Gana Gecheva

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.

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.

Development of Classification System and Biological Reference Conditions for Bulgarian Rivers and Lakes According to the Water Framework Directive

ABSTRACT The study focused on sampling procedures and analysis of biological and physico-chemical quality elements (according to the EU Water Framework Directive (WFD)) and aimed at defining reference conditions and sites, maximum ecological potential, specific physico-chemical and hydromorphological conditions for assessed surface water types of “rivers” and “lakes” categories. Biological quality elements (BQE) and their metrics were selected in compliance with WFD requirements and its additional guidelines. All five compulsory BQEs were surveyed (phytoplankton, macrophyte flora, phytobenthos, macrozoobenthos, fish fauna) towards establishing rivers and lakes ecological status and potential. Current research indicates a certain necessity for integration of all assessments and analysis of ecological status/potential and their direct link to the measurement and monitoring programmes in Bulgaria.

Ecological status assessment of Skalenski Lakes (Bulgaria)

Over the past decade new ecological indices based on phytoplankton and macrophytes were developed as part of the tools for assessment of the ecological status of water bodies. This study demonstrates the applicability of two of them (Assemblage index /Q/ and Algae Group Index /AGI/) for evaluation of water bodies from a lake type L4 as well as their comparability. Assessment of the ecological status of two lake ecosystems was performed in order to ensure successful protection, enhancement and management of lowland and semi-mountain lakes in Bulgaria. Data on the aquatic flora from Golyamo Skalensko Lake and Malko Skalensko Lake over a period of two years were used to assess their ecological status. In addition, the toxic potential of the established dominant cyanoprokaryotic species was also evaluated. Phytoplankton- and macrophyte-based metrics resulted in complementary evaluation of temporary and long-term environmental conditions. Despite the hydraulic connection and proximity between the two lakes, Golyamo Skalensko Lake and Malko Skalensko Lake appear as completely different ecosystems, according to the phytoplankton structure (species composition, number of species, abundance, seasonal succession), macrophytes and ecological status.

Phytoplankton Based Assessment of the Ecological Status and Ecological Potential of Lake Types in Bulgaria

ABSTRACT Research has been carried out of the main characteristics of phytoplankton communities in order to assess the ecological status and ecological potential of the types of lakes in Bulgaria, according to the requirements of WFD 2000/60/EC. Eighty lakes/reservoirs have been researched on the territory of the Republic of Bulgaria. The assessment was made on the basis of four main metrics (phytoplankton biovolume; Algae Groups Index; transparency, chlorophyll a) and three additional metrics (% Cyanobacteria; intensity of algal “bloom” and presence of toxic species). More than half of the researched lakes in Bulgaria are in compliance with the WFD requirements for good ecological state (high and good ecological status, maximum and good potential). A classification system for assessment of ecological status or potential has been developed using above-mentioned phytoplankton metrics. The existing 17 types of lake in Bulgaria are classified in two main groups: oligotrophic lake types and mesotrophic lake types.

Bryophyte communities’ responses to environmental factors in highly seasonal rivers

Abstract Historically, in river ecosystems close attention has been paid to aquatic vascular macrophytes, but recent literature shows the important role of bryophytes, especially in undisturbed conditions. For this reason, we explore whether aquatic bryophyte patterns change in altered physical habitats and in eutrophication along highly seasonal streams in Bulgaria. Specifically, we hypothesize that: (i) bryophyte assemblage patterns change in conditions of hydromorphological degradation and eutrophication; and (ii) bryophyte assemblage patterns can serve as a signal in assessing effects of nutrient enrichment and hydromorphological degradation. Biological data were collected for 30 river sites together with catchment land use, hydromorphological alterations (e.g. channelization, alteration of habitat and riparian vegetation, dykes), main abiotic characteristics of each site (flow velocity, substrate type, shading and mean depth) and water chemistry parameters.The data set mentioned above was used to describe the responses of bryophyte communities to two major pressures in rivers resulting in habitat destruction: hydromorphological alterations and eutrophication. The results clearly reflected that habitat degradation led to particular changes in the species-abundance patterns of bryophyte communities. Both studied pressure types resulted in loss of species and decreased bryophyte abundance. Hydromorphological degradation could be distinguished by morphological growth forms: presence of mosses of a more plastic shape (creeping pleurocarps), whereas eutrophication favours only the mesotrophic preferential Leptodictyum riparium. This moss should be applied as a conceptual signal species, the abundance of which indicates ranges of hydromorphological and nutrient pressure in seasonal rivers.

Water Quality Monitoring by Aquatic Bryophytes

Bryophytes are non-vascular plants that are in a close relationship with their immediate environment. They often have large biomass in freshwater ecosystem and high level of production. Moreover, their tissues contain elevated amount of C, N and P, and cell walls have high cation exchange capacity. Aquatic bryophytes can be used to assess freshwater pollution as indicators – presence or absence of species – or as monitors for accumulating elements. Consumption of metals and other substances by aquatic bryophytes is an important exposure pathway for consumers. The use of bryophytes for water quality assessment is well documented, but different techniques and approaches prevent standardization and their applicability on the European scale. Thus we review major findings in ‘bryomonitoring’. Data were reviewed from a range of countries, mainly in Europe, illustrating the advantages of low cost methods for monitoring water quality.