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PubMed1993

Enhancement of Population Densities of Pseudomonas putida PpG7 in Agricultural Ecosystems by Selective Feeding with the Carbon Source Salicylate.

Sodium salicylate (1,000 mug/ml) was delivered through a drip irrigation system to agricultural field soils planted to tomato and infested with Pseudomonas putida PpG7, the host of the salicylate catabolic plasmid NAH7. In nonfumigated soils infested with approximately 10 CFU of PpG7 per g in the top 30 cm, population densities were increased up to 112-fold within 14 days of the initial application of salicylate compared with the densities in the respective nonamended soils. Mean season-long population densities of PpG7 in the top 30 cm of soil were significantly increased (P < 0.01) from 216 CFU/g in nonamended soils to 1,370 CFU/g in salicylate-amended soils. In the respective rhizosphere soils, mean population densities of PpG7 were significantly increased (P < 0.01) from 92 to 2,066 CFU/cm of root. Soil fumigation interacted (P < 0.01) with salicylate amendment and further increased the mean population densities of PpG7 in nonrhizosphere soil by an additional 5,689 CFU/g of soil. This fumigation effect was not detected in rhizosphere soils. The effect of salicylate in increasing population densities of PpG7 in soil also was affected by inoculum level, field site, and soil depth. Proportionate differences were greater in soils infested with approximately 10 CFU of PpG7 per g than in comparable soils infested with 10 CFU/g. In low-inoculum soils, increases from salicylate amendments were 26- and 29-fold in rhizosphere and nonrhizosphere soils, respectively, and in high-inoculum soils, the respective increases were 5.6- and 5-fold. No increases of fungi able to utilize salicylate were detected in soils amended with salicylate. However, soil fumigation with metham-sodium significantly reduced (P < 0.01) population densities of fungal salicylate utilizers in rhizosphere and nonrhizosphere soils.

Journal Article↗

PubMed2005

Effect of chlorine dioxide gas on fungi and mycotoxins associated with sick building syndrome.

The growth of indoor molds and their resulting products (e.g., spores and mycotoxins) can present health hazards for human beings. The efficacy of chlorine dioxide gas as a fumigation treatment for inactivating sick building syndrome-related fungi and their mycotoxins was evaluated. Filter papers (15 per organism) featuring growth of Stachybotrys chartarum, Chaetomium globosum, Penicillium chrysogenum, and Cladosporium cladosporioides were placed in gas chambers containing chlorine dioxide gas at either 500 or 1,000 ppm for 24 h. C. globosum was exposed to the gas both as colonies and as ascospores without asci and perithecia. After treatment, all organisms were tested for colony growth using an agar plating technique. Colonies of S. chartarum were also tested for toxicity using a yeast toxicity assay with a high specificity for trichothecene mycotoxins. Results showed that chlorine dioxide gas at both concentrations completely inactivated all organisms except for C. globosum colonies which were inactivated an average of 89%. More than 99% of ascospores of C. globosum were nonculturable. For all ascospore counts, mean test readings were lower than the controls (P < 0.001), indicating that some ascospores may also have been destroyed. Colonies of S. chartarum were still toxic after treatment. These data show that chlorine dioxide gas can be effective to a degree as a fumigant for the inactivation of certain fungal colonies, that the perithecia of C. globosum can play a slightly protective role for the ascospores and that S. chartarum, while affected by the fumigation treatment, still remains toxic.

Chaetomium↗

PubMed1991

Thioether excretion in urine of applicators exposed to 1,3-dichloropropene: a comparison with urinary mercapturic acid excretion.

The excretion of thioethers in urine of applicators occupationally exposed to the soil fumigant 1,3-dichloropropene (DCP) was determined by the thioether assay. The mercapturic acid metabolite of E-1,3-dichloropropene, N-acetyl-S-(E-3-chloropropenyl-2-)-L-cysteine (E-DCP-MA), was the reference compound in the thioether assay. The mean recovery of E-DCP-MA was 58.5% (coefficient of variation (CV) 9%, n = 4). In non-exposed men mean background of urinary thioethers was 6.05 mmol SH/mol creatinine (n = 56). In applicators exposed to soil fumigants containing DCP, urinary excretion of thioethers followed first order elimination kinetics. Urinary half lives of elimination of thioethers were 8.0 (SD 2.5) hours based on excretion rates and 9.5 (SD 3.1) hours based on creatinine excretion. The urinary half life of elimination of thioethers was almost twofold higher compared with half lives of elimination of the mercapturic acids of Z- and E-1,3-dichloropropene. The post- minus pre-shift thioether concentrations in urine and the cumulative urinary thioether excretions correlated well with exposure to DCP. In urine samples the mean thioether concentration was 1.38 higher than mean DCP mercapturic acid concentration. This suggests the presence of unidentified thioether metabolite(s) due to exposure to soil fumigants containing DCP. According to the present data, an eight hour time weighted average exposure to the Dutch occupational exposure limit of 5 mg/m(3) DCP results in a post- minus pre-shift thioether concentration of 9.6 mmol SH/mol creatinine (95% confidence interval (95%CI) 7.4-11.8 mmol SH/mon creatinine) and in a cumulative thioether excretion of 139 micromol SH (95% CI 120-157 micromol SH). It is concluded that the thioether assay can be used to assess comparatively high levels of exposure to DCP.

Acetylcysteine↗

PubMed1992

Promotion of apple tree growth and fruit production by the EBW-4 strain of Bacillus subtilis in apple replant disease soil.

A field trial was conducted near Kelowna, British Columbia, to determine the effect of biological treatments alone and in combination with formalin fumigation in apple replant disease soil. The response was measured by the increase in cross-sectional trunk area, total shoot growth, and fruit yield of McIntosh apple trees on M.26 rootstock. The postplanting drench application of strain EBW-4 of Bacillus subtilis alone was consistently effective in increasing cross-sectional trunk area for 5 years, total shoot growth for 4 years, and fruit yield for 3 years. The biological agent EBW-4 of B. subtilis in combination with formalin fumigation was also effective in promoting total shoot growth and cross-sectional trunk area. The application of formalin fumigation alone was effective in increasing shoot growth for 2 years and cross-sectional trunk area for 1 year only. This treatment did not increase fruit yield for 3 years. The consistent performance of strain EBW-4 of B. subtilis during 1986-1991 indicates that this bacterium has the potential for biological control of replant disease under orchard conditions in the Okanagan Valley of British Columbia.

Bacillus subtilis↗

PubMed2006

Agricultural pesticide use and risk of t(14;18)-defined subtypes of non-Hodgkin lymphoma.

Pesticides have been specifically associated with the t(14;18)(q32;q21) chromosomal translocation. To investigate whether the association between pesticides and risk of non-Hodgkin lymphoma (NHL) differs for molecular subtypes of NHL defined by t(14; 18) status, we obtained 175 tumor blocks from case subjects in a population-based case-control study conducted in Nebraska between 1983 and 1986. The t(14;18) was determined by interphase fluorescence in situ hybridization in 172 of 175 tumor blocks. We compared exposures to insecticides, herbicides, fungicides, and fumigants in 65 t(14;18)-positive and 107 t(14;18)-negative case subjects with those among 1432 control subjects. Multivariate polytomous logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs). Compared with farmers who never used pesticides, the risk of t(14;18)-positive NHL was significantly elevated among farmers who used animal insecticides (OR = 2.6; 95% CI, 1.0-6.9), crop insecticides (OR = 3.0; 95% CI, 1.1-8.2), herbicides (OR = 2.9; 95% CI, 1.1-7.9), and fumigants (OR = 5.0; 95% CI, 1.7-14.5). None of these pesticides were associated with t(14;18)-negative NHL. The risk of t(14;18)-positive NHL associated with insecticides and herbicides increased with longer duration of use. We conclude that insecticides, herbicides, and fumigants were associated with risk of t(14;18)-positive NHL but not t(14;18)-negative NHL. These results suggest that defining subsets of NHL according to t(14;18) status is a useful approach for etiologic research.

Adult↗

PubMed2005

Neurologic symptoms in licensed private pesticide applicators in the agricultural health study.

Exposure to high levels of many pesticides has both acute and long-term neurologic consequences, but little is known about the neurotoxicity of chronic exposure to moderate levels of pesticides. We analyzed cross-sectional data from 18,782 white male licensed private pesticide applicators enrolled in the Agricultural Health Study in 1993-1997. Applicators provided information on lifetime pesticide use and 23 neurologic symptoms typically associated with pesticide intoxication. An indicator of more symptoms (> or = 10 vs. < 10) during the year before enrollment was associated with cumulative lifetime days of insecticide use: odds ratios (95% confidence intervals) were 1.64 (1.36-1.97) for 1-50 days, 1.89 (1.58-2.25) for 51-500 days, and 2.50 (2.00-3.13) for > 500 days, compared with never users. A modest association for fumigants [> 50 days, 1.50 (1.24-1.81)] and weaker relationships for herbicides [> 500 days, 1.32 (0.99-1.75)] and fungicides [> 50 days, 1.23 (1.00-1.50)] were observed. Pesticide use within the year before enrollment was not associated with symptom count. Only associations with insecticides and fumigants persisted when all four pesticide groups were examined simultaneously. Among chemical classes of insecticides, associations were strongest for organophosphates and organochlorines. Associations with cumulative exposure persisted after excluding individuals who had a history of pesticide poisoning or had experienced an event involving high personal pesticide exposure. These results suggest that self-reported neurologic symptoms are associated with cumulative exposure to moderate levels of fumigants and organophosphate and organochlorine insecticides, regardless of recent exposure or history of poisoning.

Adolescent↗

PubMed1988

[Cases of severe methyl bromide poisoning residing above a warehouse].

Methyl bromide has been widely used in Japan to fumigate grains and wood. One death and 3 cases of hospitalization resulted from exposure to methyl bromide at place of residence. These 4 cases were not employed and were members of one family living above a warehouse, the ground level of this building was a warehouse where herbs were stored and the second floor was their living area. On the 13th of May 1978 at 7:00 p.m., the herbs were fumigated with methyl bromide gas. The fumigator used 15 kg of methyl bromide (2 cylinders), a quantity far greater than usual. It is assumed that the concentration in the warehouse was between 10,000-15,000 ppm. Early in the morning on the 16th of May (3 days later), one of the family members, a 12-year-old girl, developed severe convulsions, and later 2 others also had severe convulsions, while the other suffered from marked mental confusion. The serum or plasma bromide ion level ranged from 280 to 600 ppm. The results of the clinical laboratory test showed that GOT exceeded the normal level in 3 out of the 4 cases. Moreover, LDH activity was above the normal range in 3 cases and CPK activity was increased in all the cases.

Adult↗

PubMed2000

Large-scale, on-site confirmatory, and varietal testing of a methyl bromide quarantine treatment to control codling moth (Lepidoptera: Tortricidae) in nectarines exported to Japan.

In total, 30,491 codling moth, Cydia pomonella (L.), 1-d-old eggs on May Grand nectarines in two large-scale tests, and 17,410 eggs on Royal Giant nectarines in four on-site confirmatory tests were controlled with 100% mortality after fumigation with a methyl bromide quarantine treatment (48 g3 for 2 h at > or = 21 degrees C and 50% volume chamber load) on fruit in shipping containers for export to Japan. Ranges (mean +/- SEM) were for percentage sorption 34.7 +/- 6.2 to 46.5 +/- 2.5, and for concentration multiplied by time products 54.3 +/- 0.9 to 74.5 +/- 0.6 g.h/m3 in all tests. In large-scale tests with May Grand nectarines, inorganic bromide residues 48 h after fumigation ranged from 6.8 +/- 0.7 to 6.9 +/- 0.5 ppm, which were below the U.S. Environmental Protection Agency tolerance of 20 ppm; and, organic bromide residues were < 0.01 ppm after 1 d and < 0.001 ppm after 3 d in storage at 0-1 degree C. After completion of larger-scale and on-site confirmatory test requirements, fumigation of 10 nectarine cultivars in shipping containers for export to Japan was approved in 1995. Comparison of LD50s developed for methyl bromide on 1-d-old codling moth eggs on May Grand and Summer Grand nectarines in 1997 versus those developed for nine cultivars in the previous 11 yr showed no significant differences in codling moth response among the cultivars.

Citrus↗

PubMed2001

Toxicity, feeding deterrence, and effect of activity of 1,8-cineole from Artemisia annua on progeny production of Tribolium castanaeum (Coleoptera: Tenebrionidae).

1,8-Cineole isolated from Artemisia annua was tested against Tribolium castaneum (Herbst) for contact toxicity, fumigant toxicity, and antifeedant activity. The adults of T. castaneum were more susceptible than larvae to both contact and fumigant toxicity of 1,8-cineole, and LD50 and LC50 values of 108.4 microg/mg body weight of adult insect and 1.52 mg/liter air were found, respectively. Furthermore, 14-d-old T. castaneum larvae were more tolerant than 16- and 18-d-old larvae and adults to the contact toxicity of 1,8-cineole, but the 16- and 18-d-old larvae have similar susceptibility. In contrast, all the larvae (14-18 d old) of T. castaneum were much more tolerant than the adults to the fumigant action, but larvae of different ages had similar susceptibility. The compound 1,8-ciineole applied to filter paper at a concentration of 3.22-16.10 mg/cm2 significantly (P < 0.05) reduced the hatching of T. castaneum eggs and the subsequent survival rate of the larvae. Adult emergence was also reduced by 1,8-cineole. Feeding deterrence of 81.9% was achieved in T. castateum adults by using a concentration of 121.9 mg/g food, whereas larvae showed 68.8% at the same concentration.

Animals↗

PubMed2002

Bioactivities of the leaf essential oil of Curcuma longa (var. ch-66) on three species of stored-product beetles (Coleoptera).

Essential oil extracted from the leaves of turmeric, Curcuma longa L., was investigated for contact and fumigant toxicity and its effect on progeny production in three stored-product beetles, Rhyzopertha dominica F. (lesser grain borer), Sitophilus oryzae L. (rice weevil), and Tribolium castaneum Herbst (red flour beetle). Oviposition-deterrent and ovicidal actions of C. longa leaf oil were also evaluated against T. castaneum. The oil was insecticidal in both contact and fumigant toxicity assays. The adults of R. dominica were highly susceptible to contact action of C. longa leaf oil, with LD50 value of 36.71 microg/mg weight of insect, whereas in the fumigant assay, adults of S. oryzae were highly susceptible with LC50 value of 11.36 mg/liter air. Further, in T. castaneum, the C. longa oil reduced oviposition and egg hatching by 72 and 80%, respectively at the concentration of 5.2 mg/cm2. At the concentration of 40.5 mg/g food, the oil totally suppressed progeny production of all the three test insects. Nutritional indices indicate >81% antifeedant action of the oil against R. dominica, S. oryzae and T castaneum at the highest concentration tested.

Animals↗

PubMed2003

Effect of d-limonene on three stored-product beetles.

d-Limonene was investigated for contact and fumigant toxicity, ovicidal effects, oviposition-deterrent, development inhibition, and feeding-deterrent activities against three stored-product beetles (Coleoptera): lesser grain borer, Rhyzopertha dominica (F.); rice weevil, Sitophilus oryzae (L.); and red flour beetle, Tribolium castaneum (Herbst). Contact and fumigant toxicity decreased as larvae aged. Contact toxicity was similar for adults of the three species tested, but R. dominica was most susceptible to fumigant activity. T. castaneum oviposition decreased as concentration of d-limonene increased and d-limonene reduced oviposition up to 92.3% at the concentration of 2.14 mg/cm2. Hatching of d-limonene-treated eggs of T. castaneum was reduced by 94.5% with no subsequent larval and adult survival at 2.14 mg/cm2 concentration. A flour disc bioassay indicated 87.7 to 96.8% feeding-deterrency by d-limonene toward all three insect species tested at the highest concentration of 60.0 mg/g food. These results suggest that d-limonene can be effectively used to suppress populations of stored-product beetles.

Animals↗

PubMed2006

Vapor phase toxicity of plant essential oils to Cadra cautella (Lepidoptera: Pyralidae).

The toxicities of 44 plant essential oils against larvae of Cadra cautella (Walker) were examined using direct contact and vapor phase toxicity bioassays and compared with the lethal activity of chlorpyrifos-methyl, diazinon, dichlorvos, and fenthion, four widely used organophosphorus insecticides. Responses varied according to plant material used and exposure dose and time. In a filter paper contact toxicity bioassay, potent toxicity was produced from buchu leaf, niaouli, and rosemary oils at 2.4 mg/cm2 and armoise, cypress, galbanum, and mace oils at 4.7 mg/cm2. In vapor phase toxicity bioassays with larvae, cypress, galbanum, niaouli, and rosemary oils were much more effective in closed containers than in open containers, indicating that the lethal effects of these oils were largely because of action in the vapor phase. As judged by 24-h LC50 values, potent fumigant action was observed with niaouli oil (64.7 mg/liter air) and rosemary oil (64.6 mg liter/air). Cypress and galbanum oils exhibited weak fumigant activity. These essential oils were less active than dichlorvos (0.86 mg/liter air). Little or no fumigant action was observed with chlorpyrifos-methyl, diazinon, and fenthion. Essential oils described herein, particularly niaouli and rosemary oils, merit further study as potential larvicides for the control of C. cautella.

Animals↗

PubMed2000

Methyl bromide 1-year dietary study in dogs.

Average human exposure resulting from consumption of methyl I bromide (MB)-fumigated food has been estimated to be 0.00125 mg/kg/day. A 1-yr feeding study in beagle dogs was conducted as a safety study in which the high-dose diet was intended to yield a methyl bromide dose of at least 100 times the calculated human dietary exposure. Diets were fumigated with MB and fed to the dogs daily, except for weekends and holidays. MB consumption each feeding day was calculated as a time weighted average (TWA) that accounted for the rate of degassing from the fumigated diet and the rate of feed consumption during the feeding period. TWA compound consumption in the loss-, mid- and high-dose groups, respectively, averaged 0.06 ¿ 0.02, 0.13 ¿ 0.03 and 0.28 ¿ 0.08 mg/kg/day in males and 0.07 ¿ 0.03, 0.12 ¿ 0.03 and 0.27 ¿ 0.09 mg/kg/day in females. Clinical observations, body weight and feed consumption, ophthalmology, clinical pathology, urinalysis, organ weights and macroscopic and microscopic pathology were comparable in control and MB-treated dogs. Under the conditions of this study. the no-observed-effect level (NOEL) for MB was at least 0.28 mg/ kg/day, or approximately 200 times the expected average human dietary exposure.

Administration, Oral↗

PubMed1985

NTP Toxicology and Carcinogenesis Studies of Propylene Oxide (CAS no. 75-56-9) in F344/N Rats and B6C3F1 Mice (Inhalation Studies).

Propylene oxide is a volatile, colorless liquid used as an intermediate in the production of polyether polyols, polyurethane foams, and unsaturated polyester resins and also as a fumigant for sterilizing a variety of materials ranging from plastic medical instruments to foodstuffs. In the United States, propylene oxide is registered as a fumigant for packaged dried prunes and glacé fruits such as candied cherries and as an insecticidal and fungicidal fumigant for bulk quantities of cocoa, gums, and processed spices. The 2-year carcinogenesis studies of propylene oxide (greater than 99.9% pure) were conducted by exposing groups of 50 F344/N rats and 50 B6C3F1 mice of each sex to air containing propylene oxide at concentrations of 0 (chamber control), 200, or 400 ppm for 6 hours per day, 5 days per week, for 103 weeks. The survival of rats exposed to propylene oxide was comparable with that of the controls; terminal body weights were lower than those of the controls for high dose males (8%) and high dose females (6%). Survival of exposed male and female mice decreased relative to that of the controls (male: control, 42/50; low dose, 34/50; high dose, 29/50; female: 38/50; 29/50; 10/50), but the difference was significant only for animals in the high dose groups. High dose female mice had a mean terminal body weight 22% below that of the controls. The respiratory epithelium of the nasal turbinates was one of the primary tissues affected in male and female rats; exposure-related increases occurred in the incidences of suppurative inflammation, epithelial hyperplasia, and squamous metaplasia. Papillary adenomas, involving the respiratory epithelium and underlying submucosal glands of the nasal turbinates, were observed in three female rats and two male rats exposed to propylene oxide at 400 ppm. The incidence of adenomas in females was significant by the trend tests. The proportions of high dose female rats with C-cell adenomas and with C-cell carcinomas of the thyroid gland were increased, but only the combined incidence of these tumors was significant (2/45; 2/35; 7/37). These tumors were not considered to be related to exposure to propylene oxide because there was no other evidence for C-cells' being a target tissue and because there was no increase in C-cell hyperplasia. The combined incidences of female rats with endometrial stromal polyps and endometrial stromal sarcomas of the uterus were significantly increased in the dosed groups (3/49; 12/50; 10/47). However, the occurrence of these lesions in the dosed groups was similar to the average (306/1,502, 20%) seen in untreated controls in NTP carcinogenesis studies, and hence this increase was not regarded as being related to exposure to propylene oxide. The respiratory epithelium of the nasal turbinates was also one of the primary tissues affected in male and female mice; exposure-related increases occurred in the incidences of inflammation, and squamous metaplasia was observed in one low dose male and two high dose female mice. One squamous cell carcinoma and one papilloma occurred in the nasal cavity of different high dose male mice, and two high dose female mice had adenocarcinomas of the nasal cavity. The endothelial cells of the submucosal vascular plexus in the nasal turbinates also appeared to be a major site affected in high dose male mice. Three high dose male and three high dose female mice had a saccular dilation (classified as angiectasis) of submucosal turbinate vessels. Further, hemangiomas were seen in the nasal cavity of 5/50 high dose male mice and 3/50 high dose female mice, and hemangiosarcomas were found in the nasal cavity of 5/50 high dose male mice and 2/50 high dose female mice. The increased incidences of hemangiomas in males and females and of hemangiosarcomas in males were statistically significant. Vascular tumors were not present in the nasal turbinates of any low dose or control mice. Under the conditions of these studies, there was some evidence of carcinogenicity for F344/N rats, as indicated by increased incidences of papillary adenomasncreased incidences of papillary adenomas of the nasal turbinates in male and female rats exposed to propylene oxide at 400 ppm. For male and female B6C3F1 mice, there was clear evidence of carcinogenicity, as indicated by increased incidences of hemangiomas or hemangiosarcomas of the nasal turbinates at 400 ppm. In the respiratory epithelium of the nasal turbinates, propylene oxide also caused suppurative inflammation, hyperplasia, and squamous metaplasia in rats and inflammation in mice.

Journal Article↗

PubMed2004

An assessment of sanitation protocols for commercial transport vehicles contaminated with porcine reproductive and respiratory syndrome virus.

The objective of this study was to develop and test a rapid (< 2 h) sanitation protocol designed for porcine reproductive and respiratory syndrome virus (PRRSV) positive commercial transport vehicles involving cold water washing and disinfection via fumigation using scale models of weaned pig trailers. The study consisted of 2 phases. Following experimental contamination of model trailers with PRRSV MN 30-100 (5 x 10(5)TCID50), phase 1 evaluated the presence or absence of PRRSV RNA by polymerase chain reaction (PCR) on swabs collected from the trailer interiors 0, 60, and 90 min after treatment. Phase 2 consisted of evaluating the infectivity of trailers 90 min posttreatment by monitoring changes in the PRRSV-status of naive sentinel pigs housed for 2 h. Treatments included washing only (treatment 1), washing plus formaldehyde fumigation (treatment 2), washing plus fumigation with glutaraldehyde-quaternary ammonium chloride (treatment 3), and washing plus overnight drying (treatment 4). Porcine reproductive and respiratory syndrome virus RNA was detected in all trailers (20 out of 20 replicates) at 60 and 90 min following the application of treatments 1 and 2. These trailers also contained infectious PRRSV, as determined by the infection of naive pigs housed in treated trailers and the testing of organic debris collected from the interior of trailers by swine bioassay. At 90 min posttreatment, all trailers treated with glutaraldehyde-quaternary ammonium chloride were PCR-negative, non-infectious to sentinel pigs, and swine bioassay negative. Similar results were observed in trailers allowed to dry for 8 h. Under the conditions of this study, it appears certain disinfectants may possess different levels of efficacy against PRRSV and PRRSV-positive models may be effectively sanitized in the absence of overnight drying.

Animals↗

PubMed2004

[Impact of automobile exhaust on membrane lipid peroxidation and protective enzyme activities in seedlings foliage of four northern broadleaved tree species].

By means of fumigating one-year-old seedlings in open top chambers, this paper studied the impact of automobile exhaust on the pH value, relative conductivity, malondialdehyde (MDA) and chlorophyll contents, superoxide dismutase (SOD) and peroxidase (POD) activities, and ascorbic acid (ASA) content in the seedlings foliage of four tree species, Acer mono, Malus baccata, Prunus ussuriensis, and Acer ginnala. During the fumigation, the seedlings were exposed to the same exhaust gas concentration (25 microg x m(-3), indicated by the NO2 concentration in exhaust) for different durations (1, 3, 5, 7 d), and to different concentrations (40, 60, 80, 100 microg NO2 x m(-3)) for same duration (2 h). The results showed that the pH value and the chlorophyll and ascorbic acid (ASA) contents decreased, whereas the relative conductivity, malondialdehyde (MDA) content, and superoxide dismutase (SOD) and peroxidase (POD) activities increased with increasing fumigation duration and exhaust concentration. Obvious interspecies variations in term of physiological features were found. After treated 7 days with 25 microg NO2 x m(-3) and treated 2 h with 100 microg NO2 x m(-3), only a 1.5% and 2.7% decrease of cell juice pH was found in A. ginnala, respectively, compared to the control. The corresponding data for P. ussuriensis was 9.42% and 13.89%, followed by M. baccata. The chlorophyll content of A. mono, A. ginnala, M. baccata and P. ussuriensis was 83.0%, 71.3%, 68.7% and 54.9%, respectively of the control after 7 days treated with 25 microg NO2 x m(-3), and the corresponding data under 100 microg NO2 x m(-3) treatment was 60.2%, 73.1%, 43.4% and 51.2%, respectively. The decrease of ASA content and Acer ginnala was less in A. mono than in M. baccata and P. ussuriensis. The relative conductivity and MDA content of A. mono increased respectively by 68.1% and 52.5% in compared with control, while those of A. ginnala had the least increment. As for the 100 microg NO2 x m(-3) treatment, the maximum increases of relative conductivity (99.8%) and MDA content (52.5%) were found in M. baccata, while the least were found in A. mono and A. ginnala. The SOD and POD activities generally increased under the highest concentration of exhaust, with the exception of M. baccata. To summarize, almost all the test physiological features of A. ginnala were least affected, suggesting its great tolerance to exhaust stress, but in contrary, the greatest variation of the physiological features and the dramatic decline of SOD and POD activities of M. baccata at the highest exhaust concentration indicated that this tree species had the least tolerance to exhaust stress.

Chlorophyll↗

PubMed2004

Metabolic responses of tropical trees to ozone pollution.

Plants fumigated with 40ppbv, 80ppbv and 120ppbv concentrations of O3 exhibited significant reduction in total chlorophyll content, RuBP carboxylase activity and net photosynthesis. The reduction in total chlorophyll activity ranged from 12 to 36% in Bauhinia variegata, 11 to 35% in Ficus infectoria and 3 to 26% in Pongamia pinnata on fumigation with O3, while the RuBP carboxylase activity was reduced by 10 to 32% in Bauhinia variegata, 10 to 23% in Ficus infectoria and 9 to 15% in Pongamia pinnata. The net photosynthesis was also reduced by 6 to 26% in B. variegata, 16 to 39% in F. infectoria and 7 to 31% in P. pinnata on fumigation with 03. The relative higher sensitivity of tropical trees to O3 suggests that the ambient air quality standards in tropical tree areas need to be stringent to prevent vegetation from air pollution.

Air Pollutants↗

PubMed1996

Pesticide appliers with mixed pesticide exposure: G-banded analysis and possible relationship to non-Hodgkin's lymphoma.

To further investigate the possible relationships between agricultural pesticide exposure and the increased risk of non-Hodgkin's Lymphoma among farm workers in the north central United States, we performed G-banded chromosome analyses of peripheral blood from workers classified according to primary types of pesticide exposure: herbicides (n = 20), insecticides (n = 18), fumigants (n = 23), and occupationally unexposed controls (n = 33). Significantly increased rearrangement frequencies were demonstrated in fumigant and insecticide appliers compared to control subjects. At certain chromosome bands there were significant excesses of breaks observed in pesticide appliers, but no breaks were observed in controls. Some of these bands contained genes with potential implications for cancer risk, including oncogenes and genes involved in tumor suppression and apoptosis. Of particular interest with regard to lymphoma risk were the excess rearrangement and breaks involving band 14q32 in fumigant appliers and the excess breaks involving band 18q21 in herbicide appliers; translocations linking 14q32 and 18q21 are the most common rearrangements observed in non-Hodgkin's lymphoma patients. The potential pathobiological relevance of these cytogenetic events warrants additional investigation at the molecular level.

Agricultural Workers' Diseases↗