Depleted Uranium and Its Effects on Humans

Migration of depleted uranium from a corroded penetrator in soil vadose zone in Bosnia and Herzegovina

Depleted uranium (DU) from corroded armor penetrators can migrate through the soil vadose zone and cause environmental problems, yet studies on such migration at former theatres of war are scarce. Here, we investigated vertical DU migration in a soil profile due to a penetrator (3-8 cm beneath the soil surface) corroded over 7 years in Bosnia and Herzegovina. The highest concentration of DU was ∼45,300 mg/kg at 6-10 cm, with the concentration decreasing markedly with increasing depth. The majority of the DU accumulated within the top 20 cm and the DU front reached ∼42 cm beneath the penetrator. In addition, particles with varying U concentrations (3-65 wt%) were observed at 0-15 cm, with U primarily co-located with O, Si, Al, maghemite, and hematite. Particularly, metaschoepite was identified at 6-10 cm. Finally, X-ray absorption spectroscopy analysis found U was hexavalent in the soil profile. These findings suggest that the downward migration of DU was likely present as a soluble form adsorbed on clay minerals and Fe oxides. Overall, we show that the rate of DU migration within the vadose zone is comparatively slow, although if the penetrator is left in the soil for decades, it could pose a serious long-term risk. ENVIRONMENTAL IMPLICATIONS: Over 90 % of the depleted uranium (DU) penetrators fired in previous conflicts missed their armored targets and were left in the soil to corrode. The corroded penetrators can not only contaminate soil but also pose a risk to groundwater. The present study examined the migration of DU in a soil profile that included a DU penetrator that had been corroding for over 7 years. Studying the dynamics of DU migration is essential to develop effective remediation strategies to mitigate long-term environmental risks and safeguard ecosystems and human health from DU contamination.

Assess human blood uranium levels of some Iraqi companies

The goal of this study is to measure the uranium concentration levels in the blood of Iraqi workers employed in certain government companies. Assessing the initial level of uranium toxicity in their blood and the possibility of health problems occurring. 184 blood samples from Iraqi government companies and the control group were collected in this study. A solid-state nuclear track detector (CR-39) was used to measure the amount of uranium present. Two drops of blood (100 μl) were placed on CR-39. The CR-39 was irradiated with a thermal neutron using the fission-track technique (241Am-9Be) to determine the uranium concentration in blood samples. The statistical analysis is carried out using the Origin Lab 2024 version. The results show the average of uranium concentration at all locations has a higher level compared to the control group. The blood samples from workers at the phosphate company had the highest amount (1.021 ± 0.050 μg/l), compared to samples from other factories. This result confirms that there is a connection between the concentration of uranium and phosphate substances. The results suggest that there is a slight increase in uranium levels that is related to both age and years of employment.

U(VI) exposure induces apoptosis and pyroptosis in RAW264.7 cells

U(VI) pollution has already led to serious harm to the environment and human health with the increase of human activities. The viability of RAW264.7 cells was assessed under various U(VI) concentration stress for 24 and 48 h. The reactive oxygen species (ROS), mitochondrial membrane potential (MMP), and superoxide dismutase (SOD) activities of RAW264.7 cells under U(VI) stress were measured. The results showed that U(VI) decreased cell activity, induced intracellular ROS production, abnormal MMP, and increased SOD activity. The flow cytometry with Annexin-V/PI double labeling demonstrated that the rate of late apoptosis increased with the increase of U(VI) concentration, resulting in decreased Bcl-2 expression and increased Bax expression. The morphology of RAW264.7 cells dramatically changed after 48 h U(VI) exposure, including the evident bubble phenomenon. Besides, U(VI) also increased the proportion of LDH releases and increased GSDMD, and Ras, p38, JNK, and ERK1/2 protein expression, which indicated that the MAPK pathway was also involved. Therefore, U(VI) ultimately led to apoptosis and pyroptosis in RAW264.7 cells. This study offered convincing proof of U(VI) immunotoxicity and established the theoretical framework for further fundamental studies on U(VI) toxicity.

Metal chelating and anti-radical activity of Salvia officinalis in the ameliorative effects against uranium toxicity

Uranium is a highly radioactive heavy metal that is toxic to living things. In this study, physiological, cytogenetic, biochemical and anatomical toxicity caused by uranium and the protective role of sage (Salvia officinalis L.) leaf extract against this toxicity were investigated with the help of Allium test. Germination percentage, root length, weight gain, mitotic index (MI), micronucleus (MN) formation, chromosomal aberrations (CAs), superoxide dismutase (SOD) and catalase (CAT) enzyme activities, malondialdehyde (MDA) levels and changes in root meristem cells were used as indicators of toxicity. In the experimental stage, a total of six groups, one of which was the control, were formed. Group I was treated with tap water, while group II and III were treated only with sage (190 mg/L and 380 mg/L). Groups IV, V and VI were germinated with uranyl acetate dihydrate (0.1 mg/mL), uranyl acetate dihydrate + 190 mg/L sage and uranyl acetate dihydrate + 380 mg/L sage, respectively. Allium cepa L. bulbs of each group were germinated for 72 h, and at the end of the period, routine preparation techniques were applied and physiological, cytogenetic, biochemical and anatomical analyzes were performed. As a result, uranium application caused a significant decrease (p < 0.05) in all physiological parameters and MI values. MN, CAs numbers, SOD and CAT enzyme activities and MDA levels increased significantly (p < 0.05) with uranium application. Uranium promoted CAs in the root tip cells in the form of fragment, vagrant chromosome, sticky chromosome, bridge and unequal distribution of chromatin. In addition, it caused anatomical damages such as epidermis cell damage, cortex cell damage and flattened cell nucleus in root tip meristem cells. Sage application together with uranium caused significant (p < 0.05) increases in physiological parameters and MI values and significant decreases in MN, CAs, SOD and CAT activities and MDA levels. In addition, the application of sage resulted in improvement in the severity of anatomical damages induced by uranium. It was determined that the protective role of sage observed for all parameters investigated was even more pronounced at dose of 380 mg/L. The protective role of sage against uranium toxicity is related to its antioxidant activity, and sage has 82.8% metal chelating and 72.9% DPPH removal activity. As a result, uranyl acetate exhibited versatile toxicity in A. cepa, caused cytotoxicity by decreasing the MI rate, and genotoxicity by increasing the frequencies of MN and CAs. And also, Sage acted as a toxicity-reducing agent by displaying a dose-dependent protective role against the toxic effects induced by uranyl acetate.

Biosorption of uranium from aqueous solutions by Azolla sp. and Limnobium laevigatum

The main goal of this study was to assess alternatives to the current challenges on environmental quality and circular economy. The former is here addressed by the treatment of radioactively contaminated solutions, and the latter by using abundant and low-cost biomass. In this paper, we examine the biosorption of hexavalent uranium (U(VI)) in a batch system using the macrophytes Limnobium laevigatum and Azolla sp. by three operational parameters: biomass dose, metal ion concentration, and contact time. Simulated solutions were firstly addressed with two biomasses, followed by studies with real liquid organic radioactive waste (LORW) with Azolla sp. The batch experiments were carried out by mixing 0.20 g biomass in 10 mL of the prepared solution or LORW. The total contact time employed for the determination of the equilibrium times was 240 min, and the initial U(VI) concentration was 0.63 mmol L^-1. The equilibrium times were 15 min for L. laevigatum and 30 min for Azolla sp. respectively. A wide range of initial U(VI) concentrations (0.25-36 mmol L^-1) was then used to assess the adsorption capacity of each macrophyte. Isotherm models validated the adsorption performance of the biosorption process. Azolla sp. presented a much higher U(VI) uptake (0.474 mmol g^-1) compared to L. laevigatum (0.026 mmol g^-1). When in contact with LORW, Azolla sp. removed much less uranium, indicating an adsorption capacity of 0.010 mmol g^-1. In conclusion, both biomasses, especially Azolla sp., can be used in the treatment of uranium-contaminated solutions.

Layers of Uranium Phosphate Nanorods and Nanoplates Encrusted on Fungus Cladosporium sp. Strain F1 Hyphae

The hyphae of Cladosporium sp. strain F1 (CFGR 2020-301-00084) were heavily encrusted with pre-synthesized uranium phosphate minerals under a wide range of pH conditions. SEM and TEM images showed that nanorods and nanoplates of uranium phosphate minerals at pH 4 and 5 and at pH 6, 7, and 8, respectively, were tightly adsorbed along the hyphae of Cladosporium sp. strain F1, while only a few uranium phosphate minerals were observed on the hyphae of Aspergillus niger VKMF 1119. Based on the physical mobility and chemical stability of uranium phosphate minerals under in situ oxidizing environmental conditions, the application of Cladosporium sp. strain F1 has potential as a novel strategy for the remediation of uranium contamination in sediments and aquifers under a wide range of pH conditions where larger amounts of phosphate are present in the environment.

Environmental and health hazards of military metal pollution

An increasing body of literature has demonstrated that armed conflicts and military activity may contribute to environmental pollution with metals, although the existing data are inconsistent. Therefore, in this paper, we discuss potential sources of military-related metal emissions, environmental metal contamination, as well as routes of metal exposure and their health hazards in relation to military activities. Emission of metals into the environment upon military activity occurs from weapon residues containing high levels of particles containing lead (Pb; leaded ammunition), copper (Cu; unleaded), and depleted uranium (DU). As a consequence, military activity results in soil contamination with Pb and Cu, as well as other metals including Cd, Sb, Cr, Ni, Zn, with subsequent metal translocation to water, thus increasing the risk of human exposure. Biomonitoring studies have demonstrated increased accumulation of metals in plants, invertebrates, and vertebrate species (fish, birds, mammals). Correspondingly, military activity is associated with human metal exposure that results from inhalation or ingestion of released particles, as well as injuries with subsequent metal release from embedded fragments. It is also notable that local metal accumulation following military injury may occur even without detectable fragments. Nonetheless, data on health effects of military-related metal exposures have yet to be systematized. The existing data demonstrate adverse neurological, cardiovascular, and reproductive outcomes in exposed military personnel. Moreover, military-related metal exposures also result in adverse neurodevelopmental outcome in children living within adulterated territories. Experimental in vivo and in vitro studies also demonstrated toxic effects of specific metals as well as widely used metal alloys, although laboratory data report much wider spectrum of adverse effects as compared to epidemiological studies. Therefore, further epidemiological, biomonitoring and laboratory studies are required to better characterize military-related metal exposures and their underlying mechanisms of their adverse toxic effects.

Weaponised uranium and adverse health outcomes in Iraq: a systematic review

Background

The US military first deployed depleted uranium (DU) weapons in Iraq during the Gulf War in 1990 and in the 2003 invasion of Iraq. Research into the health impacts of DU has been mired in debate and controversy. Research funded by the US government has denied the health risks posed by DU to the Iraqi population, while opponents have claimed that DU is responsible for increased rates of birth defects and cancers in Iraq. Others assert that the public health impacts of DU weapons remain uncertain. This systematic review identified, appraised and synthesised all human observational studies assessing adverse health outcomes associated with DU exposure among the Iraqi population. To our knowledge, no systematic review has been conducted on the topic previously.

Methods

We searched 11 electronic databases for human observational studies published between 1990 and 2020 that measured association between exposure to weaponised uranium and health outcomes (including cancer, birth defects, immune system function and mortality) among the Iraqi population. We assessed risk of bias using the Navigation Guide’s risk of bias tool and rated certainty of the evidence using the Grading of Recommendations, Assessment, Development and Evaluations approach (PROSPERO: CRD42018108225).

Results

Our searches identified 2601 records, of which 28 met our inclusion criteria. We identified five additional eligible reports from other sources. Two articles reported the results of multiple relevant studies; our final set included 33 articles reporting on 36 eligible studies. Most studies (n=30, 83%) reported a positive association between uranium exposure and adverse health outcomes. However, we found that the reviewed body of evidence suffers from a high risk of bias.

Conclusion

The available evidence suggests possible associations between exposure to depleted uranium and adverse health outcomes among the Iraqi population. More primary research and the release of missing data are needed to design meaningful health and policy interventions in Iraq.

Uranium Exposure in American Indian Communities: Health, Policy, and the Way Forward

BACKGROUND

Uranium contamination of drinking-water sources on American Indian (AI) reservations in the United States is a largely ignored and underfunded public health crisis. With an estimated 40% of the headwaters in the western U.S. watershed, home to many AI reservation communities, being contaminated with untreated mine waste, the potential health effects have largely been unexplored. With AI populations already facing continued and progressive economic and social marginalization, higher prevalence of chronic disease, and systemic discrimination, associations between various toxicant exposures, including uranium, and various chronic conditions, need further examination.

OBJECTIVES

Uranium's health effects, in addition to considerations for uranium drinking-water testing, reporting, and mitigation in reference to AI communities through the lens of water quality, is reviewed.

DISCUSSION

A series of environmental health policy recommendations are described with the intent to proactively improve responsiveness to the water quality crisis in AI reservation communities in the United States specific to uranium. There is a serious and immediate need for better coordination of uranium-related drinking-water testing and reporting on reservations in the United States that will better support and guide best practices for uranium mitigation efforts. https://doi.org/10.1289/EHP7537.

Assessment of trace metal alterations in the blood, cerebrospinal fluid and tissue samples of patients with malignant brain tumors

The pathogenesis of malignant brain tumors (MBTs) should be better understood due to the evident association between prolonged exposure to metals and increased risk of MBTs. The present research aimed to find trace metals that could contribute to the pathogenesis of MBTs. Essential trace elements (Mn, Co, Zn, Cu, Se) and relevant toxic metals (Al, Ni, As, Sr, Cd, Ce, Pt, Pb, U) in the serum, cell fraction (CF), cerebrospinal fluid (CSF) and cancerous tissue (CT) samples of MBT patients were analyzed. The results were compared with sex- and age-matched control groups. For the first time, this research showed that elemental profiles of serum, CF, CSF and CT samples in MBT patients were significantly altered compared to the appropriate controls, as well as that higher contents of trace elements (particularly Mn, Se, and Pb) could be involved in the pathogenesis of MBTs. However, the most noticeable change found was the elevated U content, indicating its considerable role as a major cerebral discriminator of the presence/absence of MBTs. The U/Se ratio could be considered as an appropriate blood marker in diagnostic MBT evaluation. The reported results could contribute to better understanding of the poorly understood pathogenesis of MBTs. Furthermore, the reported results could highlight a molecular basis for the pathophysiological changes caused by the hazardous effects of trace metals on brain homeostasis.

Mitochondrial protective and antioxidant agents protect toxicity induced by depleted uranium in isolated human lymphocytes

Depleted uranium (DU) is a by-product of the enrichment procedure of natural uranium. During production and usage, uranium may be released into the environment due to failure to follow standard procedures, thus causing environmental pollution. In this study, toxicity effects of uranium (VI) and protective role of mitochondrial permeability transition pore sealing and antioxidant agents studied by isolated human lymphocytes. Human lymphocytes were exposed to different concentrations (0.1, 0.5, 1, 2 and 5 mM) of DU for 6 h and cytotoxicity was measured by trypan blue assay. The mechanistic parameters were assessed after 1, 2 and 3 h of lymphocyte treatment with 1/2 IC50_6h (0.3 mM), IC50_6h (0.8 mM) and 2 IC50_6h (1.6 mM) of DU. The reactive oxygen species (ROS), lysosomal membrane destabilization, mitochondrial membrane potential (MMP), lipid peroxidation, GSH and GSSG levels on human lymphocytes exposed to UA, were measured. The results indicate that toxicity of U (VI) was concentration dependent on human lymphocytes. Also, U (VI) induced ROS production, MMP reduction, lysosomal membrane destabilization and lipid peroxidation in human lymphocytes. In U (VI) treated lymphocytes, decrease in intracellular GSH and raise in extracellular GSSG levels were observed. We report that mitochondrial permeability transition (MPT) pore sealing and antioxidant agents, have the capacity significantly to prevents, mitochondrial toxicity. Thus, the inhibition of mitochondrial oxidative stress and mitochondrial dysfunction by MPT pore sealing and antioxidant agents is associated with the inhibition of DU-induced mitochondrial damages and activation of apoptosis in lymphocytes.

Depleted uranium assessment and natural radioactivity monitoring in North West of Iraq over a decade since the last Gulf War

For the sake of completeness of the surveillance process concerning the spread of depleted uranium (DU) in the Arabian Gulf region, we have applied a simple gamma spectroscopy technique to evaluate its content in Al Jolan, Nazzal and Askari districts in Al Fallujah area, Iraq for the first time and after more than one decade. The measurements were carried out along the lines of the wars that have been witnessed in Iraq last period and expected to be the region of impact of residuals of a large quantity of DU. The observed radionuclides are ⁴ K and other naturally occurring radioactive members of uranium and thorium series. The obtained results show that, the average specific activity concentrations of ²²⁶Ra, ²³²Th, ⁴ K, ²¹⁰Pb ²³⁸U and ²³⁵U in different soil samples collected from Al Fallujah area, Iraq in range of 20.09 ± 4.0 to 21.94 ± 2.4, 11.51 ± 2.3 to 11.75 ± 3.2, 96.53 ± 8.0 to 112.13 ± 49.8, 19.98 ± 4.6 to 20.76 ± 4.8, 25.4 ± 3.9 to 26.1 ± 6.0 and 1.28 ± 0.18 to 1.34 ± 0.21 respectively. The obtained values of Ra_eq for all the investigated samples are less than the recommended limit of 370 Bq kg^-1 and those for H_ex are less than one. These results have been compared with the previous works and the world mean values specified by the UNSCEAR reports. The mean ratio of ²³⁸U/²³⁵U activity in all cases is about the natural value (21.73) which is less than its value in case of DU (76.92). The present obtained results of DU levels show that although a large amount of DU was released in Iraq during the Gulf wars, the tested samples are DU free. This may be attributed to the reduction of DU from the soil surface by wind or sandstorms and the downward leaching process.

The human biomonitoring study in Serbia: Background levels for arsenic, cadmium, lead, thorium and uranium in the whole blood of adult Serbian population

The purpose of this study was to establish reference values (RVs) for the occupationally- and environmentally-important toxic elements in the whole blood of adult Serbian population for the first time. Contaminated drinking water with arsenic, high share of smokers in the country, removing tetraethyl lead from the gasoline and war attack at the end of the twentieth century were some of the reasons to provide background information for arsenic (As), cadmium (Cd), lead (Pb), thorium (Th), and uranium (U) in the blood of the Serbian population. The whole blood samples were collected from the healthy respondents living in the Belgrade and surrounding areas of the capital (n = 305; w/m ratio = 154/151; mean age: 41 ± 2). The concentrations of toxic metals were determined by inductively coupled plasma-mass spectrometry (ICP-MS). Reference values were estimated as the lower limit (LL) and upper limit (UL) of the 95% confidence interval (CI), together with the selected percentiles (P2.5-P97.5). The obtained geometric mean (GM) for As, Cd, Pb, Th, and U were: 0.50 ng/g, 0.32 ng/g, 20.94 ng/g, 0.30 ng/g, and 0.06 ng/g, respectively. The influences of age, sex and lifestyle on results were considered. Women have significantly higher levels of Cd and Th than men. The increased level of Th was observed in the aged group below 40 years, while smokers had significantly higher levels of Pb and double higher level of Cd in the blood than non-smokers (p < 0.05). In comparison with other population groups worldwide, the Serbian population had significantly higher levels of Th and U (up to 100 times higher). These findings could contribute to better understanding of the molecular basis for the development of various health hazards, including the increased incidence of cancer among the Serbian population which need be confirmed by clinical studies.