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PubMed2000

Gold and palladium burden from dental restoration materials.

From 81 volunteers (16 without dental restorations, 65 with gold crowns or inlays) samples of saliva before and after chewing gum, blood, serum, urine and faeces were taken and analysed for gold (Au) and palladium (Pd). The Au concentration in all analysed biomonitors correlates significantly to the number of teeth with gold restorations. For Pd the correlations were still significant, but weaker than for Au. Persons with gold restorations show maximal Au and Pd concentrations, 10(2)-10(3) higher than the background burden. The calculated maximal daily Au load in saliva (1.38 mg Au per day) reaches the range of an oral Au therapy for rheumatoid arthritis with 6 mg Auranofin (= 1.74 mg Au per day). During this therapy severe and frequent side effects are reported. In contrast, the Au concentration in serum maximally reached from Au restorations, amounts to only approximately 1/20 of the Au level during arthritis therapy. But even under subtherapeutic doses of 1 mg Auranofin/day severe side effects have been reported (4 out of 56 cases). The mean Au blood concentration from 1 mg Auranofin daily was only 3 times higher than our maximum value. A toxicological classification of the Pd values is difficult, because no toxicological threshold limit has been established, especially for the low-level long-term burden with Pd.

Adolescent↗
PubMed2000

Incidence of chromosomes 1 and 17 aneusomy in breast cancer and adjacent tissue: an interphase cytogenetic study.

BACKGROUND: Characterization of the biopathologic events underlying the early steps of breast carcinogenesis may have a dramatic impact on reducing breast cancer mortality. Genes involved in breast tumorigenesis are localized on chromosomes 1 and 17, and numeric aberrations of these chromosomes have been correlated with breast cancer tumorigenesis and progression. According to the field cancerization hypothesis, specific chromosome aberrations may be present in breast cancer and in normal-appearing adjacent tissue. The latter changes reflect the genomic damage that follows longterm carcinogenic exposure and precede the morphologically detectable neoplastic transformation. We hypothesize that detection of these aberrations in benign breast epithelium may provide a tool for molecular risk assessment. STUDY DESIGN: Using fluorescence in situ hybridization with centromere-specific probes, we determined the status of chromosomes 1 and 17 in fresh imprints of 28 samples of primary tumors and 54 samples of their surrounding uninvolved parenchyma taken from patients undergoing operations for breast carcinoma. Ten contralateral breast biopsy specimens collected from patients with previous breast carcinoma were also evaluated as a surrogate of a high-risk group to rule out the hypothesis that chromosomal aneusomy in tumor-adjacent tissue could be related to a paracrine effect of the primary tumor. Ten samples of benign breast tissue taken from patients at low risk were used as controls to define tolerance limits for aneusomy definition. RESULTS: Using threshold values of 40% of signal loss and 13% of signal gain to define chromosome aneusomy (ie, mean + 3 SDs of the control group signals), we found the following: 1) almost all primary breast tumors were aneusomic for chromosomes 1 and 17; 2) primary breast tumor and adjacent uninvolved parenchyma shared the same pattern of chromosomes 1 and 17 aneusomy in 66.7% of patients; and 3) chromosomes 1 and 17 aneusomies in contralateral benign breast samples from high-risk patients were not different from those in primary breast tumor or adjacent tissue samples. CONCLUSIONS: These results suggest that chromosomes 1 and 17 aneusomy may represent an intermediate biomarker of breast tumorigenesis potentially useful to detect patients at high risk of breast carcinoma who may benefit from preventive interventions.

Adult↗
PubMed2006

A simplified strategy for the estimation of the exercise ventilatory thresholds.

PURPOSE: To analyze the limits of agreement between exercise ventilatory threshold values (VT1 and VT2) estimated from a combination of pulmonary gas exchange and ventilatory variables (cardiopulmonary exercise testing) and those derived from an alternative approach based on the ventilatory response only (V(E), ventilometry). METHODS: Forty-two nontrained subjects (24 males, aged 18-48, peak VO(2) = 33.1 +/- 8.6 mL.min(-1).kg(-1)) performed a maximum incremental cardiopulmonary exercise testing on an electromagnetically braked cycle ergometer. The participants breathed through a Pitot tube (Cardio2 System, MGC) and a fixed-resistance ventilometer (Micromed, Brazil), which were connected in series. HR values at the estimated VT (VTHR1 and VTHR2) were obtained by the conventional method (ventilatory equivalents, end-expiratory pressures for O(2) and CO(2), and the V-slope procedure) and an experimental approach (V(E) vs time, V(E)/time vs time, and breathing frequency vs time). RESULTS: There were no significant between-method differences on VT(HR1), VT(HR2), VT(VE1), VT(VE2), and peak V(E) (P > 0.05). After certification of data normality, a Bland-Altman analysis revealed that the mean bias +/- 95% confidence interval of the between-method differences were lower for VT(HR2) than VT(HR1) (2 +/- 9 and 0 +/- 17 bpm, respectively). VT(HR2) according to ventilometry differed more than 10 bpm from the standard procedure in 3 out of 42 subjects (9%). Between-method differences were independent of the level of fitness, as estimated from peak VO(2) (P > 0.05). CONCLUSIONS: : A simplified approach, based on the ventilatory response as a function of time, can provide acceptable estimates of the exercise ventilatory thresholds--especially VT2--during ramp-incremental cycle ergometry. This new strategy might prove to be useful for exercise training prescription in nontrained adults.

Adolescent↗
PubMed1996

[Study of the squamous cell carcinoma (SCC) antigen in benign diseases].

BACKGROUND: The values of the squamous cell carcinoma (SCC) antigen in benign diseases were studied with the aim of determining false positive values in the study of epidermoid carcinomas. METHODS: Serum determinations of the SCC antigen were performed by radioimmunoanalysis with the Abbott SCC-RIA kit. The control group was made up of a total of 719 subjects of whom 317 were healthy blood donors and 402 were healthy women with normal cervicovaginal cytology. The study group was made up of 693 women with benign diseases. RESULTS: Ninety-eight point two percent of the subjects from the control group presented values under 2.5 ng/ml, therefore this value was chosen as the maximum limit of normality. Higher values than this threshold of normality were observed in 11.7% of the 34 patients with chronic disease (0.1-18.2 ng/ml) and in 57.5% of the 40 patients with chronic renal failure (0.5-6.0 ng/ml). CONCLUSIONS: In patients with chronic liver disease or chronic renal failure, the serum determination of the squamous cell carcinoma antigen loses its value as a tumor marker of epidermoid carcinomas given the risk of obtaining false positive values.

Adolescent↗
PubMed1998

[Occupational exposure to inhalation anesthetics at the work-place of veterinary surgery].

In a prospective study we evaluated the work-place pollution by isoflurane and nitrous oxide during various anaesthetic procedures in animal surgery. The study was conducted during one working week at an University Animal Department. Trace concentrations of isoflurane and nitrous oxide were directly measured every minute in the breathing zone by means of a photoacoustic infrared spectrometer in two different operating rooms (OR) with an air turnover of 17 changes per hour. In one OR the 8-hour time-weighted average (mean +/- SEM) was calculated to be 12.3 +/- 9.9 ppm nitrous oxide and 1.9 +/- 2.5 ppm isoflurane. The other OR, where only isoflurane was used, was contaminated with 5.3 +/- 8.1 ppm isoflurane. In the first OR, the trace gas concentrations were low and comparable to values obtained under human anaesthesia in adults and children. The higher contamination in the second OR resulted from performing inhalational anaesthesia with an open mask system in birds and small animals. Although the mean values were below the recommended occupational exposure standards, some high peak values (> 300 ppm isoflurane) violated these threshold limits. We recommend the use of a local scavenging device, if other alternatives such as total intravenous anaesthesia are not possible.

Adult↗
PubMed1988

[Cutaneous vibration and thermal-cooling threshold in control subjects].

The cutaneous vibration and thermal-cooling thresholds were evaluated on the palmar side of the distal phalanx of the right index finger and on the plantar side of the distal phalanx of the right great toe in 70 control subjects without sensory symptoms and signs, aged from 13 to 83 years, by using a Vibration Sensitivity Tester and a Thermal Sensitivity Tester (Sensortek, N. J., USA). Both vibration and thermal-cooling thresholds of the index finger, and vibration threshold of the great toe were statistically significantly increased with age. Based on the data obtained from these subjects, the lower and upper limits of 95% confidence limit of the predicted value of each of the thresholds for each decade were calculated. These values are useful for the detection of the abnormal cutaneous vibration and thermal-cooling thresholds not only in general neurology, but also in occupational neurology.

Adolescent↗
PubMed2004

Approaches for the development of occupational exposure limits for man-made mineral fibres (MMMFs).

Occupational exposure limits (OELs) are an essential tool in the control of exposure to hazardous chemical agents, and serve to minimise the occurrence of occupational diseases associated with such exposure. The setting of OELs, together with other associated measures, forms an essential part of the European Community's strategy on health and safety at work, upon which the legislative framework for the protection of workers from risks related to chemical agents is based. The European Commission is assisted by the Scientific Committee on Occupational Exposure Limits (SCOEL) in its work of setting OELs for hazardous chemical agents. The procedure for setting OELs requires information on the toxic mechanisms of an agent that should allow to differentiate between thresholded and non-thresholded mechanisms. In the first case, a no-observed adverse effect level (NOAEL) can be defined, which can be the basis for a derivation of an OEL. In the latter case, any exposure is correlated with a certain risk. If adequate scientific data are available, SCOEL estimates the risk associated with a series of exposure levels. This can then be used for guidance, when setting OELs at European level. Man-made mineral fibres (MMMFs) are widely used at different worksites. MMMF products can release airborne respirable fibres during their production, use and removal. According to the classification of the EU system, all MMMF fibres are considered to be irritants and are classified for carcinogenicity. EU legislation foresees the use of limit values as one of the provisions for the protection of workers from the risks related to exposure to carcinogens. In the following paper, the research requirements identified by SCOEL for the development of OELs for MMMFs will be presented.

Humans↗
PubMed2006

Unexplained elevated serum pancreatic enzymes: a reason to suspect celiac disease.

BACKGROUND & AIMS: The frequency of elevated serum pancreatic enzymes in patients with celiac disease (CD) is unknown. The aim of this study was to evaluate the serum levels of pancreatic enzymes in CD patients. METHODS: Serum pancreatic isoamylase and lipase levels were assayed in 90 adult and 112 pediatric consecutive CD patients at diagnosis and after 12 months of gluten-free diet (GFD). Serum elastase and trypsin levels were assayed in a subgroup of adult CD patients. Pancreatic ultrasonography was also performed. RESULTS: Twenty-six adult (29%) and 29 pediatric (26%) CD patients exhibited elevated values of serum pancreatic amylase and/or lipase; trypsin was elevated in 69% and elastase in 19%. The frequency of elevated serum pancreatic enzymes observed was identical in the patients with "typical" and "atypical" CD symptoms and in the asymptomatic patients. Most of the elevated values were lower than 2-fold the threshold limits. Elevated pancreatic enzymes were not associated with alcohol consumption, drug use, presence of abdominal pain, or diabetes mellitus. Abdominal ultrasound scan showed no abnormal findings in the pancreatic region in any of the CD patients. After 12 months of GFD, pancreatic amylase was elevated in 3 cases and lipase in 2 cases; these patients had not strictly adhered to the GFD. CONCLUSIONS: We demonstrated a frequency of about 25% of elevated pancreatic enzymes values in CD patients, including subjects without gastrointestinal manifestations and apparently asymptomatic subjects. The finding of elevated serum amylase or lipase level, in the absence of signs of pancreatic disease, would appear to suggest a need to screen for celiac disease.

Adolescent↗
PubMed2005

Serum lactate level has prognostic significance after pediatric cardiac surgery.

OBJECTIVE: The determination of postoperative course after cardiac surgery has always been a challenging issue. It is more sophisticated in the pediatric age group. The aim of this investigation was to identify whether increased concentrations of lactate in arterial blood has a predictive value for postoperative morbidity and mortality after heart surgery. METHODS: From May 2002 to June 2003, 60 infants operated on at the authors' institution were included in this prospective study. The patients were divided into 2 groups according to their respective postoperative serum lactate values. After the stabilization period in the intensive care unit (first 3 hours postoperatively), samples for serum lactate were obtained from arterial blood at 3 (t1), 6 (t2), and 12 hours (t3) postoperatively. The patients were subdivided into 2 groups according to their respective mean serum lactate values. A value of 4.8 mmol/L (3 times the normal upper limit) was chosen as a threshold for serum lactate. The patients with a mean value of greater than 4.8 mmol/L (group 1) were compared with the remaining group of patients (group 2). The relationship between serum mean lactate level and intraoperative and postoperative clinical variables was evaluated. RESULTS: Among the patients in this study, 26 (43.3%) had a serum mean lactate level more than 4.8 mmol/L and 34 (56.7%) had a level of 4.8 mmol/L or less. Age, aortic cross-clamping time, cardiopulmonary bypass time, and the lowest hematocrit during cardiopulmonary bypass were significant variables that influenced the postoperative serum mean lactate level. Six patients died in the postoperative period and 54 infants survived. The hospital mortality was significantly higher in group 1 than in group 2 (19.0% v 2.9%; p = 0.037, kappa = 0.179). Multivariate analysis revealed that serum mean lactate level correlated significantly with inotrope score, intubation time, and intensive care unit stay. CONCLUSIONS: Blood lactate concentration of 4.8 mmol/L or higher during the early postoperative hours identifies a group of patients with increased risk of postoperative morbidity and mortality.

Cardiac Surgical Procedures↗
PubMed2004

Influence of electrode impedance on threshold voltage for transcranial electrical stimulation in motor evoked potential monitoring.

Motor potentials evoked by transcranial electrical stimulation (TES) are used for monitoring the motor pathways, with emphasis on the spinal cord and brainstem. The stimulus voltage threshold is the voltage below which no motor response can be elicited. It has frequently been used as a monitoring parameter. However, its value can be limited, because it is affected by the impedance of the stimulus electrode. For example, the voltage threshold can change owing to formation of oedema of the scalp. The relationship between the TES voltage threshold and the electrode impedance of different electrode types was studied and discussed in the context of neuromonitoring: 323 impedance and voltage threshold pairs were studied, and TES was performed with disc cup EEG electrodes (six), corkscrew electrodes (type I: seven, type II: eight), multiple EEG needle electrodes (16) and a large needle electrode Cz' (anode) together with a ground strip over the forehead (cathode) (286). The study found the voltage threshold to be strongly dependent on electrode impedance when the impedance was higher than 460 omega (correlation: R2=0.87; p < 0.001). Below 460 omega, which included 91% of the category with the largest electrode surfaces, 25% of the multiple EEG electrodes and 75% of type II corkscrew electrodes, no significant correlation (R2=0.0064; p=0.15) was found. It was concluded that the correlation between the TES voltage threshold and electrode impedance can be markedly reduced by using TES electrodes with large contact surfaces, resulting in limit values for these parameters. This also may improve the reliability of TES motor evoked potential monitoring.

Electric Impedance↗
PubMed2007

Use of the local Knox statistic for the prospective monitoring of disease occurrences in space and time.

The detection of clusters of events occurring close together both temporally and spatially is important in finding outbreaks of disease within a geographic region. The Knox statistic is often used in epidemiology to test for space-time clustering retrospectively. For quicker detection of epidemics, prospective methods should be used in which observed events in space and time are assessed as they are recorded. The cumulative sum (CUSUM) surveillance method for monitoring the local Knox statistic tests for space-time clustering each time there is an incoming observation. We consider the design of this control chart by determining the in-control average run length (ARL) performance of the CUSUM chart for different space and time closeness thresholds as well as for different control limit values. We also explain the effect of population density and region shape on the in-control ARL and discuss other distributional issues that should be considered when implementing this method.

Computer Simulation↗
PubMed1991

Alterations in lung function due to mixtures of organic solvents used in floor laying.

To determine the short-term and long-term effects of organic solvents on the respiratory tract, 26 male floorlayers exposed to organic solvents were compared with 36 persons unexposed to such substances. The investigation primarily included a detailed history, determination of solvent concentration in the air inhaled by the workers, long-term ECG during the entire shift and lung-function test (vital capacity, forced expiratory volume in one second, flow volume curve) as well as non-specific bronchial inhalation challenge using a 3% acetylcholine aerosol before and after the shift. The floorlayers were primarily subjected to inhalative exposure to adhesives containing mixtures of toluene, petroleum hydrocarbons, ethyl acetate, methanol and acetone or one of these substances alone. This frequently resulted in short-term value limit excesses, especially in the MAK value (standardised threshold concentration in Germany) for toluene, which is a prime component of neoprene glue. Of the 26 floorlayers, 6 complained of breathlessness and coughing, whereas 13 suffered from nasal discharge and blockage--symptoms closely related to work. The smokers in this group showed a decline in lung function during the shift--especially in the forced expiratory volume in 1 s (FEV1)--as compared with the non-smokers in this group and the persons in the control group. This probably due to the combination of noxious substances. A strong correlation between occupational age and changes in lung function was observed: the occupationally youngest workers demonstrated the highest decrease in values during the course of the shift. There was no evidence of either obstructive or restrictive respiratory disorders or of marked deviation from the European Community for Coal and Steel (ECCS) references.(ABSTRACT TRUNCATED AT 250 WORDS)

Adhesives↗
PubMed1998

[Prevention of health risks in the use of MRI procedures. Recommendations of the Radiation Protection Commission].

Magnetic resonance imaging is used routinely with much success for various problems in different medical disciplines. However, the patient is exposed to static as well as to time-dependent magnetic fields and radiofrequency electromagnetic fields. In 1997 the Strahlenschutzkommission, the German Radiological Protection Commission, passed a recommendation on the use of magnetic resonance in medical diagnostics. In this recommendation basic values related to thresholds for physiological effects and limits for restricted and unrestricted use are given. In the following the aim and applicability of this recommendation are discussed, as well as the thresholds and different limits for the static magnetic fields, the gradient fields and the radio-frequency fields. Additionally, advice is given for the protection of high-risk patients, personnel, and the general public, together with further safety advice as well as recommendations for users and manufacturers.

Dose-Response Relationship, Radiation↗
PubMed2000

Combination of signal intensity measurements of lesions in the peripheral zone of prostate with MRI and serum PSA level for differentiating benign disease from prostate cancer.

The aim of this study was to predict the benign or malignant nature of a prostatic lesion by defining a threshold value of signal intensity ratio and a limiting value of serum prostate-specific antigen (PSA) in patients with elevated PSA level. Twenty-six patients with elevated PSA level and no hypoechogenic lesions at endosonography underwent MR imaging using an endorectal body phased-array coil at 1.5 T (Siemens Magnetom Symphony). A T2-weighted turbo-spin-echo (TSE) pulse sequence was applied in a transverse orientation. Two radiologists evaluated the images. In the presence of a pathological finding they defined regions of interest (ROI) in the suspicious pathological area of the peripheral zone and in muscle for reference. The quotient of the two ROIs was calculated and then correlated with the actual PSA level. Diagnosis was confirmed by prostate biopsy. Ten of 12 patients with quotients smaller than 4 showed cancer at histology. Nine of 12 men with cancer proven by biopsy had PSA levels higher than 10 ng/ml. A significant difference (p < 0.001) was found between the quotients of cancer and quotients of chronic prostatitis, fibrosis, or glandular atrophy. The accuracy of tumor differentiation of the method was 77%. Measurement of signal intensity quotients in the peripheral zone of the prostate in combination with knowledge of defined limits of PSA levels the technique could be helpful in detecting additional cancer areas for prostate biopsy. False-negative tumor results of standard sextant biopsy can be reduced. In men with high PSA values the method has a role in differentiating between patients who require prostate biopsy and those of clinical observation.

Adult↗
PubMed1986

Nonequilibrium voltage fluctuations in biological membranes. II. Voltage and current noise generated by ion carriers, channels and electrogenic pumps.

As applications of the general theoretical framework of charge transport in biological membranes and related voltage and current noise, a number of model calculations are presented for ion carriers, rigid channels, channels with conformational substates and electrogenic pumps. The results are discussed with special reference to the problem of threshold values for sensory transduction processes and their limitations by voltage fluctuations. Furthermore, starting from the special results of model calculations, an attempt is made to determine more general aspects of electric fluctuations generated by charge-transport processes in biological membranes: different frequency dependences of voltage and current noise, and dependence of noise intensities with increasing distance from the equilibrium state.

Biological Transport↗
PubMed1995

Microdialysis probes calibration: gradient and tissue dependent changes in no net flux and reverse dialysis methods.

Probe calibrations are required for accurate estimations of extracellular concentrations in microdialysis experiments. Several methods have been developed and validated for in vivo determination of dialysis membrane recovery such as the perfusion rate method and the No Net Flux method. In this study, the No Net Flux and the reverse dialysis methods were investigated. Both measure the net transport of drug across the dialysis membrane. The recovery was defined as R = (Cin - Cout)/Cin, where Cin and Cout were the concentrations of a compound in the perfusate and in the dialysate, respectively. First, the accuracy of the No Net Flux method to estimate in vivo recovery was compared in two situations: diffusion from the probe into the dialysis medium and diffusion from the outer medium into the probe. The point of no net transport was used to estimate the concentration surrounding the probe. Neither difference between extracellular concentrations (intercept values) nor difference between recoveries were observed. Then the reverse dialysis method was tested to estimate the relative loss of drug from the perfusate when the probe was placed in a drug-free medium. Finally comparisons of the behavior of the drug diffusion across the membrane under increasing gradient conditions have shown an asymptotic profile, specific of the tissue; blood, muscle, and adipose tissue. The faster a drug was removed by microvascular transport (blood > muscle > adipocytes), the higher was the recovery, until the perfusate concentration reached a threshold value where the transport process became gradient limited and no more tissue limited.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2004

Low yield of ancillary diagnostic studies in neonates infected with Candida.

BACKGROUND: Fungal infection can be a significant complication for the critically ill neonate. However, the usefulness of extensive radiologic and ophthalmologic investigations in this population has not been thoroughly elucidated. OBJECTIVE: To report the incidence of organ fungal involvement diagnosed by ancillary testing (echocardiogram, ophthalmologic examination, brain imaging, and renal ultrasound (RUS)) among neonatal intensive care unit (NICU) patients with Candida infection. METHODS: This was a single center review of all NICU patients with Candida-positive cultures of blood, urine, peritoneal fluid, endotracheal tube aspirate, or cerebrospinal fluid from January 1, 1997 to June 1 2002. Data regarding the number of positive cultures, species isolated, and presence of specific risk factors and clinical symptoms were recorded for each case, as well as occurrence, timing and results of ancillary testing. RESULTS: In all, 66 patients had at least one positive culture for Candida. The majority (71%) were <1500 g at birth, and mean gestational age was 29.5+/-5.6 weeks. Echocardiograms were obtained in 54/66 (82%), and ophthalmology examinations were obtained in 36/66 (55%); none of these was consistent with fungal involvement. Brain imaging was performed in 50/66 (76%), only one of which was positive, in a patient with 16 positive blood cultures for Candida albicans. RUS were performed in 58/66 (88%) of patients, with concerning findings for fungal involvement in seven of the studies. RUS findings alone did not appear to consistently influence the length of therapy. CONCLUSIONS: Ancillary evaluations to investigate for fungal dissemination were undertaken frequently, but were of overall low yield. Although ancillary testing may be of limited additional value in centers with a low threshold for suspecting fungal infections and an aggressive approach to therapy, potentially important findings, which could impact management, may occur.

Brain↗
PubMedDate not supplied

Effect of in situ composting on reducing offensive odors and volatile organic compounds in swineries.

Seven swine farms were studied to find out how the in situ composting system, compared to the slatted floor pit system, influences the concentration and occurrence of malodorous compounds. Ammonia concentrations were measured with diffusion tubes. Small molecular sulfur compounds were analyzed using laminated bags and a gas chromatograph with a FP-detector. All other volatile organic compounds were analyzed by gas chromatography/mass spectrometry with simultaneous sniffing of the eluted compounds. About 400 organic compounds were identified from the air samples, and 94 suspect odorous compounds are listed in the present article. The most intense and unpleasant odors were caused by p-cresol, carboxylic acids (C2-C7), and some ketones such as 3-hydroxy-2-butanone, 2,3-butanedione, and 2-butanone. Terpenes (alpha-pinene, beta-pinene, 3-carene, and limonene), which originate from sawdust, caused the main peaks in the chromatograms of compost swineries. In swine confinement buildings where the composting system was functioning properly, the concentration of sulfur compounds, and especially of carboxylic acids, ketones, and p-cresol, fell effectively. The use of sawdust as composting material caused elevated concentrations of terpenes in the ambient air. There was clearly less airborne ammonia and hydrogen sulfide in the well-functioning compost swineries than in the poorly functioning ones. Elevated hydrogen sulfide levels were measured during turning work, however. In one composting swinery, the hydrogen sulfide level was as high as 15 mg/m3 during turning work. All the other concentrations of odorous compounds did not exceed occupational exposure limit values, but several compounds exceeded the respective threshold odor concentrations.

Air Pollutants, Occupational↗