Evaluation of DNA damage in the root cells of Allium cepa seeds growing in soil of high background radiation areas of Ramsar – Iran

Plants are unique in their ability to serve as in situ monitors for environmental genotoxins. We have used the alkaline comet assay for detecting induced DNA damage in Allium cepa to estimate the impact of high levels of natural radiation in the soils of inhabited zones of Ramsar. The average specific activity of natural radionuclides measured in the soil samples for ²²⁶Ra was 12,766 Bq kg⁻¹ whereas in the control soils was in the range of 34–60 Bq kg⁻¹. A positive strong significant correlation of the DNA damage in nuclei of the root cells of A. cepa seeds germinated in the soil of high background radiation areas with ²²⁶Ra specific activity of the soil samples was observed. The results showed high genotoxicity of radioactively contaminated soils. Also the linear increase in the DNA damage indicates that activation of repair enzymes is not triggered by exposure to radiation in HBRA.     

Intraspecific variation in Melandrium album along a radioactive contamination gradient at the Eastern Ural radioactive trace

Specific ecogenetic features of plants and parameters of seed progeny have been studied in Melandrium album cenopopulations from test plots established along the radioactive contamination gradient in the zone of the Eastern Ural Radioactive Trace (EURT), where absorbed radiation doses in buffer and impact plots exceeded the background level by factors of 2–18 and 330–418, respectively. It has been shown that interannual variation in parameters characterizing the viability of seed progeny largely depends on fluctuations of weather conditions. This dependence is more distinct in cenopopulations from the EURT than in control samples, which is indicative of interaction between radiation and other relevant ecological factors. The radioresistance of seed progeny is contingent on its viability, being independent of radiation load at the sites of maternal plant growth. Hermaphrodite plants occur only in irradiated M. album cenopopulations. This character is inherited: all F ₁ descendants of such plants grown in a vegetation experiment had hermaphrodite flowers. The mutability of seed progeny formed in the EURT zone exceeds the background level. The occurrence and frequencies of recorded anomalies has proved to vary by years and, therefore, can be interpreted as nonheritable modifications.     

Bioindication-based Estimation of Technogenic Impact on <Emphasis Type="Italic">Pinus sylvestris</Emphasis> L. Populations in the Vicinity of a Radioactive Waste Storage Facility

The spectrum and frequency of cytogenetic aberrations in the reproductive (seeds) and vegetative (foliage) organs of Scotch pine (Pinus sylvestris L.) have been studied in the vicinity of the LSK Radon facility for radioactive waste storage and processing and in a 30-km zone around the Chernobyl Nuclear Power Plant. The results indicate that the pine populations of these regions are exposed to mutagenic factors. In contrast to the 30-km Chernobyl zone, the increased environmental mutagenicity in the vicinity of LSK Radon and in the center of the city of Sosnovyi Bor is mainly accounted for by chemical factors. The results of additional acute γ-irradiation have shown an increased radiation resistance of Scotch pine seeds from the LSK Radon and Sosnovyi Bor populations. Regression analysis demonstrated a significant increase in the cytogenetic aberration rate in plants from the experimental plots throughout the study period (1997–2002).__________Translated from Ekologiya, No. 4, 2005, pp. 275–285.Original Russian Text Copyright © 2005 by Geras’kin, Vasil’ev, Dikarev, Udalova, Evseeva, Dikareva, Zimin.     

Population exposure to airborne thorium at the high natural radiation areas in India

High natural radiation areas in the coastal and peninsular India were studied for airborne thorium and resultant population exposure due to inhalation. Four locations covering three states viz., Ayiramthengu and Neendakara in Kerala, Kudiraimozhi in Tamil Nadu and Bhimilipatnam in Andhra Pradesh were investigated. External gamma radiation fields 1 m above the monazite ore bodies ranged from 200 to 3000 nGy h^-1. Soil samples showed ²³²Th specific activity varying from 0·1 to 1·5 Bq g^-1 with surface alpha activity in the range of 1·0–12·5 Bq cm^-2. Suspended particulates in the samples ranged from 60–140 μg m^-3 with ²³²Th showing a wider variation of <0·03–0·3 mBq m^-3. There was poor correlation between suspended particulates and long-lived alpha airborne activity . The resuspension factors for ²³²Th were in the range of 1·5×10^-8–7·9×10^-7 cm^-1. Higher resuspension was correlated with dry sand dunes. The upper limits for Committed Effective Dose (CED) due to inhalation of airborne ²³²Th at the respective high natural radiation areas were estimated to range from 50±30 to 300±130 μSv (5–30 mrem) per year per adult member of public assuming an activity median aerodynamic diameter of 1 μm for the airborne particulates.     

Recent Levels of Radionuclide Contamination in the Eastern Ural Radioactive Trace and Biological Effects in Local Populations of <Emphasis Type="Italic">Plantago major</Emphasis> L.

The results of the study have shown that the stocks of ⁹⁰Sr and ¹³⁷Cs in the frontal part of the EURT are 6700–15000 and 200–400 kBq/m², respectively. The coefficients of their accumulation in different herbaceous plant species in this impact zone are lower than in other areas. The accumulative capability of plants has probably decreased in the course of selection as an adaptation to the effect of radiation. The viability and growth parameters of Plantago major L. seeds from the EURT zone are similar to those of seeds from the background sample. Cenopopulations chronically exposed to radiation are characterized by a higher mutation rate in the progeny and an unstable response to additional acute irradiation in most characters studied. A high level of inbreeding is observed in all P. major cenopopulations of plantain. The cenopopulation of the impact zone is characterized by a lower variation of allozyme loci, which may be a result of stringent selection for individuals better adapted to the complex of conditions existing in its habitat.     

Dynamics of Yielding Capacity of Small Cranberry in Southern Karelia

The dynamics of yielding capacity of small cranberry (Oxycoccus palustris Pers.) were studied in three permanent sampling plots in a natural bog in southern Karelia for 28 years (1975–2002). The yield of berries varied from year to year from 1 to 179 g/m² depending on phytocenotic and, to a greater extent, climatic factors. The proportion between the number of ripe berries and the number of flowers varied from 10 to 66%. No distinct periodicity in the abundance of fruiting was revealed.__________Translated from Ekologiya, No. 4, 2005, pp. 264–268.Original Russian Text Copyright © 2005 by Yudina, Maksimova.     

Competition between the Rotifers Brachionus patulusand Euchlanis dilatata:Effect of Algal Food Level and Relative Initial Densities of Competing Species

We tested the effect of different algal (Chlorella vulgaris) levels and inoculation densities on the outcome of competition between the rotifers Euchlanis dilatata and Brachionus patulus. The experiment was performed in 36 transparent jars, each with 20 ml of a test medium. We used three Chlorella levels: 0.75 × 10⁶, 1.5 × 10⁶, and 3.0 × 10⁶ cells/ml. For each algal level, we used five different ratios of initial inoculation density. The population growth experiments were terminated after 19 days. Regardless of inoculation densities, an increase in food level resulted in an increased population abundance of both rotifer species. Regardless of food concentration,E. dilatatawas able to outcompete B. patulus at all inoculation densities when grown together. However, when Chlorella was offered in low concentration and there was a higher ratio of Brachionus to Euchlanis at the onset of the experiment, both rotifer species coexisted in more or less equal densities until the end of the experiments. When the food level was enhanced, E. dilatata totally eliminated B. patulus. The rate of population growth ranged from 0.002 to 0.578 for B. patulus and from 0.006 to 0.447 for E. dilatata. The results are discussed with respect to the factors influencing the outcome of competition between species.     

Environmental monitoring using surface water, river sediments, and vegetation: A case study in the Famatina Range, La Rioja, NW Argentina

This work discusses trace elements studied beneath the semiarid endorheic region of the Famatina Range (La Rioja, NW Argentina). The results obtained in 27 control sites allow the determination of five distinct geochemical patterns in the Famatina Range. Pattern 1 reflects the composition of underlying Paleozoic and Tertiary bedrock (background level: water pH, 7.5–9; specific conductance, 0.2–0.7 mS cm⁻¹), which is influenced by mineralization. Pattern 2 exhibits water pH, 6; specific conductance, 0.7 mS cm⁻¹; high contents of Cu, Cd, Rb, Zn, Sn, and Be in waters; and high contents of Cu, Cd, Zn, Pb, Cr, Sb, Ag, Be, Co, Ni, Bi, Rare Earth Elements (REE), Li, Ba, Cs, and Sr in sediments. Pattern 3 exhibits water pH, 3–4; specific conductance, 1.0 mS cm⁻¹; high contents of Pb, Co, Be, Au, As, Cr, Hg, Th, Ba, Cs, Rb, Sb, Y, Zr, REE, and Hf in waters; high contents of Cd, Zn, Mo, and As in sediments). Pattern 3 is also modified by the input of elements from a source external to the Famatina Range. Pattern 4 exhibits water pH, 7–8; specific conductance, 1.5–2.3 mS cm⁻¹; high contents of B, Li, Ba, Sr, and Zn in waters; high contents of Li, Cr, Sr, Ni, and Cs in sediments. Finally, Pattern 5 is developed on the red sandstones from De la Cuesta Formation (water pH, 8; specific conductance, 2.5–5.0 mS cm⁻¹; high contents of Sr, Mo, U, B, Li, Rb, and Hf in waters; high contents of B, Ba, Cs, Li, and Rb in sediments). The mobility of above-mentioned elements is mainly related to water pH changes and evaporation processes.     

Heterotrophic Nano- and Microplankton under Conditions of Anthropogenic Eutrophication of the Bay of Novorossiisk

Seasonal and long-term dynamics of heterotrophic plankton in the Bay of Novorossiisk are discussed. It is shown that specific variation in the biomass of nanoheterotrophs and infusoria is associated with the processes of anthropogenic water eutrophication. The biomass of infusoria has increased ten times and that of zooflagellates two times since 1985–1986. Infusoria of the genera Strombidium, Strobilidium, and Mesodiniumare dominant in the protozoan plankton. The annual average level of Oligotrichadevelopment in the bay is characteristic of eutrophic water bodies (112–417 mg/m³); in the spring–summer season, however, it may increase to 500–1034 mg/m³. In the part of the bay near the port, which is exposed to a strong anthropogenic impact, the biomass of ciliate protozoa can reach 2 g/m³.     

Isotope tracing of submarine groundwater discharge offshore Ubatuba, Brazil: results of the IAEA–UNESCO SGD project

Results of groundwater and seawater analyses for radioactive (³H, ²²²Rn, ²²³Ra, ²²⁴Ra, ²²⁶Ra, and ²²⁸Ra) and stable (D and ¹⁸O) isotopes are presented together with in situ spatial mapping and time series ²²²Rn measurements in seawater, direct seepage measurements using manual and automated seepage meters, pore water investigations using different tracers and piezometric techniques, and geoelectric surveys probing the coast. This study represents first time that such a new complex arsenal of radioactive and non-radioactive tracer techniques and geophysical methods have been used for simultaneous submarine groundwater discharge (SGD) investigations. Large fluctuations of SGD fluxes were observed at sites situated only a few meters apart (from 0 cm d⁻¹ to 360 cm d⁻¹; the unit represents cm³/cm²/day), as well as during a few hours (from 0 cm d⁻¹ to 110 cm d⁻¹), strongly depending on the tidal fluctuations. The average SGD flux estimated from continuous ²²²Rn measurements is 17 ± 10 cm d⁻¹. Integrated coastal SGD flux estimated for the Ubatuba coast using radium isotopes is about 7 × 10³ m³ d⁻¹ per km of the coast. The isotopic composition (δD and δ¹⁸O) of submarine waters was characterised by significant variability and heavy isotope enrichment, indicating that the contribution of groundwater in submarine waters varied from a small percentage to 20%. However, this contribution with increasing offshore distance became negligible. Automated seepage meters and time series measurements of ²²²Rn activity concentration showed a negative correlation between the SGD rates and tidal stage. This is likely caused by sea level changes as tidal effects induce variations of hydraulic gradients. The geoelectric probing and piezometric measurements contributed to better understanding of the spatial distribution of different water masses present along the coast. The radium isotope data showed scattered distributions with offshore distance, which imply that seawater in a complex coast with many small bays and islands was influenced by local currents and groundwater/seawater mixing. This has also been confirmed by a relatively short residence time of 1–2 weeks for water within 25 km offshore, as obtained by short-lived radium isotopes. The irregular distribution of SGD seen at Ubatuba is a characteristic of fractured rock aquifers, fed by coastal groundwater and recirculated seawater with small admixtures of groundwater, which is of potential environmental concern and has implications on the management of freshwater resources in the region.     

Effect of Climatic Changes on the Formation of Siberian Spruce Generations in Subglotsy Tree Stands of the Southern Urals

The correlation between climatic changes and the numbers of trees in the generations of Siberian spruce (Picea obovata Ledeb.) in subgoltsy tree stands of the Southern Urals was analyzed over the past 200 years. The results showed that the most abundant generations appeared in 1809–1816, 1821–1827, 1839–1845, 1850–1867, 1875–1887, 1891–1896, 1900–1904, 1911–1918, 1923–1932, 1944–1952, 1958–1966, and 1975–1995. Their formation proved to be related to the improvement of thermal conditions of the warm season during the five to seven years before and after the emergence of trees and conditions of the cold season in the year of their emergence, as well as to the periods of increased snow depth in late April in the years 27–32 of tree growth.     

Growth response of Scenedesmus to different concentrations of copper, cadmium, nickel, zinc, and lead

The fresh water alga Scenedesmus was cultured in graded concentration of Cu, Cd, Ni, Zn, and Pb to evaluate the effect of these cations on the growth response of Scenedesmus. The effective concentration of metal which depressed the Scenedesmus growth for Cu was 0.5 mg l⁻¹, for Cd 0.5 mg l⁻¹, for Ni 2 mg l⁻¹, and for Zn 2 mg l⁻¹. The alga exhibited tolerance for high Pb concentrations up to 30 mg l⁻¹. Exposure of a Scenedesmus cell to each metal revealed anatomical changes and chloroplast disruption especially at high metal concentrations.     

Mercury in algae of the Canary Islands littoral

The concentrations of Hg in three groups of algae (Phaeophyta, Chlorophyta, and Rhodophyta) found in the Canary Islands littoral were determined. The mean concentrations found were, respectively: Phaeophyta: 0.13 mg kg⁻¹ (range 0.01 to 2.30 mg kg⁻¹); Chlorophyta: 0.13 (range 0.025 to 0.36 mg kg⁻¹); Rhodophyta: 0.11 mg kg⁻¹ (range 0.02 to 0.28 mg kg⁻¹). There are no relevant differences in the contents of Hg at group level and at species level, only a sample of Phaeophyta presents an abnormally high concentration (>1 mg kg⁻¹), corresponding to a sampling station nearby an urban drain.     

Phenogenetic Analysis of Pygmy Wood Mouse (Apodemus uralensis Pall.) Populations in the Zone of the Eastern Ural Radioactive Trace (EURT)

Monitoring of A. uralensis populations in Kamenskii raion, Sverdlovsk oblast, in 1992–2002 and in Kaslinskii raion, Chelyabinsk oblast, in 2000–2001 revealed an increase in the proportion and diversity of minor morphogenetic aberrations and abnormalities in the structure of the cranium along the axis of the Eastern Ural Radioactive Trace (EURT). The samples from the southern and northern parts of the EURT (contaminated with ⁹⁰Sr to 500 and 4 Ci/km², respectively) were characterized by directed deviations from the control with respect to the frequencies of phenes of nonmetric cranial traits and an increase in the level of their fluctuating asymmetry in young females, which is indicative of epigenetic rearrangements in populations living in a radioactive environment.     

Intrapopulation Differentiation by the Rates of Rosette Growth and Individual Plant Development in Narrow-Leaved Hawk’s Beard (<Emphasis Type="Italic">Crepis tectorum</Emphasis> L.): Aftereffects of Long-Term Stress

Aftereffects of exposure to long-term chemical pollution with fluorine and sulfur compounds on intrapopulation differentiation of the rates of growth and development has been studied on Crepis tectorum L. progenies obtained from seeds collected in a pollution gradient and grown in a greenhouse under uniform ecological conditions. The results have shown that long-term stress (exposure to toxic gaseous pollutants) leads to significant changes in the intrapopulation structure, which are manifested in an increase in the proportion of plants with a low rate of development, a low relative rate of the linear growth of metameres (leaves), but a higher relative rate of their formation.__________Translated from Ekologiya, No. 4, 2005, pp. 243–251.Original Russian Text Copyright © 2005 by Trubina.     

Comparative Assessment of the Effects of Livestock Grazing and Periodic Cutting on Steppe Plants of Tuva

A comparative study of the effects of heavy grazing load and periodic low cutting of above-ground phytomass on three plant species—Carex pediformis, Iris humilis, and Artemisia frigida—was performed in central Tuva in 1985–1989. Similar changes in the size of anatomical structures and ecophysiological characteristics of steppe plants were observed under the impact of both factors. They included signs of accelerated aging combined with adaptive reactions aimed at the most rapid development of shoots after the cessation of stress.     

Composition and Some Ecological Features of Winter Zooplankton in Deep Stratified Lakes

For the first time, zooplankton and environmental factors have been studied in winter in the deep stratified lakes Siverskoe, Borodaevskoe, and Vydogoshch. The zooplankton consists of 18–22 species of rotifers, copepods, and cladocerans, including 15–18 specifically winter, cryophilic and eurythermic forms. The populations of zooplankters reproduce actively: males and egg-bearing females (in copepods), females with embryos and eggs in brood pouches (in cladocerans), and females with attached eggs (in rotifers) are present. In lakes Siverskoe and Borodaevskoe (depth 20–24 m), where oxygen deficiency is observed only in the bottom water layer, the zooplankton populates the greater part of the water column and forms a large aggregation in the oxycline and near the bottom. The abundance of bacteria in these zones is high (up to 4–6 × 10⁶ cells/ml). In Lake Vydogoshch (depth 16 m), oxygen deficiency extends to the middle layers, and all zooplankton is distributed above the oxycline. The biomass of winter zooplankton in Lake Siverskoe in 1983 averaged 1.26 g/m³, with a maximum of 4 g/m³; in 1993, 1.4 and 8.04 g/m²; the respective values in Lake Borodaevskoe were 0.98 and 3.1 in 1983 and 0.14 and 1.6 in 1993; in Lake Vydogoshch, 0.15 and 0.24 in 1983 and 1.25 g/m³ in 1993. The development of winter zooplankton is limited by the size of the zone of oxygen deficiency and depends on the amount of food (bacterioplankton). The distribution of zooplankton in the water column and its biomass in individual layers is determined by the rate of methane formation and oxidation.__________Translated from Ekologiya, No. 3, 2005, pp. 201–214.Original Russian Text Copyright © 2005 by Rivier.     

Application of Remote Sensing and GIS in the Management of Mangrove Forests Within and Adjacent to Kiunga Marine Protected Area, Lamu, Kenya

The status of mangroves within and adjacent to Kiunga Marine Protected Area (MPA) were assessed by means of aerial photographs and intensive ground truthing. Vegetation maps (1 : 25,000) were produced on GIS environment making it possible to store, retrieve and analyze various types of information very quickly. The maps together with the digitized information provide important tools to the management of mangroves of Kiunga MPA since various proposed treatments can now be entered and summarized thus providing useful overviews for planning, implementation and monitoring.The present inventory revealed that the existing mangrove forests within and adjacent to Kiunga MPA have a net standing volume of 2,354,004.85 m³ in 16,035.94 ha. There are eight species of mangrove trees, of which Rhizophora mucronata and Ceriops tagal are dominant. The standing volume ranges between 6.85 to 710.0 m³ ha^–1 for stem with diameter above 5.0 cm. The average volume of the entire study area was 145.88 m³ ha^–1, which corresponds to a stocking rate of 1736 stems per ha. Given its high potential productivity and regeneration, mangroves within and adjacent to Kiunga MPA have excellent prospects for sustainable exploitation.     

Variation of radiation level and radionuclide enrichment in high background area

Significantly high radiation level and radionuclide concentration along Quilon beach area of coastal Kerala have been reported by several investigators. Detailed gamma radiation level survey was carried out using a portable scintillometer. Detailed studies on radionuclides concentration in different environmental matrices of high background areas were undertaken in the coastal areas of Karunagapalli, Kayankulam, Chavara, Neendakara and Kollam to study the distribution and enrichment of the radionuclides in the region. The absorbed gamma dose rates in air in high background area are in the range 43-17,400 nGyh⁻¹. Gamma radiation level is found to be maximum at a distance of 20 m from the sea waterline in all beaches. The soil samples collected from different locations were analysed for primordial radionuclides by gamma spectrometry. The activity of primordial radionuclides was determined for the different size fractions of soil to study the enrichment pattern. The highest activity of ²³²Th and ²²⁶Ra was found to be enriched in 125-63 μ size fraction. The preferential accumulation of ⁴⁰K was found in <63 μ fraction. The minimum ²³²Th activity was 30.2 Bq kg⁻¹, found in 1000-500 μ particle size fraction at Kollam and maximum activity of 3250.4 Bq kg⁻¹ was observed in grains of size 125-63 μ at Neendakara. The lowest ²²⁶Ra activity observed was 33.9 Bq kg⁻¹ at Neendakara in grains of size 1000-500 μ and the highest activity observed was 482.6 Bq kg⁻¹ in grains of size 125-63 μ in Neendakara. The highest ⁴⁰K activity found was 1923 Bq kg⁻¹ in grains of size <63 μ for a sample collected from Neendakara. A good correlation was observed between computed dose and measured dose in air. The correlation between ²³²Th and ²²⁶Ra was also moderately high. The results of these investigations are presented and discussed in this paper.     

Reuse of mining wastewater in agricultural activities in Jordan

A pilot study was completed in the Al-Abyad area near phosphate mining activity in Jordan. Six plots of 50 m² each were planted with two types of plant species (Zea mays spp. and Medicago lupulina spp.) and irrigated using three types of water (fresh groundwater, mine wastewater, and hydride water consisting of 50% fresh and 50% mine wastewater) to investigate the suitability of utilizing mine wastewater for food production in the area. Water, soil and plant sampling was completed for each plot over different time intervals and analyzed for heavy metal (Cr⁺⁶, Ni⁺², Zn⁺² and Pb⁺²) in addition to major ionic composition of the water used for irrigation. Crop yield was estimated at the end of the experiment. Plots irrigated with mine wastewater showed slightly higher heavy metals concentrations and soil salinity during the experiment period was higher for plots irrigated with mine wastewater compared to plots irrigated with fresh water, and it was uniform through the upper 45 cm of the soil profile due to the high amount of irrigation water used during the experiment. Crop yield was inversely proportional to salinity as an increase of salinity by 2-folds resulted in reducing yield by almost 50%. However, no risk of heavy metals contamination was found in plants and soil. Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue.