Heavy metals have been associated with many fish deformities in natural populations and in laboratory produced specimens as well. Deformities in general have devastating effects on fish populations ...since they affect the survival, the growth rates, the welfare and their external image. Although the embryonic stage in respect to heavy metal exposure has been extensively studied, there is not much information available as to what happens in fish larvae and adults. In the present article, we present the available information on the effect of heavy metals on fish larvae deformities. We also address the need for more research towards the effects of metals on the subsequent life stages in order to assess the long-term consequences of heavy metal poisoning on fish organisms and possibly correlate these consequences with the environmental contamination (use as biomarkers).
•The scarce literature on heavy metals effects on fish larvae deformities is gathered.•Heavy metals mainly cause hatching delay, deformities and mortality in fish.•The main deformities caused by heavy metals on fish are spinal ones (up to 100%).•More research required on the latent sublethal effects of environmental pollutants.•Fish deformities could be used as biomarkers of environmental contamination.
Lethal cardiac complications leading to death and various arrhythmias have been reported after organophosphate and/or carbamate poisonings. The present study focuses on the long-term effects of ...repeated low-level exposure to diazinon, propoxur, and chlorpyrifos (CPF) on cardiac function in rabbits. The yearly based experimental scheme of exposure consisted of two oral administration periods, lasting 3 months and 1 month each, interrupted by an 8-month washout period (total duration 12 months). At the end of the experimental scheme, the rabbits underwent an echocardiographic evaluation under sedation, after which they were killed and the tissue and serum samples were collected. A mild localized cardiotoxic effect was established by echocardiography for the three pesticides tested. Severe histological alterations were identified, especially in the diazinon-treated animals in agreement with increased persistence of this pesticide established in the cardiac tissue. In addition, all pesticides tested increased the oxidative stress and oxidative modifications in the genomic DNA content of the cardiac tissues, each one following a distinct mechanism.
In real life, consumers are exposed to complex mixtures of chemicals via food, water and commercial products consumption. Since risk assessment usually focuses on individual compounds, the current ...regulatory approach doesn’t assess the overall risk of chemicals present in a mixture. This study will evaluate the cumulative toxicity of mixtures of different classes of pesticides and mixtures of different classes of pesticides together with food additives (FAs) and common consumer product chemicals using realistic doses after long-term exposure. Groups of Sprague Dawley (CD-SD) rats (20 males and 20 females) will be treated with mixtures of pesticides or mixtures of pesticides together with FAs and common consumer product chemicals in 0.0, 0.25 × acceptable daily intake (ADI)/tolerable daily intake (TDI), ADI/TDI and 5 × ADI/TDI doses for 104 weeks. All animals will be examined every day for signs of morbidity and mortality. Clinical chemistry hematological parameters, serum hormone levels, biomarkers of oxidative stress, cardiotoxicity, genotoxicity, urinalysis and echocardiographic tests will be assessed periodically at 6 month intervals. At 3-month intervals, ophthalmological examination, test for sensory reactivity to different types of stimuli, together with assessment of learning abilities and memory performance of the adult and ageing animals will be conducted. After 24 months, animals will be necropsied, and internal organs will be histopathologically examined. If the hypothesis of an increased risk or a new hazard not currently identified from cumulative exposure to multiple chemicals was observed, this will provide further information to public authorities and research communities supporting the need of replacing current single-compound risk assessment by a more robust cumulative risk assessment paradigm.
A new, simple, fast and sensitive method that enables the measurement of four dialkyl phosphates (DAPs) in human head hair is presented in the current study. The dialkyl phosphates, dimethyl ...phosphate (DMP), diethyl phosphate (DEP), diethyl thiophosphate (DETP) and diethyl dithiophosphate (DEDTP) are non-selective metabolites of the organophosphate pesticides (OPs). The extraction of DAPs from hair matrix was achieved by one step methanolic extraction. Head hair samples from general population and population occupationally exposed to OPs were analysed using gas chromatography–mass spectrometry (GC–MS) after derivatization with pentafluorobenzylbromide. The recovery of the target compounds was estimated at 84.3% for DMP, 116.1% for DEP, 109.0% for DETP and 91.5% for DEDTP. The limit of quantitation (LOQ) and detection (LOD) was 20 and 6
pg/mg for DMP, 10 and 5
pg/mg for DEP and DETP and 5 and 3
pg/mg for DEDTP, respectively. With-run and between-run precision as well as accuracy was estimated. The percentage of positive hair samples for DMP, DEP, DETP and DEDTP for the group of general population was 63.0%, 96.3%, 66.7%, and 70.4% respectively. The samples from the group with occupational exposure were positive for all dialkyl phosphates analysed. The median concentrations for DMP were 165.0 and 181.7
pg/mg, for DEP were 51.2 and 812.9
pg/mg, for DETP were 54.0 and 660.1
pg/mg, and for DEDTP were 40.0 and 60.6
pg/mg for the general population group and the group with occupational exposure respectively. Significant differences in the levels of the total dialkyl phosphates amongst exposed and not exposed groups were observed (
p
<
0.001). More specifically, the total ethyl phosphate (DEPs) and DAPs median concentrations were 119.5 and 301.5
pg/mg for the general population group and 1498.8 and 1694.4
pg/mg for the group with occupational exposure.
Telomeres are repeated 5'-TTAGGG-3' sequences at the end of chromosomes, which maintain genomic stability. Their length is related to a number of diseases that affect humans. Apart from cancer, ...cardiovascular diseases, diabetes and other, telomere length has been associated with chronic diseases. Chronic mental illness includes various types of mental disorders with the most common being depression, schizophrenia and stress-anxiety. The aim of this review is to summarize the current state of knowledge on the role of telomeres in these disorders and to compare telomere length variations in patients receiving medication and patients not taking treatment. Most studies report reduced telomere length in patients suffering from mental disorders, compared to the general population. Since the factors that can affect telomere length are various, more experiments and investigations are required to understand the general impact of different factors on telomere length.
Arc welding operations are considered to be risky procedures by generating hazardous welding fume for human health. This study focuses on the key characteristics, as well as dispersion models, of ...welding fumes within a work zone. Commercial and widely used types of electrodes with various types of covering (rutile, basic, acidic and rutile-cellulose) were used in a series of experiments on arc welding operations, under 100 and 150 amps of electric current. According to the results of this study, maximum levels of pollution with particles of PM
fraction occur in the workspace during arc welding operations. Disregarding the types of electrodes used, the 3D models of dispersion of the РМ
particles at the floor plane exhibit corrugated morphologies while also demonstrate high concentrations of the РМ
particles at distances 0-3 m and 4-5 m from the emission source. The morphology of these particles is represented by solid and hollow spheres, 'nucleus-shell' structures, perforated spheres, sharp-edged plates, agglomerates of the tree-like (coral) shape. At last the bifractional mechanism of fume particle formation for this type of electrodes is also shown and described. In this article results are reported, which demonstrate the hazards of the arc welding process for human health. The results of the characterization of WFs reported improve our understanding of risks that these operations pose to human health and may strengthen the need for their control and mitigation.
•The concept of dose response traces back to 8th century BC, with Hesiod’s Harmonia.•Mithridates VI Eupator was the first to approach the notion of dose response in practice.•Paracelsus was the first ...to underline the importance of dose in the final toxic result of a xenobiotic.•Bernard stated the dose response concept, Cushny, Harnack & Ehrlich formulated threshold and minimal effective dose terms.•Hornesis stems from the biphasic nature of dose response, and can enhance risk assessment strategies.
Since ancient times the concept of dose response, from a toxicological perspective, has been a matter of concern. Already by the 8th century BC and over the years, many enlightened people have attempted to interpret this phenomenon, observing and coming across its results and practical implementation through exposure to chemical substances, either from natural or synthetic sources. Nowadays, the environmental exposure of human populations to chemicals in terms of quantity and quality might differ. Nevertheless, dose response still remains an issue joining hands with scientific and technological progress. The aim of the present review is not only to briefly recount the history of the dose response concept, from ancient time theories to novel approaches, but also to draw the outline of challenges and requirements toxicology science needs to fulfill.
Intensification of crop cultivation can have detrimental environmental consequences that however can be prevented by monitoring of the specific biological indicators sensitive to changes in the ...ambient environment. In this study the impact of crop type (spring wheat and corn) and cultivation intensity on the community of ground beetles (Coleoptera: Carabidae) in the forest-steppe of Western Siberia was investigated. A total of 39 species from 15 genera were collected. Ground beetles' community was characterized by a high evenness of species distribution across the agroecosystems. The average Jaccard's similarity index for species presence/absence was 65%, and for abundance it was 54%. The significant difference in the distribution of predatory and mixophytophages ground beetles in wheat crops (U test, P < 0.05) can be justified by the constant suppression of the weed component and the use of insecticides that lead to the dominance of the predators. Fauna of wheat crops was more diverse than that in corn (Margalef index, U test, P < 0.05). No significant differences in biological diversity indexes, except for the Simpson dominance index (U test, P < 0.05, wheat), were found in ground beetle communities in crops at different levels of intensification. A certain differentiation of predatory species was caused by the selective occurrence of the litter-soil species, especially abundant in the row-crop. The specificity of the ground beetle community of corn crops may have been caused by repeated inter-row tillage, which influenced the increase in porosity and topsoil relief and contributed to the creation of favorable microclimatic conditions. In general, the applied level of agrotechnological intensification had no significant effect on the species composition and ecological structure of beetle communities in agrolandscapes. The use of bioindicators made it possible to assess the environmental sustainability of the agricultural environment and also creates the prerequisites for the development of ecologically directed correction of agrotechnological operations in agroecosystem management.
•Ground beetles (Coleoptera: Carabidae) are convenient model bioindicators for environmental research.•Crop type and its corresponding cultivation technology has an impact on the spatial differentiation of species.•The suppression of the weed component and the use of insecticides in the fields explain the dominance of predatory species.•The applied level of agrotechnological intensification had no significant effect on the species composition and ecological structure of ground beetle communities.
In this pilot study, we examined the validity and usefulness of hair nicotine–cotinine evaluation as a biomarker of monitoring exposure to tobacco. Head hair samples were collected from 22 infants ...(<2 years of age) and 44 adults with different exposures to tobacco (through either active or passive smoking) and analyzed by liquid chromatography–mass spectrometry (LC-MS) for nicotine and cotinine. Hair samples were divided into three groups, infants, passive smoker adults and active smoker adults, and into eight subgroups according to the degree of exposure. The limit of quantification (LOQ) was 0.1 ng/mg for nicotine and 0.05 ng/mg for cotinine. Mean recovery was 69.15% for nicotine and 72.08% for cotinine. The within- and between-day precision for cotinine and nicotine was calculated at different concentrations. Moreover, hair nicotine and cotinine concentrations were highly correlated among adult active smokers (R
2 = 0.710, p < 0.001), among adult nonsmokers exposed to secondhand smoke (SHS; R
2 = 0.729, p < 0.001) and among infants (R
2 = 0.538, p = 0.01). Among the infants exposed to SHS from both parents the noted correlations were even stronger (R
2 = 0.835, p = 0.02). The above results identify the use of hair samples as an effective method for assessing exposure to tobacco, with a high association between nicotine and cotinine especially among infants heavily exposed to SHS.
The study of pyrrole oxidative polymerization in toluene localized on the surface of silica gel modified with manganese oxide (IV) was carried out. The kinetics of pyrrole oxidative polymerization on ...the surface was established, a kinetic model was proposed, and its parameters were calculated. It was shown that the activation energy is close to free energy of the viscous toluene flow that indicates diffusion control of the process. The changes of the specific surface area of silica gel and the pore volume distribution along the radii during the modification with manganese dioxide and the subsequent polymerization of pyrrole were determined.
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•The deposition of PPy on the surface of silica gel modified with MnO2 is described.•The first order of pyrrole polymerization with E = 14 kJ/mol has been established.•Diffusion control of interfacial pyrrole polymerization is shown.•The depth of penetration of the reaction zone increased with increasing temperature.•After polymerization of pyrrole the specific surface area of the particles increased.
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