with such atmospheric pollutants would be beneficial.

Heavy Metals Bioindication Potential of the Common Weeds Senecio vulgaris L., Polygonum aviculare L. and Poa annua L

In recent years, heavy metals (HMs) levels in soil and vegetation have increased considerably due to traffic pollution. These pollutants can be taken up from the soil through the root system. The ability of plants to accumulate HMs into their tissues can therefore be used to monitor soil pollution. The aim of this study was to test the ruderal species Senecio vulgaris L., Polygonum aviculare L., and Poa annua L., as possible candidates for biomonitoring Cu, Zn, Cd, Cr, Ni and Pb in multiple environments. The soils analyzed in this work came from three different environments (urban, woodland, and ultramafic), and therefore deeply differed for their metal content, texture, pH, and organic matter (OM) content. All urban soils were characterized by high OM content and presence of anthropogenic metals like Pb, Zn, Cd, and Cu. Woodland soils were sandy and characterized by low metal content and low OM content, and ultramafic soils had high Ni and Cr content. This soil variability affected the bioindication properties of the three studied species, leading to the exclusion of most metals (Zn, Cu, Cr, Cd, and Pb) and one species (P. aviculare) due to the lack of linear relations between metal in soil and metal in plants. Senecio vulgaris and Poa annua, conversely, appeared to be good indicators of Ni in all the soils tested. A high linear correlation between total Ni in soil and Ni concentration in P. annua shoots (R2 = 0.78) was found and similar results were achieved for S. vulgaris (R2 = 0.88).

Efficiency of biomonitoring methods applying tropical bioindicator plants for assessing the phytoxicity of the air pollutants in SE, Brazil

In the tropical region, the greatest challenge of the biomonitoring approach is to establish linear relationships between biomarkers measured in plants and pollutant concentrations, since the bioindicator responses can be intensified or restricted by climatic variations. In southeastern Brazil, there are two regions affected by air pollution, where the Atlantic Forest remains and should be preserved. Consequently, both areas have been monitored by biomonitoring procedures using standardized and tropical plants. The industrial complex settled in Cubatão is one of the world's most famous examples of environmental pollution and degradation, with consequent decline of the Atlantic Forest. An oil refinery is among the most polluting industries in the Cubatão region. The other region is located in the Metropolitan Region of Campinas (MRC). The MRC has been affected by high levels of air pollutants originated from road traffic and is responsible for over 80% of CO, NOx, and hydrocarbon emissions and develops industrial activities that emit about 70% of the particulate matter present in the region. Both regions are distinguished by the climate, despite the fact that they are only about 130 km far from each other. Several studies carried out by our group in these regions aimed to establish the best native tree species and respective potential biomarkers for future assessment of pollution effects on tropical Forests. We present a critical review about the efficiency of native species compared to standardized bioindicator plants considering antioxidant defense system, nutrient accumulation, and microscopic aspects when exposed to atmospheric pollutants and climate.

A Streamlined Approach by a Combination of Bioindication and Geostatistical Methods for Assessing Air Contaminants and Their Effects on Human Health in Industrialized Areas: A Case Study in Southern Brazil

Industrialization in developing countries associated with urban growth results in a number of economic benefits, especially in small or medium-sized cities, but leads to a number of environmental and public health consequences. This problem is further aggravated when adequate infrastructure is lacking to monitor the environmental impacts left by industries and refineries. In this study, a new protocol was designed combining biomonitoring and geostatistics to evaluate the possible effects of shale industry emissions on human health and wellbeing. Futhermore, the traditional and expensive air quality method based on PM_2.5 measuring was also used to validate the low-cost geostatistical approach. Chemical analysis was performed using Energy Dispersive X-ray Fluorescence Spectrometer (EDXRF) to measure inorganic elements in tree bark and shale retorted samples in São Mateus do Sul city, Southern Brazil. Fe, S, and Si were considered potential pollutants in the study area. Distribution maps of element concentrations were generated from the dataset and used to estimate the spatial behavior of Fe, S, and Si and the range from their hot spot(s), highlighting the regions sorrounding the shale refinery. This evidence was also demonstrated in the measurements of PM_2.5 concentrations, which are in agreement with the information obtained from the biomonitoring and geostatistical model. Factor and descriptive analyses performed on the concentrations of tree bark contaminants suggest that Fe, S, and Si might be used as indicators of industrial emissions. The number of cases of respiratory diseases obtained from local basic health unit were used to assess a possible correlation between shale refinery emissions and cases of repiratory disease. These data are public and may be accessed on the website of the the Brazilian Ministry of Health. Significant associations were found between the health data and refinery activities. The combination of the spatial characterization of air pollution and clinical health data revealed that adverse effects were significant for individuals over 38 years of age. These results also suggest that a protocol designed to monitor urban air quality may be an effective and low-cost strategy in environmentally contaminated cities, especially in low- and middle-income countries.

Current content of selected pollutants in moss, humus, soil and bark and long-term radial growth of pine trees in the Mezaparks forest in Riga

The aim of this study was to evaluate the use of various indicators in the assessment of environmental pollution and to determine the response of pine to changes of pollution levels. Mezaparks is a part of Riga that has been subject to various long-term effects of atmospheric pollution and, in particular, historically from a large superphosphate factory. To determine the spatial distribution of pollution, moss, pine bark and soil O and B horizons were used as sorbents in this study, as well as the additional annual increment of pine trees. The current spatial distribution of pollution is best shown by heavy metal accumulation in mosses and the long-term accumulation of P₂O₅ pollution by the soil O horizon. The methodological problems of using these sorbents were explored in the study. Environmental pollution and its changes could be associated with the tree growth ring annual additional increment of Mezaparks pine forest stands. The additional increment increased after the closing of the Riga superphosphate factory.

Suitability of Tillandsia usneoides and Aechmea fasciata for biomonitoring toxic elements under tropical seasonal climate

Aechmea fasciata was evaluated for the first time as a biomonitor of toxic elements, in comparison to the biomonitoring capacity of Tillandsia usneoides, a well-established biomonitor bromeliad species. Plants of both species were exposed to air pollutants from industrial, urban, and agricultural sources, under the tropical seasonal climate, from June/2011 to April/2013, in five sites of São Paulo State, Brazil, for 8 consecutive exposure periods of 12 weeks each. The levels of essential and non-essential elements, including trace metals, were quantified at the end of each exposure. T. usneoides and A. fasciata indicated N, Fe, Zn, Co, Cr, and V as air contaminants in the studied sites, during wet and dry seasons and both species were recommended for qualitative biomonitoring. Concentration levels of N, Ca, S, Fe, Zn, Cu, B, Co, and Ni were significantly higher in T. usneoides than in A. fasciata. However, A. fasciata showed a higher effective retention capacity of Ni, Pb, V, Cu, Fe, Cr, and Co during field exposure, as indicated by the estimate of enrichment factor relative to basal concentrations. This species is more suitable for detecting the atmospheric pollution level of those metals than the T. usneoides. Both species indicated adequately the seasonal differences in the pollution levels of several elements, but T. usneoides presented higher ability for biomonitoring the spatial variations and for indicating more properly the sources of each element in the studied region than the A. fasciata.

Levels of Cadmium in White and Brown Meat of Warty Crab (Eriphia verrucosa)

European Union regulations that establish the maximum cadmium (Cd) levels for crab take into account only concentrations found in crab muscle (white meat), mainly from appendages; therefore, other organs and tissues (brown meat) are excluded. The objective of the present study was to evaluate Cd levels in both white and brown crab meat, in order to achieve a more complete assessment of health risk related to human consumption of warty crab. Microwave digestion and atomic absorption spectrometry were used to determine Cd concentrations in warty crab (Eriphia verrucosa) samples collected from the southern Tyrrhenian Sea in Italy. Cd concentrations in all samples of white crab meat were found to be very low (below the limit of quantification), although brown crab meat showed significantly higher Cd concentrations (up to 5.629 mg/kg wet weight; mean value, 1.465 mg/kg). Thus, the consumption of brown meat, common among certain populations of the Mediterranean region, where whole crustaceans are traditionally eaten, substantially increased Cd intake, resulting in alarmingly high estimated weekly intake values.

Polybrominated diphenyl ethers (PBDEs) in herbaceous Centaurium erythraea affected by various sources of environmental pollution

Polybrominated diphenyl ethers (PBDEs) are persistent xenobiotics with harmful effects on humans and wildlife. Their levels in the environment and accumulation in biota must be carefully controlled especially in species harvested from wild populations and commonly used as medicines. Our objective has been to determine PBDE concentrations (BDEs 28, 47, 66, 85, 99, 100, 153, 154, 183 and 209) in Centaurium erythraea collected at sites with various levels of environmental pollution. PBDE congener profiles in C. erythraea were dominated by BDE209, which accounted for 47-89% of the total PBDE burden in the plants. Principal Component and Classification Analysis, which classifies the concentration of PBDEs in C. erythraea, allowed us to distinguish the pattern of these compounds characteristic for the origin of pollution: BDEs 28, 47, 66, 85, 99, 100 for lignite and general chemical industry and the vicinity of an expressway and BDEs 183 and 209 for a thermal power plant and ferrochrome smelting industry. Careful selection of sites with C. erythraea for medicinal purposes is necessary as this herb can accumulate PBDEs while growing at polluted sites.

δ(34)S values and S concentrations in native and transplanted Pleurozium schreberi in a heavily industrialised area

Sulphur is an element found in surplus in anthropogenic areas and one of the minerals responsible for the development of acid rains. The analysis of stable S isotopes provides a powerful tool for studying various aspects of the biogeochemical circulation of sulphur. δ(34)S values and S concentrations were determined in a 90-day experiment with the native moss Pleurozium schreberi from rural, urban and industrial sites in Upper Silesia in southern Poland. At the same time P. schreberi from a control site was transplanted to the same rural, urban and industrial sites and the δ(34)S values and S concentrations were determined in the same 90-day experiment. (34)S enrichment (up to 4.7‰) in the mosses tested indicates that these plants responded to environmental pollution stress. Sulphur isotopic composition in the transplanted P. schreberi was related to S concentrations in this species after 90 days of the experiment. Higher δ(34)S values and S concentrations were noted in native mosses than in those transplanted from rural and urban sites while an opposite situation was reported in industrial sites. The transplanted P. schreberi was a better sulphur bioindicator than the native moss in more polluted industrial sites and worse in less polluted rural and urban sites.

Active moss biomonitoring for extensive screening of urban air pollution: Magnetic and chemical analyses

In this study, active magnetic biomonitoring of moss for particulate air pollution and an assessment of heavy metals and polycyclic aromatic hydrocarbons (PAHs) were performed for the entire metropolitan area of Belgrade. Two mosses, Sphagnum girgensohnii (a species of the most recommended biomonitoring moss genus) and Hypnum cupressiforme (a common moss in the study area), were used. During the summer of 2013, moss bags were exposed at 153 sampling sites, forming a dense network of sites. A type II regression model was applied to test the interchangeable use of the two moss species. Significantly higher levels of all measured pollutants were recorded by S. girgensohnii in comparison with H. cupressiforme. Based on the results, the mosses could not be interchangeably used in urban areas, except for the biomonitoring of Cu. Nevertheless, according to the relative accumulation factors obtained for both moss species, similar city zones related to high, moderate and low levels of air pollution were distinguished. Moreover, new pollution hotspots, omitted by regulatory monitoring, were identified. The results demonstrate that moss magnetic analysis represents an effective first step for obtaining an overview of particulate air pollution before more expensive chemical analyses. Active moss biomonitoring could be applied as a pragmatic approach for optimizing the representativeness of regulatory monitoring networks.

Metal distribution in soils of an in-service urban parking lot

Increasing traffic is becoming one of the main sources of metal pollution in urban areas. To investigate the possible impacts of traffic-related activities on metal distribution in soils, a total of 370 soil samples were collected in a ground parking space in service for about 20 years in Chengdu, China. The concentrations of Cu, Fe, Mn, Pb, Rb, Sr, Ti, and Zn in soils were measured using portable energy-dispersive X-ray fluorescence. Soil samples exhibited various levels of metal pollution ranging from no pollution to borderline moderate pollution for Zn and Pb, with median enrichment factors following the order of Zn (2.7), Pb (2.2), Sr (1.9), Cu (1.8), Fe (1.3), Rb (1.1), and Mn (0.5). Both cluster analysis and spatial distribution mapping demonstrated that Pb, Zn, Cu, Mn, Sr, and Fe concentrations in the parking space were influenced by traffic, with strong spatial variation in different areas of the parking space. These metals shared similar spatial distribution patterns with relatively elevated concentrations in the four corners, left and right sides and entrance and rear areas, compared with the metal concentrations in the central area. Such spatial patterns revealed the influences of yellow road paint, wear and tear of vehicular parts including brakes and tires, as well as tailpipe emissions. The pollution sources in the parking space were identified as yellow road paint and vehicular emissions. This study highlights that metal pollution in the parking areas should be given more attention.

Multilingual education of students on a global scale and perspective-international networking on the example of bioindication and biomonitoring (B&B technologies)

Living or formerly living organisms are being used to obtain information on the quality of the general health status of our environment by bioindication and biomonitoring methods for many decades. Thus, different roads toward this common scientific goal were developed by a lot of different international research groups. Global cooperation in between various scientific teams throughout the world has produced common ideas, scientific definitions, and highly innovative results of this extremely attractive working field. The transdisciplinary approach of different and multifaceted scientific areas-starting from biology, analytical chemistry, via health physics, up to social and economic issues-have surpassed mental barriers of individual scientists, so that "production" of straightforward common results related to the influence of material and immaterial environmental factors to the well-being of organisms and human life has now reached the forefront of international thinking. For the further sustainable development of our common scientific "hobby" of bioindication and biomonitoring, highest personal energy has to be given by us, being teachers to our students and to convince strategically decision makers as politicians to invest (financially) into the development of education and research of this innovative technique. Young people have to be intensively convinced on the "meaning" of our scientific doing, e.g., by extended forms of education. One example of multilingual education of students on a global scale and perspective is given here, which we started about 3 years ago.

Evaluation of toxic metal (Hg, Cd, Pb), polychlorinated biphenyl (PCBs), and pesticide (DDTs) levels in aromatic herbs collected in selected areas of Southern Italy

This study provides, for the first time, data regarding levels of toxic metals (Hg, Cd, and Pb) and organochlorine compounds (PCBs and DDTs) in various aromatic herbs as rosemary (Rosmarinus officinalis), sage (Salvia officinalis), laurel (Laurus nobilis), oregano (Origanum vulgare), and spearmint (Mentha viridis) collected in some towns of the Southern Italy with different anthropogenic and population pressure. Metal and organochlorine compound concentrations were determined using atomic absorption spectrophotometer and gas-chromatography mass spectrometer (GC/MS), respectively. Pb emerged as the most abundant element, followed by Cd and Hg, while between organochlorine compounds, PCB concentrations were higher than those of DDTs. The pollutant concentrations were found to vary depending on the different herbs. The highest Pb levels were observed in rosemary (1.66 μg g(-1) dry weight) and sage (1.41 μg g(-1) dry weight), this latter showing also the highest Cd concentrations (0.75 μg g(-1) dry weight). For PCBs, the major concentrations were found in rosemary (2.75 ng g(-1) dry weight) and oregano (2.39 ng g(-1) dry weight). The principal component analysis applied in order to evaluate possible similarities and/or differences in the contamination levels among sampling sites indicated differences area-specific contamination.

Traffic-related trace element accumulation in roadside soils and wild grasses in the Qinghai-Tibet Plateau, China

This research examines traffic-source trace elements accumulations and distributions in roadside soils and wild grasses in the Qinghai-Tibet Plateau. A total of 100 soil samples and 100 grass samples including Achnatherum splendens, Anaphalis nepalensis, Artemisia sphaerocephala, Carex moorcroftii, Iris lacteal, Kobresia myosuroides, Oreosolen wattii, Oxytropis ochrocephala and Stellera chamaejasme were collected at 100 sites from different road segments. The contents of metals and metalloids, including Cu, Zn, Cd, Pb, Cr, Co, Ni and As, in the soil and grass samples were analyzed using ICP-MS. The total mean concentrations of the eight trace elements in soils are Cu (22.84 mg/kg), Zn (100.56 mg/kg), Cd (0.28 mg/kg), Pb (28.75 mg/kg), Cr (36.82 mg/kg), Co (10.24 mg/kg), Ni (32.44 mg/kg) and As (21.43 mg/kg), while in grasses are Cu (9.85 mg/kg), Zn (31.47 mg/kg), Cd (0.05 mg/kg), Pb (2.06 mg/kg), Cr (14.16 mg/kg), Co (0.55 mg/kg), Ni (4.03 mg/kg) and As (1.33 mg/kg). The metal and metalloid concentrations in the nine grass species were all below the critical values of hyperaccumulators. The mean values and Multivariate Analysis of Variance (MANOVA) results indicate that: (1) the concentrations of the trace elements in the soils are higher than those in the grasses, (2) the concentrations of Cu, Zn, Cd, Pb in the soils decrease as the roadside distance increases, (3) the concentrations of trace elements in the grasses are the highest at 10 m from the road edge, (4) the higher the traffic volume, the higher the concentrations of the trace elements in the roadside soils and grasses, and (5) when the land cover is meadow, the lower the sand content in the soil, the lower the trace element concentrations. With a trace element’s bioavailability represented by its transfer factor (TF) from the soil to the grass, the TFs of the eight trace elements are not in the same orders for different grass species.

Heavy metals in canned tuna from Italian markets

Fish is a good source of nutrients for humans but can pose a risk to human health because of the possible presence of some xenobiotics such as heavy metals and persistent organic contaminants. Constant monitoring is needed to minimize health risks and ensure product quality and consumer safety. The aim of the present study was to use atomic absorption spectrometry to determine the concentrations of some heavy metals (Hg, Pb, and Cd) in tuna packaged in different kinds of packages (cans or glass) in various countries (Italy and elsewhere). Concentrations of Cd and Hg were within the limits set by European Commission Regulation (EC) No 1881/2006 and in many samples were below the detection limit. Pb concentrations exceeded European limits in 9.8% of the analyzed samples. These results are reassuring in terms of food safety but highlighted the need to constantly monitor the concentrations of heavy metals in fish products that could endanger consumer health.

First study on anthropogenic Pt, Pd, and Rh levels in soils from major avenues of São Paulo City, Brazil

Over the last years, investigations on the increase of platinum (Pt), palladium (Pd), and rhodium (Rh) levels in urban environments of big cities all over the world - especially to catalytic converters emissions - have been grown up enormously. São Paulo City is the 6th largest megacity in the world having about 20 million inhabitants and an ever increasing seven million motor vehicle fleet. In spite of this, there has never been an investigation regarding Pt, Pd, and Rh levels in the city. In the present study, Pt, Pd, and Rh concentrations were determined in soils adjacent to seven main high-density traffic avenues in the metropolitan region of São Paulo City. Inductively coupled plasma mass spectrometry was employed - after ultrasound-assisted aqua regia leaching - as analytical technigue. The results showed concentration levels up to 378 ng g(-1) for Pd, 208 ng g(-1) for Pt, and 0.2 to 45 ng g(-1) for Rh. These levels are much higher than those considered for the geochemical background of soils, indicating a catalytic converter source. Due to the different Pt/Pd/Rh ratio in Brazilian automobile catalytic converters, lower levels of Pt/Pd ratios compared with other similar studies were observed. The obtained results are the first data for monitoring Pt, Pd, and Rh pollution in São Paulo City soils.

Phytoforensics, dendrochemistry, and phytoscreening: new green tools for delineating contaminants from past and present

As plants evolved to be extremely proficient in mass transfer with their surroundings and survive as earth's dominant biomass, they also accumulate and store some contaminants from surroundings, acting as passive samplers. Novel applications and analytical methods have been utilized to gain information about a wide range of contaminants in the biosphere soil, water, and air, with information available on both past (dendrochemistry) and present (phytoscreening). Collectively these sampling approaches provide rapid, cheap, ecologically friendly, and overall "green" tools termed "Phytoforensics".