Ecotoxicological risks associated with land treatment of petrochemical wastes. I. Residual soil contamination and bioaccumulation by cotton rats (Sigmodon hispidus)

Dietary High Sodium Fluoride Impairs Digestion and Absorption Ability, Mucosal Immunity, and Alters Cecum Microbial Community of Laying Hens

(1) Background: This study was conducted to investigate the effects of dietary fluoride (F) on tissue retention, digestive enzymes activities, mucosal immunity, and cecum microbial community of laying hens. (2) Methods: Total of 288 37-week-old Hy-Line Gray laying hens with similar laying rate (85.16% ± 3.87%) were adapted to the basal diets for ten days, and then allocated into three groups at random (n = 9, 6, 6 replicates/group). The concentrations of F in the diets were 31.19 (the control group, CON), 431.38 (F400, low-F group) and 1237.16 mg/kg (F1200, high-F group), respectively. The trial lasted for 59 days. (3) Results: Results suggested that F residuals in duodenum responded to dietary F concentrations positively. The activities of amylase, maltase and lactase were decreased in high-F group, compared with those in the control group. The mRNA expression levels of jejunum and ileum secretory immunoglobulin A (sIgA) and Mucin 2, and sIgA concentrations were decreased inhigh-F group, than those in the control group. The observed operational taxonomic units (OTUs) of laying hens in high-F group were higher than the CON and low-F groups, and the bacterial structure was different from the other two groups. The Lactobacillus was higher in the control group, while Gammaproteobacteria, Escherichia-Shigella, Streptococcaceae, and Enterobacteriaceae were higher in the high-F group. (4) Conclusions: The actual results confirmed that dietary high F intake increased the F residuals in duodenum, and reduced the digestion and absorption of nutrients and immunity via decreasing the activities of digestive enzymes, impairing intestine mucosal immunity, and disturbing the cecum microbial homeostasis of laying hens.

Adsorptive Removal of Fluoride from Water Using Nanomaterials of Ferrihydrite, Apatite, and Brucite: Batch and Column Studies

This study investigated the adsorptive removal of fluoride from simulated water pollution using various (hydro)oxide nanomaterials, which have the potential to be used as sorbents for surface water and groundwater remediation. Tested nanomaterials include hematite, magnetite, ferrihydrite, goethite, hematite-alpha, hydroxyapatite (HAP), brucite, and four titanium dioxides (TiO₂-A [anatase], TiO₂-B [rutile], TiO₂-C [rutile], and TiO₂-D [anatase]). Among 11 (hydro)oxide nanomaterials tested in this study, ferrihydrite, HAP, and brucite showed two to five times higher removal of fluoride than other nanomaterials from synthetic fluoride solutions. Freundlich and Redlich-Peterson adsorption isotherms better described the adsorptive capacity and mechanism than the Langmuir isotherm based on higher R ² values, indicating better fit of the regression predictions. In addition, the adsorption kinetics were well described by the intraparticle diffusion model. Column studies in a fixed bed continuous flow through system were conducted to illustrate the adsorption and desorption behavior of fluoride on ferrihydrite, HAP, or brucite. Experimental results fitted well with the Thomas model because of the R ² values at least 0.885 or higher. By comparisons of the adsorption capacity and the rate constant, columns packed with ferrihydrite exhibited not only faster rates but also higher sorption capacity than those packed with HAP or brucite. Desorption tests in deionized water showed that the adsorbed fluoride could be desorbed at a lower efficiency, ranging from 4.0% to 8.9%. The study implicated that (hydro)oxide nanomaterials of iron calcium and magnesium could be effective sorptive materials incorporated into filtration systems for the remediation of fluoride polluted water.

Chromosomal instability in rodents caused by pollution from Baikonur cosmodrome

An assessment of the health status of ecosystems exposed to man-made pollution is a vital issue for many countries. Particularly it concerns the consequences of contamination caused by the activity of the space industry. Each rocket launch is accompanied by the introduction of parts of the rocket propellant into the environment. This study aims to scrutinize the effect of the components of rocket fuel on the induction of lipid peroxidation and chromosomal aberrations on rodents inhabiting the area exposed to pollution from Baikonur cosmodrome. The results showed the increase of the level of lipid hydroperoxide and malondialdehyde in the livers of Citellus pygmaeus Pallas and Mus musculus L., which indicates an augmentation of free radical activity and DNA damage. The cytogenetic analysis of bone marrow cells revealed that the frequency of chromosomal aberrations was a few times higher in the rodents from contaminated territory. The signs of oxidative stress and high level of chromosomal aberrations indicate the environmental impact of the cosmodrome, and its possible toxic and mutagenic effects on ecosystems.

Suppressive effects of dietary high fluorine on the intestinal development in broilers

Fluoride (F) is a well-recognized hazardous substance. Ingested F initially acts locally on the intestines. The small intestine plays a critical role in the digestion, absorption, and defense. In this study, therefore, we investigated the effects of fluorine on the intestinal development by light microscopy, transmission electron microscopy, and histochemistry. A total of 280 one-day-old avian broilers were randomly divided into four groups and fed on a corn-soybean basal diet as control diet (fluorine, 22.6 mg/kg) or the same basal diet supplemented with 400, 800, and 1,200 mg/kg fluorine (high fluorine groups I, II, and III) in the form of sodium fluoride for 42 days. The results showed that the intestinal gross, histological, and ultrastructural changes were observed in the high fluorine groups II and III. Meanwhile, the intestinal length, weight, viscera index, villus height, crypt depth, villus height to crypt depth ratio, diameter, muscle layer thickness, and goblet cell numbers were significantly lower (p < 0.01 or p < 0.05), and the intestinal diameter to villus height ratio was markedly higher (p < 0.01 or p < 0.05) in the high fluorine groups II and III than those in control group. In conclusion, dietary fluorine in the range of 800-1,200 mg/kg obviously altered the aforementioned parameters of the intestines, implying that the intestinal development was suppressed and the intestinal functions, such as digestion, absorption, defense, or osmoregulation were impaired in broilers.

Assessment of mercury concentrations in small mammals collected near Las Vegas, Nevada, USA

Mercury concentrations in liver and hair tissue were determined for five species of small mammals captured near Las Vegas, Nevada, USA. These data were then used to evaluate the suitability of using hair as a noninvasive technique for determining body burdens of mercury. A total of 104 small mammals were captured and analyzed; four main species were examined and included: Dipodomys merriami, Chaetodipus penicillatus, Peromyscus eremicus, and Neotoma lepida. Mean mercury concentrations were highest in N. lepida, followed by D. merriami, C. penicillatus, and P. eremicus respectively. Positive associations were found between hair and liver taken from D. merriami (r = 0.647) and C. penicillatus (r = 0.533) indicating that hair may be a suitable indicator of body burdens in these two species.

Spatial distribution of dental fluorosis in roe deer (Capreolus capreolus) from North Bohemia (Czech Republic) and its relationships with environmental factors

We assessed the spatial variation of fluoride load on the local ecosystem in the Czech part of the Ore Mountains region and its southern foothills - a heavily polluted part of Europe's "Black Triangle" region. Dental fluorosis in roe deer (Capreolus capreolus) served as a biomarker of fluoride exposure and thus as an indicator of environmental pollution by fluoride. The mean dental lesion index of fluorosis (DLI) calculated from the analyzed mandibles of wild roe deer (>or=2 years of age) was assigned to the hunting ground from which the specimens originated and classified into one of the eight fluorosis categories. Environmental factors potentially related to dental fluorosis (atmospheric deposition of sulfur, concentration of fluoride in and pH of surface waters, geomorphologic features, bedrock and soil type, and vegetation cover), which were represented in the study by GIS layers, were examined to explain the distribution pattern and severity of fluorosis in the roe deer. The study revealed that 75.5% of 616 analyzed mandibles showed dental fluorosis to different extent, with individual DLIs ranging from 0 to 21. The spatial pattern of marked fluorosis on the Czech side continues that found in a previous study on the German side of the Ore Mountains. Together they create a landscape island around several thermal power plants in the region. General Linear Model (GLM) analyses revealed significant relationships between degree of forest damage, soil type, and atmospheric sulfur deposition from air pollution and dental fluorosis, expressed as mean DLI in the roe deer.

Population dynamics of cotton rats (Sigmodon hispidus) inhabiting abandoned petroleum landfarms in Oklahoma, USA

Previous work by our group has shown bioaccumulation of contaminants and alterations in the immune system of hispid cotton rats (Sigmodon hispidus) inhabiting petrochemical waste sites (landfarms). We studied populations of cotton rats inhabiting petrochemical landfarms or uncontaminated reference sites. Cotton rat populations inhabiting abandoned landfarms experienced reduced summer population densities and lower mean monthly survival, with maximum densities 65% that of populations inhabiting non-contaminated grassland (reference) sites. Survival was lower in populations from landfarms (0.62+/-0.04) compared to reference sites (0.75+/-0.04), with differences most notable during summer months. Cotton rat populations sampled from landfarms had even sex ratios and a lower proportion of juveniles compared to populations from reference sites. No differences were observed in the weight of epididymides, testes, uteri, or ovaries, and no differences in fecundity were detected among sites.

Ecotoxicological risks associated with land treatment of petrochemical wastes. II. Effects on hepatic phase I and phase II detoxification enzymes in cotton rats

The purpose of this study was to evaluate possible exposure and resultant hepatic effects of petrochemical waste on cotton rats (Sigmodon hispidus) living on landfarmed sites. Male and female cotton rats were collected in summer, fall, and winter from four landfarm sites and four ecologically similar reference sites. Hepatic methoxyresorufin O-deethylase (MROD) activity was significantly induced in male and female rats collected from landfarms compared to rats collected from reference sites. In contrast, changes in ethoxyresorufin O-deethylase (EROD) activity were inconsistent due to season, sex, and treatment variation. A significant decrease in EROD and MROD activity was found in cotton rats held for 48 h prior to sacrifice compared to rats euthanized on the day of capture. These results indicate that when using hepatic EROD and MROD activities as biochemical markers of exposure to aryl hydrocarbon receptor agonists, animals should be euthanized as quickly as possible after capture. The cotton rats collected from one landfarm unit exhibited a pattern of consistent elevation of EROD, MROD, and pent-oxyresorufin O-deethylase (PROD) activity. This unit also had a pattern of elevated CYP1A2 protein expression determined by Western blotting. There were no consistent alterations from contaminant exposure on hepatic glutathione S-transferase (GST) activity, glutathione levels, or CYP1A1 protein. Hepatic EROD and MROD activities varied considerably between seasons and sex of rats. In conclusion, consistent induction of hepatic EROD and MROD activities in cotton rats was found in three out of four sampled landfarm sites compared to the rats collected from the reference sites, indicating exposure to contaminants-likely polyaromatic hydrocarbons.