Marcelo Enrique Conti

Biological monitoring: lichens as bioindicators of air pollution assessment--a review.

Often as part of environmental impact studies and, above all, to obtain authorisations in accordance with prescriptions from the Ministry for the Environment (Italy), surveys and controls that use biological indicators are required. This is because such indicators are valid instruments for evaluating the quality of the air ensuing from the subject (often an industrial plant) of the Environmental Impact Assessment (EIA). In this context, this paper aims to analyse some of the theoretical aspects of biological monitoring and to provide a progress report on the use of lichens as bioindicators of air quality, with a particular eye to the situation in Italy. The object of this paper is that of pointing out the most important lines in the current state of knowledge in this field, evaluating the methodological applications and their advantages/disadvantages with respect to traditional surveying methods.

Honeybees and their products as potential bioindicators of heavy metals contamination

The concentrations of three representative heavy metals(cadmium, chromium and lead) were measured by atomic absorptionspectroscopy in honeybees and in apiarys products (honey,pollen, propolis, and wax). Samples were collected from fivedifferent sampling points: four from areas surrounding the cityof Rome, and the fifth in the city center which receives intensevehicular traffic. All apiaries employed for this study werespecifically constructed without any metal part in order toavoid the risk of contamination of the assayed materials.Sample collection was conducted over a 3-month period (6samplings for honey and pollen, 3 sampling for propolis and wax,2 samplings for honeybees, all of which were collected in duplicate). Experimental data revealed, in general,statistically significant differences between the backgroundlevels of heavy metals recorded from the reference sites and thelevels measured in the site located in the center of the city ofRome.These results indicate that honeybees and, to a lesser extent,some of their products (pollen, propolis, wax, but not honey),can be considered representative bioindicators of environmentalpollution.

Lazio region (central Italy) honeys: a survey of mineral content and typical quality parameters.

Abstract A survey of 84 samples of commercial honeys of different botanical origin, collected all over the Lazio region (central Italy) was carried out in order to assess their quality. Typical quality parameters of honey (pH, sugar content, moisture, water activity – aw), and mineral content (Na, K, Ca, Mg, Cu, Fe, Mn and Zn) were measured. Mean values for quality parameters were: pH, 4.32; sugars, 82.03 °brix; moisture, 16.57%; aw, 0.57. Mineral elements were determined by atomic absorption spectrometry. Potassium was the most abundant of the elements determined. The mean values were (μg/g wet wt): Na, 96; K, 472; Ca, 47.7; Mg, 37.0; Cu, 0.31; Fe, 4.51; Mn, 3.00; Zn, 3.14. The analytical results obtained on the Lazio honeys indicate a good level of quality and confirm the general image of healthy food associated with this product.

Size-dependent concentrations of trace metals in four Mediterranean gastropods

In order to gain more information on the possible use of four gastropod species as metal biomonitors for the Mediterranean area, the influence of body weight upon Cd, Cr, Cu, Pb and Zn concentrations was studied in specimens collected at locations with different degrees of environmental pollution. The selected species were the marine snails Monodonta turbinata Born and Monodonta mutabilis Philippi, and the limpets Patella caerulea L. and Patella lusitanica Gmelin. Significant differences between metal concentrations in individuals from different stations were tested by ANCOVA on log-transformed data with log body weight as covariate. For all species a positive correlation between metal concentrations and body weight was observed, which means that the largest individuals contained the highest levels of metals. The inclusion of body weight as covariate in the statistical analysis explained from 81% to 99% of the metal variability within the organisms and enabled the achievement of improvements in the detection of differences among sites. The four selected species provided a rather univocal picture of bioavailable metal loads at the different stations of the experimental area. Except for Cd, the metal concentrations recorded at the clean stations were found to lie in the range of the lowest values reported in the literature and can be employed as useful background levels which can be referred to for intraspecific comparison within the Mediterranean area. It is concluded that in view of its distribution, unambiguous identification, resistance to pollution and accumulation patterns M. turbinata has considerable potential as a biomonitor of trace metals over the Mediterranean.

Baseline Trace Metals in Seagrass, Algae, and Mollusks in a Southern Tyrrhenian Ecosystem (Linosa Island, Sicily)

Trace elements were analyzed in organisms collected at five sampling stations along coastal areas of Linosa Island, Sicily (southern Tyrrhenian Sea, Italy). Concentrations of Cd, Cr, Cu, Pb, and Zn were measured in Posidonia oceanica L. Delile tissues, the two brown algae Padina pavonica (L.) Thivy and Cystoseira sp., and the two gastropod mollusks Monodonta turbinata Born and Patella caerulea L. Seawater samples were also collected at each site to assess soluble metal concentrations and to gain relevant information on their bioaccumulation ability. Data were processed by multivariate techniques, such as principal component analysis (PCA) and linear discriminant analysis on PCA factors. The scoreplots obtained showed that the pollutant distribution is more significantly correlated with species than with sites. For seaweeds, P. oceanica was associated with higher Cd, Cu, and Zn levels; Padina species had higher Cr concentrations, and Cystoseira had higher Pb levels. For mollusks, Monodonta species had high concentrations of Cu and Cr and Patella species were associated with Cd. Some general metal bioaccumulation patterns are described but no one sampling site was more contaminated than the others. The hypothesis of Linosa island serving as a reference ecosystem for baseline trace metal levels in southern Tyrrhenian areas is indeed supported by the statistical comparison among other southern Tyrrhenian ecosystems performed with Kruskall Wallis and Mann-Whitney tests. For P. oceanica leaves, P. pavonica, M. turbinata, and P. caerulea, this study confirms their usefulness as possible cosmopolitan biomonitors of trace metals in marine Mediterranean areas.

A biomonitoring study: trace metals in seagrass, algae and molluscs in a marine reference ecosystem (Southern Tyrrhenian Sea)

Marine organisms were tested as possible biomonitors of heavy metal contamination in Ustica (island of the Southern Tyrrhenian Sea). The concentrations of Cd, Cr, Cu, Pb and Zn were measured in the phanerogam Posidonia oceanica L. Delile, the two brown algae Padina pavonica (L.) Thivy and Cystoseira sp., and the two gastropod molluscs Monodonta turbinata Born and Patella caerulea L. collected at five coastal stations on the island of Ustica. The biomonitors examined showed a high ability to accumulate metals, with concentration factors higher than 10³, with respect to the concentration (soluble fraction) in marine waters. The data from this study were also compared with those previously obtained from uncontaminated sites in the Sicilian sea (Favignana island, Italy) and those obtained from the area of the Gulf of Gaeta (Tyrrhenian Sea, central Italy). Results clearly show the diversity between these three marine ecosystems.

Algae as biomarkers, bioaccumulators and toxin producers

Uncontrolled accumulation of wastes in marine environments involves an increase in organic substances and/or nutrients, as well as toxicity. The consequences of this enrichment for the homeostasis of ecosystems are unpredictable. The best studied consequence of such enrichment is eutrophication (Conti, 1996). Natural or anthropogenic eutrophication is the enrichment of a water body in nutrients, utilisable by algae. Sources of these nutrients are the atmosphere, rivers, soil erosion and runoff from catchment areas, sewage, industrial effluents, fertilizers, and waste disposal from animal farms. Mathematical models predicting pollutant dispersion and pollutant bioavaibility may make a substantial contribution to the study of the marine pollution phenomena and may be a valuable tool for the description of the pollution flux (Benedini and Cicioni, 1992). Generally, mathematical models refer to the propagation and transport of particular pollutants originating from one-point contamination sources and also in this case need a broad spectrum of experimental data. This requirement is particularly true for sea ecosystems, owing to the large number of required variables and to the various effects on different species and ecosystems. For these reasons, biomonitoring programmes in sea environments are very important. Establishing the pollutant level in organisms may help to evaluate the possible toxicity for various species at different levels of the trophic chain.

Lichen Usnea barbata as biomonitor of airborne elements deposition in the Province of Tierra del Fuego (southern Patagonia, Argentina).

Lichen Usnea barbata was tested as a possible biomonitor of atmospheric deposition in a supposedly pristine environment Tierra del Fuego (Argentina). Lichen samples were collected in 2005 and again in 2006 in 71 sites covering almost the entire region. The aim of the study was to evaluate the bioaccumulation of 26 elements in order to define the background levels in the region. The quantification was carried out by the sector field inductively coupled plasma mass spectrometry. No relevant temporal accumulation patterns between 2005 and 2006 sampling campaigns were observed. Then, the results were submitted to multivariate statistical analysis (cluster and principal component analyses). Cluster analysis produced a dendrogram where the 71 sites were divided into four clusters at (Dlink/Dmax)100<30. The areas and the elements were correlated according to the element concentrations by principal component analysis. Four significant components that accounted for 67% were obtained. Cluster 1 was mainly composed of sites of Ushuaia-Road 3 (E area) and it was characterized by high levels of Cd, Co, Ni, Pb, Sb, and W in lichens. The present study has revealed the good capacity of U. barbata to reflect the baseline levels of elements in the environment at a regional scale level. The presence of certain level of elements in lichens agrees with the hypothesis that Tierra del Fuego is not a relatively pristine environment as occasionally supposed. However, when comparing our results with other countries, Tierra del Fuego lichens have a very low content of the measured elements.

Simple, fast, and low-contamination microwave-assisted digestion procedures for the determination of chemical elements in biological and environmental matrices by sector field ICP-MS

A simple and convenient method for the digestion of animal tissues, lichens, and plants for 33 metals measured by sector field inductively coupled plasma mass spectrometry (SF-ICP-MS) was described. Microwave-assisted acid digestions were performed at atmospheric pressure by means of a multi-samples rotor designed for processing a large number of samples at once in screw-capped disposable polystyrene liners. The digested samples were filled up to final volume directly in the polystyrene liners ready for elemental quantification. Seven certified reference materials, namely BCR 184 (bovine muscle), BCR 186 (pig kidney), DORM-2 (dogfish muscle), BCR 422 (cod muscle), BCR 62 (olive leaves), BCR 100 (beech leaves), and BCR 482 (lichen) were analysed to verify the accuracy of the method. The linearity range, limit of quantification, precision, and recovery by addition of non-certified elements were also assessed. All elements, with the exception of Hg in BCR 184 and As in BCR 186, were above the quantification limit and blank concentrations, and good agreement existed between found and target values in bovine muscle, pig kidney, and cod muscle. Significant deviations were observed for Al, Co, Cr, Mn, and Ni in dogfish muscle and for Ca, Cr, Fe, and Hg in lichens and plants. The proposed digestion procedure offers a low contamination risk, simplicity, speed, low cost, and applicability in routine analysis, and the SF-ICP-MS method allowed metals from a fraction of ng g−1 to hundreds of µg g−1 to be quantified in one analytical run.

A statistical approach applied to trace metal data from biomonitoring studies

This work underlines the importance of the statistical procedures necessary for the significant assessment of analytical data of heavy metals derived from marine organisms (biomonitors) collected at five stations in Ustica at the Southern Tyrrhenian Sea. The statistical method described indicates that, where the differences among the averages of Pb, Cu and Zn concentrations in the molluscs of the sites analysed tested with ANOVA are significant, it is necessary to conduct multiple comparison tests in order to determine which average is significantly different from the other. Using the method described, it is possible to indicate which site or sites is/are more contaminated in comparison with the other sites. This way it is possible to make a preliminary evaluation of the basal levels of trace metals present in the reference marine ecosystem under study.