Morphological, biochemical, and histopathological indices and contaminant burdens of cotton rats (Sigmodon hispidus) at three hazardous waste sites near Houston, Texas, USA

Male cotton rats (Sigmodon hispidus) were studied at three industrial waste sites near Houston, Texas, to determine whether various morphological, biochemical, and histopathological indices provided evidence of contaminant exposure and toxic insult. Only modest changes were detected in cotton rats residing at waste sites compared with reference sites. No single parameter was consistently altered, except hepatic cytochrome P-450 concentration which was lower ( [Formula: see text] ) at two waste sites, and tended to be lower ( [Formula: see text] ) at a third waste site. Elevated petroleum hydrocarbon concentrations were detected in rats at one waste site, but contaminant burdens of rats from the other sites were unremarkable. Unlike rats captured in summer, those trapped in winter exhibited hepatocellular hypertrophy and up to a 65% increase in liver: body weight ratio, cytochrome P-450 concentration, and activities of aniline hydroxylase, aryl hydrocarbon hydroxylase, and glutathione S-transferase. Although genotoxicity has been previously documented in cotton rats residing at two of the waste sites, biomarkers in the present study provided little evidence of exposure and damage.     

Ecotoxicity revealed in parasite communities of Sigmodon hispidus in terrestrial environments contaminated with petrochemicals

Several studies have documented contaminant-induced alterations in host-parasite relationships of vertebrate hosts in aquatic environments, suggesting this functional relationship may be useful for monitoring community-level effects of stressors in terrestrial systems. We hypothesized that gastrointestinal helminth communities of hispid cotton rat (Sigmodon hispidus) hosts would be sensitive to exposure to complex mixtures of petrochemicals in soils of tallgrass prairie habitats contaminated with oil refinery wastes. Parasite communities were surveyed (1993-95) on three contaminated and two reference sites on an oil refinery complex in Oklahoma. Abundance of Schizotaenia sigmodontis infections was two-fold higher in hosts from reference than contaminated sites. Strongyloides sigmodontis exhibited pronounced seasonal differences in prevalence and abundance in host populations from reference sites, with much higher seasonal variation compared to hosts from contaminated sites. Other helminth species, including Schizotaenia sigmodontis, Protospirura muris, Longistriata adunca, also exhibited seasonal fluctuations in abundance. Differences in species richness and composition were also observed, with hosts from the reference sites consistently supporting a higher mean number of species compared to those from contaminated sites. Differences in community structure indicate that host-parasite relationships can provide another useful method for monitoring community-level impacts of contamination in a terrestrial system.     

Fluoride accumulation and toxicity in wild small mammals

Populations of two species of small mammal, the field vole (Microtus agrestis L.) and the bank vole (Clethrionomys glareolus L.), inhabiting grasslands contaminated by industrial sources of fluoride were examined for fluoride concentrations in skeletal tissue and for morphological changes in the teeth. Concentrations of fluoride in teeth and bones were higher for C. glareolus than for M. agrestis at the chemical works and smelter sites. Severe dental lesions were recorded on the incisor and molar teeth of both species at the chemical works and smelter sites, with less marked damage at the mine tailings dam. This is attributed to inter-site differences in fluoride speciation and the consequent effects on the availability of fluoride in the diet for bioassimilation.     

Tissues and hair residues and histopathology in wild rats (Rattus rattus L.) and Algerian mice (Mus spretus Lataste) from an abandoned mine area (Southeast Portugal)

Data gathered in this study suggested the exposure of rats and Algerian mice, living in an abandoned mining area, to a mixture of heavy metals. Although similar histopathological features were recorded in the liver and spleen of both species, the Algerian mouse has proved to be the strongest bioaccumulator species. Hair was considered to be a good biological material to monitor environmental contamination of Cr in rats. Significant positive associations were found between the levels of this element in hair/kidney (r=0.826, n=9, p<0.01) and hair/liver (r=0.697, n=9, p=0.037). Although no association was found between the levels of As recorded in the hair and in the organs, the levels of this element recorded in the hair, of both species, were significantly higher in animals captured in the mining area, which met the data from the organs analysed. Nevertheless, more studies will be needed to reduce uncertainty about cause-effect relationships.     

Efficacy and toxicity of self-polishing biocide-free antifouling paints

The ban on harmful substances in antifouling paints requires the development of new antifouling strategies. Alternatives should be as effective as conventional paints but of lower toxicity. In the present study two commercially available, self-polishing antifouling paints were examined in order to get information on their antifouling properties and toxicological potential. Efficacy was shown in settlement assays with the marine barnacle species Balanus amphitrite, however, efficacy was related to toxic effects observed on target and non-target organisms. Toxicity of the paint extracts was concentration-dependent and differed according to the paint and the species investigated. Toxicity could at least partially be attributed to zinc leached from the paints. Effects of a water-soluble paint were more pronounced in larvae of B. amphitrite, Artemia salina and in the green algae Dunaliella tertiolecta. Embryos of the freshwater species Danio rerio and Vibrio fisheri were more affected by a paint based on organic solvents.     

QSAR study on the toxicity of substituted benzenes to the algae (Scenedesmus obliquus).

50% effective inhibition concentration 48h-EC50 of 40 substituted benzenes to the algae (Scenedesmus obliquus) was determined. The energy of the lowest unoccupied molecular orbital (E(LUMO)) was calculated by the quantum chemical method MOPAC6.0-AM1. By using E(LUMO) and the hydrophobicity parameter log K(OW) the quantitative structure-activity relationship model (QSAR) was developed: log1/EC50=0.272 logK(OW) - 0.659E(LUMO) + 2.54, R2 = 0.793, S.E. = 0.316, F = 71.07, n = 40. A series of equations were obtained about the measured EC50 values of different subclasses of compounds. For those compounds containing double -NO2, their toxicity may be related chiefly to the intracellular reduction of -NO2 obtaining electron, while for anilines and phenols, K(OW) contributes most to the QSAR and E(LUMO) very little.     

Arsenate and perchlorate toxicity, growth effects, and thyroid histopathology in hypothyroid zebrafish Danio rerio

Exposure to perchlorate or other thyrotoxic compounds can cause hypothyroidism in most vertebrates, and this may affect levels of endogenous antioxidants and cause oxidative stress. Arsenic also induces oxidative stress in animals by modifying the antioxidant capacity and may alter the thyroid homeostasis. Therefore, hypothyroidism may affect the toxicity of arsenate. In order to test this hypothesis, zebrafish (Danio rerio) were made hypothyroid by exposure to perchlorate, and toxicity of arsenate in hypothyroid and euthyroid fish was compared. The endpoints were LC50 and thyroid histopathology. Additionally, the recovery of thyroid histopathological indices after cessation of perchlorate exposure was determined. The current study showed that 96 h LC50 of perchlorate anion and arsenate ion to juveniles fish (37 day post-fertilization) were 2532 and 56 mg l(-1), respectively. In addition, hypothyroid fish were more sensitive to arsenate, with a 96 h LC50 of 43 mg l(-1). Growth rates were also significantly retarded by perchlorate exposure. After cessation of perchlorate exposure, there was recovery of thyroid histopathology in terms of epithelial cell height, but not colloid area or growth rate. In conclusion, perchlorate enhances arsenate toxicity to juvenile zebrafish, and the rate of thyroid recovery after cessation of perchlorate exposure depends on the endpoints examined.     

A two-generational reproductive toxicity study of zinc in rats

A two-generation reproductive toxicity study of zinc chloride (ZnCl(2)) was conducted in rats. F(o) male and female rats were administered 0.00 (control), 7.50 (low), 15.00 (mid) and 30.00 (high) mg/kg/day of ZnCl(2). Selected F(1) male and female rats were exposed to the same doses received by their parents (F(o)). Exposure of F(0) parental rats to ZnCl(2) showed significant reduction in fertility, viability (days 0 and 4), and the body weight of F(1) pups from the high-dose group but caused no effects on litter size, weaning index, and sex ratio. Similarly, the continued exposure of F(1) parental rats to ZnCl(2) also reduced fertility, liter size, viability (day 0), and the body weight of F(2) pups within the high-dose group but caused no effects on weaning index and sex ratio. Exposure of ZnCl(2) to F(0) and F(1) parental males resulted in a significant reduction in their body weights, and the F(0) and F(1) parental females did not show any significant difference in their body weights compared to their control groups. However, the postpartum dam weights of both F(0) and F(1) female rats were significantly reduced compared to their controls. Exposure of ZnCl(2) to F(o) and F(1) generation parental rats did not produce any significant change of their clinical signs as well as their clinical pathology parameters, except the alkaline phosphotase (ALK) level, which showed an upward trend in both sexes of both generations. Exposure of ZnCl(2) to F(0) rats resulted in a reduction of brain, liver, kidney, spleen and seminal vesicles weights of males and in the spleen and uterus of females. Similarly, exposure of F(1) rats to ZnCl(2) also resulted in reduction of brain, liver, kidney, adrenal, spleen, prostate and seminal vesicles weights of males and in spleen and uterus of females. ZnCl(2) exposure resulted in grossly observed gastro-intestianla (GI) tract, lymphoreticular/hematopoietic, and reproductive tract lesions in parental rats in both generations. Reduced body fat was also recorded in F(1) parental rats.     

A two-generational reproductive toxicity study of zinc in rats

A two-generation reproductive toxicity study of zinc chloride (ZnCl₂) was conducted in rats. F_o male and female rats were administered 0.00 (control), 7.50 (low), 15.00 (mid) and 30.00 (high) mg/kg/day of ZnCl₂. Selected F₁ male and female rats were exposed to the same doses received by their parents (F_o). Exposure of F₀ parental rats to ZnCl₂ showed significant reduction in fertility, viability (days 0 and 4), and the body weight of F₁ pups from the high-dose group but caused no effects on litter size, weaning index, and sex ratio. Similarly, the continued exposure of F₁ parental rats to ZnCl₂ also reduced fertility, liter size, viability (day 0), and the body weight of F₂ pups within the high-dose group but caused no effects on weaning index and sex ratio. Exposure of ZnCl₂ to F₀ and F₁ parental males resulted in a significant reduction in their body weights, and the F₀ and F₁ parental females did not show any significant difference in their body weights compared to their control groups. However, the postpartum dam weights of both F₀ and F₁ female rats were significantly reduced compared to their controls. Exposure of ZnCl₂ to F_o and F₁ generation parental rats did not produce any significant change of their clinical signs as well as their clinical pathology parameters, except the alkaline phosphotase (ALK) level, which showed an upward trend in both sexes of both generations. Exposure of ZnCl₂ to F₀ rats resulted in a reduction of brain, liver, kidney, spleen and seminal vesicles weights of males and in the spleen and uterus of females. Similarly, exposure of F₁ rats to ZnCl₂ also resulted in reduction of brain, liver, kidney, adrenal, spleen, prostate and seminal vesicles weights of males and in spleen and uterus of females. ZnCl₂ exposure resulted in grossly observed gastro-intestianla (GI) tract, lymphoreticular/hematopoietic, and reproductive tract lesions in parental rats in both generations. Reduced body fat was also recorded in F₁ parental rats.     

Ecotoxicological studies of environmental samples from Buenos Aires area using a standardized amphibian embryo toxicity test (AMPHITOX).

The toxicity of 34 environmental samples from potentially polluted and reference stations were evaluated by means of the AMPHITOX test from acute to chronic exposure according to the toxicity found in each sample. The samples were obtained from surface and ground water, leaches, industrial effluents and soils. The data, expressed in acute, short-term chronic and chronic Toxicity Units (TUa, TUstc and TUc) resulted in a maximal value of 1000 TUc, found in a leach, while the lower toxicity value was 1.4 TUa corresponding to two surface water samples. In five samples (four providing from reference places) no toxicity was detected. The results point out the possibility of evaluating the toxicity of a wide diversity of samples by means of AMPHITOX as a customized toxicity test. The fact that almost all samples with suspected toxicity in rivers and streams from the Metropolitan area of Buenos Aires city resulted toxic, indicates the need of enhanced stewardship of chemical substances for environmental and human health protection purposes.     

Protective effects of thymoquinone and diallyl sulphide against malathion-induced toxicity in rats

Environmental Science and Pollution Research - Malathion is a potent organophosphate insecticide that inhibits acetylcholinesterase (AChE) enzyme. Our experimental objective was to investigate the...     

Ameliorative effects of corn silk extract on acetaminophen-induced renal toxicity in rats

Environmental Science and Pollution Research - The current study aimed to investigate the protective effect of corn silk methanolic extract (CSME) against acetaminophen (APAP)-induced...     

Impact of the toxicity of Cylindrospermopsis raciborskii (Woloszynska) Seenayya & Subba Raju on laboratory rats in vivo

In vivo laboratory studies of toxicity were performed on Wistar rats using a methanol extract produced by the natural population of Cylindrospermopsis raciborskii (abundance of 2.13 × 10⁵ trichomes mL⁻¹) collected at Aleksandrovac Lake (Serbia). HPLC analysis showed that the extract contains 6.65 μg cylindrospermopsin (CYN) mg⁻¹. The rats were killed 24 or 72 h after a single intraperitoneal injection of C. raciborskii extract in concentrations of 1500, 3000, 6000 and 12,000 μg kg⁻¹ body weight (bw) and an equivalent amount of CYN as present in the highest dose of the extract (79.80 μg CYN kg⁻¹ bw). The genotoxic effect on the livers treated with C. raciborskii was evaluated using comet assay and potential induction of oxidative stress as the toxicity mechanism associated with the presence of CYN in extract. The results from the analyses of DNA damage in the comet tail length, tail moment and percentage of DNA in the tail in the liver indicated that administration of extract and CYN present statistically significant difference when compared with the negative control group. Although an increase in the frequency of selected parameters induced by the CYN was observed in the liver, this damage was less than the damage resulting from the administration of the highest dose of extract. The changes in the biochemical parameters of the hepatic damage showed that the application of single doses of the extract and CYN did not cause serious liver damage in rats. The extract and CYN significantly increased oxidative stress in rats’ liver after a single exposure.

     

Efficacy of the botanical extract (myrrh), chemical insecticides and their combinations on the cotton leafworm,Spodoptera littoralis boisd (lepidoptera: Noctuidae)

Abstract

Effects of the botanical extract (myrrh), Commiphora molmol, and the sublethal treatments of profenofos/chlorofluazuron, fenvalerate and pyriproxyfen on the larvae of S. littoralis were investigated. The results showed that myrrh induced the highest activity after 7 days of treatment with concentration of 10000 ppm and the percentage of mortality reached 44.4%. The chemical insecticide profenofos/chlorofluazuron appeared to be the most effective treatment, giving a mortality of 54% after one day of treatment with a concentration of 100 ppm. Different treatments showed adverse effects on pupation, emerging adults and larval duration. The highest concentration of myrrh (10000 ppm) induced 35% pupation. No pupa was obtained with profenofos/chlorofluazuron while fenvalerate and pyriproxyfen gave 13.3% at 50 ppm. At 10000 ppm of myrrh, 25% adult was emerged, also fenvalerate and pyriproxyfen decreased the emerging moth to 13.3% at 50 ppm. For control there was no larval mortality at 7 days and the percentages of pupation and adult emergence were 90%. Bioassays were also conducted to test the joint action of myrrh applied in binary mixtures with each chemical insecticide on Spodoptera larvae. Results of the bioassay of mixtures indicated antagonistic effects on larval mortality. However, combination of myrrh with profenofos/chlorofluazuron showed additive effect. Also, the degree of pupation and emerging moth varied considerably when myrrh combined with the chemical insecticides. The present work shows the strong efficacy of the botanical extract (myrrh) which could be used alone or in combination with sublethal doses of certain insecticides to control the cotton leafworm.     

Macrophage activity and histopathology of the lymphohematopoietic organs in male Wistar rats orally exposed to single or mixed pesticides

The noxious effects of low or effective dose exposure to single or mixed pesticides on macrophage activity and the lymphohematopoietic organs were investigated. Male Wistar rats were orally exposed to dichlorvos, dicofol, endosulfan, dieldrin and permethrin, either as single or combined mixtures during a 28-day study containing eight groups: one group received a semipurified diet (non-treated); two groups received a semipurified diet containing low dose mixture (dieldrin 0.025 mg/kg, endosulfan, 0.6 mg/kg, dicofol 0.22 mg/kg, dichlorvos 0.23 mg/kg, permethrin 5 mg/kg) or an effective dose mixture (dichlorvos 2.3 mg/kg, dicofol 2.5 mg/kg, endosulfan 2.9 mg/kg, dieldrin 0.05 mg/kg and permethrin 25.0 mg/kg), respectively; the other five groups received a semipurified diet containing each single pesticide in effective doses. At sacrifice, the thymus, spleen, mesenteric lymph nodes, Payer's patches and bone marrow were removed for histological analysis. Peritoneal macrophages were obtained to determine the phagocytosis and spreading indexes and tumoral necrosis factor alpha (TNF-α), nitric oxide (NO) and H₂O₂ production. Exposure to pesticide mixtures did not alter the percentage of macrophage phagocytosis and spreading, TNF-α production or the NO and H₂O₂ release when compared to the non-treated group. Neither was there any apparent evidence that a pesticide mixture at low or effective doses altered the histological structure of the lymphohematopoietic organs. The findings indicate that short-term treatment with pesticide mixtures did not induce an apparent immunotoxic effect in male Wistar rats.     

Efficacy of the botanical extract (myrrh), chemical insecticides and their combinations on the cotton leafworm, Spodoptera littoralis boisd (Lepidoptera : Noctuidae)

Effects of the botanical extract (myrrh), Commiphora molmol, and the sublethal treatments of profenofos/chlorofluazuron, fenvalerate and pyriproxyfen on the larvae of S. littoralis were investigated. The results showed that myrrh induced the highest activity after 7 days of treatment with concentration of 10000 ppm and the percentage of mortality reached 44.4%. The chemical insecticide profenofos/chlorofluazuron appeared to be the most effective treatment, giving a mortality of 54% after one day of treatment with a concentration of 100 ppm. Different treatments showed adverse effects on pupation, emerging adults and larval duration. The highest concentration of myrrh (10000 ppm) induced 35% pupation. No pupa was obtained with profenofos/chlorofluazuron while fenvalerate and pyriproxyfen gave 13.3% at 50 ppm. At 10000 ppm of myrrh, 25% adult was emerged, also fenvalerate and pyriproxyfen decreased the emerging moth to 13.3% at 50 ppm. For control there was no larval mortality at 7 days and the percentages of pupation and adult emergence were 90%. Bioassays were also conducted to test the joint action of myrrh applied in binary mixtures with each chemical insecticide on Spodoptera larvae. Results of the bioassay of mixtures indicated antagonistic effects on larval mortality. However, combination of myrrh with profenofos/chlorofluazuron showed additive effect. Also, the degree of pupation and emerging moth varied considerably when myrrh combined with the chemical insecticides. The present work shows the strong efficacy of the botanical extract (myrrh) which could be used alone or in combination with sublethal doses of certain insecticides to control the cotton leafworm.     

Comparison of heavy metal toxicity in life stages (spermiotoxicity, egg toxicity, embryotoxicity and larval toxicity) of Hydroides elegans

A toxicity test was developed to examine the effects of heavy metal contaminants on the early life stages of the marine polychaete. We have studied the effects of metals on fertilization and early development of marine polychaete Hydroides elegans. These heavy metals have often been found in polluted ground and water near industrial discharges, and have therefore been detected from time to time in the food chain. They have been reported to alter various reproduction functions in various animals including marine populations. The toxic effect of mercury, cadmium, lead, nickel and zinc on sperm viability, fertilization, embryogenesis and larvae of H. elegans was examined. We observed that the rate of fertilization decreased when the sperm was incubated with heavy metals. Treatment of eggs with each metal did not prevent fertilization, but delayed or blocked the first mitotic divisions, and altered early embryonic development. All these effects were observed at relatively high concentrations. However, bio-accumulation in sediments and aquatic organisms have been reported. Polychaete eggs may then be in contact with very high concentrations of these heavy metals in areas where these metals are not handled or stocked properly, and then develop into abnormal embryos. In addition to bivalves and sea-urchins, polychaete embryos can provide biological criteria for seawater quality standards taking into account the sensitivity of the invertebrates and their contribution in detection of harmful chemicals with no marked effect on the species. Our results indicate that the early development of H. elegans is highly sensitive to heavy metals and this polychaete can be routinely employed as a test organism for ecotoxicity bioassays in tropical and subtropical regions.     

Ameliorative effect of zinc oxide nanoparticles against potassium bromate-mediated toxicity in Swiss albino rats

Environmental Science and Pollution Research - Potassium bromate (PB) is a commonly used food additive, a prominent water disinfection by-product, and a class IIB carcinogen. It exerts a various...