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Archives of Environmental Contamination and Toxicology (v.42, #3)
Toxicity of Tetracyclines and Tetracycline Degradation Products to Environmentally Relevant Bacteria, Including Selected Tetracycline-Resistant Bacteria by B. Halling-Sørensen; G. Sengeløv; J. Tjørnelund (pp. 263-271).
Tetracyclines used in veterinary therapy invariably will find their way as parent compound and degradation products to the agricultural field. Major degradation products formed due to the limited stability of parent tetracyclines (tetracycline, chlortetracycline, and oxytetracycline) in aqueous solution were theoretically identified at various environmental conditions, such as pH, presence of chelating metals, and light. Their potency was assessed on sludge bacteria, tetracycline-sensitive soil bacteria, and tetracycline-resistant strains. Several of the degradation products had potency at the same concentration level as tetracycline, chlortetracycline, and oxytetracycline on both the sludge and the tetracycline-sensitive soil bacteria. Further, both 5a,6-anhydrotetracycline and 5a,6-anhydrochlortetracycline had potency on tetracycline-resistant bacteria supporting a mode of action different from that of the parent compounds.
Determination of Toxicokinetic Parameters for Bioconcentration of Water-Soluble Fraction of Petroleum Hydrocarbon Associated with No. 0 Diesel in Changjiang Estuary and Jiaozhou Bay: Model Versus Mesocosm Experiments by X. Wang; J. Zhang; X. Shi; C. Zhu; Y. An; S. Jun; R. Li; M. Zhu; S. Chen (pp. 272-279).
A method is proposed for determination of toxicokinetic parameters for bioconcentration by phytoplankton of the water-soluble fraction (WSF) of petroleum hydrocarbon (PH) associated with No. 0 diesel, in which WSF-PH concentration in phytoplankton cells, C A(d) , is estimated by subtracting concentration in water (S-bottle) containing a phytoplankton sample from that in a C-bottle without phytoplankton. It was demonstrated that C A(d) agrees well with the concentration found by direct ultrasonication extraction of collected cells, C A(ind) (r = 0.88, p < 0.0001), and its uncertainty was about 17.6%. Mesocosms in 25-m3 ethylene vinyl acetate or 4-m3 polyethylene bags were performed at two sites in China: Changjiang Estuary in spring/summer 1998 and Jiaozhou Bay in autumn 1999 and spring/summer 2000. The experiments were designed to determine toxicokinetic parameters, including specific rates of uptake and elimination, and bioconcentration factor (BCF), for bioconcentration of WSF-PH by phytoplankton. A modified kinetic two-compartment model for bioconcentration of WSF-PH by phytoplankton was developed to estimate the toxicokinetic parameters. In the model, the influence of phytoplankton growth on bioconcentration and WSF-PH decline due to biotic and abiotic processes other than bioconcentration, such as volatilization, microbial degradation, phytolysis, and sorption expressed as an exponential-decay equation, are taken into account. Size-dependent BCF was observed in the laboratory experiment. BCFs were 1.0 × 104 in summer in Changjiang Estuary, 1.6 × 104 in summer, and 1.1 × 104 in autumn in Jiaozhou Bay. The difference in BCF may be interpreted by its size dependence.
Soil Metabolism of Isoxaflutole in Corn by J. Rouchaud; O. Neus; H. Eelen; R. Bulcke (pp. 280-285).
The herbicide isoxaflutole 1 (5-cyclopropyl-4-isoxazolyl)[2-(methylsulfonyl)-4-(trifluoromethyl)phenyl]-methanone) has been applied preemergence at the rate of 125 g ha−1 on corn crops grown on fields located in regions different as to their soil textures. Its metabolite diketonitrile 2 (2-cyano-3-cyclopropyl-1-(2-methylsulfonyl-4-trifluoromethylphenyl)propane-1,3-dione)—which is the herbicide's active compound—and its nonherbicide metabolite 3 (2-methylsulfonyl-4-trifluoromethylbenzoic acid) were measured in the 0–10 cm surface soil layer of the corn crops after the treatment and until the harvest. At the opposite of what occurred in plant shoots, the transformation of isoxaflutole 1 into diketonitrile 2 was not immediate in soil. In the 0–10 cm surface soil layer, this transformation occurred progressively according to an apparent second-order kinetics, and the soil half-lives of isoxaflutole 1 self were comprised between 9 and 18 days. The adsorption of isoxaflutole 1 onto the solid phase of the soil and its organic matter should explain the stabilization effect of soil, increased by the application of fresh organic fertilizer. The sum of the concentrations of isoxaflutole 1 and diketonitrile 2 disappeared in the 0–10 cm surface soil layer according to an apparent first-order kinetics, and the soil half-lives of this sum were comprised between 45 and 65 days. The sum of the concentrations of isoxaflutole 1 and of its metabolites diketonitrile 2 and acid 3 did not account for the amount of isoxaflutole 1 applied. The discrepancy increased with the delay after the application, showing that the acid 3 was further metabolized in soil into common nontoxic products, and ultimately into CO2. The conjunction of the adsorption of isoxaflutole and its metabolites (which reduced their mobilities) onto the soil and its organic matter, and their further metabolism should explain why isoxaflutole and its metabolites were not detected in the 10–15 and 15–20 cm surface soil layers during the crops.
The Potential Association Between Menta Deformities and Trace Elements in Chironomidae (Diptera) Taken from a Heavy Metal Contaminated River by E. A. Martinez; B. C. Moore; J. Schaumloffel; N. Dasgupta (pp. 286-291).
Elevated morphological deformity rates in Chironomidae larvae have been attributed to such pollutants as oil tars, pesticides, organochlorines, and heavy metals. The potential of chironomids as biological indicators of heavy metal contamination and bioavailability in a contaminated ecosystem was assessed. Chironomid larvae and river sediment were collected from the Coeur d' Alene River system, Idaho, USA, contaminated with heavy metals from mining activities. Chironomid larvae collected at contaminated sites exhibited mouthpart deformity proportions between 3.8 and 10.3% compared to the control site of 0.9%. As, Cd, Cu, Ni, Pb, and Zn were determined in both larvae and sediment samples. Significant correlation between metal concentrations and deformity rates were observed for all metals except Ni. The data also suggests that feeding habits may influence differences in pollution tolerance among genera.
Biological Responses of Lumbriculus variegatus Exposed to Fluoranthene-Spiked Sediment by P. F. Landrum; M. L. Gedeon; G. A. Burton; M. S. Greenberg; C. D. Rowland (pp. 292-302).
Lumbriculus variegatus was used as a bioassay organism to examine the impact of the sediment-associated polycyclic aromatic hydrocarbon (PAH) fluoranthene on behavior, reproduction, and toxicokinetics. The number of worms increased between the beginning and end of the experiment at 59 μg g−1 fluoranthene, but at the next higher treatment (108 μg g−1) the number of worms found was lower and not different from the control. Worms exposed to 95 μg g−1 also exhibited increased reproduction when fed a yeast-cerophyl-trout chow mixture. On a total biomass basis, only the 95 μg g−1 exposure with food exhibited a statistically significant increase over the nonfed control. Evaluation of reproduction at the two highest treatments was compromised by a brief aeration failure 2 days before the end of the experiment. The behavioral responses were followed as changes in biological burial rate (sediment reworking rate) of a 137Cs-labeled marker layer. The biological burial rate increased toward a plateau as the concentration increased from the control (3.9 μg g−1 dry weight total PAH) to 355 μg g−1 dry weight fluoranthene in sediment. The aeration failure had minimal impact on the determination of reworking rate because all the data for the rate determination were collected prior to the aeration failure. Uptake and elimination rates declined with increasing treatment concentration across the range of fluoranthene concentrations, 59–355 μg g−1 dry weight sediment. The disconnect between the increasing biological burial rates and the decreasing toxicokinetics rates with increasing exposure concentration demonstrates that the toxicokinetic processes are dominated by uptake and elimination to interstitial water. The bioaccumulation factor (concentration in the organisms on a wet weight basis divided by the concentration in sediment on a dry weight basis) ranged from 0.92 to 1.88 on day 10 and declined to a range of 0.52 to 0.99 on day 28 with the lowest value at the highest dose.
Cellular Biomarkers in Native and Transplanted Populations of the Mussel Perumytilus purpuratus in the Intertidal Zones of San Jorge Bay, Antofagasta, Chile by A. Riveros; M. Zúñiga; A. Hernandez; A. Camaño (pp. 303-312).
Cellular biomarkers were measured in the mussel Perumytilus purpuratus from intertidal zones of San Jorge Bay, Antofagasta, Chile. They were also used to measure sublethal effects on individuals exposed to Cu under laboratory conditions. Lysosomal stability in hemocytes, and the degree of vacuolization and the content of lipofuscin granules in digestive cells were the cellular responses measured. Three study sites were established in San Jorge Bay: Coloso, E.R., and Reference. Both E.R. and Coloso receive effluent discharges. Reference does not receive any sewage discharges. Before sampling, mussels from Reference were transplanted into the intertidal zone of each site. Samplings were obtained at the beginning, after 45 days, and after 90 days after transplantation. Seawater samples for total dissolved Cu analysis and adult mussels (P. purpuratus) from native and transplanted populations were collected each time. Cellular biomarkers and Cu concentrations in gonads, gills, and remaining tissues (gut and muscle) were measured. Mussels from Reference were exposed to sublethal Cu concentrations (5, 10, 20, 30, 40, and 80 μg L−1) during 45 days under laboratory conditions. Lysosomal stability was measured in mussel hemocytes by means of the neutral red retention assay. The degree of vacuolization and the extent of lipofuscin granules were determined in the digestive cells by image analysis of histological sections stained with the Schmorl's method. Seawater Cu concentrations and tissue Cu concentrations in P. purpuratus were higher in E.R. than in Reference and Coloso (p < 0.02). Native mussel populations from E.R. showed lower lysosomal stability (p < 0.05), higher vacuolization degree (p < 0.001), and lower amounts of lipofuscin granules (p < 0.001) than those from Coloso and Reference. Transplanted mussel to E.R. showed significant reduction in lysosomal stability (p < 0.05) and in extent of lipofuscin granules (p < 0.05) and significant increase in vacuolization degree (p < 0.05), whereas Reference and Coloso are not significantly dissimilar between them. Seawater Cu concentration was positively correlated with Cu content in gonads (r 2 = 0.61; p < 0.02), gills (r 2 = 0.66; p < 0.01), remaining tissues (r 2 = 0.56; p < 0.05), and the degree of vacuolization (r 2 = 0.65; p < 0.01) and negatively with lysosomal stability (r 2 = 0.79; p < 0.001) and lipofuscin granules extent (r 2 = 0.53; p < 0.05). Mussels exposed to Cu under laboratory conditions showed decreased lysosomal stability (over 30 μg Cu L−1) (p < 0.02) and increased degree of vacuolization (at 80 μg Cu L−1) (p < 0.05) and an increased lipofuscin granules extent (although differences among treatments were not statistically significant).
Perfluorooctane Sulfonate in Oysters, Crassostrea virginica, from the Gulf of Mexico and the Chesapeake Bay, USA by K. Kannan; K. J. Hansen; T. L. Wade; J. P. Giesy (pp. 313-318).
Concentrations of perfluorooctane sulfonate (PFOS), a metabolite of several sulfonated perfluoroorganic compounds, were measured in oysters collected from 77 locations in the Gulf of Mexico and Chesapeake Bay of the United States. PFOS was detected in oysters collected from 51 of the 77 locations at concentrations ranging from < 42 to 1,225 ng/g on a dry weight basis. This study provides baseline data for future monitoring programs to examine long-term trends in concentrations of PFOS.
Mercury in Morelet's Crocodile Eggs from Northern Belize by T. R. Rainwater; B. M. Adair; S. G. Platt; T. A. Anderson; G. P. Cobb; S. T. McMurry (pp. 319-324).
Recent studies have examined mercury accumulation in crocodilians. However, though most researchers have focused on tissue concentrations, few have examined mercury levels in crocodilian eggs. In July 1995, we analyzed mercury in 31 nonviable Morelet's crocodile (Crocodylus moreletii) eggs collected from eight nests across three localities in northern Belize. All eggs were found to contain mercury. Based on an individual egg basis, mean concentration of mercury for all three localities was among the lowest reported for any crocodilian species. When localities were examined separately, mean concentrations for Laguna Seca and Gold Button Lagoon were comparable to those observed in other studies, and the mean for Sapote Lagoon was the lowest ever reported. Based on mean nest concentrations, mercury in eggs from Laguna Seca was approximately two- and tenfold higher than for Gold Button Lagoon and Sapote Lagoon, respectively. Variability in mercury concentrations among localities is likely the result of site-specific differences in mercury input, bioavailabilty, and bioaccumulation. Mercury concentrations were relatively uniform in eggs from the same nest and among nests from the same localities. The presence of mercury in Morelet's crocodile eggs suggests exposure in adult females, developing embryos, and neonates. However, crocodiles in these areas show no overt signs of mercury toxicity, and no indication of population decline is evident. A paucity of data on the effects of mercury on crocodilians precludes meaningful speculation as to the biological significance of tissue and egg concentrations. Controlled laboratory studies and long-term population monitoring are needed to address these questions.
Copper Speciation and Accumulation in the Gill Microenvironment of Carp (Cyprinus carpio) in the Presence of Kaolin Particles by S. Tao; A. Long; R. W. Dawson; F. Xu; B. Li; J. Cao; J. Fang (pp. 325-331).
Carp were exposed to copper adsorbed on kaolin particles at various concentrations (0–2.4 mg/L), and net accumulation due to elevated adsorbed copper in the surrounding water was observed. Copper speciation in the water and fish gill microenvironment was modeled in the presence and absence of kaolin using a chemical speciation program (MINTEQA2). The adsorption affinity constants of kaolin for copper at various pH values used in the speciation calculations were experimentally determined, and the quantitative relationship between the affinity constant and pH was modeled. Copper accumulations in fish gills exposed to kaolin-adsorbed copper was then observed. The results indicate that desorption occurred in the fish gill microenvironment due to both mucus competition of copper and slight increase in water pH. Furthermore, the available copper species increased as a result of desorption, causing a net accumulation of Cu by the gills.
Effects of Sublethal Levels of Tributyltin Chloride in a New Toxicity Test Organism: The Chinese Rare Minnow (Gobiocypris rarus) by Z. Qun-Fang; J. Gui-Bin; L. Ji-Yan (pp. 332-337).
A newly developed toxicity test organism, the Chinese rare minnow (Gobiocypris rarus), which has similar merits to some common experimental fishes and could become a standardized test species for China, was used in a short-term study with emphasis on accumulation in fish muscles and cytological effects of sublethal concentrations of tri-n-butyltin chloride (TBT). The 1-year-old fish were exposed for 1 or 2 weeks to a concentration range of 50 to 5,000 ng TBT/L in static systems. Hepatosomatic Index (HSI) and Gonad Somatic Index (GSI) sensitively showed the adverse effects of TBT to the fish. Compared with the nominal TBT concentrations in water phase, 459-(5,000 ng TBT/L, 1 week) to 4,065- (50 ng TBT/L, 2 weeks)-fold higher concentrations of butyltin species were detected in the corresponding exposure fish muscle. Contaminations of TBT in muscle tissue increased with both the exposure levels and exposure time. The cellular pathological effects in the liver were studied. These included vacuoles with increasing number and size, swelling of mitochondria, abnormal nuclei, and decreases of rough endoplasmic reticulum cisternaes. The results confirmed that the Chinese rare minnow (G. rarus) could be utilized as a useful species to evaluate water toxicity in the laboratory.
Platinum Group Elements in the Feathers of Raptors and Their Prey by K. H. Jensen; S. Rauch; G. M. Morrison; P. Lindberg (pp. 338-347).
Platinum (Pt), palladium (Pd), and rhodium (Rh) concentrations were determined in the feathers of three raptor species in Sweden, the sparrowhawk (Accipiter nisus), the peregrine falcon (Falco peregrinus), and the gyrfalcon (Falco rusticolus), as well as the main prey of the sparrowhawk (the house sparrow, Passer domesticus) and the gyrfalcon (the willow grouse, Lagopus lagopus).The analysis of feathers from 1917–1999 revealed a clear temporal trend, with significantly higher Rh concentrations in sparrowhawk and peregrine falcon after 1986. There is evidence for increasing platinum group element (PGE) concentrations from 1917 to 1999 in peregrine falcon and sparrowhawk. This suggests that feathers reflect increased PGE concentrations in the environment over this time period. Mean concentrations of PGE in feathers of raptors after 1986 ranged from 0.3 to 1.8 ng g−1 for Pt, 0.6 to 2.1 ng g−1 for Pd (indicative values), and 0.1 to 0.6 ng g−1 for Rh. House sparrows in urban areas had significantly higher Pt and Pd concentrations than urban sparrowhawks. The higher Pd concentrations in relation to Pt and Rh may indicate the greater mobility of Pd in the environment.Although PGE concentrations are generally higher in birds living in urban areas, no significant spatial trend could be established. This is partly due to the widespread distribution of automobiles and partly because birds forage and integrate PGE exposure over large areas.Laser ablation analysis demonstrates that PGE contamination of feathers is predominantly external, consisting of small particles in the nanometer size range. Other indications of external contamination are that Pt and Pd levels are significantly higher in the vane than in the shaft and that PGE relative ratios (except Pd) reflect urban particles.
In Vitro Study of Methylmercury in Blood of Bottlenose Dolphins (Tursiops truncatus) by S. Ancora; R. Rossi; P. Di Simplicio; L. Lusini; C. Leonzio (pp. 348-353).
The biochemical behavior of methylmercury (MeHg) in dolphin blood was investigated in vitro. MeHg distribution between plasma and erythrocytes and its release from erythrocytes into plasma or medium without SH group was determined. At the subcellular level its distribution among different thiol-containing molecules was also investigated in erythrocytes and plasma. When blood was treated with 0.1 mM MeHg, about 98.1% was found in red cells and 1.9% in plasma; only 0.6% of MeHg present in the cellular compartment was bound to membranes.Hemoglobin (Hb) and albumin, principal proteins containing SH groups (PSH), and glutathione (GSH) appeared to be the main targets of MeHg in dolphin blood. Gel filtration of stroma-free hemolysate of treated red blood cells (RBCs) revealed that MeHg was almost equally present in high (52.5%) and low (47.5%) molecular weight fractions, whereas in plasma it only eluted with proteins (high molecular weight fractions). Hemoglobin was identified as the main intracellular protein binding MeHg. The exchange reaction of MeHg between GSH and dolphin hemoglobin was also evaluated and the equilibrium constants calculated.
Elevated Concentrations of Trace Elements in Caspian Seals (Phoca caspica) Found Stranded During the Mass Mortality Events in 2000 by Y. Anan; T. Kunito; T. Ikemoto; R. Kubota; I. Watanabe; S. Tanabe; N. Miyazaki; E. A. Petrov (pp. 354-362).
Concentrations of V, Mn, Fe, Cr, Co, Cu, Zn, As, Se, Mo, Ag, Cd, Tl, Hg, Pb, and organic mercury (Org-Hg) were determined in liver, kidney, and muscle of healthy Caspian seals (Phoca caspica) collected in 1998. These concentrations were compared with those of seals infected with canine distemper virus (CDV) found stranded along the coastal areas in 2000. Concentrations of toxic elements (As, Ag, Cd, Tl, Hg, Pb, and Org-Hg) in Caspian seals stranded in 2000 were comparable or lower than those of samples collected in 1998 and in other pinnipeds. Thus it may be inferred that these elements were not the causative agents in the deaths of the seals. In contrast, concentrations of Zn and Fe were much higher in diseased Caspian seals than those in other pinnipeds. Zinc concentrations in all tissues of Caspian seals also increased during 1993–2000. Furthermore, negative correlations were found between blubber thickness and hepatic and renal Zn concentrations. These results imply the disturbance in homeostatic control and nutritional status of essential elements in Caspian seals stranded in 2000.
Content and Redistribution of Vitamin E in Tissues of Wistar Rats Under Oxidative Stress Induced by Hydrazine by J. Antosiewicz; A. Matuszkiewicz; R. A. Olek; J. J. Kaczor; W. Ziółkowski; T. Wakabayashi; J. Popinigis (pp. 363-368).
Hydrazine toxicity is associated with generation of several kinds of free radicals and oxidative stress in cell. Experiments in vivo have demonstrated that oxidative stress could either diminish or increase concentration of vitamin E in some tissues. Thus in the present study we performed experiments to determine whether hydrazine-induced oxidative stress would change the tissue levels of the vitamin. Seven days of hydrazine intoxication led to accumulation of different amounts of vitamin E: 215% in the liver, 118% in the heart, 135% in the spleen, and 100% in the muscle over control value. There were no changes in the level of the vitamin in kidney and pancreas, despite its significant depletion in the serum. In tissue that accumulated vitamin E after hydrazine treatment, an increased of oxidative stress measured by the concentration of lipid-soluble fluorophore was observed. Significant increases of 107%, 46%, 72%, and 58% over control values were observed in the liver, heart, spleen, and muscle, respectively. Rats treated with hydrazine and pharmacological doses of α-tocopherol accumulated higher concentrations of vitamin E in all studied tissues compared with the α-tocopherol-only treated rats. However, in tissues with elevated levels of fluorophore as liver, heart, spleen, and muscle, the accumulation of vitamin E was 5.03, 4.5, 4.03, and 4.6 times higher than in α-tocopherol-treated rats, respectively. Vitamin E concentration was much higher than in kidney and pancreas, where the accumulation was only 2.31 and 2.6 times higher.On the other hand, 3 days of hydrazine treatment did not change either the level of lipid-soluble fluorophore or the level of vitamin E in the liver mitochondria, microsomes, and homogenate. In skeletal muscle vitamin E caused decreased lipofuscin accumulation, and in pancreas vitamin E increased lipofuscin accumulation. Our data indicate that hydrazine is able to modify significantly vitamin E status in different rat tissues. {texp}Vitamin E is a lipid-soluble molecule that exerts its action mainly in biological membranes, protecting them from damaging factors. The function of vitamin E is connected with its wide range of properties. One of the main properties of vitamin E is its antioxidative action: it can react with peroxyl, alkoxyl, and superoxide radicals as well as physical quenching of singlet oxygen (Halliwell and Gutteridge 1989).The scavenging activity of vitamin E allows it to protect unsaturated lipids of biological membranes from the oxidation caused by free radical species. Moreover, it has been recently demonstrated that membrane proteins can also be protected from oxidation by vitamin E (Takenaka et al. 1991). Vitamin E is also able to protect biological membranes from phospolipases and products of their action, free fatty acids and lysophospholipids (Kagan 1989). In vivo experiments on animals have demonstrated that vitamin E decreases the toxicity of several compounds, including nitrogen dioxide (Elsayed and Mustafa 1982), hydrazine (Antosiewicz et al. 1994a), and methyl ethyl ketone peroxide (MEKP) (Ando and Tappel 1985). Moreover, it has been observed that vitamin E treatment can diminish carcinogenic properties of some toxins (Cook and McNamara 1980). On the other hand, increased susceptibility to cigarette smoke was observed in rats maintained on a basal vitamin E–deficient diet (Chow et al. 1984). Because of these properties, great attention has been focused on the status of vitamin E in tissues.Some pathological conditions can influence distribution of vitamin E in an organism. Decreased levels of vitamin E in plasma and an increased in lungs were observed after oxidative stress induced by tobacco smoke (Chow et al. 1989). Similar phenomena were observed in the pancreas during acute pancreatitis (Antosiewicz et al. 1995). However, oxidative stress induced by MEKP lowers the level of vitamin E both in blood and liver (Warren and Reed 1991). Decreased vitamin E content in muscle was observed after endurance training, which also is accompanied by oxidative stress (Packer et al. 1989). Intoxication by 1,2-dibromoethane, which is not connected with oxidative stress, led to depletion of hepatic vitamin E levels but at the same time an elevation of the level in plasma (Warren et al. 1991). An increase of vitamin E content in the heart and simultaneously a decrease in the liver was observed in rats following dietary fatty acid manipulation (Chautan et al. 1990). An increase of linoleate content in adipose tissue led to a decrease in the content of vitamin E in the plasma (Witting 1972). In the tissues of aged animals, changes in lipid composition (Barret and Horton 1975), increased lipid peroxidation (Uysal et al. 1989) and accumulation of vitamin E (Weglicki et al. 1969) were observed. It seems clear from the literature that the modification of vitamin E status in tissues can be influenced by such factors as oxidative stress and tissue lipid composition.Hydrazine and its derivatives are used in industry as well as in medicine. Some drugs used for treatment of tuberculosis and hypertension are derivatives of hydrazine. However, hydrazine and its derivatives posses a toxic activity that is connected with the generation of different kinds of free radicals. Most of the radical species are generated from hydrazine at the level of cytochrome P450 (Noda et al. 1987) in the liver. Hydrazine-derived free radicals can induce oxidative stress (Antosiewicz et al. 1994a).In the present study we use hydrazine as a toxin, which both induces oxidative stress and changes fatty acids composition in the liver (Wakabayashi et al. 1987), to investigate its effect on vitamin E distribution in several rat tissues. The experiments presented here were designed to address three major questions: (1) Does hydrazine-induced oxidative stress influence the level of vitamin E in a similar manner to oxidative stress caused by tobacco smoke in lungs or that induced by MEKP in the liver? (2) Is the accumulation or depletion of vitamin E caused by oxidative stress tissue-specific? (3) Can pharmacological doses of vitamin E protect rats from hydrazine toxicity? Our results indicate that hydrazine induces accumulation of vitamin E in liver, heart, spleen, and muscle but decreases its concentration in the serum. We also observed antioxidant and pro-oxidant activity of vitamin E.
Exposure of Ground-Rig Applicators to the Herbicide Bromoxynil Applied as a 1:1 Mixture of Butyrate and Octanoate by A. J. Cessna; R. Grover (pp. 369-382).
Bromoxynil is a herbicide used extensively on the Canadian prairies for weed control in cereal production. This is a report on exposure to and absorption of bromoxynil by farmers during handling, transferring, mixing, and then applying the herbicide to cereal crops using tractor-drawn ground-rigs. The 14 individual spray operations, in which farmers applied 9 kg of bromoxynil (phenol equivalent, p.e.) to 32 ha, lasted from 113 to 549 min and involved one to five tank fills. In five of the spray operations, the farmers wore neoprene gauntlet-style protective gloves. Tractors, equipped with cabs, were used in nine spray operations.Air sampling, hand washes, and dermal patch dosimeters served as the basis to calculate the amount of bromoxynil (p.e.) available for inhalation, deposition on the hands, and deposition under a standardized set of protective clothing. Tractors, equipped with cabs, decreased inhalation exposure by a factor of ∼ 10. Use of gauntlet-style neoprene protective gloves decreased dermal exposure to the hands region of the body by 25 times, whereas two layers of laundered cotton provided a protective effect of > 15 in the chest region.The median value for the amount of bromoxynil (p.e.) inhaled was 0.018 μg kg BW−1 kg (p.e.)−1 for the 14 spray operations. The hands region of the body was the area most exposed to bromoxynil (p.e.), the median value of dermal deposition to the hands being 808 μg (p.e.) compared to 1,600 μg (p.e.) for the whole body, when protective gloves were not worn. The urinary excretion pattern of bromoxynil (p.e.) did not demonstrate an obvious maximum followed by a continuous decline to background concentrations. Instead, the amounts excreted increased over the first few days after application and then tended to remain relatively constant during the remainder of the 10-day sampling period. The median value for urinary excretion was 2.22 ng g creat−1 kg BW−1 kg (p.e.)−1.
Cleanup of Gloves Contaminated with Granular Terbufos and Tefluthrin by C. Guo; J. Stone; H. M. Stahr; M. Shelley (pp. 383-388).
Chemical-resistant gloves are used for protection from pesticides in farming operations. Cleanup of gloves after pesticide contamination was the focus of this research. Nitrile, neoprene, and barrier laminate glove specimens were exposed to 300 mg terbufos or tefluthrin granules for 3 or 30 min in petri dishes in a laboratory. Specimens were cleaned by flush with running water or LaunderOmeter washing with detergent. Following the cleanup treatments, specimens were dried and placed in test tubes with solvents to extract pesticide residue. Levels of contamination remaining were determined by gas chromatography. The residue remaining varied with exposure time, material type, cleanup method, and pesticide. Flush was more effective with the shorter exposure time. Tefluthrin was more effectively removed than terbufos. Barrier laminate was confirmed as a single-use material. Cleanup procedures reduced contamination in nitrile and neoprene, but findings show that these materials retained residue after cleanup.