Lilyana Yurukova

Mosses as biomonitors of atmospheric heavy metal deposition: Spatial patterns and temporal trends in Europe

In recent decades, mosses have been used successfully as biomonitors of atmospheric deposition of heavy metals. Since 1990, the European moss survey has been repeated at five-yearly intervals. Although spatial patterns were metal-specific, in 2005 the lowest concentrations of metals in mosses were generally found in Scandinavia, the Baltic States and northern parts of the UK; the highest concentrations were generally found in Belgium and south-eastern Europe. The recent decline in emission and subsequent deposition of heavy metals across Europe has resulted in a decrease in the heavy metal concentration in mosses for the majority of metals. Since 1990, the concentration in mosses has declined the most for arsenic, cadmium, iron, lead and vanadium (52-72%), followed by copper, nickel and zinc (20-30%), with no significant reduction being observed for mercury (12% since 1995) and chromium (2%). However, temporal trends were country-specific with sometimes increases being found.

Nitrogen concentrations in mosses indicate the spatial distribution of atmospheric nitrogen deposition in Europe

In 2005/6, nearly 3000 moss samples from (semi-)natural location across 16 European countries were collected for nitrogen analysis. The lowest total nitrogen concentrations in mosses (<0.8%) were observed in northern Finland and northern UK. The highest concentrations (≥ 1.6%) were found in parts of Belgium, France, Germany, Slovakia, Slovenia and Bulgaria. The asymptotic relationship between the nitrogen concentrations in mosses and EMEP modelled nitrogen deposition (averaged per 50 km × 50 km grid) across Europe showed less scatter when there were at least five moss sampling sites per grid. Factors potentially contributing to the scatter are discussed. In Switzerland, a strong (r(2) = 0.91) linear relationship was found between the total nitrogen concentration in mosses and measured site-specific bulk nitrogen deposition rates. The total nitrogen concentrations in mosses complement deposition measurements, helping to identify areas in Europe at risk from high nitrogen deposition at a high spatial resolution.

Country-specific correlations across Europe between modelled atmospheric cadmium and lead deposition and concentrations in mosses

Previous analyses at the European scale have shown that cadmium and lead concentrations in mosses are primarily determined by the total deposition of these metals. Further analyses in the current study show that Spearman rank correlations between the concentration in mosses and the deposition modelled by the European Monitoring and Evaluation Programme (EMEP) are country and metal-specific. Significant positive correlations were found for about two thirds or more of the participating countries in 1990, 1995, 2000 and 2005 (except for Cd in 1990). Correlations were often not significant and sometimes negative in countries where mosses were only sampled in a relatively small number of EMEP grids. Correlations frequently improved when only data for EMEP grids with at least three moss sampling sites per grid were included. It was concluded that spatial patterns and temporal trends agree reasonably well between lead and cadmium concentrations in mosses and modelled atmospheric deposition.

Heavy metal and nitrogen concentrations in mosses are declining across Europe whilst some “hotspots” remain in 2010

In recent decades, naturally growing mosses have been used successfully as biomonitors of atmospheric deposition of heavy metals and nitrogen. Since 1990, the European moss survey has been repeated at five-yearly intervals. In 2010, the lowest concentrations of metals and nitrogen in mosses were generally found in northern Europe, whereas the highest concentrations were observed in (south-)eastern Europe for metals and the central belt for nitrogen. Averaged across Europe, since 1990, the median concentration in mosses has declined the most for lead (77%), followed by vanadium (55%), cadmium (51%), chromium (43%), zinc (34%), nickel (33%), iron (27%), arsenic (21%, since 1995), mercury (14%, since 1995) and copper (11%). Between 2005 and 2010, the decline ranged from 6% for copper to 36% for lead; for nitrogen the decline was 5%. Despite the Europe-wide decline, no changes or increases have been observed between 2005 and 2010 in some (regions of) countries.

Water pollutant monitoring with aquatic bryophytes: a review

Bryophytes are non-vascular plants with large biomass and high production level in freshwaters. Aquatic bryophytes are used to assess the ecological status. They are a stress-tolerant group, and many species have a wide trophic range. Aquatic bryophytes are used as indicators by the presence or absence of a pollutant, or as monitors to measure pollutant concentrations. Here, we review major advances in bryomonitoring from a range of countries, mainly in Europe. Monitored elements include Ba, Cd, Cr, Cu, Co, Ni, Pb, Zn, Fe, Mn, V, 137Cs, 134Cs, 235U, 236Ra, 232Th and 40K. We illustrate the advantages of low-cost methods for monitoring water quality. Biomonitoring includes (1) passive observation and analysis of native bryophytes and (2) active biomonitoring based on species transplantation for a fixed exposure period. Two widespread northern hemisphere aquatic mosses, Fontinalis antipyretica and Platyhypnidium riparioides, are the most common biomonitors.

Assessment of Pollution with Aquatic Bryophytes in Maritsa River (Bulgaria)

Bryophyte species composition and 26 common physico-chemical and inorganic chemical parameters were assessed at 23 selected sites in the Maritsa River (BG) over a 4-year period. Principal components analyses (PCA) of both bryophytes and water variables distinguished different locations in the ecosystem. The data imply that the content of elements measured in bryophytes represents river contamination, while species compositional patterns reflect hydromorphology and general degradation. This study for the first time combined aquatic bryophyte occurrence, the bioaccumulation of 17 macro-and microelements in 17 species, and 26 water factors by principal components analysis (PCA) in an assessment of river pollution.

Possibilities of using deciduous tree species in trace element biomonitoring in an urban area (Plovdiv, Bulgaria)

Leaves of Acer platanoides L., Aesculus hippocastanum L. and Betula pendula Roth. were collected from urban sites with different anthropogenic impact in the city of Plovdiv (Bulgaria). Concentrations of Cd, Cr, Cu, Fe, Pb and Zn in foliage samples were analyzed by ICP–MS. Three studied deciduous trees clearly showed variations in element concentrations depending on the sampling site (Pb, Fe, Cr) and the plant species (Zn). Betula pendula was found to be a better bioaccumulator for the elements Cr, Cd, and especially for Zn. Our approach could be successfully applied in the monitoring of air pollution due to trace elements in urban areas, regardless of their size and topography.

Cross-border response of mosses to heavy metal atmospheric deposition in Southeastern Bulgaria and European Turkey

First cross-border atmospheric pollution of 11 heavy metals and toxic elements assessed by Hypnum cupressiforme was reported for a part of Southeastern Europe (Southeastern Bulgaria and European Turkey). Moss monitoring technique followed the main requirements of European Moss Survey. Moss samples were collected in April 2006 both in Bulgaria and Turkey. Concentration of Al, As, Cd, Cr, Cu, Fe, Ni, Pb, Sb, V, and Zn were determined by ICP-AES. Interlaboratory parallel calibration (exchanged four moss samples from each country), standard reference moss materials (M2 and M3) results ensured the study. ANOVA showed no differences between measured results in both laboratories at the 99% confidence level. Principle Component Analyze proved two factors: F1 group of Al, As, Cd, Cr, Fe, Ni, and V and F2 of Cu, Pb, and Zn as main atmospheric pollutants. Results obtained showed approximately Cu and Pb high concentrations around Istanbul and Burgas and Zn pollution in Istanbul district. Arsenic cross-border atmospheric pollution in the study area of Southeastern Europe was found.

Monitoring of aquatic mosses and sediments: a case study in contaminated rivers, Bulgaria

Aquatic mosses and sediments were monitored along Topolnitsa River Basin (Bulgaria), copper-producing and mining region. Six mosses were applied as biomonitors: Bryum turbinatum, Fontinalis antipyretica, Leptodictyum riparium, Platyhypnidium riparioides, Rhizomnium punctatum and Sciuro-hypnum plumosum. Background levels were determined for both plants and fine fraction of sediments collected from an unpolluted site. Contamination factors (CFs) and metal pollution index at each site were presented. The highest sediment enrichment with toxic elements was found in Zlatishka River. Strong increase above background levels showed all 13 heavy metals and toxic elements in biomonitors from stations at Zlatishka and Pirdopska rivers. The two moss species adopted as biomonitors for the first time – Bryum turbinatum and Rhizomnium punctatum – showed high CFs for several heavy metals and contributed to chemical pollution pattern assessment. The parallel use of mosses and sediments in the monitoring study, as well as the applied statistical tools, led to the conclusion that mosses as higher plants revealed pollution patterns not detected by sediments. Results also showed that in a seriously contaminated aquatic environment, which requires rapid assessment, different moss species can be applied for water-monitoring purposes to present preliminary picture of pollution patterns and to direct further studies.

Distribution and Bioindication Role of Aquatic Bryophytes in Bulgarian Rivers

ABSTRACT The distribution and abundance of aquatic bryophytes, and 10 physico-chemical parameters of river water have been studied in 204 river sites in Bulgaria, 15 river types. Forty-nine bryophyte species were registered at 51 sites. The commonest species were Platyhypnidium riparioides, Fontinalis antipyretica, Brachythecium rivulare and Leptodictyum riparium. Principal component analysis revealed that the sites with higher abundance of Leptodictyum riparium were in inverse correlation with sites where the rest 3 species occurred. Canonical correspondence analysis indicated that 9 of the 10 selected environmental parameters significantly influenced bryophytes distribution. The study comprised and analyzed data from macrophyte surveys in Bulgaria undertaken as a part of two EU-funded projects during 2009.