Assessment of Long-Term Radiological Effects on Plants and Animals from a Deep Geological Repository: No Discernible Impact Detected

This study investigates whether non-human biota are protected against harmful effects of ionizing radiation after a possible future release of radioactive matter from a planned repository for spent nuclear fuel. Radiation dose rates to a broad spectrum of organisms were calculated based on data from sampled organisms and modeled activity concentrations. Calculations were performed with the ERICA Tool, a software program which applies a screening dose-rate value of 10 microgray per hour (μGy h^?1) for all types of organisms. Dose rates below this value are thought to result in minimal risk to the individual or population. All calculated dose rates were below the screening value and below the lowest relevant band of “derived consideration levels” proposed by the International Commission on Radiological Protection. This provides a sound basis for arguing that no individuals or populations of examined species would be harmfully affected by a possible radioactive release from the repository.     

Pollution status and risk assessment of trace elements in Portuguese water,soils, sediments,and associated biota: a trend analysis from the 80s to 2021

Pollution of water bodies and sediments/soils by trace elements remains a global threat and a serious environmental hazard to biodiversity and human’s health. Globalization and industrialization resulted in the increase and availability of these substances in the environment posing unpredictable adverse effects to living organisms. To determine pollution status and risk contamination by trace elements, data available in the literature of the last 40 years on trace elements occurrence in three environmental matrices (water bodies, sediments/soils, and biota) from Continental Portugal were collected (about 90 studies). Data were compared to water and sediment quality guidelines to assess potential ecological risks. Most environmentally relevant hazardous elements include Zn, Cu, Cd, Pb, and As. Various studies found trace elements at levels higher than those considered safe by environmental guidelines. In surface waters, Al, Zn, Se, and Ag were found above aquatic life limits in about 60% of the reviewed papers, while Cu, Zn, and As exceed those values in more than 60% of mining waters. Hg and Cd in sediments from mining areas exceeded aquatic life limits and potential ecological risk showed extremely high risk for most of the elements. The data compiled in this review is very heterogenous, varying in terms of sampling schemes, trace elements analysed, and spatiotemporal settings. This heterogenicity leads to data differences that make meaningful comparisons difficult. Nevertheless, the compilation of scattered environmental spatial and temporal trace elements data, of either natural sources or human activity as well as the ultimate effect on biological systems, is of the upmost importance to broaden its knowledge, risk assessment, and implementation of mitigation measures.

     

Treelines will be understood once the functional difference between a tree and a shrub is

Trees are taller than shrubs, grasses, and herbs. What is the disadvantage of being tall so that trees are restricted to warmer regions than low stature life forms? This article offers a brief review of the current state of biological treeline theory, and then explores the significance of tallness from a carbon balance, freezing resistance, and microclimatological perspective. It will be argued that having of a woody stem is neither a burden to the carbon balance nor does it add to the risk of freezing damage. The physiological means of trees to thrive in cold climates are similar to small stature plants, but due to their size, and, thus, closer aerodynamic coupling to air circulation, trees experience critically low temperatures at lower elevation and latitude than smaller plants. Hence, trees reach a limit at treeline for physical reasons related to their stature.     

Treelines Will be Understood Once the Functional Difference Between a Tree and a Shrub Is

Trees are taller than shrubs, grasses, and herbs. What is the disadvantage of being tall so that trees are restricted to warmer regions than low stature life forms? This article offers a brief review of the current state of biological treeline theory, and then explores the significance of tallness from a carbon balance, freezing resistance, and microclimatological perspective. It will be argued that having of a woody stem is neither a burden to the carbon balance nor does it add to the risk of freezing damage. The physiological means of trees to thrive in cold climates are similar to small stature plants, but due to their size, and, thus, closer aerodynamic coupling to air circulation, trees experience critically low temperatures at lower elevation and latitude than smaller plants. Hence, trees reach a limit at treeline for physical reasons related to their stature.     

Elemental and radioactivity analysis of rocks and soils of some selected sites in southwestern Nigeria

The elemental and radioactivity analyses of rock and soil samples from some selected sites in southwestern Nigeria have been done. Measurements of the elemental compositions and activity concentrations of ²³⁸U, ²³²Th, and ⁴⁰K were carried out using nuclear activation analysis technique and gamma spectrometry with high purity germanium detector, respectively. The results obtained provide reference data, allowing observation of possible future changes due to future radiological contamination. The activity concentrations of the natural radionuclides measured in the rocks were higher than those of the soils. The mean concentration of the major and minor elements in the rock and soil samples followed the order Al > Ca > Na > K > Mg > Fe > Ti and Mn > Ba > V > As > Cr > Ni > Zn > Cu, respectively. The radiological hazard and pollution risks associated with the natural radionuclides and heavy metals in the samples were assessed. The results obtained for the annual effective dose equivalent (AEDE), internal hazard, external hazard, and representative gamma indices were lower than their respective maximum permissible limit of 1 mSv y^?1 for AEDE and 1 for internal hazard, external hazard, and representative gamma indices as recommended by the International Commission on Radiological Protection (ICRP). The results of the geo-accumulation index, enrichment factor, and the pollution load index indicate that the soils of the study area are uncontaminated with the heavy metals measured except Ado-Ekiti, Ikere, and Igbara-Odo soils which are moderately contaminated with Arsenic (As).     

Vulnerability of Canadian aquatic ecosystems to nuclear accidents

Several cesium and strontium bioaccumulation models are used widely in national and international guidance for ecological and human health risk assessments for radiocesium (¹³⁴Cs and ¹³⁷Cs) and radiostrontium (⁹⁰Sr), but have not been used to make predictions of radiological risk from nuclear accidents under variable environmental conditions on broad geographical scales. In this paper, we first present models for predicting the bioaccumulation of cesium and strontium by aquatic biota based on ambient concentrations of dissolved potassium and calcium, respectively, and then test these models using independent data from aquatic ecosystems at Canadian nuclear sites. Secondly, models yielding the best predictions across a wide range of input parameters were selected to estimate bioaccumulation factors (BAFs) for cesium and strontium in aquatic ecosystems across Canada, using trophic level of organisms and dissolved potassium for cesium and calcium concentrations for strontium as predictor variables, and presented as contour maps of radiological risk. The models show that risk from bioaccumulation of cesium and strontium can vary by several orders of magnitude depending on site-specific environmental conditions and trophic ecology. Overall, our results suggest that single-parameter approaches taken by regulatory standards may either over- or under-predict radiological risk at many locations, and are thus not readily suitable to inform siting decisions for new nuclear developments.     

Radiometric and environmental impacts of mill tailings at experimental plant processing unit,Allouga, Egypt

Abstract

Uranium mining and ore processing are known to be harmful to the environment and human health if the waste generated is not managed properly. The aim of the present study is to determine the radiological indices in the mill tailings and review the possible attempts to utilize and minimize its hazardous effect. The activity concentrations of natural radionuclides, ²³⁸U, ²³²Th, ²²⁶Ra, and ⁴⁰K have been measured by gamma spectrometry using HP-Ge detector. The average activity concentrations of ²³⁸U, ²³²Th, ²²⁶Ra, and ⁴⁰K in the tailings wastes were 2071.8, 59.92, 6921.262, and 445. 57?Bq/kg respectively which are higher than the international average limit. The ranges of hazard indices such as Radium equivalent activity (Ra_eq), external hazard index (H_ex), internal hazard index (H_in), γ-radiation hazard index I_γ, Dose rate (nGy/h) and annual effective dose equivalent (AED), were estimated. Uraniumm isotopic ratios in the ore –material and mill tailing samples indicate migration out of radionuclides to the surrounding environment causing contamination and many dangerous diseases. Fairly, all investigated tailing waste samples do not satisfy the universal standards, the studied wastes relatively still have high uranium contents and need reprocessing.     

Acute toxic hazard evaluations of glyphosate herbicide on terrestrial vertebrates of the oregon coast range

GOAL, SCOPE AND BACKGROUND: The degree to which dose responses of model organisms (lab rodents) can adequately predict dose responses of free-ranging wild mammals or amphibians is unknown, and the relative sensitivity of such species to body loading of a toxicant such as glyphosate is seldom reported. For relative effects of dosage, we compare sensitivity of nine wild vertebrate species to effects of high doses of glyphosate in Swiss-Webster laboratory mice both by gavage and by intraperitoneal injection. We also evaluate sublethal effects of herbicide exposure on behavior and reproductive success of one mammal and one amphibian species. METHODS: Comparisons of acute toxicity of glyphosate were made with intraperitoneal dosings of technical glyphosate isopropylamine salt to nine species of terrestrial vertebrates (five amphibians, four mammals) and compared with responses in Swiss-Webster laboratory mice. Animals collected from sites that had no recent herbicide application were allowed 7-14 days to equilibrate in captivity before treatment. RESULTS: Median lethal dose ranged from 800 to 1,340 mg kg(-1) in mammals, and 1,170 to >2,000 mg kg(-1) in amphibians, with Oregon vole being the most sensitive. White lab mice were in the middle of the mammalian range. Tailed frog, at >2,000 mg kg(-1) was the least sensitive. Calibration of IP sensitivity to oral administration by gavage indicated that roughly four times as much glyphosate must be administered to obtain a comparable estimate of lethality. Administration by gavage in highly concentrated solutions tended to cause physical injury, hence may prove less useful as a relative indicator of toxicity. When sublethal dosages were given to roughskin newts or chipmunks, mobility and use of cover appeared largely unaffected. DISCUSSION: Direct toxic effects of spraying glyphosate under normal forest management seem unlikely for the nine species examined. Nor could we detect significant indirect effects of exposure on behavior and use of cover features in two species. There may be effects on other aspects of the field biology of these animals, such as reproductive rates, which we did not investigate. Recent field data indicate that changes in habitat quality following herbicide application can result in high reproductive activity in species associated with the grasses and forbs that proliferate following field applications. CONCLUSIONS: When compared to field data on body burdens of wild mammals exposed after aerial application of glyphosate at maximum rates in forests, there seems to be a large margin of safety between dosages encountered and those causing either death or limitation of movement, foraging or shelter. RECOMMENDATIONS AND PERSPECTIVES: Margins of safety for small mammals and amphibians appear to be large under any probable exposure scenarios, however our results indicate high variability in responses among species. Uncertainty introduced into field studies from unknown sources of mortality (e.g, likely predation) must be considered when interpreting our results.     

Model of the Long-Term Transport and Accumulation of Radionuclides in Future Landscapes

Assessments of radiological impacts on humans and other biota from potential releases to the biosphere from a deep geologic repository for spent nuclear fuel are associated with several challenges. Releases, if any, will likely occur in a far future and to an environment that will have experienced substantial transformations. Such releases would occur over very long periods during which environmental conditions will vary continuously due to climate change and ecosystem succession. Assessments of radiological impacts must therefore be based on simulations using models that can describe the transport and accumulation of radionuclides for a large variety of environmental conditions. In this paper we describe such a model and show examples of its application in a safety assessment, taking into account results from sensitivity and uncertainty analyses of the model predictions.     

Source-pathway-receptor investigation of the fate of trace elements derived from shotgun pellets discharged in terrestrial ecosystems managed for game shooting

Spent shotgun pellets may contaminate terrestrial ecosystems. We examined the fate of elements originating from shotgun pellets in pasture and woodland ecosystems. Two source-receptor pathways: i) soil-soil pore water-plant and ii) whole earthworm/worm gut contents - washed and unwashed small mammal hair were investigated. Concentrations of Pb and associated contaminants were higher in soils from shot areas than controls. Arsenic and lead concentrations were positively correlated in soils, soil pore water and associated biota. Element concentrations in biota were below statutory levels in all locations. Bioavailability of lead to small mammals, based on concentrations in washed body hair was low. Lead movement from soil water to higher trophic levels was minor compared to lead adsorbed onto body surfaces. Lead was concentrated in earthworm gut and some plants. Results indicate that managed game shooting presents minimal risk in terms of element transfer to soils and their associated biota.     

Trace metals and organometals in selected marine species and preliminary risk assessment to human beings in Thane Creek area, Mumbai

Trace metals and organometals were estimated in different types of marine organisms (fish, bivalve, crab and prawn) collected from the Trans-Thane Creek area, Mumbai. Thane Creek area is considered as most polluted area due to industrial discharges. Potential risks associated with consumption of marine organisms collected from this particular area to human beings were assessed. Concentrations of ten trace elements (As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb and Zn) in the edible part of marine organisms were analysed by atomic absorption spectrometer and differential pulse anodic stripping voltametric technique. Methyl mercury and tributyl tin were estimated using gas chromatograph-mass spectrometer in combination with solid phase micro extraction (SPME). An assessment of the risk on human beings due to consumption of marine organism was undertaken using toxic reference benchmark, namely the reference dose (RfD). The hazard index (HI), sum of hazard quotients calculated for all the pollutant showed that the risks from consumption of fish and marine organisms as a whole were generally low and are within safe limits.     

U- and Th-series radionuclides in snowshoe hare (Lepus americanus) taken near U mill tailings close to Elliot Lake, Ontario, Canada

Snowshoe hare (Lepus americanus) trapped near U tailings had higher concentrations of (226)Ra in their bones (250 +/- 94 mBq g(-1) dry wt) than those from local control sites 3-15 km from the tailings (20-30 mBq g(-1) dry wt) and those from a distant control site 880 km away from the U mining area, which were below the detection limit (DL) (3.7 mBq g(-1) dry wt). Most chyme (stomach content) samples contained 226Ra below DL. Concentration ratios of 226Ra from tissues of local plants, considered important in the hare's diet, to bone ranged from 0.22 to 8.60. Concentrations of 210Pb and 210Po (95-245 mBq g(-1) dry wt) were not significantly different among tailings and control site populations. Disequilibrium between these isotopes and their precursors was noted. No significant accumulation of U and Th was noted at any site. Higher concentrations of 228Th compared to 232Th are attributed to accumulation of 228Ra in a manner similar to that of 226Ra. Based on bone 226Ra and 210Po contents, the maximum internal dose rates to the skeleton and the maximum life-time dose of hare living near tailings were 3.9 x 10(-5) Gy d(-1) and 4.2 x 10(-2) Gy, respectively. These rates were below the threshold required to produce osteosarcoma in other mammals and were considered unlikely to adversely affect hare during their lifetime. Radionuclide uptake by the animals was concluded to have no environmental significance in the transport of radionuclides from tailings to other locations.     

Healing the wounds in the landscape—reclaiming gravel roads in conservation areas

Reclaiming abandoned and unmaintained roads, built originally for forestry and mineral extraction, is an important part of ecological restoration, because the roads running through natural habitats cause fragmentation. The roads can be reclaimed in a passive way by blocking access to the road, but successful seedling recruitment may require additional management due to the physical constraints present at the road. We established a full factorial study to compare the effects of three road reclaiming measures, namely ripping, creation of safe sites by adding mulch and pine seed addition, on soil processes, recovery of understorey vegetation and seedling recruitment in three conservation areas in eastern Finland. We surveyed soil organic matter, frequency and cover of plant functional types, litter and mineral soil, and number of tree seedlings. The soil organic matter was, on average, 1.3-fold in the 50-cm-deep ripping treatment relative to unripped and 20-cm-deep ripping treatments. The germination and survival of deciduous seedlings and grass establishment were promoted by adding mulch. The addition of pine seeds counteracted the seed limitation and enhanced the regeneration of trees. The treatment combination consisting of ripping, adding mulch and pine seed addition enhanced the vegetation succession and tree-seedling recruitment most: the cover of grasses, herbs and ericaceous dwarf shrubs was 1.3–7.6-fold and the number of coniferous tree seedlings was 3.4–7.1-fold relative to the other treatment combinations. Differences between short-term (1–3 years) and longer-term (6 years) results indicate the need for a sufficient observation period in road reclamation studies.     

Cancer risk assessment after exposure from natural radionuclides in soil using Monte Carlo techniques

Purpose  

The purpose of this paper is to assess fatal cancer risk after external and internal (inhalation and ingestion) exposure from natural radionuclides in soil like ²³⁸U, ²³²Th, ⁴⁰K, and ²²⁶Ra on the territory of Bela Crkva, Serbia. Although receiving doses are low from sources like natural radionuclides in soil, because of stochastic effects of ionizing radiation, risk for developing cancer exists and can be quantified.     

Lead and zinc in sediments and biota from Maarmorilik, West Greenland: an assessment of the environmental impact of mining wastes on an Arctic fjord system

Lead and zinc levels in sediments and biota from the fjord system surrounding the lead/zinc mine at Maarmorilik, West Greenland, were investigated to evaluate the impact of waste rock and marine-deposited tailings on the marine biota. Concentrations of metal in the sediment were up to 8,922 +/- 622 microg g(-1) (dry wt.) for lead and 19,351+/- 476 microg g(-1) (dry wt.) for zinc. Levels of lead and zinc were also elevated in a suite of monitor organisms. The feeding modes of the organisms were used to explain the sources of metals to the organisms. After closure of the mine, the concentrations of metals in the upper centimetres of the sediments decreased, and a decreased impact of metals on the brown alga Fucus distichus was observed. However, the metals in the sediments still affect the marine biota in the area.     

PCB problems in the future: foresight from current knowledge

The present paper overviews the forthcoming PCB problems from current knowledge of their use, environmental contamination and toxicology. From a global point of view, PCB levels in the environmental media and biota are unlikely to decline in the near future due to the greater quantities of PCBs still in use than the quantity that has already escaped into the open environment. Considering all the information on the occurrence, distribution and behaviour of PCBs in the ecosystems, the marine mammals are probably the most vulnerable and possible target organisms in forthcoming long-term PCB toxicity. The recent isomer-specific analyses suggest that the intrinsic toxicity of PCBs principally resulted from the coplanar PCB congeners which may impose a greater toxic threat than chlorinated dioxins and furans to humans and wildlife. The measures necessary to reduce further discharge of PCBs into the environment should be set in motion immediately, otherwise there may be a subsequent deleterious biological impact.     

The seasonal and spatial patterns of ingestion of polyfilament nylon fragments by estuarine drums (Sciaenidae)

Introduction  

Artisanal fisheries in tropical estuaries are an important economic activity worldwide. However, gear (e.g. ropes, nets, buoys, crates) and vessels are often in use under dangerous conditions. Polyfilament nylon ropes are used until they are well beyond human and environmental safety limits. Severe wear and tear results in the contamination of the environment with micro-fragments. The spread of these fragments in the marine environment and their ingestion by the biota are documented in the scientific literature and are increasing concerns. The aim of this study was to evaluate the ingestion of plastic fragments by two fish (drum) species in relation to seasonal, habitat and fish size–class variation.     

Characterisation of bio-aerosols during dust storm period in N–NW India

Bio-investigations for pollen and spores were performed on dry free-fall dust and PM₁₀ aerosol samples, collected from three different locations separated by a distance of 600 km, situated in dust storm hit region of N–NW India. Presence of pollen of trees namely Prosopis (Prosopis juliflora and Prosopis cinearia), Acacia, Syzygium, Pinus, Cedrus, Holoptelea and shrubs namely Ziziphus, Ricinus, Ephedra and members of Fabaceae, Oleaceae families was recorded but with varying proportions in the samples of different locations. Poaceae, Chenopodiaceae/Amaranthaceae, Caryophyllaceae, Brassicaceae and Cyperaceae (sedges) were some of the herb pollen identified in the samples. Among the fungal spores Nigrospora was seen in almost all samples. Nigrospora is a well known allergen and causes health problems. The concentration of trees and shrubs increases in the windward direction just as the climate changes from hot arid to semiarid. The higher frequency of grasses (Poaceae) or herbs could either be a result of the presence of these herbs in the sampling area and hence the higher production of pollen/spores or due to the resuspension from the exposed surface by the high-intensity winds. But we cannot ascertain the exact process at this stage. The overall similarity in the pollen and spore assemblage in our dust samples indicates a common connection or source(s) to the dust in this region. Presence of the pollen of the species of Himalayan origin in our entire samples strongly point towards a Himalayan connection, could be direct or indirect, to the bioaerosols and hence dust in N–NW India. In order to understand the transport path and processes involved therein, present study needs further extension with more number of samples and with reference to meteorological parameters.     

Extension of coupled multispecies metal transport and speciation (TRANSPEC) model to soil

Atmospheric deposition of metals emitted from mining operations has raised metal concentrations in the surrounding soils. This repository may be remobilized and act as a source of metals to nearby surface aquatic systems. It is important to understand metal dynamics and the impact of various chemistry and fate parameters on metal movement in the soil environment in order to evaluate risk associated with metals in terrestrial ecosystems and accurately establish critical discharge limits that are protective of aquatic biota. Here we extend our previously developed coupled multispecies metal fate-TRANsport and SPECiation/complexation (TRANSPEC) model, which was applicable to surface aquatic systems. The extended TRANSPEC, termed TRANSPEC-II, estimates the partition coefficient, K(d), between the soil-solid and -soluble phases using site-specific data and a semi-empirical regression model obtained from literature. A geochemical model calculates metal and species fractions in the dissolved and colloidal phases of the soil solution. The multispecies fugacity/aquivalence based fate-transport model then estimates inter-media transport rates such as leaching from soil, soil runoff, and water-sediment exchanges of each metal species. The model is illustratively applied to Ni in the Kelly Lake watershed (Sudbury, Ontario, Canada), where several mining operations are located. The model results suggest that the current atmospheric fallout supplies only 4% of Ni removed from soil through soil runoff and leaching. Soil runoff contributes about 20% of Ni entering into Kelly Lake with the rest coming from other sources. Leaching to groundwater, apart from runoff, is also a major loss process for Ni in the soil. A sensitivity analysis indicates that raising soil pH to above 6 may substantially reduce metal runoff and improve water quality of nearby water bodies that are impacted by runoff.     

Potential impacts of water injection dredging on water quality and ecotoxicity in Limehouse Basin, River Thames, SE England, UK

The use of water injection dredging (WID) is increasing in the UK's inland waterways and marinas. Jets of water are injected under low pressure directly into bottom sediment creating a turbulent water-sediment mixture that flows under the influence of gravity. Many of these sediments are highly contaminated and little is known of the effects of contaminant release on water quality or the risk to biota living in both the sediment and the water column. Sediment cores were collected from Limehouse Basin, a proposed WID site in SE England and current sediment toxicity was assessed using a number of techniques. Comparison of metal data to US sediment quality guidelines indicated intermediate levels of toxicity while, calculation of acid volatile sulphide to simultaneously extracted metal ratios underestimated the potential toxicity to sediment dwelling organisms. In contrast, porewater ammonia concentrations were in excess of all published ecotoxicological guidelines and indicate serious risk to biota. Re-suspension experiments were used to mimic the effects of WID on overlying water quality and ecotoxicity tests were carried out on elutriates using Daphnia magna to examine the impacts on biota. Concentrations of a range of metals in the elutriates predict that adverse biological effects would be observed during WID, however only 10% of the elutriate samples caused an adverse effect on Daphnia. Limehouse Basin is a complex aquatic environment receiving predominantly fresh waters while the sediments have high porewater chloride concentrations reminiscent of previous tidal inputs to the basin, making the choice of test organism problematic.