Long-Term Continuous Exposure to Sulfur Dioxide and Fly Ash Mixtures

Three groups of cynomolgus monkeys and three groups of guinea pigs were exposed to mixtures of sulfur dioxide (SO₂) and fly ash while one group of each species was used as a control group. The exposure concentrations for SO₂ were 0.1, 1.0, and 5 ppm, and 0.5 mg/cu m of fly ash was combined with each of the SO₂ concentrations. The duration of exposure was 52 weeks in guinea pigs and 78 weeks in monkeys. Pulmonary function tests and serum biochemical and hematological analyses were conducted prior to and during the exposure period. At termination of exposure, microscopic examination of the lung was performed. Analysis of the data revealed that no adverse effects in guinea pigs or monkeys could he attributed to exposure to the mixtures of SO₂ and fly ash.     

Effect of Acute Sulfur Dioxide Exposure on Bronchial Clearance in the Donkey

The effects of 30-minute sulfur dioxide (SO₂) inhalation exposures on the bronchial clearance of radioactive monodisperse ferric oxide particles were studied in three miniature donkeys. The SO₂ concentrations ranged from 26 to 713 ppm. No impairment of bronchial clearance was observed at levels below 300 ppm. Higher concentrations produced severe cough and either slowing or transient arrest of bronchial clearance.     

Tissue distribution of S-sulfonate metabolites following exposure to sulfur dioxide

S-Sulfonate compounds (RS-SO^?₃, metabolites of sulfur dioxide (SO₂), were formed, presumably by the sulfitolysis of disulfide bonds, in the tracheas of male New Zealand White rabbits exposed continuously to either 10 ppm SO₂ for 1–72 hr or to 3 ppm SO₂ for 3–24 hr. An apparent equilibrium between inhaled SO₂ and tracheal wall RS-SO^?₃ concentration was established after 3 hr resulting in 53 and 107 nmoles/gm dry wt of trachea for 3 and 10 ppm SO₂ respectively, the latter RS-SO^?₃ concentration representing an approximately seven-fold increase above endogenous levels. S-Sulfonates were formed in the soft membranous tissues of the walls, the underlying connective tissue support, and in the mucus of exposed rabbits. Exposures longer than 24 hr caused a gradual rise in tracheal wall RS-SO^?₃ concentration which we ascribed to increased mucus production. The toxicological implications of sulfitolysis of disulfide bonds in tracheal mucus are discussed. S-Sulfonate metabolites were also formed in the plasma during inhalation of 10 ppm SO₂, thereby providing evidence for its absorption into the blood. There was, however, minimal RS-SO^?₃ formation in the distal parenchymatous tissue of the posterior lung lobes and no evidence of exogenous RS-SO^?₃ in the descending aorta in spite of a high concentration of sulfite-reactive disulfide bonds at both sites. We interpreted these results as reflecting the relative concentrations of sulfite at these sites during SO₂ inhalation and concluded that, with the possible exception of the lower lung, there was no evidence for the transport of sulfite to tissues removed from the site of SO₂ absorption.     

Exposure assessment of non-electric ice resurfacer operators in indoor ice rinks: a pilot study

Exposure of ice resurfacer operators to indoor air contaminants was measured in six indoor ice arenas. A standardized questionnaire on technical and operational features was employed and indoor airborne concentrations of carbon monoxide (CO), carbon dioxide (CO₂), nitric oxide (NO), nitrogen dioxide (NO₂), sulfur dioxide (SO₂), and total volatile organic compounds (VOCs) were measured. Air samples were collected using a range of direct reading instruments attached to the driver’s seat of the resurfacer. The range of mean exposure concentrations via positional sampling (i.e. as close as able to the operator’s breathing zone) were 5.7–7.4 ppm, 694–2171 ppm, <0.5 to 0.5 ppm, and < 0.1 to 0.2 ppm, for CO, CO₂, NO, and NO₂, respectively. Exposure levels for SO₂ and VOC were below detection. Overall, each of the measured indoor air contaminants was found to be below its respective occupational exposure limits (OEL), suggesting that the risk of hazardous exposure is low. The use of natural gas as a fuel source is believed to contribute to low contaminant concentrations.     

Respiratory symptoms associated with sulfur dioxide exposure

Summary Exposures to sulfur dioxide (SO₂) have been associated with progressive, dose-dependent bronchoconstriction in sensitive individuals. The clinical significance of such changes remains poorly characterized. We studied subjective responses following exposure to low level concentrations of SO₂ (< 1 ppm) in a group of 10 healthy and 10 asthmatic subjects. The number and severity of complaints associated with SO₂ increased with concentrations in both healthy and asthmatic subjects. Asthmatics indicated progressive lower respiratory complaints, such as wheezing, chest tightness, dyspnea and cough with increasing levels of SO₂ while healthy subjects complained more frequently of upper airway complaints such as taste and odor with increasing levels of SO₂. Exercise increased the frequency of lower airway symptoms in asthmatics but led to no increases in symptoms in healthy subjects.From the Pulmonary Section, Yale University School of Medicine, P.O. Box 3333, 333 Cedar Street, and the John B. Pierce Foundation Laboratories, New Haven, CT 06510 (203) 785-4165Presented in part at the International Conference on Indoor Air Pollution August 10–24, 1984     

Toxic and sublethal effects of carbaryl on a freshwater catfish,Mystus vittatus (Bloch)

The effects of carbaryl (1-naphthalenyl methylcarbamate), commonly used in agricultural operations, have been studied with reference to survival, behavior, food intake, growth, and conversion efficiency of the catfishMystus vittatus. At a concentration of 32.5 ppm, carbaryl caused 100% mortality within 24 hr; the 72 hr LC₅₀ was 17.5 ppm. At concentrations of 12.5 ppm and below, it caused no mortalities within 72 hr. But such sublethal concentrations accelerated the swimming activity and increased the frequency of opercular beats. The latter response was dose-dependent. These behavioral changes were the immediate response to the toxicant and were indicators of possible stress. A 27-day exposure to sublethal concentrations of carbaryl led to a decrease in feeding rate and growth rate. The latter decreased from 10.15 mg/g/day (freshwater) to 2.84 mg/g/day (12.5 ppm). The reduced growth and conversion efficiency may be due to the expenditure of more energy for the purpose of maintenance. Therefore, the insecticide is considered to be a metabolic Stressor.     

Atmospheric Pollutants and the Pathogenesis

Influenza-infected mice exposed continuously to 20 ppm of sulfur dioxide (SO₂) for seven days after virus exposure developed more pneumonia than virus control mice. Dose-response experiments suggested that the post virus SO₂-induced increase in influenzal pneumonia began at about 7 to 10 ppm. The increase in pneumonia was not influenced by altering the virus dosage within a 5 to 100 mouse infectious dose range. A similar increase (15% to 20%) in influenzal pneumonia was observed when mice were exposed to 25 ppm of SO₂ prior to initiation of virus infection. The SO₂ exposure had no effect on the growth of influenza virus in the lungs of mice. Rather, the increase in She amount of pneumonia was associated with SO₂ concentrations which induced low-grade, inflammatory lesions in the lung.     

Pulmonary function and sulphur dioxide, some preliminary findings.

In an extensive series of experiments, involving a total of twenty-five healthy normal subjects, increases in airways resistance have been seen when low concentrations (1–3 ppm) of SO₂ have been inhaled deeply, and after higher concentrations (5–30 ppm) have been inhaled normally. Deep breathing was used to increase the inspiratory velocity to overcome absorption in the upper respiratory tract, thereby achieving better penetration of the SO₂ into the lung. A wide range of sensitivities to SO₂ was found among the subjects, and in general, the changes in airways resistance were short-lived. The relevance of these results to the effects of urban atmospheres containing SO₂ is discussed.     

Anti-oxidants reduce the acute adverse effects of residual oil fly ash on the frog palate mucociliary epithelium

There is evidence indicating that oxidants play a pivotal role in determining air pollution-dependent lung injury. In the present study we explored the role of oxidants present in ambient particles in causing damage to the mucociliary epithelium. We explored the protective effects of pretreatment with three substances (n-propyl gallate, DL-alpha-tocopherol acetate, and EDTA) on the frog palate exposed to residual oil fly ash (ROFA). The parameters analyzed were mucociliary transport (MCT) and ciliary beating frequency (CBF) after 0, 10, 20, 30, 60, and 120 min of exposure. MCT was decreased significantly by ROFA (P < 0.001), with a significant interaction effect (P = 0.02) between the duration of exposure and treatment with antioxidants. The inhibitory effects on MCT of the substances tested were significantly different (P = 0.002); vitamin E was similar to control (Ringer) and different from all other groups. CBF showed no significant effect of duration of exposure (P = 0.465), but a significant interaction between duration of exposure and treatments was observed (P = 0.011). Significant differences were detected among treatments (P < 0.001), with ROFA and n-propyl gallate at concentrations of 50 microM presenting a short-lived increase in CBF, which was not observed in the remaining groups. The results showed that both MCT and CBF were affected within a short period (100 min) of exposure to ROFA and that the presence of antioxidant substances, such as vitamin E (4 mg/mL) and n-propyl gallate (300 microM), protected against the mucociliary impairment induced by ROFA on the frog palate.     

Respiratory responses of young adult asthmatics to sulfur dioxide exposure under simulated ambient conditions

Twenty-four young adult asthmatic volunteers were exposed to 0, 0.25, and 0.50 ppm SO₂ in random order at 1-week intervals. Exposures, conducted in a controlled-environment chamber at 23°C and 90+% relative humidity, lasted 1 hr and incorporated alternating 10-min periods of moderate exercise (mean exercise ventilation about 27 liters/min) and rest. Airway resistance was measured before exposure, after the first exercise period, and near the end of exposure. Forced expiratory performance was measured after the final airway resistance measurement. Exposure-relatable symptoms were recorded before, during, and after exposure periods. None of these measures of response showed statistically significant variation attributable to SO₂, although small significant increases in resistance attributable to exercise were found. These negative results contrast with previous positive findings in asthmatics exposed to SO₂ via mouthpiece. The differences may relate to effects of mouthpiece breathing on respiratory defenses, or to interindividual variations in bronchial reactivity to SO₂.     

William Francis Ashe,Jr. 1909–1966

Homes of 98 children diagnosed as suffering from bronchiolitis and bronchopneumonia were investigated in Lagos, Nigeria. Estimates of the duration of these infants’ exposure to smoke emanating from burning firewood was approximately an average of 3.13 hours a day. The children were found to be exposed to average concentrations of 940.2 ppm of CO; 8.6 ppm of No₂; 37.8 ppm of SO₂, and possibly 85.6 ppm of benzene.

These gases at these concentrations could easily irritate the respiratory tract of these infants who could hardly complain or run away from the smoke.     

Toxicity of heavy metals and salts to eurasian watermilfoil (Myriophyllum spicatum L.)

The toxicity of various heavy metals and salts to Eurasian watermilfoil (Myriophyllum spicatum L.) was determined under controlled growth conditions. Toxicants were added to water or to soil in systems with and without woods earth in the substrate.Fifty precent inhibition of root weight occurred with concentrations of 0.25 ppm Cu⁺², 1.9 ppm Cr₂O₇ ^–2, 3.4 ppm Hg⁺², 2.9 ppm AsO₂ ^–1, 7.4 ppm Cd⁺², 2.5 ppm Al⁺³, 9.9 ppm Cr⁺³, 41.2 ppm Ba⁺², 21.6 ppm Zn⁺², 13.3 ppm NH₄ ⁺¹, 22.4 ppm CN^–1, 143 ppm B₄O₇ ^–2, 363 ppm Pb⁺², 10,228 ppm Na₂SO₄, and 8,183 ppm NaCl. Soil increased toxicity of Cr⁺² and Ba⁺² but decreased toxicity of Cr₂O₇ ^–2, Cu⁺², Cd⁺², Al⁺³, and Hg⁺². In distilled water, CaCl₂ increased toxicity of Cr⁺³ but not Cr₂O₇ ^–2.For most toxicants there was a consistent relationship between inhibition of length and inhibition of weight and between inhibition of roots and inhibition of shoots. However, Cr₂O₇ ^–2 disproportionately decreased dry weight, and Hg⁺² and Na₂SO₄ disproportionately decreased stem length growth. With Cd⁺² and Cu⁺² stem length was greater relative to other measures of growth. Toxicity of Na₂SO₄ and NaCl was the same when concentrations were calculated as osmotic pressure but not when calculated as Na atoms or as total molecules/L.     

Effects of dietary exposure to fumonisins from Fusarium moniliforme culture material (M-1325) on the reproductive performance of female mink

Adult female mink (Mustela vison) were fed diets that contained Fusarium moniliforme culture material that provided low- or high-dose dietary concentrations of 86 or 200 ppm fumonisin B₁, 22 or 42 ppm fumonisin B₂, and 7 or 12 ppm fumonisin B₃, respectively, from approximately two weeks prior to breeding through gestation and lactation. Breeding performance of the females was not affected by consumption of the fumonisin diets. However, 58% of the mated females fed the high-dose diet (254 ppm total fumonisins) whelped compared to 100% of those fed the control and low-dose diets (115 ppm fumonisins). There was a statistically significant, dose-dependent decrease in kit (young mink) body weights at birth and a notable, but non-significant, decrease in litter size. The percentage of stillborn kits was directly proportional to the concentration of fumonisins in the dams' diets. Fumonisin concentrations in milk collected from those fed the high-dose diets were approximately 0.7% of the dietary fumonisin concentrations. Lactational exposure to fumonisins did not significantly decrease kit survival from birth through three weeks of age. Hepatic cell vacuolation was present in 25% of the control and 80% of the high-dose adults. No treatment-related gross or histologic lesions were observed in the kit mink. Numerous differences in hematologic and serum chemical parameters were noted between the control and fumonisin-exposed mink.     

Acute Hematologic and Hemorheologic Effects of Sulfur Dioxide Inhalation

Fifty male rats were exposed to 0.87 ppm sulfur dioxide (SO₂) for 24 hr. Hematologic and hemorheologic parameters measured in this group were compared with the results of a control group of 51 male rats. Hematocrit values were found to be higher (p < .005) in the SO₂-treated group (43.55 ± 0.41%, mean ± standard error), when compared to the control group value (41.97 ± 0.35%). Sulfhemoglobin values were also higher (p < .0001) in the SO₂-treated group (0.60 ± 0.08%) than the control group (0.08 ± 0.02%). Osmotic hemolysis ratio was slightly increased (p < .05) in the 0.55% sodium chloride solution. However, whole blood and packed cell viscosities were lower in the SO₂-treated animals, while there was no significant difference in the plasma viscosities. The mechanism of these effects could not be clarified completely, but structural and functional effects of SO₂ inhalation on peripheral erythrocytes were discussed.     

Pollen mitosis and pollen tube growth inhibition by SO2 in cultured pollen tubes of Tradescantia

Mature pollen of Tradescantia paludosa Anders. Sax clone-3 was collected from greenhouse grown plants and desiccated in the dark for 4–5 hours. The pollen was sown on microslides coated with lactose agar medium (supplemented with 0.02% colchicine). Five minutes after sowing, pollen cultures were treated with various concentrations (0.075–2000 ppm) of SO₂ obtained from the chemical reaction between K₂S₂O₅ and HCl. Treatments were carried out in an airtight Plexiglas chamber throughout the full incubation period of 19 hours. Treated and control pollen cultures were fixed and stained in aceto-carmine or Feulgen reaction to determine the tube lengths and mitotic indices. Results of repeated experiments indicated that the values of mitotic indices dropped from the normal 38.7% in the control to the range of 24.3-3.8% when treated with 0.075–50.00 ppm of SO₂. Pollen tube growth was inhibited from the normal length of 1.5 mm in the control to the range of 800-100 μm when treated with 10–2000 ppm of SO₂. The inhibitory effect of SO₂ rpresumably resulted from physiological disturbance of the cell and severe damage to chromosomes of both generative and tube nuclei of the pollen tubes.     

Sulphur-dioxide induced bronchial hyperreactivity against acetylcholine

Summary The effect of sulphur-dioxide (SO₂) on the bronchial reactivity against acetylcholine (ACH) is carried out on 25 dogs. The dogs were exposed initially to acetylcholine aerosol, then to SO₂ for 1 hr and again to ACH. 3 such cycles were repeated. The concentration of SO₂ used were 1, 2, 5 and 10 ppm and the controls were given room air in place of SO₂.The parameters studied were intrathoracic pressure as the indicator of bronchoconstriction, blood oxygen and carbon-dioxide, tidal volume, respiratory rates and arterial blood pressure. All the SO₂ exposed animals have shown a significant increase of bronchial sensitivity than those of the controls. Maximum sensitization was induced by 2 ppm. The reaction provoked by 1 and 5 ppm were almost of the same order and little smaller than 2 ppm but greater than those produced by 10 ppm. The peak reactions against ACH observed for 1, 2 and 5 ppm were 3, 2 and 1 hr of exposure, respectively. After attaining the peak points, the reactions declined in all the 3 groups. But no such trend was obtained for those animals exposed to 10 ppm of SO₂.The role of small concentration of SO₂ as bronchial sensitizing agent against ACH is discussed.Diese Forschung wurde mit Unterstützung des Vereins zur Untersuchung von Einwirkungen der Luftverschmutzung auf die Volksgesundheit e.V. durchgeführt.     

Relationship between the airway response to inhaled sulfur dioxide,isocapnic hyperventilation,and histamine in asthmatic subjects

Summary To determine whether bronchoconstriction induced by sulfur dioxide can be predicted by the airway response to inhaled histamine, we exposed on two days 46 patients with asthma to air or 0.5 ppm SO₂. The exposure protocol consisted of 10 min of tidal breathing followed by 10 min of isocapnic hyperventilation at a rate of 301/min. Airway response was measured before (baseline) and after hyperventilation in terms of specific airway resistance, SRaw. Exposure to air increased baseline mean (SD) SRaw from 6.27 (2.12) to mean (SD) maximum post-hyperventilation SRaw of 9.10 (4.38) cmH₂O^*s (P < 0.0001). Exposure to SO₂ increased mean (SD) baseline SRaw from 6.93 (3.29) to mean (SD) maximum posthyperventilation SRaw of 18.21 (18.69) cmH₂O^*s (P < 0.0001). Mean (SD) effect of SO₂. defined as difference between maximum post-hyperventilation SRaw after SO₂ versus air was 9.11 (16.14) cmH₂O^*s. When evaluated individually, 26 and 34 of the 46 patients showed an airway response to hyperventilation of air and SO₂, respectively. Airway response to histamine was determined as the histamine concentration necessary to increase specific airway resistance by 100%, PC₁₀₀SRaw. The airway response after SO₂ and PC₁₀₀SRaw showed a weak but significant correlation (R = –0.48), whereas the responses to hyperventilation and SO₂ did not correlate. We suggest that the mechanisms by which histamine and SO₂ exert their bronchomotor effects are different and that in asthmatic patients the risk of pollutant-induced asthmatic symptoms can be poorly predicted by histamine responsiveness.Supported by a grant from the Minister für Jugend, Familie und Gesundheit, Bonn, Federal Repubic of GermanyDedicated to Johannes Piiper on the occasion of the 65th birthday     

The Temporal and Spatial Variations of Acid Aerosols in the GeothermalArea of Metropolitan Taipei, Taiwan

This study involved sampling over 1 year of data on exposure to acid aerosols in the geothermal area of metropolitan Taipei. The temporal and spatial variations of the concentrations of acid aerosols were assessed by sampling at three sites: A, B, and C. Results indicate that the SO₂ concentrations lead the concentrations of other acid aerosols at site C because two active fumaroles surround this site. The mean SO₂ concentrations at sites A, B, and C were 2.4, 2.4, and 6.2 ppb. Previous studies have found that H₂S levels were highest at site C. However, the SO₄⁻² and H⁺ concentrations among the three sites were similar. The mean aerosol SO₄⁻² concentrations were 7.0, 5.7, and 5.7 μg m⁻³ at sites A, B, and C, respectively; their H⁺ concentrations were 5.5, 4.2, and 5.4 nmolm⁻³. No seasonal variations are observed for most of the acid aerosols in the geothermal area except that the types of hot spring affect the SO₄⁻² concentration nearby. The different seasonal fluctuation among the sites reflect the determinant of SO₄⁻² emission from different geothermal sources. Sulfur-rich aerosols and some SO₂ emitted from geothermal sources are obvious. The predominance of nitrogen-containing gases (sum of NO₂ + HNO₂ + HNO₃) over SO₂ indicates the importance of the anthropogenic origin of emissions. The effect of multiple exposures to sulfur-rich aerosol (including H₂S, SO₂, and SO₄⁻²), H⁺, and nitrogen-containing aerosols on the health of nearby residents warrants concern.     

Synthesis and biological activity of CCK peptides with antagonist activity for CCK-A-receptor

The synthesis of a series of cholecystokinin analogues derived from the well-known antagonist Ge 410 (Suc-Tyr(SO₃)-Met-Gly-Trp-Met-Asp-β-phenethylamide) is reported. Replacements of -Trp by -Trp, Asp by Glu and Met by Nle were carried out and the resulting changes in biological activities investigated. All compounds synthesized were tested for their ability to inhibit CCK-induced contraction on isolated guinea pig ileum. SAR studies for these compounds are discussed.