Development of composite materials based on chrome-containing waste and polyurethane binder

The results of a study of the effect of the type and consumption of binder and plasticizers on the physicochemical characteristics of composite materials obtained using chromium-containing fibrous wastes from leather production are presented. The absence of chromium compounds in water extracts of composites has been established, which confirms the environmental safety of new composite materials.

Study of changes in biochemical indices in workers employed in underground mining of chrome ore

Introduction. Underground mining of chrome ores is characterized by constant exposure to chemical factors on production workers, leading to changes in critical organs and systems. The aim of the work was to study changes in some biochemical parameters in workers engaged in underground mining of chrome ores. Materials and methods included assessing the chromium content in the air of the working area and biological media of workers, the study of many biochemical parameters and protein fractions of blood serum, modelling of cause-and-effect relationships. Results. The workers of the observation group compared to the comparison group showed a significant (up to 1.5 times) increase in the level of chromium in the blood and urine, an increase in the level of IgE specific to chromium - up to 1.6 times, the activity of ALAT and γ-HT in the blood serum - up to 1.3 times, the level β2-microglobulins in serum and urine - up to 1.6 times, serum creatinine levels, slowing of GFR, increased serum AOA, β-globulins and γ-globulins levels. Conclusion. The constant presence of chromium compounds in the air of the working area of mineworkers leads to an elevated concentration of chromium in the blood and its excretion in the urine. The workers of the studied production showed an increase in the level of many laboratory indicators of adverse effects on the liver and kidneys, the immune and antioxidant systems. Changes in the protein fractions of blood serum were revealed in workers at the mine mining chromium ores.

Impact of Environmental and Lifestyle Use of Chromium on Male Fertility: Focus on Antioxidant Activity and Oxidative Stress

Male reproductive tissues are strongly susceptible to several environmental and lifestyle stressors. In general, male reproductive health is highly sensitive to oxidative stress, which results in reversible and/or irreversible changes in testosterone-producing cells, spermatogenesis, and sperm quality. Chromium compounds are widely used in the +3 and +6 valence states, as food supplements, and in the industrial field, respectively. Chromium (III) compounds, i.e., Cr(III)-tris-picolinate, [Cr(pic)3], known as chromium picolinate, are used as nutritional supplements for the control of diabetes, body weight, and muscular growth. However, previous studies showed that animal models exposed to chromium picolinate experienced degenerative changes in spermatogenesis. Contradictory results are documented in the literature and deserve discussion. Furthermore, the long-term effects of chromium picolinate on the antioxidant system of treated subjects have not been properly studied. Comprehensive studies on the role of this compound will help to establish the safe and useful use of chromium supplementation. On the other hand, chromium (VI) compounds are widely used in several industries, despite being well-known environmental pollutants (i.e., welding fumes). Chromium (VI) is known for its deleterious effects on male reproductive health as toxic, carcinogenic, and mutagenic. Previous studies have demonstrated severe lesions to mouse spermatogenesis after exposure to chromium (VI). However, workers worldwide are still exposed to hexavalent chromium, particularly in electronics and military industries. Data from the literature pinpoints mechanisms of oxidative stress induced by chromium compounds in somatic and germ cells that lead to apoptosis, thus underlining the impairment of fertility potential. In this review, we analyze the benefits and risks of chromium compounds on male fertility, as well as the mechanisms underlying (in)fertility outcomes. Although supplements with antioxidant properties may maximize male fertility, adverse effects need to be investigated and discussed.

FORMATION OF LEATHER QUALITY INDICATORS OF DIFFERENT TYPES OF LEATHER RAW MATERIALS WITH THE USE OF MONTMORILONITE

The tanning process is important in stabilizing the collagen structure of the derma. Сhrome tanning is the traditional option. The basic chromium sulfate is used in the production of 80% of leather in use. A peculiarity of chromium tanning turns out to be an inefficient use of chromium compounds, since almost 40% of tannins remain in wastewater. Considering the disadvantages of using chromium compounds, scientific research on the replacement and use of rather eco-friendlier substances has been conducted for a long time. One of the directions of ecologization of leather manufacturing is the use of modified montmorillonite dispersions in various technological processes such as tanning, filling, dyeing, fat-liquoring, etc. Researches have been aimed at identifying the feasibility of making leather for the uppers of children’s shoes from different types of leather raw materials using modified dispersions of montmorillonite at the stage of tanning. According to the technology of making leather, cattle (medium heifer), goat and sheep skins were used for the upper of the shoes. The analysis of leather quality indicators from different types of raw materials obtained with the use of chromefree tanning. It is proved that hides from raw materials of goats and sheepskins in comparison with cattle are characterized by increased yield area by 3.5-7.2 %, thickness by 0.8-2.6 %, volume yield by 4.5-6.1 % and uniformity of quality indicators in different topographic areas. The level of indicators of physical and mechanical, hygienic properties and chemical composition of leather of different types of raw materials is almost identical within the requirements of regulatory documents. It is advisable to use for children’s shoes leather from raw goat and sheepskin given the peculiarities of the manufacture of children’s shoes, dimensional characteristics of parts, requirements for dimensional stability and shape conservation.

Increased urine chromium concentrations in a worker exposed to lead chromate due to medicinal herb intake

Background: Hexavalent chromium compounds are sensitizers of the skin and lung. Chronic exposure to hexavalent chromium compounds is associated with respiratory effects and ulceration and perforation of the nasal septum. Such compounds are also considered carcinogens of the lung and nasal and paranasal sinus. Objectives: To demonstrate the importance of studying occupational and non-occupational exposure when assessing the concentration of substances in the urine. Case study: A study was conducted of environmental chromium concentrations in the workplace. In addition, an occupational medical examination was performed, recording activities inside and outside the workplace, eating habits, blood lead and urine chromium at the beginning and end of the workday. Results: One worker exposed to lead chromate presented high chromium concentrations in urine (up to 62 µg/l before the working day and 52 µg/l at the end of the working day). Environmental chromium concentrations in the workplace were below 0.25 µg/m3. In view of the results, a full study was conducted of the patient’s habits outside work. He reported having bought a kilo of a medicinal herb infusion at a street market three weeks previously. The concentration of total chromium in the prepared infusion was 12000 µg/l. The patient stopped consuming the medicinal herb. Subsequently, the urine chromium analysis was below 0.5 µg/l. Discussion and Conclusions: This case is interesting because it demonstrates that the consumption of medicinal herbs can interfere with biological monitoring of workers exposed to hexavalent chromium compounds. This may give rise to confusion and can also create legal problems for companies and workers. It is important to provide advice to workers and to investigate their habits outside work, especially when there is a discrepancy between environmental and biological values. In this case, the increase in urinary chromium is due to the consumption of medicinal herbs.

The fate of chromium in soils

<p>The large industrial utilization of chromium compounds originates heavy environmental and health risks concerns. Chromium has a double behavior, as Cr(III), is an essential element to living beings but also a very harmful carcinogenic as Cr(VI). Hexavalent chromium is a powerful oxidant easily reduced to chromium(III). The fact of the compounds of chromium(III) being considered kinetically inert induces their environmental abandon without any concerns about their real final fate. Nowadays there is an increasing interest on chromium bioremediation in soils.</p><p>Depending on soils composition, the interaction between the chromium(III) compounds and both organic and inorganic soil components can originate an increase of the solubility of the chromium(III) compounds together with acid-base and redox reactions. The change on the solubility of chromium compounds can be monitored from the composition of the soil solutions from where plants can have access to the ionic species of chemical elements. The presence of organic matter is usually associated to the existence of reducing environments, while the presence of manganese oxides is associated to oxidizing environments. Here is analysed the influence of these two environments in the composition of soil solutions and the consequent availability to plants, as well as the design of the soil remediation programs.</p>

Effects of Different Chromium Compounds on Hematology and Inflammatory Cytokines in Rats Fed High-Fat Diet

The aim of the study was to determine how a high-fat diet supplemented with various forms of chromium affects hematological and immune parameters of the blood of rats. The rats received a standard diet or a high-fat diet supplemented with chromium at 0.3 mg/kg body weight (BW) in the form of chromium(III) picolinate, chromium(III)-methionine or nano-sized chromium. Selected hematological parameters were determined in the blood of the rats, including total white blood cell (WBC) count, leukogram, red blood cell (RBC) count, hemoglobin level (HGB), hematocrit (HCT), platelet count (PLT) and platelet percentage (PCT), as well as immune parameters: levels of immunoglobulins A and E (IgA and IgE), interleukin-6 (IL-6), interleukin-2 (IL-2), and tumor necrosis factor α (TNF-α); activity of ceruloplasmin (Cp); and levels of caspase 3 and 8 (Casp3 and Casp8). Feeding rats a high-fat diet increased blood markers of induction of inflammation, ie pro-inflammatory cytokines IL-6 and TNF-α, and also significantly increased IgE. The diet had no effect on the blood count, except for an increase in the number of neutrophils. The chromium compounds tested, particularly Cr-Met and Cr-NPs, stimulated the immune system of the rats, as indicated by increased concentrations of IgA, IgE, IL-2, IL-6, TNF-α, and Cp. Given the increase in inflammatory mediators induced by chromium, it should not be used to mitigate the effects of a high-fat diet. Moreover, chromium picolinate and chromium nanoparticles were shown to increase the content of caspase 3 and 8 in the blood of rats, which indicates a pro-apoptotic effect. The effects of the use of chromium nanoparticles include reductions in the WBC count and in the thrombocyte count (leuko- and thrombopenia). Taking account these data the use of chromium as dietary supplement should be reconsidered.

The state of the red bone marrow in rats depending on age in case of poisoning with lead acetate and potassium dichromate

Introduction: The current ecological situation is described by a rapid increase in air pollution through various chemical emissions. Aim: The study aims to define how the level of lead and chromium compounds affects the parameters of red bone marrow and blood in animals and how these processes depend on their age. Material and methods: To study the toxic intraday effect of heavy metals, a metal probe was used for combined priming of rats with lead acetate and potassium dichromate. The indicators were analyzed with the use of a cytogram, and the indices of the ratio between young and mature forms were calculated. The obtained factual material was subjected to computer processing with the calculation of the Student’s criterion and confidence intervals. Results and discussion: It was established that in young rats there is an accumulation of polychromatophilic cells with a large amount of hemoglobin, which leads to a violation of their maturation – with that, the subsequent stage of division passes very quickly, when, upon transforming into orthochromatic normoblasts, they pass into the blood after 15–20 h, forming a variant of terminal division. In old animals, there was a decrease in total bone marrow cellularity and severe anemia. Conclusions: After the experiments and profound analysis, the author of the study defined the difference of toxic effects on young and old animals.