Accidental Release Research Articles

Parent Communication and Decision Making About Firearm Storage.

Many youths in the United States have access to an unlocked firearm in their home, and accidental discharge of unlocked firearms is a prevalent cause of pediatric injury and death. Discussions between adult family members have the potential to positively influence firearm storage practices. In families with two parenting adults, we tested the following hypotheses: (1) firearms will be more likely to be stored locked and unloaded when both parties are involved in the storage decision, and (2) both parties will be more likely to be involved in the storage decision when they have better relationship functioning and less avoidant communication. Cross-sectional survey using a stratified random sample of an area probability- and address-based panel. Participants were 749 adults aged 18-64 living in the United States with firearms and children in their households. Overall, 62% of families stored guns locked and unloaded and in 55% both parenting adults were highly involved in storage-related decision making. Families where both parties were highly involved in these decisions had 1.65 times the odds of storing firearms safely (95% CI = 1.21-2.27). Odds of both being highly involved in these decisions were much lower in partnerships with more avoidant communication (OR = 0.16, 95% CI = 0.08-0.32) and higher in partnerships with more relationship satisfaction (OR = 1.08, 95% CI = 1.05-1.12). Safe storage is most likely when both parenting adults are involved in the storage decision. Further research is needed to determine how to support productive within-family communication and decision making about this issue.

Use of major ions to evaluate groundwater chemistry and identify hydrochemical processes in a shallow coastal aquifer in southeast Brazil

Coastal aquifers of southeastern Brazil have a fundamental role in economic and social terms, as it is a densely populated region with intense economic activity. The present research was carried out in the coastal region of the State of Rio de Janeiro and enclosed the Brazilian Nuclear Power Plants (NPP) site. The study aimed to assess the hydrochemistry of the shallow aquifer at the NPP's site and surroundings. The hydrochemical study was carried out based on data from 12 water samples, collected in October 2018, in which parameters were measured in situ (such as electrical conductivity, total dissolved solids, temperature, and pH) and in the laboratory (such as alkalinity; Ca2+, Mg2+, Na+, K+; Cl−, SO42−, and silicon). Using Piper and Chadha diagrams, the research identified four water types: Group 1 (Ca2+–Na+–HCO3−), Group 2 (Ca2+–HCO3−), Group 3 [Ca2+ (Na+ rich)–HCO3−], and Group 4 (Na+–Cl−). From the hillsides towards the beach line, the research results suggest a hydrochemical evolution of local groundwater from Group 1 (high rainwater influence), passing through Group 3 (intermediate between Group 1 and 2) and Group 2 (rock influence), to Group 4 (seawater like). The waters of groups 1 to 3 showed potential for base cation exchange (softening or freshening process), while, in Group 4, the potential is for reverse cation exchange (hardening or salinizing process). In a general hydrogeology context, the methods and applied techniques proved to be particularly efficient in identifying potential hydrochemical processes. Noteworthy is the freshening cation exchange identified in the shallow aquifer at NPP’s site. Therefore, theoretically, in case of an accidental release of radionuclides from the NPP to the aqueous phase, the local clay lenses can capture the divalent cation Ra2+ in a natural contamination attenuation process.

Chemical process route selection based upon potential environmental risk of chemical releases

Chemical process route selection is a key decision taken during the preliminary design stage of chemical plant development. This work presents a risk-based methodology that can be used to select the most inherently environmentally friendly chemical process route among alternate routes to produce a chemical. An index called Inherent Environmental Risk Index for Chemical Release (Chem-IERI) is proposed which represents the potential environmental risk due to a total loss of containment event in the plant. The risk index incorporates three parameters, namely the magnitude of environmental impact, the occurrence frequency of the accidental chemical release event that results in the environmental impact and the vulnerability of the environmental element where the impact is observed. Eight environmental impacts are considered and a methodology to estimate the vulnerability of environmental elements to these impacts is proposed. A higher index value indicates a higher environmental risk. The index developed was applied to assess four possible process routes to produce acetone. Propene oxidation process route showed the lowest Chem-IERI value while cumene oxidation process route showed the highest indicating the least inherent environmental friendliness.

Designer biochar with enhanced functionality for efficient removal of radioactive cesium and strontium from water

Radioactive elements released into the environment by accidental discharge constitute serious health hazards to humans and other organisms. In this study, three gasified biochars prepared from feedstock mixtures of wood, chicken manure, and food waste, and a KOH-activated biochar (40% food waste + 60% wood biochar (WFWK)) were used to remove cesium (Cs+) and strontium (Sr2+) ions from water. The physicochemical properties of the biochars before and after adsorbing Cs+ and Sr2+ were determined using X-ray diffraction (XRD), Fourier-transform infrared (FT-IR) spectroscopy, extended X-Ray absorption fine structure (EXAFS) spectroscopy, X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy–energy-dispersive X-ray spectroscopy (SEM-EDX). The WFWK exhibited the highest adsorption capacity for Cs+ (62.7 mg/g) and Sr2+ (43.0 mg/g) among the biochars tested herein. The removal of radioactive 137Cs and 90Sr exceeded 80% and 47%, respectively, in the presence of competing ions like Na+ and Ca2+. The functional groups present in biochar, including –OH, –NH2, and –COOH, facilitated the adsorption of Cs+ and Sr2+. The Cs K-edge EXAFS spectra revealed that a single coordination shell was assigned to the Cs–O bonding at 3.11 Å, corresponding to an outer-sphere complex formed between Cs and the biochar. The designer biochar WFWK may be used as an effective adsorbent to treat radioactive 137Cs- and 90Sr-contaminated water generated during the operation of nuclear power plants and/or unintentional release, owing to the enrichment effect of the functional groups in biochar via alkaline activation.

An insightful overview of the distribution pattern of polycyclic aromatic hydrocarbon in the marine sediments of the Red Sea

AbstractPolycyclic aromatic hydrocarbons (PAHs) are produced during the combustion of coal and oil, and they can cause sediment contamination. Marine sediments are an important source of information regarding human activities in coastal regions and the long-term fate of xenobiotics. PAHs are a serious environmental problem for marine ecosystems because of their detrimental health impacts on species, including endocrine-disrupting activities. The type of organic contaminants in marine sediments is determined by their origin, with PAHs classed as either petrogenic or pyrogenic. Accidental or deliberate discharges and spills of oil from ships, particularly tankers, offshore platforms, and pipelines, especially in the Kingdom of Saudi Arabia, are the most obvious and visible sources of oil pollution in the marine environment. The current review study will be extremely important and beneficial as a desk review as a result of the growing human population and rapid development in the area. The distribution pattern of PAHs along the Red Sea coastal sediments was limited. The majority of research along Saudi Arabia’s Red Sea coast demonstrates pyrogenic and petrogenic origins of PAHs, as well as in other parts of the world. Industrial activity, municipal waste runoff, petroleum spills, and sewage runoff have a significant impact on PAH distribution throughout the Red Sea’s coastal estuaries. However, after the Gulf war in 1992, much of the attention was occurred especially in the Arabian Gulf coast of Saudi Arabia. This study portrayed a comparison of distribution pattern of PAHs with the other parts of the world as well.

Occurrence and Uptake of Heavy Metals in Soil and Plant (Tomato) Associated with Crude Oil Contamination

The general increase of heavy metal content in the soil has been largely caused by crude oil spillage. This study investigates the possibility of tomato (Lycopersicon esculentum Miller) to sorb heavy metals present in crude oil. Crude oil of 0 mL (control), 75 and 150 mL were mixed thoroughly with 15 kg of loamy soil (dry weight) in perforated plastic buckets, as the experimental pots and left for 4 days before transplanting tomato seedlings. After 12 weeks of transplanting, heavy metals analysis was carried out on plant’s fruits, leaves, stems and roots. Physicochemical analyses show that control soil had the lowest organic carbon (3.07 %) while 150 mL had the highest mean organic carbon content (8.24 %). The silt, clay and sand constituents were not significantly different (p > 0.05) in both treated and untreated soil. The control had the least pH value (6.1) while the lead (Pb) content in soil was highest in 150 mL (0.33 mg/kg) but was not significantly different (p > 0.05) from control (0.26 ) and 75 mL (0.30 mg/kg). Lead (Pb) and Cadmium (Cd) were not detected in leaves and fruits. However, bioaccumulation factor (BAF) of Cd and Ni in stem were greater than 1. Although, the concentrations of these heavy metals falls below toxic levels, its consumption could lead to adverse health effects in both man and animals through bioaccumulation or biomagnification.
 HIGHLIGHTS
 
 Countries with poor hydrocarbon pollution regulation are more challenging with oil spills, either through accidental discharges or indiscriminate disposal of hydrocarbon waste
 Plants essentially need some metals such as iron, copper among others, for their growth and other metabolic activities. However, at excess of specific limits, these metals adversely affect plant growth
 In this study, bioaccumulation factors (BAF) of Cd and Ni in the stem were greater than 1, this shows that the tomato plant is a hyperaccumulator of Cd and Ni from the soil
 
 GRAPHICAL ABSTRACT

Assessment of genetically modified maize MON89034 × 1507 × MIR162 × NK603 × DAS-40278-9 for food and feed uses, under regulation (EC) No 1829/2003 (application EFSA-GMO-NL-2018-151).

Genetically modified maize MON 89034 × 1507 × MIR162 × NK603 × DAS‐40278‐9 was developed by crossing to combine five single events: MON 89034, 1507, MIR162, NK603 and DAS‐40278‐9. The GMO Panel previously assessed the five single maize events and 16 of the subcombinations and did not identify safety concerns. No new data on the single maize events or the assessed subcombinations were identified that could lead to the modification of the original conclusions on their safety. The molecular characterisation, comparative analysis (agronomic, phenotypic and compositional characteristics) and the outcome of the toxicological, allergenicity and nutritional assessment indicate that the combination of the single maize events and of the newly expressed proteins in the five‐event stack maize does not give rise to food and feed safety and nutritional concerns. The GMO Panel concludes that five‐event stack maize, as described in this application, is as safe as the non‐GM comparator and non‐GM maize varieties tested. In the case of accidental release of viable five‐event stack maize grains into the environment, this would not raise environmental safety concerns. The GMO Panel assessed the likelihood of interactions among the single events in nine of the maize subcombinations not previously assessed and concludes that these are expected to be as safe as the single events, the previously assessed subcombinations and the five‐event stack maize. The post‐market environmental monitoring plan and reporting intervals are in line with the intended uses of maize MON 89034 × 1507 × MIR162 × NK603 × DAS‐40278‐9. Post‐market monitoring of food/feed is not considered necessary. The GMO Panel concludes that the five‐event stack maize and its subcombinations are as safe as its non‐GM comparator and the tested non‐GM maize varieties with respect to potential effects on human and animal health and the environment.

Morphological characteristics and flashing mechanism of superheated liquid jets released from rectangular breaches

The leakage of liquefied gases such as liquefied hydrocarbons and liquid chlorine is usually accompanied by an intense phase transition that results in two-phase release. This two-phase release will lead to fire, explosion, toxic diffusion and other major dangerous accidents, seriously endangering the safety of personnel and ecological environment, resulting in inestimable losses. To deepen the understanding of such accidents, a 20L tank was used to simulate the accidental release of superheated liquid and study its accident behavior. This work simulated different breaches by using different shapes of nozzles with equal cross-sectional area and more focused on rectangular nozzles. Besides, the influence of initial temperature (110–130 °C) and pressure (6–16 bar) was also taken into account. A high-speed camera was used to record the external morphological characteristics of the superheated liquid jets released from the nozzles. The jet angle and half-width were extracted as the quantitative characterization of the external morphology by threshold processing algorithm. The results revealed that the rectangular nozzle jet (RNJ) has a different external morphology from the circular nozzle jet (CNJ) due to the presence of vortex and axis-switching phenomena. Aspect ratio plays an important role in the determination of external morphology of the RNJ and there is a critical aspect ratio AR = 3. In addition, this study also demonstrates that the rectangular nozzle has a different flashing mechanism from the circular nozzle, which is the underlying reason for the different external morphologies. In summary, compared to the traditional circular breach, rectangular breach has a significant promotion effect on the jet flashing, and the industrial medium released from the slit breach will have a greater impact range, resulting in more serious consequences of accidents.

(Digital Presentation) Thermal Runaway Initiation, Propagation and the Potential for Propagation Inhibition in Commercial Automotive Lithium-Ion Cells and Modules

Lithium-ion batteries, containing flammable electrolytes, have become safer in many ways since their invention. As the technology matures, energy and power densities increase: the European Council for Automotive R&D set 2030 (cell level) targets for battery electric vehicle energy density of 1000 Wh L-1, with 450 Wh kg-1 specific energy and 1800 W kg-1 peak specific power. This rise in energy and power densities increases the risk of accidental release of energy from the batteries and thermal runaway (TR). Safety is thus a key concern when designing a lithium-ion battery system for electric vehicles (EV).TR relates to fast heating of a battery cell caused by exothermic chemical decomposition reactions of the materials inside the cells. It develops in a cell when heat is generated and cannot be dissipated quickly enough to the surroundings, giving rise to an abrupt (exponential) temperature increase and subsequent reaction rate increase. During TR, various exothermic side reactions can occur, leading to temperature increase, accompanied by pressure increase as electrolyte evaporates and venting. This can result in the emission of highly flammable gas and the formation of toxic atmosphere, as well as, in fire and, in very rare circumstances, in explosion. The corresponding temperature increase in adjacent cells (or modules) might then be sufficient to cause them to also go into TR – leading to a process known as thermal runaway propagation (TRP).Fit-for purpose testing procedures to assess the risks associated with TRP are therefore of utmost importance and the focus should always be the safety of the EV occupants, bystanders, first responders and property. Some tests in current standards and regulations try to simulate internally driven failures (e.g. internal short circuit), but whether these tests are suitable to represent field failures remains an open question.This work will give an insight into two selected TR initiation methods assessed within JRC’s TR initiation and propagation test campaigns, namely (a) localised rapid external heating, as developed and patented internationally by NRC (National Research Council Canada) and (b) ceramic nail penetration, as described in the IEC TR 62660-4 standard. It examines the response of short-stacks of pouch cells extracted from automotive batteries after TR is triggered in a single cell. Experimental data and analysis to better understand how TR propagates and the potential for TRP inhibition will be reported. The potential of inhibiting TRP is explored on 2- and 5-cell assemblies with a multi-layer, porous, composite insulation material between cells. Separating the cells can delay significantly TRP in adjacent cells in modules constructed with pouch cells, whereas TRP may be slowed and even inhibited as the thickness of the multilayer material varies.

Simulating Flow and Hazardous Gas Dispersion by Using WRF–CFD Coupled Model under Different Atmospheric Stability Conditions

In this paper, the Weather Research and Forecasting (WRF) model is coupled with the computational fluid dynamics (CFD) model to study the diffusion model of the accidental leakage of hazardous gas under different atmospheric stability conditions. First, the field test at Nanjing University was used to validate the different turbulence models of CFD. The experimental data confirm that the realizable k-ε model can describe the behavior of hazardous gas diffusion. On this basis, the diffusion process of the accidental release of tracer gas under different atmospheric stability conditions is simulated. The results show that atmospheric stability has a significant effect on the flow field distribution and the area of plume of hazardous substances. The ambient wind deflects under unstable conditions and vertical turbulence is slightly larger than that under neutral and stable conditions. Under stable conditions, the dilution of harmful gases is suppressed due to weak turbulent mixing. In addition, stable atmospheric conditions can increase near-surface gas concentrations.

Physics and flame morphology of supersonic spontaneously combusting hydrogen spouting into air

Spontaneous ignition resulting from the accidental release of high-pressure hydrogen is an important safety issue, and the self-ignition flame can eventually induce a jet flame. However, the links between the self-ignition flame inside a tube and an external jet flame are unclear. Hence, this paper presents a study on how the self-ignition flame transforms into the jet flame in the near-field region of the nozzle. Effects of release pressure and tube length are investigated. Changes in release conditions can lead to changes in the flow characteristics of the self-combustible jet at the nozzle. Results show that the difference in the flow parameters is manifested in three aspects, which directly contribute to the diversity of transition forms. The expansion processes and shock structure govern the flame transition. The expansion process consists of two typical stages, which lead to two different flame morphologies. Besides, the presence of discontinuous surfaces in the shock wave structure can cause the self-ignition flame to extinguish or re-ignition in some transition processes, resulting in the flame appearing in different zones during different transitions. Finally, five forms of flame transition are proposed and their formation reasons are analyzed. Dominant factors and links between different transitions are eventually identified.

Методы расчета дрейфа тяжелых облаков с учетом движения среды

Peculiarities are considered related to the numerical integration of the diffusion equations for describing the formation and motion (drift) of explosive clouds formed on the territories of industrial facilities as a result of the accidental releases of combustible substances. The relevance of the study is associated with the fact that when the contents of an emergency release are mixed with an air, an explosive and flammable mixture is formed. The process of its combustion is determined by the volumetric concentration of the combustible substance. At concentrations below the lower concentration limit of ignition, combustion or explosion of the mixture is completely excluded. If the concentration of the mixture is between the lower and upper concentration limits of ignition, then there is an explosion. When the concentration of the mixture is above the upper concentration limit of ignition, a flash fire or a fireball occurs. Thus, the information is required on the parameters of the explosive mixture that may form due to the accidental release. Accidental releases can occur under the most adverse atmospheric environment and weather conditions. As a result, the focus of the article is on determining the parameters of an explosive cloud in the conditions of drift under the influence of a slight movement of the atmosphere (the most unfavorable scenario for the development of an accident). The results of numerical calculations of the diffusion equation with allowance for the mobility of the atmosphere are presented. The presence of a weak wind is the most unfavorable situation in terms of the drift of an explosive cloud. The methods and criteria are substantiated that allow obtaining the most correct results of calculating its motion.

Assessment of genetically modified oilseed rape MON 94100 for food and feed uses, under regulation (EC) No 1829/2003 (application EFSA-GMO-NL-2020-169).

Oilseed rape MON 94100 was developed to confer tolerance to dicamba herbicide. The molecular characterisation data and bioinformatic analyses do not identify issues requiring food/feed safety assessment. None of the identified differences in the agronomic/phenotypic and compositional characteristics tested between oilseed rape MON 94100 and its conventional counterpart needs further assessment, except for the levels of carbohydrates, calcium and ADF in seeds, which do not raise nutritional and safety concerns. The GMO Panel does not identify safety concerns regarding the toxicity and allergenicity of the dicamba mono‐oxygenase (DMO) protein as expressed in oilseed rape MON 94100. The GMO Panel finds no evidence that the genetic modification impacts the overall safety of oilseed rape MON 94100. In the context of this application, the consumption of food and feed from oilseed rape MON 94100 does not represent a nutritional concern in humans and animals. The GMO Panel concludes that oilseed rape MON 94100 is as safe as the conventional counterpart and non‐GM oilseed rape reference varieties tested, and no post‐market monitoring of food/feed is considered necessary. In the case of accidental release of viable oilseed rape MON 94100 seeds into the environment, this would not raise environmental safety concerns. The post‐market environmental monitoring plan and reporting intervals are in line with the intended uses of oilseed rape MON 94100. The GMO Panel concludes that oilseed rape MON 94100 is as safe as its conventional counterpart and the tested non‐GM oilseed rape reference varieties with respect to potential effects on human and animal health and the environment.

The Effect of Storage Temperature on Threat Zone Caused by an Ammonia Release from a Storage Tank

In this study, the threat zone that may occur as a result of an accidental release of an-hydrous ammonia, a flammable and highly toxic substance (Flammability:1, Health:3, NFPA 704), which has many uses, was investigated. A fire can be prevented by taking precautions such as not keeping ignition sources in the environment as a result of the ac-cidental release of ammonia gas. However, although its ignition is prevented, it can cause harm to humans and the environment due to its highly toxic nature. Therefore, the toxicity of ammonia was taken into account in this study. A common type of storage of anhydrous ammonia is in a horizontal cylindrical tank at ambient temperature and its vapor pres-sure. Therefore, in this type of storage, storage is carried out at different temperatures in different seasons. This study aims to examine the effect of storage temperature on the size of the threat zone, taking into account the knowledge that the storage temperature will change in seasonal conditions. Areal Locations of Hazardous Atmosphere (ALOHA) and DOW’s Chemical Exposure Index (DOW CEI) methods were used to determine the size of the threat zone, and the results obtained from these two methods were compared. The advantages and disadvantages of the two methods were presented. It is thought that this study will guide the relevant people such as operators who use these methods in calculating the hazard distances in the establishments that store ammonia and will provide awareness that the storage temperature affects the size of the threat zone.

Effects of activation parameters on Zeolitic imidazolate framework JUC-160-derived, nitrogen-doped hierarchical nanoporous carbon and its volatile iodine capture properties

Despite its importance in the nuclear industry, the uncontrollable use and/or accidental release of iodine in the environment pose serious threats to human health and endanger wildlife. Therefore, effective removal of radioiodine from various environmental media is necessary to circumvent its adverse effect. Herein, we report on an excellent and highly efficient capture of iodine by ZIF (JUC-160)-derived ultra-porous carbon. The ultra-porous carbon, obtained through KOH activation at high temperature, displayed unprecedented iodine capture properties with uptake capacities of 1567 mg g−1 and 821 wt.% in the aqueous and vapor phases, respectively. Various conditions including activation temperature and residency time effects on material properties and uptake performances were evaluated. The results showed that iodine uptake increased with increasing activation temperature; while activation time beyond 60 min was not favorable because the carbon materials were completely gasified. Kinetics and Isotherm fitting with the experimental data was done to assess sorption behavior of the derived carbon materials and their interactions with iodine. The results showed that chemisorption was the dominant medium through which iodine was captured as confirmed by both pseudo-second order and Langmuir models. Furthermore, the main mechanism involved in the process was mainly attributed to electron donor-acceptor interactions wherein the oxygen-containing functional groups and nitrogen active sorption sites of the carbon materials acted as electron donors. This work provides insight into optimizing KOH activation temperature and residency time for best performance of iodine adsorbents.

Evaluation of the Performance of the WRF Model in a Hyper-Arid Environment: A Sensitivity Study

Accurate simulation of boundary layer surface meteorological parameters is essential to achieve good forecasting of weather and atmospheric dispersion. This paper is devoted to a model sensitivity study over a coastal hyper-arid region in the western desert of the United Arab Emirates. This region hosts the Barakah Nuclear Power Plant (BNPP), making it vital to correctly simulate local weather conditions for emergency response in case of an accidental release. We conducted a series of high-resolution WRF model simulations using different combinations of physical schemes for the months January 2019 and June 2019. The simulated results were verified against in-situ meteorological surface measurements available offshore, nearshore, and inland at 12 stations. Several statistical metrics were calculated to rank the performance of the different simulations and a near-to-optimal set of physics options that enhance the performance of a WRF model over different locations in this region has been selected. Additionally, we found that the WRF model performed better in inland locations compared to offshore or nearshore locations, suggesting the important role of dynamical SSTs in mesoscale models. Moreover, morning periods were better simulated than evening ones. The impact of nudging towards station observations resulted in an overall reduction in model errors by 5–15%, which was more marked at offshore and nearshore locations. The sensitivity to grid cell resolution indicated that a spatial resolution of 1 km led to better performance compared to coarser spatial resolutions, highlighting the advantage of high-resolution simulations in which the mesoscale coastal circulation is better resolved.

Analogue Application of Behaviour and Transport of Naturally Occurring Strontium in Cold-Region Aquatic Environments to 90Sr

Quantification and scientific observations of the fate and transport of dissolved strontium in water systems, particularly cold climate water systems, are severely lacking. In this work, in an experiment conducted at a temperature of 6 °C, the observation of strontium precipitation along with calcium carbonate minerals from cold wastewater is investigated. ICP-MS is used for metal analyses where the distribution of the species and saturation state of minerals along with a surface complexation model was performed using the public-use USGS geochemical modeling software, PHREEQC (PH Redox Equilibrium (in C language)). Sample media were analyzed using XPS and Raman spectroscopy. The results suggest that the loss of strontium from natural waters is via the process of co-precipitation with calcite, a calcium carbonate polymorph. The observations and findings are intended to be useful to quantify the loss of 90Sr from the water, in the case of an unplanned release from a nuclear reactor-operated facility. The results indicate that the precipitation model is a robust and reliable approach to predicting and monitoring the behaviour and transport of strontium that may occur in natural environments as a result of an accidental nuclear release.

Evaluation of interactive effects of phosphorus-32 and copper on marine and freshwater bivalve mollusks

Purpose Contaminants seldom occur in isolation in the aquatic environment. While pollution of coastal and inland water bodies has received considerable attention to date, there is limited information on potential interactive effects between radionuclides and metals. Whether by accidental or controlled release, such contaminants co-exist in aquatic ecosystems and can pose an enhanced threat to biota. Using a range of biological responses, the study aimed to evaluate relative interactive effects on representative freshwater and marine bivalve species. Methods An integrated, multi-biomarker approach was adopted to investigate response to copper (Cu, 18 μg L−1), a known environmentally relevant genotoxic metal and differing concentrations of phosphorus-32 (32P; 0.1 and 1 mGy d−1), alone and in combination in marine (Mytilus galloprovincialis) and freshwater (Dreissena polymorpha) mussels. Genetic and molecular biomarkers were determined post-exposure and included DNA damage (as measured by the comet assay), micronuclei (MN) formation, γ-H2AX foci induction and the expression of key stress-related genes (i.e. hsp70/90, sod, cat, gst). Results Overall, using a tissue-specific (i.e. gill and digestive gland) approach, genotoxic response was reflective of exposures where Cu had a slight additive effect on 32P-induced damage across the species (but not all), cell types and dose rates. Multivariate analysis found significant correlations between comet and γ-H2AX assays, across both the tissues. Transcriptional expression of selected genes were generally unaltered in response to contaminant exposures, independent of species or tissues. Conclusions Our study is the first to explore the interactive effects of ionizing radiation (IR) and Cu on two bivalve species representing two ecological habitats. The complexity of IR-metal interactions demonstrate that extrapolation of findings obtained from single stressor studies into field conditions could be misrepresentative of real-world environments. In turn, environmental protective strategies deemed suitable in protecting biota from a single, isolated stressor may not be wholly adequate.

Radiological consequence analysis for hypothetical accidental release from Nigerian Research Reactor-1

Radiological dispersion study is a key element in safety analysis report (SAR) of every nuclear facility for the purpose of emergency response planning. In this work, computational approach was used to determine the total effective dose and ground deposition at critical positions onsite and offsite of the Nigerian Research Reactor-1 (NIRR-1) facility which will be useful in the ongoing development of final SAR for NIRR-1 Low Enriched Uranium (LEU) core. In the methodology used, NIRR-1 LEU core was depleted with TRITON module of SCALE 6.2.3 code and the fission inventory in the core was calculated after a continuous operation at full power of 231.931MWD/MTU for 918 Effective Full Power Days (EFPD) at an operation regime of 3 h per day, 3 days per week and 48 weeks per year. Hot Spot was employed for atmospheric transport and dose calculations with consideration of different accidental scenarios in which 20%, 30%, 60% and 100% gaseous inventory was hypothetically released into the atmosphere. From the results obtained, the total effective dose to maximum exposed workers at 10 m and maximum exposed members of public at 300 m from the reactor were 3.10mSvand0.43mSv respectively for the worst-case scenario with 100% release while the maximum ground deposition was 5.5×106Bq/m2 with corresponding maximum ground shine dose rate of 7.5×10−4mSv/hr. This results are at least one order of magnitude below the dose limits recommended by the International Commission on Radiological Protection (ICRP) and indicate that the present LEU core of NIRR-1 is unlikely to cause any detectable health effect on workers and members of public in the event that 100% of its gaseous inventory is released into air in the environment. Hence it could unequivocally be said that the population is safe from the operation of NIRR-1 in its present location.

Impact of invasive insects on native insect communities

Several biophysical factors are leading to the loss of biodiversity, among them the dominance of exotic invasive species on native communities is important. Their dominance can lead to changes in the structure of insect communities, by competing and displacing native species to other crops or habitats. These changes can impact the herbivore's natural enemies in invaded areas by diverging them from suitable herbivores and altering their biological control process. The development of edible insects and derived products at an industrial scale can also have an impact on the local fauna by the risks of spillover and accidental release in nature. Several area-wide integrated pest management programs are also using the sterile insect technique to control insect pests and disease' vectors. This technique is becoming largely used; however, its application as 'non-intrusive to the environment' is controversial particularly when eradication is concerning species that are at the basis of food webs.