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1.
Fathead minnows, 30 days old, were exposed to technical grade bromacil and diuron in flow-through tests to determine acute toxicity. LC50 values for bromacil were 185, 183, 182 and 167 mg/L at 24, 48, 96, and 168 hr, respectively; and for diuron, 23.3, 19.9, 14.2, and 7.7 mg/L at 24, 48, 96, and 192 hr, respectively. Eggs, newly hatched fry, and juvenile fish were continuously exposed to lower concentrations of the herbicides for 64 days. Growth was significantly reduced (p 0.01) at the lowest bromacil exposure of 1.0 mg/L. Therefore, it was not possible to determine a no effect concentration. The no effect concentration for diuron was 33.4 g/L, while the lowest concentration which resulted in adverse effects was 78.0 g/L. Adverse effects at 78.0 g/L were an increased incidence of abnormal or dead fry immediately after hatch (p 0.01) and decreased survival throughout the exposure period (p 0.05). Neither herbicide accumulated significantly in fish tissue, as bioconcentration factors were <3.2 and 2.0 for bromacil and diuron, respectively. Rainbow trout (Salmo gairdneri) injected with radiolabeled bromacil or diuron eliminated over 90% of the radioactivity within 24 hr. Parent compound and metabolites were detected in the aquarium water in both cases. Metabolites of diuron recovered from the water included 3,4-dichloroaniline and several demethylated products.  相似文献   

2.
In acute tests of toxicity, two cladocerans,Daphnia galeata mendotae andCeriodaphnia lacustris, and the calanoid,Diaptomus oregonensis, were more sensitive to fenvalerate thanDaphnia magna, the organism used in standard laboratory bioassays. The 48-hr EC50s for each species/stage in order of increasing sensitivity were adultD. magna — 2.52 g/L;D. magna (48-hr old) — 0.83 g/L; adultD. galeata mendotae — 0.29 g/L; adultC. lacustris — 0.21 g/L;D. galeata mendotae (48-hr old) — 0.16 g/L; adultDiaptomus oregonensis — –0.12 g/L. No toxicity was observed when these organisms were exposed to a range of concentrations of the emulsifiable concentrate without fenvalerate (the EC blank).Rates of filtration of the14C-labelled alga,Chlamydomonas reinhardii byD. galeata mendotae, C. lacustris andD. oregonensis were decreased significantly at sublethal concentrations of fenvalerate after only 24-hr exposure.Ceriodaphnia lacustris showed the greatest sensitivity with rates of filtration significantly decreased at 0.01 g fenvalerate/ L. Concentrations of fenvalerate 0.05 g/L resulted in decreased rates of filtration byD. galeata mendotae. A concentration of 0.10 g fenvalerate/ L caused rates of filtration to increase inD. oregonensis. whereas 0.05 and 0.5 g/L resulted in a decrease in these rates.Rates of assimilation of algae byD. galeata mendotae, C. lacustris andD. oregonensis exposed to similar concentrations of fenvalerate were decreased at concentrations 0.05 g fenvalerate/L. Changes in rates of assimilation were not as sensitive a parameter of toxicity as changes in rates of filtration. The EC blank had no significant effects on rates of filtration or assimilation for all three species.  相似文献   

3.
Toxic effects of the herbicides dinoseb and paraquat, both individually and combined, on embryonic development and hatching ofFasciola hepatica miracidia were assessed by exposing the eggs to varying concentrations (0–20 g/ml) of each of the herbicides. The results showed that dinoseb has an LC50 value of 4.3 g/ml, paraquat has an LC50 of 4.9 g/ml and the mixture of both dinoseb and paraquat has an LC50 of 7.1 g/ml. Based on the LC50 values, dinoseb is slightly more toxic than paraquat on the tested organisms. The results also showed that the mixture of dinoseb and paraquat is significantly less toxic than the individual pesticides.Eggs ofF. hepatica cultured in either dinoseb or paraquat both individually and combined showed a delay of embryonic development and hatching of the miracidia. Eggs cultured in 0–2 g/ml of dinoseb, paraquat and their mixture, fully embryonated and hatched within 14–16 days, while eggs cultured in 4–6 g/ml of the same herbicides showed a delay of four days for embryonic development and hatching of their miracidia.  相似文献   

4.
Beauveria bassiana spores and metabolites were evaluated for toxicity and pathogenicity to Mysidopsis bahia. Static acute 96-h tests were conducted with 24-h-old M. bahia using either conidiospores; the mycotoxin, beauvericin, or a nonpolar extract of the mycelia. Conidiospore densities of 1.5×106/ml caused high mortalities. These mortalities were attributed to a high particulate density since heat-killed controls also proved lethal. Beauvericin, a cyclic depsipeptide produced by some strains of B. bassiana, was toxic at an LC50 of 0.56 mg/L. The toxicity of beauvericin persisted in sterile seawater for at least 3, but not, 8 weeks. A nonpolar extract of mycelia from B. bassiana, which contained approximately 1% beauvericin by weight, was toxic at an LC50 of 84.2 mg/L. In contrast, a nonpolar extract of mycelia from the fungal weed pathogen, Colletotrichum gloeosporioides f. sp. aeschynomene, was not toxic when tested up to 70.4 mg/L.Contribution No. 840, Environmental Research Laboratory, U.S. EPA, Gulf Breeze, FL 32561.  相似文献   

5.
Forty-nine isolates of Campylobacter pylori were tested for their susceptibility to twenty antibiotics and four anti-ulcer agents by an agar dilution technique. Penicillin and amoxycillin were the most active drugs (MIC90, 0.06 /ml); erythromycin, cefazolin, minocycline, ciprofloxacin, ofloxacin and gentamicin were sligthtly less active (MIC90, 1 g/ml). Moderate activity was found for doxycyclin, rifampin, nitrofurantoin, norfloxacin, pefloxacin, enoxacin, paromomycin, metronidazole and tinidazole. All strains were resistant to trimethoprim (MIC > 512 g/ml). Nalidixic acid (MIC90, > 256 g/ml) and colistin (MIC90, > 64 gg/m1) had little to no activity. Of four anti-ulcer drugs, only bismuth subcitrate showed activity (MIC90, 64 g./ml).Strains resistant to all 4-quinolones were found in patients who had previously received ofloxacin as part of a clinical trial aimed at eradication of C. pylori. These isolates remained susceptible to amoxycillin, tetracyclines and to other classes of antibiotics.Corresponding author.  相似文献   

6.
To evaluate the association between sleeping pill/tranquilizer (SP/T) use and quality of life (QOL) among cancer patients. Patients and methods: Oncology patients (n=909) in three Israeli hospitals were interviewed in clinics, day centers and in-patient departments regarding SP/T use in the previous week. Crude and adjusted QOL scores, measured using the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire-C30 (EORTC QLQ-C30), were compared in users vs. non-users. Results: Sleeping pill/tranquilizer use was self-reported by 234 (25.7%) participants, but rarely documented in medical charts. Factors associated with SP/T use were female gender (adjusted Odds ratio, OR: 1.79; 95% Confidence interval, CI: 1.22–2.62, age (OR: 4.6; 95% CI: 1.66–12.53 for age 70+), place of birth (OR: 1.97; 95% CI: 1.19–3.26 for Eastern Europe compared with Israel), concomitant use of painkillers (OR: 2.88; 95% CI: 1.97–4.20) and presence of cardiovascular disease (OR: 2.41; 95% CI: 1.48–3.91). Controlling these factors as well as disease status, users had a poorer QOL on all functional scales (P<0.001) as well as global QOL. Furthermore, users reported increased severity of symptoms, especially fatigue, insomnia, pain, dyspnea and constipation (P<0.01), compared to non-users. Conclusions: Use of SP/T, reported by one fourth of cancer patients, was associated with substantially poorer QOL and increased severity of symptoms. Causal inference is not possible given the cross-sectional design. Periodic inquiry regarding use of these medications in the Oncology Clinic is recommended since it may identify patients with poor QOL and unmet needs.  相似文献   

7.
A new sublethal toxicity test was developed in this study to measure the effect of copper and lead on the motility of coral larvae. Larval motility was significantly affected by copper and lead doses immediately after dosing. The copper EC50 values for motility of Goniastrea aspera brain coral larvae (12 h, 21 g/L; 24 h, 16 g/L; 48 h, 22 g/L) were much lower than the copper LC50 values for G. aspera larval survival (6 h, 260 g/L, and 24 h, 121 g/L, for 5-day-old larvae and 6 h, 248 g/L, and 24 h, 136.64 g/L, for 6-day-old larvae) during the early part of the experiments. However, at later times, the LC50 values (48 h, 40 g/L, for 5-day-old larvae and 48- h, 87 g/L, for 6-day-old larvae) were similar to the EC50 values for larval motility. The lead 72-h EC50 value for G. aspera larval motility (2900 g/L) was much lower than the lead 72-h LC50 value for larval survival (9890 g/L). The results show that larval motility can be a useful parameter to measure in order to determine the sublethal effects of trace metals on coral larvae.  相似文献   

8.
Long-term investigations of polychlorinated hydrocarbon levels in mothers' milk were made from 1969 to 1976. The levels ofp,p-DDE, p,p DDT, dieldrin and PCB in mothers' milk were within the range reported by others. However, -BHC(Hexachlorocyclohexane) levels in the milk were 10 times that found in non-Japanese. A gradual decrease in the -BHC level in the milk was observed during this period. In contrast, the levelsof p,p-DDE,p,p-DDT, dieldrin and PCB were consistent for the 7-year period. A significant correlation between the levels of PCB andp,p-DDE in mothers' milk and blood was observed in the 1974–1976 samples. However, after prohibition of the use of chlorinated hydrocarbons, this relationship was less apparent in the 1972–1973 samples.  相似文献   

9.
Temporal trends of organochlorine pesticides such as -hexachlorocyclohexane (-HCH), hexachlorobenzene (HCB), and 1,1-dichloro-2,2-bis(p-chlorophenyl)-ethylene (p,p-DDE), were determined in freshwater prawn (Macrobrachium nipponense) collected from Lake Kasumigaura in 1978 to 2000. The organochlorine pesticides elucidated a 72.4% decrease in -HCH, from 42 (1978) to 11.6 ng/g fat (2000); an 89.6% decrease in HCB, from 1.64 (1978) to 0.17 ng/g fat (2000); and an 87.3% decrease in p,p-DDE, from 97.5 (1978) to 12.4 ng/g fat (1992). After organochlorine pesticide prohibition in 1971, the declining trend of -HCH, HCB, and p,p-DDE concentrations persisting in the prawns could be approximated by exponential equations.  相似文献   

10.
Alternate Shewhart-type statistical control charts, called g and h charts, are developed and evaluated for monitoring the number of cases between hospital-acquired infections and other adverse events, such as heart surgery complications, catheter-related infections, surgical site infections, contaminated needle sticks, and other iatrically induced outcomes. These new charts, based on inverse sampling from geometric and negative binomial distributions, are simple to use and can exhibit significantly greater detection power over conventional binomial-based approaches, particularly for infrequent events and low defect rates. A companion article illustrates several interesting properties of these charts and design modifications that significantly can improve their statistical properties, operating characteristics, and sensitivity.  相似文献   

11.
Summary Seventy male air grinder operators and 72 age-matched control workers were examined. Both groups of workers worked in the warm climate (20°–33°C) of southern Taiwan. None of the workers had symptoms of white fingers. The investigation program comprised: (1) case history, (2) physical examination, (3) determination of maximal motor conduction velocity, proximal and distal sensory conduction velocity (NCV) of the median and ulnar nerves of the right upper extremity, (4) measurement of skin temperature, nail press test, pain threshold and vibratory sense threshold of the upper extremities, and (5) testing of the motor function. The dose-effect correlation between the NCV, various function tests and total operating time (TOT) was performed by multiple stepwise regression analyses. The regression analyses revealed a statistically significant correlation (dose/effect) between the six NCV, vibratory sense threshold, pain threshold and age, as well as TOT.  相似文献   

12.
The toxicity of mercury (HgCl2), copper (CuCl2: 5 H2O), nickel (NiSO4: 6 H2O), lead (Pb(CH3COO)2: 3 H2O) and cobalt (CoCl2: 6 H2O) was studied under standardized conditions in embryos and larvae of the zebrafish,Brachydanio rerio. Exposures were started at the blastula stage (2–4 h after spawning) and the effects on hatching and survival were monitored daily for 16 days. Copper and nickel were more specific inhibitors of hatching than cobalt, lead, and mercury. Nominal no effect concentrations determined from the dose-response relationships (ZEPs, Zero Equivalent Points) for effect on hatching time were 0.05 g Cu/L, 10 g Hg/L, 20 g Pb/L, 40 g Ni/L and 3,840 g Co/L, and those for effect on survival time were 0.25 g Cu/L, 1.2 g Hg/L, 30 g Pb/L, 80 g Ni/L, and 60 g Co/L. The no effect concentrations for Ni, Hg and Pb are consistent with previously reported MATC values for sensitive species of fish. The no effect concentrations for copper are 1–2 orders of magnitude lower than previously reported values. The major reason for the latter discrepancy was considered to be the absence of organics that can complex copper ions in the reconstituted water that we used, which had a hardness of 100 mg/L (as CaCO3) and a pH of 7.5–7.7. Unexposed controls were started with embryos from different parental zebrafishes and the parental-caused variability in early embryo mortality, median hatching time and median survival time were estimated.  相似文献   

13.
A toxicity identification evaluation (TIE) was conducted on the effluent from a petrochemical plant which discharges into an estuary. The effluent had been consistently toxic to mysid shrimp (Mysidopsis bahia) but not toxic to sheepshead minnows (Cyprinodon variegatus). Phase I effluent toxicity characterization tests revealed that treatment of the effluent with a cation exchange resin (Amberlite® IR-120 Plus) was partially effective at reducing, but not removing, toxicity. Phase II characterization tests revealed that four cations varied with toxicity: Ca and Sn were positively correlated with increasing toxicity; Mg and K were negatively correlated with increasing toxicity. Toxicity tests with SnCl2 revealed that the toxicity threshold for Sn was far above the concentrations present in the raw effluent. Reduction of Ca was shown to result in a significant improvement in survival, but some toxicity still remained. Further augmentation of the treated effluent with CaCl2, MgCl2, and KBr to restore the concentrations of Ca, Mg, K, and Br to natural seawater concentrations resulted in survival of all exposed organisms. Repeated success of this treatment regime on additional samples of the effluent as well as mock effluent studies confirmed that ion imbalance was the sole source of toxicity in this effluent. Process source water composition and essential ion balance are discussed as important components of marine effluent TIEs.  相似文献   

14.
Polychlorobiphenyls (PCBs), DDT (p,p-DDT,p,p-DDD, andp,p-DDE and HCH isomers (hexachlorocyclohexanes including , , and isomers) were determined in a marine food chain, including seawater, zooplankton, myctophid, squid and striped dolphin collected from the western North Pacific waters. The concentrations of these pollutants increased in higher trophic levels, where the highest bioconcentration factors (concentration ratio in organisms to water), as much as 107, were obtained from both PCBs and DDT in striped dolphin. The proportions of highly chlorinated biphenyls,p,p-DDE and -HCH increased in higher-ranking predators. These observations suggest that the bioaccumulation mechanisms in lower trophic levels depend primarily on the physicochemical properties of pollutants, whereas those in higher trophic levels are affected by the biodegradability of the pollutants and the metabolic capacity and life-span of the organisms.  相似文献   

15.
Sex steroid concentrations in urine samples from post-menopausal women have been associated with risk of various chronic diseases. The basic requirement for the assessment of risk in such large-scale epidemiological studies is that subjects be ranked accurately by their average, long-term hormone levels. We examined the reproducibility over time of measurements of urinary testosterone (T), 5-androstane-3, 17-diol (ADIOL), estrone (E1), estradiol (E2), 2-hydroxy estrone and 2-hydroxy estradiol, (2(OH)-E), 16-hydroxyestrone (16(OH)-E1) and the ratio of 2(OH)-E and 16(OH)-E1, in a representative sub-sample of post-menopausal women (n = 43) participating in an ongoing prospective cohort study. Women collected three first morning urine voids on different occasions, with average time difference between the first and the third urine sample of 5.1 years. T, ADIOL, E1 and E2 were measured by radio immunoassay after enzymatic hydrolysis, solid-phase extraction and HPLC purification of the samples, while 2(OH)-E and 16(OH)-E1 were assayed by solid-phase enzyme immunoassay after enzymatic hydrolysis. Intra-class correlation co-efficients (ICCs) over time were very good for T (r = 0.85), acceptable for E2, E1 and ADIOL (r > 0.55), but low for 2(OH)-E, 16(OH)-E1 and their ratio (r < 0.46). The adjustment for creatinine concentrations did not increase these correlations.  相似文献   

16.
Continuous-flow toxicity tests were conducted to determine acute toxic effects of butoxy-ethanol ester (BOEE) and propylene glycol butyl ether ester (PGBEE) formulations of 2,4-D on juvenile chinook salmon (Oncorhynchus tshawytscha) and steelhead-rainbow trout (Salmo gairdneri). A chronic toxicity test with chinook salmon egg-to-fry was conducted to determine effects of BOEE on survival and growth. The hydrolysis in water of 2,4-D esters to 2,4-D acid was influenced by the presence of fish. Median lethal concentrations (96-hr LC50 values) indicated that PGBEE (170 to 355 g/L) was slightly more toxic (37 to 57%) than BOEE (303 to 525 g/L). The LC50 values also indicated that chinook salmon were generally more sensitive than steelhead-rainbow trout and that fry and smolts were equally sensitive to the 2,4-D esters. Static tests substantially underestimated BOEE toxicity when compared to dynamic tests. Based on reduced survival and growth of chinook salmon alevins and fry, the estimated maximum safe chronic exposure concentration under these test conditions is 40 g/L BOEE.  相似文献   

17.
Microencapsulated permethrin (penncapthrin) was evaluated under laboratory conditions for its toxicity toward several nontarget aquatic invertebrates. Average LC50 estimates for selected lotic invertebrates, based on a one hour dosing regime, were: 2.71 mg/L forSimulium vittatum, 4.59 mg/L forHydropsyche spp., and 13.41 mg/L forIsonychia bicolor. In acute static tests withDaphnia magna, there was no significant difference (p0.05) between the toxicity of penncapthrin at 96 h (LC50 range: 6.80–22.5 g/L) and the EC formulation at 72 h (LC50 range: 0.6–21 g/L). Comparatively, the toxicity of microencapsulated methyl parathion (penncap-m) was not significantly different from that of penncapthrin towardD. magna, the former having LC50 estimates ranging form 0.3–12.25 g/L. LC50 estimates associated withDaphnia pulex ranged from 19 to 131 g/L. The toxicity of penncapthrin and penncap-m towardD. pulex was difficult to determine because of frequent control mortality due to food deprivation resulting from the need to run tests for longer than 48 h. In successful tests, LC50 estimates ranged from 19 to 28 g/L for penncapthrin and 0.08 to 25 g/L for penncap-m after 72 h exposure. In long term toxicity tests, 95% of D. magna at 1 g/L, 44% at 10 g/L, and 20% at 15 g/L survived after 39 days exposure. Less than 15% ofD. pulex survived over the same concentration range following 32 days exposure. Despite some drawbacks, long-term toxicity tests were more appropriate than short-term tests for evaluating microencapsulated sticides because of reduced variability in LC50 estimates and lower control mortality.  相似文献   

18.
Emergency room (ER) utilization and hospitalization were studied as indicators of the impact of improvements in pediatric primary care services in an Israeli development town, Ofakim, population 12,000. One of the two pediatric services was upgraded in 1976 through the introduction of pediatric faculty, integration of preventive and curative services and conversion of the medical records to a problem-oriented format ( experimental clinic B ). The primary care system remained unchanged in the second clinic ( traditional clinic A ). During 1980, ER utilization by the B clinic population was 9.3/100 compared with 17.6/100 for the A clinic population. Fifty two percent of the B clinic population patients reaching the ER were hospitalized compared with 25% of A clinic patients.The lower ER utilization rate represents a significant saving for the health services, and educational interventions are suggested from the study. Analysis of ER utilization data seems to offer useful information for overall planning and monitoring of ambulatory services for a community.Corresponding author.  相似文献   

19.
Summary Exhaled air was analyzed for tetrachloroethene (PER) in teachers and 4–5-year-old pupils of a kindergarten situated near a factory, and in residents of an old folks' home situated near a former chemical waste dump. The PER concentrations were higher in the exhaled air of children living near the factory (mean 24 g/m3, n=6) than in control children (mean 2.8 g/m3, n=11). In the old folks' home, the PER concentrations in the exhaled air of people living on the first floor were higher (mean 7.8 g/m3, n=10) than in the exhaled air of the people living on the second floor and higher (mean 1.8 g/m3, n=19). From the results of this study, it is clear that in environmental exposure to tetrachloroethene, biological monitoring of exhaled air is a simple, efficient, effective and convenient method of assessing total ambient exposure of both young and aged subjects.  相似文献   

20.
A host-endoparasitoid relationship was investigated under metal stress.Lymantria dispar (gypsy moth) larvae were reared on artificial diets contaminated with two concentrations of cadmium (2 and 10 g/g), lead (4 and 20 g/g), copper (10 and 50 g/g) and zinc (100 and 500 g/g), all based on dry weight. Following parasitization in the first premoulting period byGlyptapanteles liparidis, the eclosal success ofG. liparidis and the developmental rates of both species were investigated and compared with controls. Additionally, metal concentrations were monitored in host individuals and parasitoids by flame and flameless AAS. The developmental rate of the endoparasitoid positively correlated with that of the host. A negative relationship was found between the number of closedG. liparidis and the developmental rate of the host. No correlation was found between the extent of metal contamination and parasitization success.Correlation of results led to the conclusion that the elevated metal concentrations did not affectG. liparidis directly, but that parasitoid development is more likely to be influenced by alterations in the trophic situation within the host larvae due to metal stress.  相似文献   

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