Ethyl benzene should be considered ototoxic at occupationally relevant exposure concentrations

2008 ◽  
Vol 24 (4) ◽  
pp. 241-246 ◽  
Author(s):  
A Vyskocil ◽  
T Leroux ◽  
G Truchon ◽  
F Lemay ◽  
M Gendron ◽  
...  
Keyword(s):  
Animal Studies ◽  
Current Evidence ◽  
Ethyl Benzene ◽  
Combined Exposure ◽  
Exposure Limits ◽  
Short Term ◽  
Animal Data ◽  
Short Term Exposure ◽  
Permissible Exposure Limits ◽  
Occupational Settings

Organic solvents can produce ototoxic effects in both man and experimental animals. The objective of this study was to review the literature on the effects of low-level exposure to ethyl benzene on the auditory system and consider its relevance for the occupational settings. Both human and animal investigations were evaluated only for realistic exposure concentrations based on the permissible exposure limits. In Quebec, the Time-Weighed Average Exposure Value for 8 h (TWAEV) is 100 ppm (434 mg/m3) and the Short-Term Exposure Value for 15 min (STEV) is 125 ppm (543 mg/m3). In humans, the upper limit for considering ototoxicity data relevant to the occupational exposure situation was set at STEV. Animal data were evaluated only for exposure concentrations up to 100 times the TWAEV. In workers, there is no evidence of either ethyl benzene-induced hearing losses or ototoxic interaction after combined exposure to ethyl benzene and noise. In rats, ethyl benzene affects the auditory function mainly in the cochlear mid-frequency range and ototoxic interaction was observed after combined exposure to noise and ethyl benzene. Further studies with sufficient data on the ethyl benzene exposure of workers are necessary to make a definitive conclusion. Given the current evidence from animal studies, we recommend considering ethyl benzene as an ototoxic agent.

Ototoxicity of trichloroethylene in concentrations relevant for the working environment

2008 ◽  
Vol 27 (3) ◽  
pp. 195-200 ◽  
Author(s):  
A Vyskocil ◽  
T Leroux ◽  
G Truchon ◽  
F Lemay ◽  
F Gagnon ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Convincing Evidence ◽  
Working Environment ◽  
Exposure Limits ◽  
Additive Interaction ◽  
Animal Data ◽  
Short Term Exposure ◽  
Adverse Effect Level ◽  
Effect Level ◽  
Permissible Exposure Limits

Organic solvents can cause hearing loss themselves or promote noise-induced hearing loss. The objective of this study was to review the literature on the effects of low-level exposure to trichloroethylene on the auditory system and consider its relevance for the occupational settings. Both human and animal investigations were evaluated only for realistic exposure concentrations based on the Quebec permissible exposure limits: 50 ppm 8-h time-weighed average exposure value (TWAEV) and 200 ppm short-term exposure value (STEV). In humans, the upper limit for considering ototoxicity data relevant to the occupational exposure situation was set at the STEV. Animal data were evaluated only for exposure concentrations up to 100 times the TWAEV. There is no convincing evidence of trichloroethylene-induced hearing losses in workers. In rats, trichloroethylene affects the auditory function mainly in the cochlear mid- to high-frequency range with a lowest observed adverse effect level (LOAEL) of 2000 ppm. No studies on ototoxic interaction after combined exposure to noise and trichloroethylene were identified in humans. In rats, supra-additive interaction was reported. Further studies with sufficient data on the trichloroethylene exposure of workers are necessary to make a definitive conclusion. In the interim, we recommend considering trichloroethylene as an ototoxic agent.

Nitroethane Documentation of proposed values of occupational exposure limits (OELs)

2017 ◽  
Vol 33 (1(91)) ◽  
pp. 97-113
Author(s):  
Andrzej Sapota ◽  
Małgorzata Skrzypińska-Gawrysiak ◽  
ANNA KILANOWICZ
Keyword(s):  
Occupational Exposure ◽  
The Body ◽  
Exposure Level ◽  
Occupational Exposure Limits ◽  
Exposure Limits ◽  
Short Term ◽  
Cellulose Esters ◽  
Limit Values ◽  
Exposure Limit ◽  
Short Term Exposure

Nitroethane is a colorless oily liquid with a mild fruity odor. It is used mainly as a pro-pellant (e.g., fuel for rockets), and as a solvent or dissolvent agent for cellulose esters, resins (vinyl and alkyd) and waxes, and also in chemical synthesis.Occupational exposure to nitroethane may occur during the process of its production and processing. There are no data on air concentra-tions of nitroethane in occupational exposure. In 2010–2015, workers in Poland were not exposed to nitroethane concentrations exceed-ing the maximum allowable value – 75 mg/m3 (the limit value valid since 2010).Nitroethane can be absorbed into the body via inhalation of its vapors or by ingestion.The discussed cases of nitroethane acute poi-soning caused by an accidental ingestion of artificial fingernail remover containing pure nitroethane concerned children under three years. Few hours after ingestion, cyanosis and sporadic vomiting were observed in children. The methemoglobin level reached 40÷50%.Neither data on chronic nitroethane poisoning in humans nor data obtained from epidemio-logical studies are available.On the basis of the results of acute toxicity studies nitroethane has been categorized in the group of hazardous compounds. However, eye and dermal irritation or allergic effects have not been evidenced. The studies of sub-chronic (4 and 90 days) and chronic (2 years) exposure to nitroethane per-formed on rats and mice (concentration range 310 ÷ 12 400 mg/m3) revealed the methemo-globinogenic effect of this compound and a minor damage to liver, spleen, salivary gland and nasal turbinates.Niroethane has shown neither mutagenic nor carcinogenic effects. Its influence on fertility has not been evidenced either. After chronic exposure (2 years) of rats to ni-troethane at concentration of 525 mg/m3 (the lowest observed adverse effect level – LOAEL), a slight change in a body mass of exposed fe-male animals and subtle changes in biochemi-cal parameters were observed, but there were no anomalies in hematological and histopatho-logical examinations.The value of 62 mg/m3 has been suggested to be adopted as the MAC value for nitroethane after applying the LOAEL value of 525 mg/m3 and relevant coefficients of uncertainty. The STEL value for nitroethane was proposed ac-cording to the methodology for determining short term exposure level value for irritating substances as three times MAC value (186 mg/m3) to prevent the effects of sensory irri-tations in humans. Because of its methemoglo-binogenic effect, 2% Met-Hb has been suggest-ed to be adopted as the value of biological ex-posure index (BEI), like the value already adopted for all methemoglobinogenic sub-stances.The Scientific Committee on Occupational Exposure Limits (SCOEL) proposed the time-weighted average (TWA) for nitroethane (8 h) as 62 mg/m3 (20 ppm), short-term exposure limit (STEL, 15 min) as 312 mg/m3 (100 ppm) and “skin” notation.Proposed OEL and STEL values for nitroethane were subjected to public consultation, con-ducted in 2011 by contact points, during which Poland did not raise any objections to the pro-posals. The proposed values for nitroethane by SCOEL has been adopted by the Advisory Committee on Safety and Health at Work UE (ACSH) and included in the draft directive establishing the IV list of indicative occupa-tional exposure limit values.

scholarly journals Annual NO2 as a Predictor of Hourly NO2 Variability: Do Defra UK’s Heuristics Make Sense?

Atmosphere ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 385
Author(s):  
Ashley Mills ◽  
Stephen Peckham
Keyword(s):  
Sensitivity Test ◽  
Data Uncertainty ◽  
Sufficient Condition ◽  
Medical Evidence ◽  
Exposure Limits ◽  
Short Term ◽  
Annual Average ◽  
Weakly Coupled ◽  
Short Term Exposure ◽  
The Uk

Background: In the UK an hourly objective exists for NO2 concentrations and assessment against this objective is required for various administrative purposes. The vast majority of NO2 measurement in the UK is non-hourly however. Thus, Defra guidance provides a heuristic to estimate hourly objective exceedance likelihood from an annual average. Methods: We examine the performance of this heuristic using a Europe wide dataset containing over 20,000 site-years of data, and perform a sensitivity test to account for data uncertainty. Results: The heuristic misses 64% of sites that break the hourly objective. The heuristic is neither a necessary nor sufficient condition for predicting hourly objective breaches. The sensitivity test reveals that the heuristic is input-fragile. Conclusions: The heuristic performs poorly, is weakly coupled to medical evidence, and work is needed to develop new short term exposure limits for NO2.

Urea – inhalable fraction. Documentation of proposed values of occupational exposure limits (OELs)

2017 ◽  
Vol 33 (4(94)) ◽  
pp. 5-25
Author(s):  
Katarzyna Konieczko ◽  
JOLANTA Skowroń
Keyword(s):  
Animal Studies ◽  
Animal Feed ◽  
Catalytic Reduction ◽  
Reproductive Toxicity ◽  
Raw Material ◽  
Alcoholic Beverages ◽  
Crystalline Solid ◽  
Hazardous Substance ◽  
Exposure Limits ◽  
Short Term Exposure

Urea is a non-flammable, colorless or white crystalline solid. It has a faint aroma of ammonia and a cooling, saline taste. It is hygroscopic, very well soluble in water. During long-term storage and in aqueous solutions urea partly decomposes with the release of ammonia and carbon dioxide. Urea is used as a: component of fertilizer and animal feed; raw material for production of plastics, flame-proofing agents, adhesives, medicines, cosmetics and household products; reductant in selective catalytic reduction (SCR) systems used to reduce NOx emissions from stationary and mobile sources; deicing compound on roads, railroad tracks and airport runways; in the food industry as an additive for bakery products, alcoholic beverages and gelatine-based products and as a reagent in laboratories. In 2012, world production of urea was estimated to be around 184 million tonnes and is projected to increase further. In the European Chemicals Agency, urea was registered by 5 companies from Poland. The number of workers exposed to urea in 2 of these plants is a total of 201 people. Urea is an endogenous product, formed in the liver in the urea cycle from ammonia formed by the catabolism of amino acids and proteins, is then excreted by the kidneys. An adult man excretes about 20 ÷ 35 g of urea in the urine during the day. Most of the information on the effects of urea in humans comes from patients with renal insufficiency who have elevated urea levels. Adverse effects of urea include: headache, nausea, vomiting, syncope, confusion, electrolyte abnormalities in the blood. Urea has a slight irritating effect on the eyes and does not irritate the skin. At concentrations above 10% urea has a keratolytic effect - it facilitates peeling and increases the permeability of the stratum corneum, thereby increasing the therapeutic activity of many topical medications. Based on animal studies urea has low acute and chronic toxicity and no carcinogenic or reproductive toxicity. Urea does not meet the classification criteria as a CLP hazardous substance. Due to very low vapor pressure, exposure is possible only to urea dust. Therefore, in order to protect workers from the nuisance of particulate matter (dust) of urea, the MAC (TWA) value of 10 mg/m3 was recommended as for other dusts not classified for toxicity but posing a hazard for visibility reasons. There is no basis for determining the short-term exposure limit value (STEL) and the biological exposure index value (BEI).

scholarly journals Quantification of volatile organic compounds in smoke from prescribed burning and comparison with occupational exposure limits

2014 ◽  
Vol 14 (5) ◽  
pp. 1049-1057 ◽  
Author(s):  
E. Romagnoli ◽  
T. Barboni ◽  
P.-A. Santoni ◽  
N. Chiaramonti
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Prescribed Burning ◽  
The United States ◽  
Smoke Inhalation ◽  
Exposure Limits ◽  
Short Term ◽  
Short Term Exposure ◽  
Volatile Organic ◽  
Measured Mass

Abstract. Prescribed burning represents a serious threat to personnel fighting fires due to smoke inhalation. The aim of this study was to investigate exposure by foresters to smoke from prescribed burning, focusing on exposure to volatile organic compounds (VOCs). The methodology for smoke sampling was first evaluated. Potentially dangerous compounds were identified among the VOCs emitted by smoke fires at four prescribed burning plots located around Corsica. The measured mass concentrations for several toxic VOCs were generally higher than those measured in previous studies due to the experimental framework (short sampling distance between the foresters and the flame, low combustion, wet vegetation). In particular, benzene, phenol and furfural exceeded the legal short-term exposure limits published in Europe and/or the United States. Other VOCs such as toluene, ethybenzene or styrene remained below the exposure limits. In conclusion, clear and necessary recommendations were made for protection of personnel involved in fighting fires.

scholarly journals Quantification of the volatile organic compounds in the smoke from prescribed burning and comparison with the occupational exposure limits

2013 ◽  
Vol 1 (6) ◽  
pp. 6499-6520
Author(s):  
T. Barboni ◽  
P.-A. Santoni
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Prescribed Burning ◽  
Smoke Inhalation ◽  
Exposure Limits ◽  
Short Term ◽  
Exposure Limit ◽  
Short Term Exposure ◽  
Volatile Organic ◽  
Very High

Abstract. Prescribed burning represents a serious threat to the personnel fighting fires because of smoke inhalation. This study aims to increase the knowledge about foresters exposure to the prescribed burning smoke by focusing on exposure to volatile organic compounds (VOCs). We initially assessed the methodology for smoke sampling. Then, we identified potentially dangerous molecules among the VOCs identified at 4 prescribed burning sites located around Corsica. The values measured were very high, exceeding the exposure limits, particularly for benzene, phenol, and furfural, whose concentrations were above short-term exposure limit (STEL) values. In conclusion, obvious but necessary recommendations were made for the protection of the personnel involved in fighting fires on a professional basis.

scholarly journals Importance of Systematic Reviews and Meta-analyses of Animal Studies: Challenges for Animal-to-Human Translation

2020 ◽  
Vol 59 (5) ◽  
pp. 469-477
Author(s):  
Zahra Bahadoran ◽  
Parvin Mirmiran ◽  
Khosrow Kashfi ◽  
Asghar Ghasemi
Keyword(s):  
Systematic Reviews ◽  
Animal Studies ◽  
Animal Experiments ◽  
Clinical Applications ◽  
Current Evidence ◽  
Exclusion Criteria ◽  
Safety And Efficacy ◽  
Balanced Assessment ◽  
Animal Data ◽  
Meta Analyses

Results of animal experiments are used for understanding the pathophysiology of diseases, assessing safety and efficacy of newly developed drugs, and monitoring environmental health hazards among others. Systematic reviews and meta-analyses of animal data are important tools to condense animal evidence and translate the data into practical clinical applications. Such studies are conducted to explore heterogeneity, to generate new hypotheses about pathophysiology and treatment, to design new clinical trial modalities, and to test the efficacy and the safety of the various interventions. Here, we provide an overview regarding the importance of systematic reviews and meta-analyses of animal data and discuss common challenges and their potential solutions. Current evidence highlights various problems and challenges that surround these issues, including lack of generalizability of data obtained from animal models, failure in translating data obtained from animals to humans, poor experimental design and the reporting of the animal studies, heterogeneity of the data collected, and methodologic weaknesses of animal systematic reviews and meta-analyses. Systematic reviews and meta-analyses of animal studies can catalyze translational processes more effectively if they focus on a well-defined hypothesis along with addressing clear inclusion and exclusion criteria, publication bias, heterogeneity of the data, and a coherent and well-balanced assessment of studies' quality.

Occupational ototoxicity of n-hexane

2008 ◽  
Vol 27 (6) ◽  
pp. 471-476 ◽  
Author(s):  
A Vyskocil ◽  
T Leroux ◽  
G Truchon ◽  
M Gendron ◽  
N El Majidi ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Inhalation Exposure ◽  
Weighted Average ◽  
Convincing Evidence ◽  
Auditory Function ◽  
Exposure Limits ◽  
Upper Limit ◽  
Animal Data ◽  
Time Weighted Average ◽  
Occupational Settings

The ability of chemicals to produce hearing loss themselves or to promote noise-induced hearing loss has been reported for some organic solvents. The objective of this study was to review the literature on the effects of low-level exposure to n-hexane on the auditory system and consider its relevance for occupational settings. Both human and animal investigations were evaluated only for realistic exposure concentrations based on the permissible inhalation exposure limits. In Quebec, the time-weighted average exposure value (TWAEV) for 8 h is 50 ppm. In humans, the upper limit for considering ototoxicity data relevant to the occupational exposure situation was set at five times the TWAEV. Animal data were evaluated only for exposure concentrations up to 100 times the TWAEV. There is no convincing evidence of n-hexane-induced hearing loss in workers. In rats, n-hexane seems to affect auditory function; however, the site of these alterations cannot be determined from the present data. Further studies with sufficient data on the exposure of workers to n-hexane are necessary to make a definitive conclusion. In the interim, we recommend considering n-hexane as a possibly ototoxic agent.

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