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PubMed1981

Effects of pesticides on activities of enzymes and microorganisms in a clay soil.

Laboratory experiments were conducted to determine the effect of 32 pesticides applied at 2 levels on populations of microorganisms, activities of urease, dehydrogenase, phosphatase and nitrogenase in a clay loam incubated for 1 week. Results indicated that a decrease in bacterial number was observed with thiram for 2 days and stimulation with chlorpyrifos after 7 days. Some fungicides and fumigants inhibited fungal numbers for 2 days. The recovery was rapid and stimulatory effects on microbial numbers were evident in many samples. None of the pesticides inhibited soil urease drastically. Formazan formation was not suppressed vigorously by the treatments. With the exception of DD and Vorlex at a high level, none of the treatments inhibited phosphatase in the hydrolysis of p-nitrophenyl disodium orthophosphate. A temporary decrease in nitrogenase activity in acetylene (C2H2) reduction was observed with many pesticides. The low amount of pesticides applied to the clay loam is unlikely to have detrimental effects on soil microbes and the enzymes important to soil fertility.

Acetylene↗
PubMed1990

Pesticide contamination of ground water in the United States--a review.

Over 70 pesticides have been detected in ground water. Aldicarb and atrazine along with the soil fumigants EDB and DCP and DBCP have been the pesticides most frequently detected in ground water. Atrazine concentrations have been correlated with high nitrate concentrations. The triazine herbicides, simazine and cyanazine, have also been detected in ground water. The annual amount of recharge, soil type, depth of aquifer from the surface, nitrate contamination and soil pH are important field parameters in determining ground-water contamination potential by pesticides. Pesticide leaching is reduced by proper choice of crop rotation, increasing pesticide application efficiency, and integrated pest management.

Acetamides↗
PubMed1997

Balancing phosphine in manure fermentation.

The evolution of phosphine gas during the anaerobic batch fermentation of fresh swine manure was detected and correlated to the production of methane and hydrogen sulphide. A close temporal relationship between phosphine liberation and methane formation was found. However, the gaseous phosphine released from manure during fermentation only represents a tiny fraction of the overall phosphine balance. The majority of phosphine is captured in solid manure constituents. This matrix-bound phosphine is eliminated by more than 50% during anaerobic batch-fermentation. Seasonally determined phosphine concentrations in biogas and manure from two large-scale manure treatment plants also revealed net losses of phosphine in fermentation. Consequently, manure has to be considered more as a sink of phosphine rather than a phosphine-generating medium. Furthermore, a close relationship between phosphine in the feed of swine and manure of these swine was observed, implying that phosphine residues in the feed (possibly as a result of grain fumigation) represent an important source of phosphine in manure technologies that is relevant before the faecals of swine enter manure treatment plants.

Air Pollutants↗
PubMed1999

A 2-year inhalation study of phosphine in rats.

Phosphine is a highly toxic gas used as a fumigant, a dopant in semiconductor manufacturing, and in the production of organophosphines. In a chronic toxicity and oncogenicity study of phosphine, 60 male and female F344 rats per group were exposed via whole-body inhalation for 6 h/day, 5 days/wk for up to 104 wk to mean concentrations of 0, 0.3, 1, or 3 ppm phosphine. Three parts per million was considered the maximum exposure level because of lethality seen at higher exposure levels in previous repeat dose studies. Ten rats per sex per group were sacrificed after 52 wk of exposure. Survivors were sacrificed after 104 wk of exposure. There were no phosphine-related effects seen on clinical observations, body weight, food consumption, hematology, clinical chemistry, urinalysis, or ophthalmology. There were no phosphine-related macroscopic findings or effect on absolute or relative organ weights. No histomorphologic alterations attributable to phosphine exposure were seen. In conclusion, under the conditions of this study, there were no treatment-related changes suggestive of a toxic or carcinogenic effect seen in rats following 52 wk or 2 yr of whole-body inhalation exposure to 0.3, 1, or 3 ppm phosphine.

Animals↗
PubMed2006

Treatment of landfill leachate by irrigation and interaction with landfill gas.

The treatment efficiency of landfill leachate irrigation and the effect of landfill gas addition were investigated in a vegetated compost/gravel substrate by monitoring soil moisture content, drainage water volume and quality in a two years lysimeter experiment. Landfill leachate irrigation exceeding 350 mm increased soil moisture and drainage volumes owing to the deterioration of the vegetation resulting from high sodium chloride inputs. Even so sodium chloride was lost in between the irrigation periods, the total reduction of the landfill leachate volume by irrigation decreased from 71% in the first year to 38% in the second year. Landfill gas addition also increased drainage volumes, but was less pronounced. Twenty-two percent of magnesium was retained under landfill leachate irrigation, while decreasing pH values, redox potential and high initial concentrations in the substrate released calcium, iron and potassium. Ninety-eight percent of ammonium was removed by irrigation, but 44% of the applied ammonium was leached as nitrate after oxidation took place due to a decreased uptake after the vegetation deteriorated. Landfill gas fumigation influenced landfill leachate treatment by decreasing the redox potential and the pH and increasing the drainage water content, which improved the retention of total nitrogen and sulfate, but increased the release of iron, calcium and magnesium. To conclude, landfill leachate irrigation is a valuable treatment option to minimize leachate quantities and remove ammonium independent from the presence of landfill gas if salt accumulation is avoided.

Drainage, Sanitary↗
PubMed1986

Radiation preservation of foods of plant origin. III. Tropical fruits: bananas, mangoes, and papayas.

The current status of research on the use of ionizing radiation for shelf life improvement and disinfestation of fresh tropical fruits like bananas, mangoes, and papayas are reviewed. The aspects covered are influence of maturity and physiological state of the fruits on delayed ripening and tolerance to radiation; varietal responses; changes in chemical constituents, volatiles, respiration, and ethylene evolution; biochemical mechanisms of delayed ripening and browning of irradiated fruits; and organoleptic quality. The efficacy of the combination of hot water dip and radiation treatments for control of postharvest fungal diseases are considered. The immediate potential of radiation as a quarantine treatment, in place of the currently used chemical fumigants, for disinfestation of fruit flies and mango seed weevil are discussed. Future prospects for irradiation of tropical fruits are discussed in the light of experience gained from studies conducted in different countries.

Amino Acids↗
PubMed1986

Radiation preservation of foods of plant origin. Part IV. Subtropical fruits: citrus, grapes, and avocados.

Current information on the use of ionizing radiation for improving the storage of subtropical fruits like citrus, grapes, and avocados is reviewed. The feasibility of applying radiation either alone or in combination with other physical or chemical treatments for the control of postharvest fungal diseases is considered. Irradiation effects on the physiology of the fruits as related to respiration, ethylene evolution, changes in major chemical constituents, and quality are discussed. The recent trends in the possible use of irradiation as an alternative treatment to chemical fumigants for disinfestation of citrus and avocados and the prospects for the future application of irradiation for preservation of some of these fruits are outlined.

Citrus↗
PubMed1999

Inhibition of catalase by sulfite and oxidation of sulfite by H2O2 cooperating with ascorbic acid.

An oxidative detoxification of sulfite, which originates from sulfur dioxide taken up into a leaf, has not yet been fully understood. In this study, we discuss that redox reactions between sulfite and H2O2 have an important role for the detoxification of sulfite. Sulfite was oxidized by H2O2 and during the redox reaction, oxygen consumption was observed. The oxygen consumption was partially inhibited by superoxide dismutase, indicating that O2- is generated during the redox reaction. Oxidation of sulfite by H2O2 was also observed in the presence of ascorbic acid, and during the oxidation, no significant oxidation of ascorbic acid and no consumption of oxygen were observed. Sulfite inhibited catalase of cell-free extracts of spinach, pea and broad bean leaves. These results suggest that when leaves are fumigated with SO2 in the light, catalase is inactivated resulting in the accumulation of H2O2 in leaves, which can oxidize sulfite without generating active oxygen species like O2- as long as ascorbate is present in leaves.

Ascorbic Acid↗
PubMed1999

Does ozone exposure protect from photoinhibition?

Tropospheric ozone and high light intensities are two stress factors that often occur simultaneously under natural conditions. Ozone is well known to form oxygen radicals in the apoplastic water and long lasting photoinhibition can cause photooxidative damage also by formation of several species of oxygen radicals. We were interested whether moderate levels of ozone would be able to modulate the response of leaves to photoinhibitory conditions naturally occurring around noon on a bright day. Cuttings of Populus sp. were cultivated in two separate greenhouse-compartments adapted as fumigation chambers. In the two compartments plants were grown in ambient air containing about 20 nmol mol(-1) ozone and in elevated ozone concentrations supplied for 8 h per day. During the midday of bright days Fv/Fm decreased by the same amount in all leaves, indicating photoinhibition. At the same time Fo increased in control leaves more than in ozone-exposed leaves indicating a higher amount of heat-deactivating PSII centres in the latter. This was confirmed by a higher epoxidation state in ozone-exposed leaves during midday of a bright day. The contents of chlorophyll a and chlorophyll b were significantly decreased in ozone-exposed leaves. In older leaves the ratios chlorophyll a : b, and xanthophylls: chlorophyll b were increased indicating an adaptation to higher light stress. From this we conclude that by increasing the amount of heat-deactivating centres ozone seems to protect PSII from photoinhibition.

Chlorophyll↗
PubMed1986

Chronic toxicology and carcinogenesis studies of Telone II by gavage in Fischer-344 rats and B6C3F1 mice.

Telone II (technical grade, 1,3-dichloropropene), a soil fumigant, was evaluated in chronic toxicology/carcinogenicity studies using Fischer-344 (F344) rats and B6C3F1 mice of both sexes. Doses administered were 0, 25, or 50 mg/kg to rats and 0, 50, or 100 mg/kg to mice. Telone II was given in corn oil by gavage 3 times per week for 104 wk. Ancillary studies were conducted to determine time-related effects, in which dose groups containing 5 male and 5 females rats were killed after receiving Telone II for 9, 16, 21, 24, or 27 mo. The primary organs affected were the forestomach (rats and mice), urinary bladder (mice), lung (mice), and liver (rats). Compound-related non-neoplastic lesions included basal-cell or epithelial hyperplasia of the forestomach (rats and mice), epithelial hyperplasia of the urinary bladder (mice), and hydronephrosis (mice). Neoplastic lesions associated with administration of Telone II included squamous-cell papillomas of the forestomach (male and female rats, female mice), squamous-cell carcinomas of the forestomach (Male rats, female mice), transitional-cell carcinomas of the urinary bladder (female mice), alveolar/bronchiolar adenomas (female mice), and neoplastic nodules of the liver (male rats). Although cis- and trans-1,3-dichloropropene are the principal components of Telone II, the presence of 1% epichlorohydrin, a direct-acting mutagen and carcinogen added as stabilizer, may have influenced the development of forestomach lesions. The results of the ancillary studies supported the findings of the carcinogenesis studies and demonstrated the time-dependent development of lesions in the forestomach (basal-cell hyperplasia and squamous-cell papilloma). Under the conditions of these gavage studies, Telone II was shown to be carcinogenic in male and female F344 rats and female B6C3F1 mice. Although the study in male B6C3F1 mice was considered inadequate because of the low survival resulting from suppurative inflammation of the heart (myocarditis) in the control group, there was some indication of Telone II-related increases of transitional-cell carcinomas of the urinary bladder, squamous-cell papillomas of the forestomach, and alveolar/bronchiolar adenomas and carcinomas of the lung.

Allyl Compounds↗
PubMed1994

Reactive oxygen species produced in metal-catalyzed oxidation of bis(trifluoromethyl)disulfide and protection by ZE.

Bis(trifluoromethyl)disulfide (TFD), used as an industrial fumigant, was found to generate a thiyl free radical as seen by EPR/spin trapping. Oxygen appears to be an absolute requirement for radical production. The results obtained in this investigation implicate the production of thiyl and reactive oxygen species (ROS), superoxide radical anion and hydroxyl radicals, during TFD autoxidation. The rate of production of these free radical intermediates was found to increase in the presence of iron(III) and copper(II). In addition, the metal ion chelator DETAPAC and ROS scavengers ethanol, mannitol, and PEG-SOD/catalase were found to inhibit free radical production. Reactive oxygen species were not formed when a high-potency zinc plus antioxidant, ZE caps, was present. These results provide support for the pro-oxidation of TFD and a protective role for zinc.

Animals↗
PubMed2006

Cytochrome-c oxidase inhibition in 26 aluminum phosphide poisoned patients.

INTRODUCTION: Aluminum phosphide (ALP) is used worldwide to fumigate grain. ALP poisoning, though reported from different parts of world, is most common in north, northwest and central India. In the presence of moisture, ALP liberates phosphine, which is highly toxic. The mechanism of action of phosphine is not known though experimental studies show that it inhibits cytochrome-c oxidase leading to inhibition of mitochondrial oxidative phosphorylation. PATIENTS AND METHODS: We estimated cytochrome-c oxidase activity in platelets of patients who had ingested ALP and compared them with those in healthy controls and in patients with shock due to other causes (cardiogenic shock, septic shock and hemorrhagic shock). RESULTS: After analysis of variance using Kruskal-Wallis test followed by Mann Whitney U test, significant inhibition of cytochrome-c oxidase activity could be found in ALP-poisoned patients compared to healthy controls (z = -5.513, p < 0.001) and in patients with shock due to other causes (z = -2.344; p < 0.05). There was no significant difference in inhibition in those who survived ALP poisoning compared to those who died from ALP poisoning (t = 0.02768; p > 0.05). CONCLUSION: Though inhibition of cytochrome-c oxidase in platelets does not have prognostic value, it suggests that interruption of mitochondrial oxidative phosphorylation as a result of cytochrome-c oxidase inhibition may lead to multi-organ dysfunction and therapeutic strategies to maintain enzyme activity may help in managing these patients.

Adolescent↗
PubMed1986

Effect of the pH value when treating concentrate protein with formaldehyde on protein protection in the rumen.

Nine samples of soybean extracted meal were treated by fumigation in plastic bag with 0.5 g formaldehyde/100 g crude protein, the pH ranging from 2.1 to 10.7. The studies showed that with rising pH (x) the proportion of totally bound (y1, % of formaldehyde amount used) and irreversibly bound (y2) formaldehyde increased (y1 = 77.7 + 1.56x, y2 = 28.2 + 2.04x), whilst the reversible proportion remained constant (45.4% of formaldehyde amount used). The lysine detectable (g/16 g N) after HCl hydrolysis was reduced due to pH raising (y = 101 - 0.67x). Solubility and fermentability of the soybean protein in the rumen were found to rise though. Consequently, the formaldehyde content of the protein was positively correlated with the content of soluble N and fermentable N, respectively, and negatively correlated with the lysine content. These experimental results allow to conclude that the desired protein protection to be attained by treating soybean extracted meal with formaldehyde, is greatly influenced by the respective pH value. To reach maximum protection of the protein against microbial degradation in the rumen (N degradation after 12 hours incubation less than or equal to 20% of total N), the pH value should be below 5. The contents of totally, reversibly or irreversibly bound formaldehyde does not allow any conclusion regarding the protein protection attained. The apparently increased binding rate of formaldehyde is presumably due to the fact that here the reaction stops at the stage of methylol formation (molar proportion 1:1). Under the conditions of acid protein hydrolysis for lysine determination, the released formaldehyde obviously reacts irreversibly with the E-NH2 group of lysine.

Animals↗
PubMed2000

Central nervous system toxicity and early peripheral neuropathy following dermal exposure to methyl bromide.

CASE REPORT: We describe a case of early peripheral neuropathy and central nervous system toxicity as a result of acute predominantly dermal exposure to methyl bromide. A 32-year-old male was admitted after an accidental predominantly dermal exposure to methyl bromide while fumigating soil for pest control. The patient suffered dermal burns and vesicles on the upper and lower limbs. One week following exposure, he developed progressive weakness of the lower limbs, ataxia, paresthesiae of both legs and the left arm, hyperactive tendon reflexes in the lower limbs, and left Babinski sign. Nerve conduction velocity testing was compatible with axonal neuropathy. The patient recovered gradually from his burns. Three months postexposure he showed no signs of central nervous system toxicity, but the peripheral neuropathy was still present. DISCUSSION: Neurological effects primarily referable to the central nervous system following severe inhalation of methyl bromide have frequently been reported. The patient described in this study developed an unusual early peripheral neuropathy following dermal exposure. Peripheral neuropathy can be an outcome of methyl bromide intoxication, but is usually a late sequela of acute central nervous system toxicity or an aftereffect of repetitively inhaled chronic exposure. In this case, exposure to methyl bromide through abraded skin caused early peripheral neuropathy and central nervous system toxicity.

Administration, Cutaneous↗
PubMed2005

Retinal degeneration and other eye disorders in wives of farmer pesticide applicators enrolled in the agricultural health study.

Retinal degeneration is the leading cause of visual impairment in older adults. An association between retinal degeneration and fungicide use was observed previously among farmer pesticide applicators in the Agricultural Health Study, a large study of farm families from Iowa and North Carolina. The objective of this investigation was to determine whether wives of these farmer pesticide applicators were at increased risk of retinal degeneration. Self-reported cross-sectional data obtained via questionnaire between 1993 and 1997 from 31,173 wives were used. Associations of specific pesticides and groups of pesticides based on function (fungicides, herbicides, insecticides, and fumigants) or chemical structure (organophosphates, organochlorines, and carbamates) with eye disorders were evaluated using logistic and hierarchical logistic regression analyses. Self-reported retinal degeneration was associated with the wife's fungicide use (odds ratio = 1.9, 95% confidence interval: 1.2, 3.1) after adjustment for age and state of residence. Specific fungicides that appeared to drive this association were maneb or mancozeb and ziram. No associations between pesticide use and other eye disorders were found. Although these findings for retinal degeneration are based solely on self-reported disease, they are consistent with those reported for farmer pesticide applicators. These findings suggest that exposure to some fungicides and other pesticides may increase the risk of retinal degeneration and warrant further investigation.

Adult↗
PubMed1990

The determination of urinary 3-methyladenine by immunoaffinity chromatography-monoclonal antibody-based ELISA: use in human biomonitoring studies.

A mouse monoclonal antibody (Mab) was prepared which showed high specificity for a potential marker of exposure to methylating carcinogens such as 3-methyladenine (3-MeAde). In a low-temperature (4 degrees C) ELISA a linear calibration curve was obtained between 3 and 50 fmol/well. In combination with an immunoaffinity (IA) column prepared from a 3-MeAde rabbit antiserum, the ELISA was used to determine 3-MeAde in urine. The IA-ELISA method was validated by comparison with results obtained by an IA-GC-MS method. The effect of consuming a low 3-MeAde diet on urinary 3-MeAde excretion was investigated in a human volunteer. Urine collected during a 'normal' diet exhibited the characteristic variation in 3-MeAde levels previously observed (9.5 micrograms/24 h, SD = 4.4, n = 5). In contrast, 3-MeAde excretion was markedly lower and less variable on days when the diet was closely controlled (0.63 microgram/24 h, SD = 0.08, n = 3). Dietary intake of 3-MeAde on the latter days was between 0.37 and 0.43 microgram/day, indicating that most, if not all, of the 3-MeAde seen in previous experiments was derived from the diet. The origin of dietary 3-MeAde is not known, but may be related to fumigant use. Dietary manipulation affords the possibility of carrying out model studies, in volunteers, on 3-MeAde intake and formation in vivo.

Adenine↗
PubMed1985

Proportionate mortality among male corn wet-milling workers.

Workers in the corn wet-milling industry are exposed to grain dusts, pesticides and fumigants, acids, solvents, sulphur dioxide, and other chemicals used in the manufacture of starch, oil, syrup, and dextrins. In a preliminary investigation of the long-term health effects of occupational exposures in this industry, deaths among active and retired corn wet-milling workers were identified from records of a trade union. Underlying cause of death for workers who died between 1947 and 1981 was determined from death certificates. Cause-specific Proportionate Mortality Ratios (PMR's) were computed for white and black males using US males as a comparison with adjustments for age, race, and calendar year of death. There were deficits of deaths from respiratory and digestive diseases. Among whites, mortality from chronic nephritis, bladder cancer, and lymphatic and haematopoietic malignancies was elevated. There was an elevated frequency of deaths due to diabetes and a threefold excess of pancreatic cancer deaths among blacks. Crude work history information indicated a small cluster of pancreatic cancer deaths among whites and blacks who had worked in production processes that convert corn starch to syrup and dextrins. An elevated frequency of deaths from leukaemia was seen among white maintenance workers.

Black People↗
PubMed1991

The effects of indoor environmental factors on respiratory illness in primary school children in Kuala Lumpur.

The effects of indoor environmental factors on respiratory illness were studied in 15017-12 year old school children in Kuala Lumpur. Exposure to mosquito coil smoke for at least three nights a week was independently associated with asthma and persistent wheeze. Passive smoking, defined as sharing a bedroom with an adult smoker, was independently associated with a chest illness in the past year. No relationships were found between exposure to kerosene stoves, wood stoves, fumigation mat mosquito repellents or aerosol insecticides and respiratory illness. Host factors predictive of at least one respiratory outcome included family history of chest illness, history of allergy, male sex, hospitalization in the neonatal period and low paternal education. With 95% confidence, avoidance of regular exposure to mosquito coil smoke and passive smoking could reduce the prevalences of persistent wheeze, asthma and chest illness by up to 29%. Measurements of lung function confirmed the validity of questions pertaining to wheezing and asthma in the study questionnaire.

Child↗