Respiratory disorders in aluminum smelter workers

LNC000152 Mediates Aluminum-Induced Proliferation of Reactive Astrocytes

Aluminum is a metal element with significant neurotoxicity, and there is a substantial correlation between aluminum exposure and cognitive dysfunction. Glial fibrillary acidic protein (GFAP) is widely used as a marker of reactive astrocyte proliferation in response to pathological injury of the central nervous system. Studies of various neurodegenerative diseases have confirmed that the expression changes in GFAP are associated with nerve injury. We investigated the role of LNC000152 in the aluminum-induced reactive proliferation of astrocytes. By establishing two aluminum-exposed cell models of rat primary astrocytes and CTX-TNA2 cell lines, we examined the expression of LNC000152 and GFAP and detected cell proliferation with EdU and cell cycle changes with flow cytometry. The role of aluminum in promoting glial cell proliferation was verified; the expression levels of LNC000152 and GFAP increased with the concentration of aluminum exposure. Intervention of LNC000152 expression by siRNA technology revealed that LNC000152 affected glial cell responsive proliferation by influencing GFAP expression. These results suggest that LNC000152 plays a role in the reactive proliferation of astrocytes induced by aluminum.

Mechanism and impact of heavy metal-aluminum (Al) toxicity on male reproduction: Therapeutic approaches with some phytochemicals

Heavy metals are ubiquitous environmental toxicants that have been known to have a serious effect on human and animal health. Aluminum (Al) is a widely distributed metal in nature. Al exposure has a detrimental impact on human fertility. This review focused on Al-induced male reproductive toxicity and the potential therapeutic approaches with some phytochemicals. Data from the literature showed that Al exposure is accompanied by a drastic decline in blood levels of FSH, LH, and testosterone, reduced sperm count, and affected sperm quality. Al exposure at high levels can cause oxidative stress by increasing ROS and RNS production, mediated mainly by downregulating Nrf2 signaling. Moreover, several investigations demonstrated that Al exposure evoked inflammation, evidenced by increased TNF-α and IL-6 levels. Additionally, substantial evidence concluded the key role of apoptosis in Al-induced testicular toxicity mediated by upregulating caspase-3 and downregulating Bcl2 protein. The damaging effects of Al on mitochondrial bioenergetics are thought to be due to the excessive generation of free radicals. This review helps to clarify the main mechanism involved in Al-associated testicular intoxication and the treatment strategy to attenuate the notable harmful effects on the male reproductive system. It will encourage clinical efforts to target the pathway involved in Al-associated testicular intoxication.

Impact of welding occupation on serum aluminium level and its association with physical health, cognitive function, and quality of life: a cross-sectional study

OBJECTIVE

There is an occupational health concern about welders' inhalation of toxic aluminium fumes. We investigated whether serum aluminium level (SAL) and demographic variables can significantly predict physical health parameters, cognition, and quality of life (QoL) among welders.

METHODS

The cross-sectional study involved 100 age- and location-matched men (50 welders and 50 non-welders). SAL obtained using a graphite furnace atomic absorption spectrometer, and data collected using blood pressure and body mass index (BMI) apparatuses, biodata form, pain rating scale, General Practitioner Assessment of Cognition, WHOQoL-BREF, and Nordic musculoskeletal symptoms (MSS) questionnaire were analysed using independent samples t test, chi-square, Pearson's correlation, and hierarchical linear regression.

RESULTS

Welders had significantly higher SAL (mean difference [MD] = 1.77 µg/L, p < 0.001), lower QoL (MD = 3.92, p = 0.039), and higher prevalence of MSS on the neck (χ2 = 10.187, p = 0.001), shoulder (χ2 = 9.007, p = 0.003), upper back (χ2 = 6.832, p = 0.009), and knee (χ2 = 12.190, p < 0.001) than non-welders. There was a significant bivariate association between SAL, systolic blood pressure (β = 0.313, p = 0.002), and BMI (β = 0.279, p = 0.005), but not pain intensity, cognition, or QoL. SAL remained a significant predictor of systolic blood pressure after adjustment for physical health and QoL parameters (β = 0.191, p = 0.044). The association between SAL and social QoL became significant after adjustment for physical health and other QoL domains (β = - 0.210, p = 0.032) and demographic variables (β = - 0.233, p = 0.046).

CONCLUSION

Welders had significantly higher SAL, musculoskeletal symptoms, blood pressure, and lower QoL than non-welders. SAL was associated with adverse physical health parameters and social-related QoL, not cognition. We recommend routine aluminium bioavailability and physical health checks among welders.

Aluminum neurotoxicity and autophagy: a mechanistic view

It is strongly believed that aluminum is one of the insalubrious agents because of its neurotoxicity effects and influences on amyloid β (Aβ) production and tau protein hyperphosphorylation following oxidative stress, as one of the initial events in neurotoxicity. The autophagy process plays a considerable role in neurons in preserving intracellular homeostasis and recycling organelles and proteins, especially Aβ and soluble tau. Thus, autophagy is suggested to ameliorate aluminum neurotoxicity effects, and dysfunction of this process can lead to an increase in detrimental proteins. However, the relationship between aluminum neurotoxicity and autophagy dysregulation in some dimensions remains unclear. In the present review, we want to give an overview of the autophagy roles in aluminum neurotoxicity and how dysregulation of autophagy can affect aluminum neurotoxicity.

Aluminium exposure leads to neurodegeneration and alters the expression of marker genes involved to parkinsonism in zebrafish brain

Aluminium, despite being extremely widespread in the world, is a non-essential metal to human metabolism. This metal is known to have toxic effects on a variety of organs including the brain and is considered an etiological factor in neurodegenerative diseases. However, the molecular mechanisms by which aluminium exerts neurotoxic effects are not yet completely understood. Zebrafish is an animal model also used to study neurodegenerative diseases since the overall anatomical organization of the central nervous system is relatively conserved and similar to mammals. Adult zebrafish were exposed to 11 mg/L of Al for 10, 15, and 20 days and the neurotoxic effects of aluminium were analysed by histological, biochemical, and molecular evaluations. Histological stainings allowed to evaluation of the morphology of the brain parenchyma, the alteration of myelin and the activation of neurodegenerative processes. The expression of the Glial Fibrillary Acidic Protein, a marker of glial cells, was evaluated to observe the quantitative alteration of this important protein for the nervous system. In addition, the poly(ADP-ribose) polymerase activity was measured to verify a possible oxidative DNA damage caused by exposure to this metal. Finally, the evaluation of the markers involved in Parkinsonism was assessed by Real-Time PCR to better understand the role of aluminium in the regulation of genes related to Parkinson's neurodegenerative disease. Data showed that aluminium significantly affected the histology of cerebral tissue especially in the first periods of exposure, 10 and 15 days. This trend was also followed by the expression of GFAP. At longer exposure times, there was an improvement/stabilization of the overall neurological conditions and decrease in PARP activity. In addition, aluminium is involved in the deregulation of the expression of genes closely related to Parkinsonism. Overall, the data confirm the neurotoxicity induced by aluminium and shed a light on its involvement in neurodegenerative processes.

Interactions between Environmental Factors and Glutathione S-Transferase (GST) Genes with Respect to Detectable Blood Aluminum Concentrations in Jamaican Children

Aluminum (Al) is a metallic toxicant at high concentrations following natural or unnatural exposures. Dietary intake is considered as the main source of aluminum exposure in children. We used data from 366 typically developing (TD) children (ages 2−8 years) who participated as controls in an age- and sex-matched case−control study in Jamaica. We investigated additive and interactive associations among environmental factors and children’s genotypes for glutathione S-transferase (GST) genes (GSTT1, GSTM1, GSTP1), in relation to having a detectable blood aluminum concentration (BAlC) of >5.0 μg/L, using multivariable logistic regression models. Findings from interactive models revealed that the odds of having a detectable BAlC was significantly higher among children who ate string beans (p ≤ 0.01), whereas about 40% lower odds of having a detectable BAlC was observed in children with higher parental education level, (p = 0.02). A significant interaction between consumption of saltwater fish and GSTP1 in relation to having a detectable BAlC using either co-dominant or dominant genetic models (overall interaction p = 0.02 for both models) indicated that consumption of saltwater fish was associated with higher odds of having a detectable BAlC only among children with the GSTP1 Ile105Val Ile/Ile genotype using either co-dominant or dominant models [OR (95% CI) = 2.73 (1.07, 6.96), p = 0.04; and OR (95% CI) = 2.74 (1.08, 6.99), p = 0.03]. Since this is the first study from Jamaica that reports such findings, replication in other populations is warranted.

Multi-Elemental Analysis of Human Optic Chiasm-A New Perspective to Reveal the Pathomechanism of Nerve Fibers' Degeneration

The effect of metals on the functioning of the human eye is multifactorial and includes enzyme activity modulation, trace metal metabolic pathways changes, and cytotoxic activity. Functional dysfunctions appear mostly as a result of the accumulation of toxic xenobiotic metals or disturbances of micronutrients’ homeostasis. So far, the affinity of selected metals to eye tissues, i.e., the cornea, choroid, lens, and anterior chamber fluid, has been most studied. However, it is known that many eye symptoms are related to damage to the optic nerve. In order to fill this gap, the aim of the study is to perform a multi-element analysis of tissue collected postmortem from optic chiasm and optic nerves. A total of 178 samples from 107 subjects were tested. The concentrations of 51 elements were quantified by inductively coupled plasma mass spectrometry (ICP-MS) after the wet-mineralization step. In terms of elemental composition, the optic chiasm is dominated by two trace elements, i.e., iron (Fe) and zinc (Zn), besides macro-elements Ca, K, Na, P, and Mg. The subjects formed a homogeneous cluster (over 70% subjects) with the highest accumulation of aluminum (Al). The remaining two departing clusters were characterized by an increased content of most of the elements, including toxic elements such as bismuth (Bi), uranium (U), lead (Pb), chromium (Cr), and cadmium (Cd). Changes in elemental composition with age were analyzed statistically for the selected groups, i.e., females, males, and subjects with alcohol use disorder (AUD) and without AUD. A tendency of women to lose Se, Cu, Zn, Fe with age was observed, and a disturbed Ca/Mg, Na/K ratio in subjects with AUD. Although the observed trends were not statistically significant, they shed new light on the risks and possible pathologies associated with metal neurotoxicity in the visual tract.

Evaluating tissue levels of the eight trace elements and heavy metals among esophagus and gastric cancer patients: A comparison between cancerous and non-cancerous tissues

BACKGROUND

Considering the affecting role of environmental factors including trace elements and heavy metals on the upper gastrointestinal (GI) cancers, there is paucity of empirical research in tissue evaluations.

OBJECTIVES

The present study aimed to measure the tissue content of some trace elements and heavy metals such as zinc (Zn), chromium (Cr), manganese (Mn), tin (Sn), copper (Cu), aluminum (Al), lead (Pb), and iron (Fe) in esophagus and gastric cancerous tissues compared to the adjacent healthy tissues.

METHODS

In a cross-sectional study, the aforementioned trace elements and heavy metals were evaluated among patients with esophagus and gastric cancers. During endoscopy, multiple samples were taken from cancerous lesions and the adjacent healthy tissues. The classic flame atomic absorption spectroscopy (FAAS) method was employed as the study framework.

RESULTS

Fifty patients with the mean age of 53.92 ± 8.73 were enrolled in the current study. Thirteen patients suffered from esophageal cancer and thirty-seven patients were afflicted with gastric cancer. The results revealed significant differences in the median concentrations of Zn, Cr, Sn and, Cu (P < 0.05) between the two groups. Although there were no significant changes in the tissue content in the esophageal samples, in the median concentrations of Zn, Cr and, Sn (P < 0.05) in gastric tissues, significant differences were observed. Further, the results indicated that gender enacted an affecting role in the level of some trace elements and heavy metals.

CONCLUSION

The tissue contents of some elements were altered in gastric and esophageal cancers; this difference may reflect the underlying mechanism of cellular changing during the tumorigenesis or direct exposure of these elements. It seems that under the shade of other coexisting risk factors, larger cohort studies are suggested to be conducted to investigate other probable aspects in this area of interest.

Nose-only inhalations of high-dose alumina nanoparticles/hydrogen chloride gas mixtures induce strong pulmonary pro-inflammatory response: a pilot study

OBJECTIVE

Solid composite propellants combustion, in aerospace and defense fields, can lead to complex aerosols emission containing high concentrations of alumina nanoparticles (Al₂O₃ NPs) and hydrogen chloride gas (HCl_g). Exposure to these mixtures by inhalation is thus possible but literature data toward their pulmonary toxicity are missing. To specify hazards resulting from these combustion aerosols, a pilot study was implemented.

MATERIALS AND METHODS

Male Wistar rats were nose-only exposed to Al₂O₃ NPs (primary size 13 nm, 10 g/L suspension leading to 20.0-22.1 mg/m³ aerosol) and/or to HCl_g aerosols (5 ppm target concentration) following two exposure scenarios (single exposures (SE) or repeated exposures (RE)). Bronchoalveolar lavage fluids (BALF) content and lungs histopathology were analyzed 24 h after exposures.

RESULTS

Repeated co-exposures increased total proteins and LDH concentrations in BALF indicating alveolar-capillary barrier permeabilization and cytolysis. Early pulmonary inflammation was induced after RE to Al₂O₃ NPs ± HCl_g resulting in PMN, TNF-α, IL-1β, and GRO/KC increases in BALF. Both exposure scenarios resulted in pulmonary histopathological lesions (vascular congestions, bronchial pre-exfoliations, vascular and interalveolar septum edemas). Lung oxidative damages were observed in situ following SE.

CONCLUSION

Observed biological effects are dependent on both aerosol content and exposure scenario. Results showed an important pro-inflammatory effect of Al₂O₃ NPs/HCl_g mixtures on the lungs of rat 24 h after exposure. This pilot study raises concerns toward potential long-term pulmonary toxicity of combustion aerosols and highlights the importance for further studies to be led in order to define dose limitations and exposure thresholds for risk management at the work place.

High-Dose Aluminum Exposure Further Alerts Immune Phenotype in Aplastic Anemia Patients

This study explored the relationship between immunological status and clinical characteristics of aplastic anemia (AA) patients to plasma aluminum levels, which were increased after constant exposure to high levels of this metal. Sixty-two AA patients (33 cases with high and 29 cases with low or no exposure to aluminum) and 30 healthy controls were selected for this study. Aluminum in human albumin solution was measured by inductivity coupled plasma mass spectrometry. IL-10, IL-12, IL-17, and INF-γ levels were measured by enzyme-linked immunosorbent assay. The distribution of lymphocyte subsets were determined by flow cytometry. The expression levels of immunoglobulins and complement C3 and C4 were also measured. Exposure to high aluminum raised the levels of serum aluminum in AA patients (P < 0.01). The levels of hemoglobin and complement C4 were lower in AA patients with high aluminum exposure (P < 0.05 and < 0.01, respectively). The percentage of CD4+ T cells and the ratio of CD4+/ CD8+T cells in peripheral blood in AA patients with high aluminum exposure were higher compared with control AA patients (P < 0.05 in both cases), while the percentage of CD8+ T cells was significantly lower than that in non-aluminum-exposed AA patients (P < 0.05). Compared with non-aluminum-exposed AA patients, the level of IL-10 in the high aluminum-exposed AA group was significantly higher (P < 0.05 in both cases). The immunological and clinical characteristics of AA patients from regions of high aluminum exposure are different to those in from non-aluminum areas. These results suggest that high aluminum exposure alters the immune system in patients suffering from AA.

Biochemical, histological, and neuro-physiological effects of long-term aluminum chloride exposure in rats

This study aimed to evaluate the effect of daily sublethal doses of aluminum (Al) on hematological, physiological, biochemical, and behavioral changes in male albino Wistar rats. In addition, Al tissue accumulation and histopathological changes in the cerebral cortex, liver, and kidney were examined. The rats were randomly separated into three groups. Group 1 included rats who received the median deadly dose (LD₅₀) of aluminum chloride (AlCl₃), group 2 served as the control, and group 3 was treated with a non-lethal dose of AlCl₃ (1.5 mg/kg) intraperitoneally for 45 days. At defined time intervals, hepatic and renal specific enzymes and biochemical activity were measured. In addition, we examined Al accumulation, the condition of the liver via histological methods, and the impact on the cerebral cortex. In comparison to the controls, rats treated with AlCl₃ exhibited a rise in AST, ALT, and ALP enzyme activity. We also saw a significant decrease in body weight and a decrease in total protein, lipids, cholesterol, acetylcholinesterase (AChE), RBCs, and Hb levels compared to the control group. Histopathological examination suggested severe changes in the liver, kidney, and cerebral cortex of the rats. The current study indicates that sublethal daily exposure to AlCl₃ causes hazardous effects, as increased Al concentration in the body is shown to induce detrimental biochemical and histological changes as well as decreased body weight. Therefore, careful attention should be given to treatments requiring long exposure in patients and the potential for accumulation via food and drinking.

Cancer and noncancer mortality among aluminum smelting workers in Badin, North Carolina

BACKGROUND

Badin, North Carolina, hosted an aluminum smelting plant from 1917 to 2007. The Concerned Citizens of West Badin reported suspected excess cancer mortality among former employees. This study aimed to investigate these concerns.

METHODS

The study cohort was enumerated from United Steel Workers' records of workers employed from 1980 to 2007. Cause-specific mortality rates in the cohort were compared with North Carolina population mortality rates using standardized mortality ratios (SMRs), standardized by age, sex, race, and calendar period. We estimated cause-specific adjusted standardized mortality ratios (aSMRs) using negative controls to mitigate healthy worker survivor bias (HWSB). Standardized rate ratios (SRRs) were calculated to compare mortality rates between workers ever employed vs never employed in the pot room.

RESULTS

All-cause mortality among Badin workers was lower than in the general population (SMR: 0.81, 95% confidence interval [CI]: 0.71-0.92). After adjusting for HWSB, excesses for all cancers (aSMR: 1.55, 95% CI: 1.10-2.21), bladder cancer (3.47, 95% CI: 1.25-9.62), mesothelioma (17.33, 95% CI: 5.40-55.59), and respiratory cancer (1.24, 95% CI: 0.77-1.99) were observed. Black males worked the highest proportion of their employed years in the pot room. Potroom workers experienced higher respiratory cancer (SRR: 2.99, 95% CI: 1.23-7.26), bladder cancer (SRR: 1.58, 95% CI: 0.15-15.28), and mesothelioma (SRR: 3.36, 95% CI: 0.21-53.78) mortality rates than never workers in the pot room.

CONCLUSIONS

This study responds to concerns of a group of former aluminum workers. The results, while imprecise, suggest excess respiratory and bladder cancers among pot room workers in a contemporary cohort of union employees at a US smelter.

Aluminium toxicosis: a review of toxic actions and effects

Aluminium (Al) is frequently accessible to animal and human populations to the extent that intoxications may occur. Intake of Al is by inhalation of aerosols or particles, ingestion of food, water and medicaments, skin contact, vaccination, dialysis and infusions. Toxic actions of Al induce oxidative stress, immunologic alterations, genotoxicity, pro-inflammatory effect, peptide denaturation or transformation, enzymatic dysfunction, metabolic derangement, amyloidogenesis, membrane perturbation, iron dyshomeostasis, apoptosis, necrosis and dysplasia. The pathological conditions associated with Al toxicosis are desquamative interstitial pneumonia, pulmonary alveolar proteinosis, granulomas, granulomatosis and fibrosis, toxic myocarditis, thrombosis and ischemic stroke, granulomatous enteritis, Crohn's disease, inflammatory bowel diseases, anemia, Alzheimer's disease, dementia, sclerosis, autism, macrophagic myofasciitis, osteomalacia, oligospermia and infertility, hepatorenal disease, breast cancer and cyst, pancreatitis, pancreatic necrosis and diabetes mellitus. The review provides a broad overview of Al toxicosis as a background for sustained investigations of the toxicology of Al compounds of public health importance.

Human health risk associated with the management of phosphorus in freshwaters using lanthanum and aluminium

The use of geo-engineering materials to manage phosphorus in lakes has increased in recent years with aluminium and lanthanum based materials being most commonly applied. Hence the potential impact of the use of these compounds on human health is receiving growing interest. This review seeks to understand, evaluate and compare potential unintended consequences on human health and ecotoxicological risks associated with the use of lanthanum- and aluminium-based materials to modify chemical and ecological conditions in water bodies. In addition to their therapeutic use for the reduction of intestinal phosphate absorption in patients with impaired renal function, the phosphate binding capacity of aluminium and lanthanum also led to the development of materials used for water treatment. Although lanthanum and aluminium share physicochemical similarities and have many common applications, their uptake and kinetics within the human body and living organisms importantly differ from each other which is reflected in a different toxicity profile. Whilst a causal role in the development of neurological pathologies, skeletal lesions, hematopoietic disorders and respiratory effects has unequivocally been demonstrated with increased exposure to aluminium, studies until now have failed to find such a clear association after exposure to lanthanum although caution is warranted. Our review indicates that lanthanum and aluminium have a distinctly different profile with respect to their potential effects on human health. Regular monitoring of both aluminium and lanthanum concentrations in lanthanum-/aluminium-treated water by the responsible authorities is recommended to avoid acute accidental or chronic low level accumulation.

AlCl3 inhibits LPS-induced NLRP3 inflammasome activation and IL-1β production through suppressing NF-κB signaling pathway in murine peritoneal macrophages

Aluminum (Al), a common environmental pollutant, has been reported to inhibit the immune functions of macrophage. However, the mechanisms involved remain unclear. In this study, murine peritoneal macrophages were exposed to 0, 0.27, 0.54, and 1.08 mg/mL of aluminium chloride (AlCl₃) for 24 h, and then treated with 1 μg/mL lipopolysaccharide (LPS) for another 6 h. No addition of both AlCl₃ and LPS serviced as control group. We observed that AlCl₃ has cytotoxicity in murine peritoneal macrophages, showing a decrease in cell viability and an increase in lactate dehydrogenase release. Besides, AlCl₃ exposure restrained the LPS-induced NLR pyrin domain containing 3 (NLRP3) inflammasome activation presented as NLRP3 expressions reduction, caspase-1 cleavage inhibition and interleukin 1 beta (IL-1β) maturation lessened. Meanwhile, AlCl₃ exposure decreased LPS-induced IKKβ activity, IκBα phosphorylation, the phosphorylation and mRNA expression of NF-κB p65, as well the genes expression and concentration in medium supernatant of tumor necrosis factor alpha (TNF-α) and interleukin 6 (IL-6). The results suggested that AlCl₃ inhibited the activation of NF-κB signaling pathway induced by LPS, which maybe one of the upstream signals involved in the inhibition of NLRP3 inflammasome activation by AlCl₃. This research can provide theoretical basis for understanding the immune toxicity of Al, and deepening the cognition of Al exposure hazards to immune response.

The toxic effect of sodium fluoride on Spodoptera frugiperda 9 cells and differential protein analysis following NaF treatment of cells

Accumulation of excess fluoride has a destructive effect on the environment, endangering human health, affecting organism growth and development, and leading to damage to the biological chain, thereby affecting ecological environment balance. In recent years, numerous studies focused on the molecular mechanisms associated with fluoride toxicity; however, fluoride-toxicity mechanisms in insect cells remain unclear. This study explored the toxic impact of sodium fluoride (NaF) on Spodoptera frugiperda 9 (Sf9) insect cells. High concentrations of NaF (10^-4 M, 10^-3 M and 10^-2 M) resulted in cell enlargement, cell membrane blurring and breakage, and release of cellular contents. Dose-response curves indicated that NaF-specific inhibition rates on Sf9-cell activity increased along with increases in NaF concentration, with a half-inhibitory concentration (IC₅₀) for NaF of 5.919 × 10^-3 M at 72 h. Compared with controls, the percentages of early and late apoptotic and necrotic cells clearly increased based on observed increases in NaF concentrations. Two-dimensional gel electrophoresis combined with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry was used to detect differentially expressed proteins in Sf9 cells treated with IC₅₀ NaF, identifying 17 proteins, seven of which were upregulated and 10 downregulated. These results demonstrated that Sf9 cells showed signs of NaF-mediated toxicity through alterations in cell morphology, apoptosis rates, and protein expression.

Overview of the Relationship Between Aluminum Exposure and Health of Human Being

Aluminum is a type of ubiquitously existing naturally and widely used metal in our world. It is combined with other elements and forms different compounds. In different pH and due to other conditions, it can be released into ions of different valence states. Our century is an "aluminum age"; aluminum is used in many fields of our daily life, such as vaccine adjuvant, antacids, food additives, skin care products, cosmetics, and cooking wares, and may be as elements or contaminants appeared in a lot of foods, including infant formulae, milk products, juice, wine, sea foods, and tea. It also appears in drinking water due to the water treatment process, or naturally coming from weathering rocks and soils, or released from rocks and soils caused by pollution-induced acid rain. Due to good physical and chemical property, aluminum is being tremendously utilized in many industries. In a lot of production and process procedures, aluminum particulates are seriously exposed by workers. Many factors, such as silicon, citrate, iron, calcium, fluoride, etc., can affect absorption of aluminum in human body. Human being ingests aluminum through the respiratory and digestive system and skin. Aluminum can affect our health, especially impair central nervous system. The important damage is cognitive impairment in Al-exposed peoples, Alzheimer's disease and other neurodegenerative disorders have been related with aluminum exposure, and aluminum has been proposed as etiology.

Pulmonary fluorosis: a review

The increased industrialization and improvised human lifestyle lead to a surge in environmental pollution nowadays. Even the chemicals which are known as prophylactic agents were currently liable to be toxic. One among them is inorganic fluoride whose wider application in numerous processes makes it as an inevitable environmental contaminant and industrial pollutant. Although the systemic toxicity of fluoride has been extensively studied, still there is lacuna in the field of pulmonary fluoride toxicity. Hence, we have focused on the molecular mechanism of action of fluoride compounds on pulmonary system. A study of literatures that focused on the potential physiological and toxicological consequences of fluoride on pulmonary system was carried out. The goal of this review is to present an overview of the research carried out till date on the molecular aspects of fluoride exposure with emphasis on pulmonary system and their possible mechanisms.

Inflammation in induced sputum after aluminium oxide exposure: an experimental chamber study

INTRODUCTION

Workers in aluminium production are exposed to a complex mixture of particles and gases potentially harmful to the airways, among them aluminium oxide (Al2O3). With the use of an exposure chamber, we aimed to examine the effects of short-term controlled exposure to Al2O3 on lung function and inflammatory markers in healthy volunteers.

METHODS

15 men (age 19-31) were exposed in random order to clean air or Al2O3 particles (3.8-4.0 mg/m(3)) for 2 h including 30 min exercise (stationary bike, 75 W). The permissible exposure level (PEL) for Al2O3 by Occupational Safety and Health Administration, USA, is 5 mg/m(3) time weighted average (TWA). Sham and particle exposures were separated by at least 2 weeks. Spirometry was carried out, and induced sputum and blood samples were collected 48 h before and 4 and 24 h after exposure.

RESULTS

Levels of sputum neutrophils (mean (±SEM)) was increased 24 h post-Al2O3 vs pre-Al2O3 exposure (43% (4) vs 31% (4), p=0.01) and the protein level of interleukin (IL)-8 had a 4.8 (0.9)-fold change increase 24 h after exposure (p<0.01). Following Al2O3 exposure, gene signatures in sputum were significantly increased related to several pathways.

CONCLUSIONS

The present study suggests that controlled exposure to Al2O3 particles at levels below PEL (TWA) induces airway inflammation in healthy humans marked by elevated neutrophils and elevated IL-8. In addition, increased expression of genes associated with several biological processes was observed in sputum. Interestingly, inhaled Al2O3-induced effects were localised to the airways and not systemic.

Speciation of fluoride in workroom air during primary production of aluminium

Exposure to fluorides (F(-)) and particulate matter (PM) was assessed by personal sampling with use of Respicon® sampler in Prebake and Søderberg pot rooms in seven aluminium smelters. The inhalable PM mass was dominated by the extra-thoracic aerosol sub-fraction, which contributed with around 70% for both Prebake and Søderberg pot room workers. Quantitative and qualitative differences in exposure were found between pot room workers in smelters using these two technologies. Prebake pot room workers were exposed to 1.4 to 1.7 times higher PM concentrations than Søderberg pot room workers, depending on aerosol sub-fraction. Prebake pot room workers were also exposed to 2.5 to 2.9 higher air concentrations of water-soluble F(-) (FWS(-)) and 2.8 to 5.3 higher air concentrations of non water-soluble F(-) (FAS(-)) than Søderberg pot room workers, depending on aerosol sub-fraction. However, exposure to hydrogen fluoride (HF) was 1.3 times higher among Søderberg pot room workers. The relative amount of FWS(-), however, was higher among Søderberg pot room workers, while the relative amount of particulate F(-) (sum of FWS(-) and FAS(-)) was higher among Prebake pot room workers (6.5 vs. 3.9%). Exposure to the same PM concentration yielded higher FWS(-) and FAS(-) air concentrations among Prebake compared to Søderberg pot room workers.

Systematic review of potential health risks posed by pharmaceutical, occupational and consumer exposures to metallic and nanoscale aluminum, aluminum oxides, aluminum hydroxide and its soluble salts

Abstract Aluminum (Al) is a ubiquitous substance encountered both naturally (as the third most abundant element) and intentionally (used in water, foods, pharmaceuticals, and vaccines); it is also present in ambient and occupational airborne particulates. Existing data underscore the importance of Al physical and chemical forms in relation to its uptake, accumulation, and systemic bioavailability. The present review represents a systematic examination of the peer-reviewed literature on the adverse health effects of Al materials published since a previous critical evaluation compiled by Krewski et al. (2007) . Challenges encountered in carrying out the present review reflected the experimental use of different physical and chemical Al forms, different routes of administration, and different target organs in relation to the magnitude, frequency, and duration of exposure. Wide variations in diet can result in Al intakes that are often higher than the World Health Organization provisional tolerable weekly intake (PTWI), which is based on studies with Al citrate. Comparing daily dietary Al exposures on the basis of "total Al"assumes that gastrointestinal bioavailability for all dietary Al forms is equivalent to that for Al citrate, an approach that requires validation. Current occupational exposure limits (OELs) for identical Al substances vary as much as 15-fold. The toxicity of different Al forms depends in large measure on their physical behavior and relative solubility in water. The toxicity of soluble Al forms depends upon the delivered dose of Al(+3) to target tissues. Trivalent Al reacts with water to produce bidentate superoxide coordination spheres [Al(O2)(H2O4)(+2) and Al(H2O)6 (+3)] that after complexation with O2(•-), generate Al superoxides [Al(O2(•))](H2O5)](+2). Semireduced AlO2(•) radicals deplete mitochondrial Fe and promote generation of H2O2, O2 (•-) and OH(•). Thus, it is the Al(+3)-induced formation of oxygen radicals that accounts for the oxidative damage that leads to intrinsic apoptosis. In contrast, the toxicity of the insoluble Al oxides depends primarily on their behavior as particulates. Aluminum has been held responsible for human morbidity and mortality, but there is no consistent and convincing evidence to associate the Al found in food and drinking water at the doses and chemical forms presently consumed by people living in North America and Western Europe with increased risk for Alzheimer's disease (AD). Neither is there clear evidence to show use of Al-containing underarm antiperspirants or cosmetics increases the risk of AD or breast cancer. Metallic Al, its oxides, and common Al salts have not been shown to be either genotoxic or carcinogenic. Aluminum exposures during neonatal and pediatric parenteral nutrition (PN) can impair bone mineralization and delay neurological development. Adverse effects to vaccines with Al adjuvants have occurred; however, recent controlled trials found that the immunologic response to certain vaccines with Al adjuvants was no greater, and in some cases less than, that after identical vaccination without Al adjuvants. The scientific literature on the adverse health effects of Al is extensive. Health risk assessments for Al must take into account individual co-factors (e.g., age, renal function, diet, gastric pH). Conclusions from the current review point to the need for refinement of the PTWI, reduction of Al contamination in PN solutions, justification for routine addition of Al to vaccines, and harmonization of OELs for Al substances.