Occupational Exposure Risk for Swine Workers in Confined Housing Facilities

2019 ◽  
Vol 25 (1) ◽  
pp. 37-50 ◽  
Author(s):  
Alvin C. Alvarado ◽  
Bernardo Z. Predicala
Keyword(s):  
Hydrogen Sulfide ◽  
Occupational Exposure ◽  
Weighted Average ◽  
Respirable Dust ◽  
Exposure Risk ◽  
Exposure Limits ◽  
Exposure Limit ◽  
Short Term Exposure ◽  
Swine Workers ◽  
Time Weighted Average

Abstract. Extended exposure of swine barn workers to noise and airborne contaminants has been reported to be associated with various health problems. In this study, the actual exposure of workers to respirable dust, gases (ammonia and hydrogen sulfide), and noise in swine production operations was monitored in order to determine the contribution of specific activities in the barn to potential adverse health impacts to swine workers. Selected workers in a swine barn facility were outfitted with a personal monitoring system that included a respirable dust sampler, ammonia (NH3) and hydrogen sulfide (H2S) gas monitors, and a noise dosimeter as they performed their regular duties during their workday. From a total of 50 monitoring days spanning winter and summer months, results showed that the occupational exposure of swine workers to respirable dust, NH3, H2S, and noise while performing their daily assigned tasks was generally below the respective time-weighted average exposure limits for each hazard. However, a number of tasks showed high likelihood for elevated occupational exposure risk. Respirable dust concentrations exceeded the time-weighted average limit of 3 mg m-3 while feeding and weighing pigs. These activities also exceeded the short-term exposure limit (35 ppm) for NH3. Dangerous levels of H2S were generated when draining manure from manure collection pits in the production rooms. Noise levels exceeded the recommended 15 min exposure limit (100 dBA) when weighing and loading pigs for market. The occupational exposure risks for workers to barn contaminants can be reduced through measures that control the generation of contaminants at their source, by removing generated contaminants from the work environment, as well as by outfitting the workers with protective devices that prevent personal exposure to contaminants. Keywords: Ammonia, Barn worker, Dust, Hydrogen sulfide, Noise, Occupational exposure, Risk, Swine.

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.

4,4’- Isopropylidenediphenol – inhalable fraction. Documentation of proposed values of occupational exposure limits (OELs)

2018 ◽  
Vol 34 (4(98)) ◽  
pp. 5-40
Author(s):  
Jan Gromiec
Keyword(s):  
Occupational Exposure ◽  
Bisphenol A ◽  
Respiratory System ◽  
Mammalian Cells ◽  
Epoxy Resins ◽  
Exposure Limits ◽  
Exposure Limit ◽  
Short Term Exposure ◽  
Occupationally Exposed

4,4’- Isopropylidenediphenol (bisphenol A) is a white solid present in the form of crystals or flakes. It is used mostly in the production of epoxy resins (appr. 95% of its consumption). It is also used in the polycarbonate plastics, unsaturated polyester, polysulphonte and polyacrylate resins as well as flame retardants. Polycarbonate plastics are used to make products such as emulsions for thermal printers employed for printing tickets, labels, receipts, faxes etc. The routes of occupational exposure during production and application of bisphenol A are the respiratory system and the skin. The exact number of occupationally exposed to 4,4’- isopropylidenediphenol is not known but taking into account the wide use of polycarbonate and polyester resins it can be counted in thousands. Because of only trace amounts of bisphenol A in most of the resins, the levels of exposure are usually minimal. In Poland 4,4’- isopropylidenediphenol is used mainly as a component of glues for electronic parts, PVC stabilizer, addition components of epoxy resins and brake fluids. In 2010 only 4 persons were reported as occupationally exposed to bisphenol A dust in concentrations exceeding Polish OEL (5 mg/ m3) – 2 in the crop and animal production, hunting and related service activities sector and 2 in the water transport sector. In 2013 no workers exposed above OEL value were reported. Oral LD50 values beyond 2 000 mg/kg bw were found in the rat and mouse, and dermal LD50 values above 2 000 mg/kg are evident in the rabbit. 4,4’- Isopropylidenediphenol has been classified as Repr. 1.B, H360F (may damage fertility or the fetus) and substance that causes serious eye damage (H318) and may cause respiratory system irritation (H355). In workers having occupational contact with 4,4’- isopropylidenediphenol irritation of eyes, skin and respiratory system was observed. In animal experiments it was clearly shown that bisphenol A did not cause skin irritation, however, it was shown that the compound is an eye irritant. Slight and transient nasal tract epithelial damage was observed in rats exposed to bisphenol A dust which suggests that it appears to have a limited respiratory irritation potential. There are several reports of patients with dermatitis responding to BPA in patch tests, however, it is unclear whether bisphenol A or related epoxy resins were the underlying cause of the hypersensitive state. No reliable sensitisation animal data from experiments meeting the required standards are available. Toxicity of bisphenol A has been tested on mice, rats and dogs. The compound administered orally caused mainly a decrease in body weight gain; minor changes in organ weight, mostly in liver; respiratory disorders, diarrhea and death. From chronic experiments the liver and kidney seem to be the target organs. There are no in vivo data on mutagenic activity of bisphenol A. It also does not appear to produce either gene mutations or structural chromosome aberrations in bacteria, fungi or mammalian cells in vitro. The compound did not induce gene mutations in yeasts; sister chromatid exchange tests carried out on mammalian cells also gave negative effects. No information on human cancerogenicity of 4,4’- isopropylidenediphenol has been found in the literature and databases available. In a 103-week test on rats and mice of both sexes no convincing evidence indicating carcinogenic action of bisphenol A was found. Some studies indicate negative action of 4,4’- isopropylidenediphenol on reproduction which is a result of a mechanism of its action – in in vivo test the compound was found to bind to the nuclear estrogen receptors. However, data on the embryotoxic activity of bisphenol A and its effects on reproduction are not conclusive. Contradictory findings between the studies have been reported in several studies in rodents which was thoroughly discussed in the EFSA Report of 2015. In studies carried out in accordance with the FDA/NTCR standards 4,4’- isopropylidenediphenol effects on reproduction have been seen only at high doses showing also other toxic effects. Comprehensive tests with a wide range of doses did not confirm effects of 4,4’- isopropylidenediphenol on reproduction and development at low doses below 5 mg/kg bw. In Chinese epidemiological studies, impaired sperm quality in workers occupationally exposed to bisphenol A has been found, however, the effect of other concurrent exposures cannot be excluded. 4,4’- Isopropylidenediphenol in all species studied is conjugated with glucuronic acid and excreted as glucuronid with urine. The major route of excretion is via faeces; regardless of the route of entry 50-80% of the administered dose is eliminated with faeces in the unchanged form. In humans the compound is excreted as glucuronide or sulphate conjugates in urine. In Poland as well as in most other countries 5 mg/m3 as OEL and 10 mg/m3 as STEL have been established for 4,4’- isopropylidenediphenol. Scientific Committee on Occupational Exposure Limits (SCOEL) has proposed to establish an Indicative Occupational Exposure Limit (IOEL) in workplace air at the level of 2 mg/m3 taking the inhalation NOAEC of 10 mg/m3 from the rat study as a starting point for recommending an OEL. The critical effect in this study was respiratory tract irritation. According to SCOEL there is no toxicological basis for recommending an additional specific short-term exposure limit (STEL). Assignment of “skin” notation was also not recommended. The proposed OEL value for 4,4’- isopropylidenediphenol (inhalable fraction) has been derived from its irritating action on nasal tract epithelium in an inhalation study on experimental animals. The proposed OEL value is 2 mg/m3. This value should also protect workers against toxic effects on liver and kidney. There are no grounds for establishing a short-term exposure limit (STEL) nor for recommending a biological limit value (BLV). It is also proposed to introduce the following assignments: “I” – irritating substance and “A” – sensitizing substance.

Use of Methanol as a Coolant During Machining of Aluminum in a Shipbuilding Environment: A Failure to Assess and Manage Risk

2014 ◽  
Vol 955-959 ◽  
pp. 1061-1064 ◽  
Author(s):  
Thomas Neil McManus ◽  
Assed N. Haddad
Keyword(s):  
Weighted Average ◽  
Threshold Limit Value ◽  
Breathing Zone ◽  
Short Term ◽  
Limit Value ◽  
Diffusion Tubes ◽  
Exposure Limit ◽  
Long Duration ◽  
Short Term Exposure ◽  
Time Weighted Average

Minimization of harm during the conduct of work is one of the most important tenets of industrial hygiene. Organizations make changes to solve perceived problems. What appears to be expedient for solving a problem can create serious risks totally unrecognized by the proponent. This investigation reports on such a situation involving the use of methanol as a lubricant during machining of aluminium panels using a router. Spot samples for methanol were measured using colorimetric detector tubes and samples of long duration by colorimetric diffusion tubes utilizing similar chemistry. Both were positioned in the breathing zone. Most of the spot samples exceeded the 8-hour TLV-TWA (Threshold Limit Value-Time-Weighted Average) of 200 ppm and the TLV-STEL (Short-Term Exposure Limit) of 250 ppm. The two long duration samples also exceeded the TLV-TWA. A change in the operation prevented collection of additional long duration samples. By these measures, workers were overexposed to methanol during this activity. An additional serious consequence from use of methanol in this manner was risk of fire. This situation illustrates the complexity of decisions affecting workplace operations. What appears to be expedient for solving a problem may be totally inappropriate.

Mixmaster exposure to dust during mixing of wildland fire retardant chemicals

2002 ◽  
Vol 11 (1) ◽  
pp. 65
Author(s):  
Terry M. Spear ◽  
Curtis E. Cannell
Keyword(s):  
Hydrogen Cyanide ◽  
Wildland Fire ◽  
Weighted Average ◽  
Fire Retardant ◽  
Assessment Model ◽  
Respirable Dust ◽  
Personal Hygiene ◽  
Exposure Limits ◽  
Local Exhaust Ventilation ◽  
End Use

A study was performed at two air tanker/retardant bases to determine the mixmaster’s exposure to dust derived from mixing dry fire retardant compounds. Personal sampling for both inhalable and respirable dust was conducted while the mixmaster mixed fire retardant compounds to form a retardant slurry. Personal samples were also analysed for a colorant in the retardants and hydrogen cyanide. Hazard quotients were calculated for average and upper-end use scenarios using a risk assessment model from Labat-Anderson, Incorporated. The exposure analysis revealed that the 8-h time weighted average (TWA) concentrations were within applicable occupational exposure limits for the inhalable and respirable dust fractions as well as for the colorant and hydrogen cyanide. When the mean inhalable exposure concentration was used to calculate chemical intake, hazard quotients were above 1 at both retardant bases, indicating a potential for non-carcinogenic health effects. Exposure control methods recommended from this study include substitution of a liquid concentrate fire retardant, installation of local exhaust ventilation systems, good housekeeping and personal hygiene. We also recommend the use of personal protective equipment including a filtering facepiece, half-mask respirator; eye protection, and protective clothing such as gloves and coveralls.

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

2018 ◽  
Vol 34 (2(96)) ◽  
pp. 35-59 ◽  
Author(s):  
Andrzej Starek
Keyword(s):  
Renal Failure ◽  
Acute Renal Failure ◽  
Occupational Exposure ◽  
Potassium Bromate ◽  
Male Rats ◽  
Intragastric Administration ◽  
Exposure Limits ◽  
Carcinogenic Agent ◽  
Short Term Exposure ◽  
Polychromatic Erythrocytes

Potassium bromate (V), (KBrO3) exists as white crystals, crystalline powder or granules. It is highly soluble in water, tasteless and odourless. Potassium bromate is a strong oxidizing agent. In the past it has been used as food additive in flour milling, as an ingredient in fish-paste in Japan, in cheese making, in beer malting, as a component of cold hair wave liquid and an oxidizing compound. Moreover, bromate is formed as a by-product of water disinfection by ozonation and is frequently detected in tap and bottled water. In fact bromate is one of the most prevalent disinfection by-product of surface water. Occupational exposure to potassium bromate occurs mainly in production plants during packaging processes. In Poland, about 1 160 persons were exposed to this compound in 2016. Bromate caused many acute poisonings by accidental ingestion, mainly among children, and more often ingested for tentative suicide by young women, especially hairdressers. In the acute phase of poisoning, gastrointestinal disturbances, irreversible hearing loss, and acute renal failure were observed. Acute renal failure was associated with hemolytic uremic syndrome. There are no data on chronic intoxication of humans by potassium bromate and epidemiological studies on this subject. On the basis of the value of median lethal dose (LD50) per os in rat, potassium bromate has been classified as a compound belonging to the category „Toxic”. Major toxic signs and symptoms in animals after a single intragastric administration of potassium bromate were tachypnea, hypothermia, diarrhea, lacrimation, suppression of locomotor movement, ataxic gait, and animals lying in a prone position. At autopsy the major findings were strong hyperemia of glandular stomach mucosa and congestion of lungs. Microscopically, necrosis and degenerative changes of the proximal tubular epithelium and hearing cells of internal ear were found. It was stated that the compound is not irritating, corrosive or sensitizing. In subchronic and chronic exposure of rodents, potassium bromate led to liver and kidney dysfunction and tubular epithelial damage. Potassium bromate had mutagenic and clastogenic effects. It induced point mutations, structural chromosome aberrations, micronuclei in polychromatic erythrocytes in male mice, DNA oxidative damage by modification of deoxyguanosine to 8-hydroxydeoxyguanosine, and DNA double-strand breakage. Potassium bromate induced neoplasms in rodents and exerted promotion effect in comparison with well-known carcinogens. Besides from preneoplastic changes, expressed by high incidences of renal cell tumors and dysplastic foci, bromate induced solid neoplasms, such as adenomas and adenocarcinomas in a rat kidney and thyroid, and mesotheliomas of peritoneum and tunica vaginalis testis. The European Union classified potassium bromate as a substance that can cause cancer (Group 1.B), whereas IARC classified it as a presumably carcinogenic agent for human (Group 2.B). In principle, effects of bromate on reproduction and ontogenetic development of offspring were not observed. Animal studies suggest that a kidney is a critical organ in the exposure to potassium bromate. The results of subchronic exposure of male rats to potassium bromate administered with drinking water were used to calculate the value of MAC-NDS. The critical effects in kidney were: an increase of organ weight and dose-dependent histopathological alterations defined as epithelium urinary tract hypertrophy. The NOAEL value is 1.5 mg/kg b.w./day. For the calculation of the maximum allowable concentration (MAC) value, 5 uncertainty factors with total value of 24 were used. Based on this estimation it is proposed to accept the MAC-TWA value for potassium bromate at 0.44 mg/m3. The risks of kidney and thyroid cancer in condition of occupational exposure are 2.2 · 10-3 and 0.6 · 10-3, respectively. There is no reason to determine the value of short-term exposure limit (STEL) and the biological exposure index (BEI). „Carc.1.B” notation (carcinogenic substance) was proposed

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

2018 ◽  
Vol 34 (4(98)) ◽  
pp. 89-109
Author(s):  
Katarzyna Konieczko
Keyword(s):  
Occupational Exposure ◽  
Water Soluble ◽  
Male Rats ◽  
Electrolyte Imbalance ◽  
Dust Exposure ◽  
Laboratory Animals ◽  
Crystalline Solid ◽  
Exposure Limits ◽  
Limit Value ◽  
Short Term Exposure

Phenolphthalein is a colorless and odorless crystalline solid; in a powdered form white or pale yellow. It is non-volatile, practically insoluble in water, but it dissolves in ethanol. Phenolphthalein is not known to occur as a natural product. The synthetic substance is used as a pH indicator in laboratories, during work on metal surfaces in galvanizing plants as well as for measuring the saturation of concrete with carbon dioxide. Until the end of the 20th century, it was widely used as a component of non-prescription laxatives – in 1999 FDA removed phenolphthalein from the list of substances considered safe. In 2016 in Poland 255 enterprises were reported to work with phenolphthalein (mainly laboratories) and there were 2500 occupationally exposed people. Phenolphthalein used in therapeutic doses was well tolerated. Only a few side effects were reported: abdominal discomfort, nausea, reduced blood pressure and weakness. Chronic use of phenolphthalein resulted in widening of the colon, reduced thickness of the lining of the mucosa, gastric disorders, dehydration and electrolyte imbalance. In a 13-week study in which phenolphthalein was administered to laboratory animals with diets, mice turned out to be a more sensitive species from rats. Changes in testes and epididymides were observed in males and hypoplasia and bone marrow necrosis in males and females. The results of genotoxicity studies indicated that phenolphthalein acts as a promutagen and exerts a clastogenic effect after metabolic activation. Studies on the effect of phenolphthalein on the reproduction of animals indicated its harmful effect on reproductive functions of males. In the EU, phenolphthalein is classified as a category-2 mutagen and category-2 reproductive toxicant (due to its effect on fertility). A small increase in the risk of colorectal cancer and ovarian cancer was observed in case-control studies in patients using phenolphthalein-based laxatives (especially with intensive use of these agents), but the relationship was not statistically significant. In a 2-year NTP carcinogenicity study a significant increase in the number of benign phaeochromocytomas and adenomas of renal tubular epithelium was observed in male rats. There was also a significant increase in histiocytic sarcomas in mice of both sexes and in malignant lymphomas (of all types) and thymic lymphomas and benign ovarian tumors in females. Based on these experiments phenolphthalein has been identified as a substance reasonably anticipated as human carcinogen (NTP R). The experiment on heterozygous p53 (+/-) mice of both sexes confirmed an increase in lymphoma cases. Phenolphthalein is classified by European Union experts as a category-1B of carcinogenic substances, i.e. known or presumed human carcinogens, however the classification is largely based on animal evidence. The European Chemicals Agency (ECHA) identified phenolphthalein as a substance of very high concern (SVHC). Based on the NTP test results, the additional risk of malignant lymphoma at 8.25 mg/m3 occupational exposure to phenolphthalein for 40 years is 10-4. A concentration of 8 mg/m3 was proposed as the MAC-TWA value for phenolphthalein. Since phenolphthalein is a poorly water-soluble solid, only dust exposure of the substance will occur in the work environment, hence the proposed MAC value should concern the inhalable fraction of the substance. It is proposed to label phenolphthalein as "Carc. 1B" indicating that phenolphthalein is a category-1B carcinogen and "Ft" due to reprotoxicity. There are no bases for establishing the short-term exposure limit value (STEL) and the limit value in biological material (BEI).

Occupational Toxicology

2002 ◽  
Keyword(s):  
Weighted Average ◽  
Ambient Air ◽  
Chemical Exposure ◽  
Daily Basis ◽  
Average Concentration ◽  
Work Place ◽  
Industrial Workers ◽  
Limit Values ◽  
Exposure Limit ◽  
Short Term Exposure

Industrial workers make up the segment of the population that is most vulnerable to chemical injury. To protect them from occupation-related harm, the American Conference of Governmental and Industrial Hygienists publishes annually revised threshold limit values (TLVs) (1), guidelines for permissible chemical exposure at the work place. TLV refers to concentrations of substances in parts per million or milligrams per cubic meter in the air to which most workers can be exposed on a daily basis without harm. These values apply to the work place only. They are not intended as guidelines for ambient air quality standards for the population at large. Obviously, genetic variations and diverse lifestyles (such as smoking, alcohol use, medication, and drug use) must be considered. Hypersensitive individuals may be adversely affected by exposure to certain chemicals even within the limits of the TLV. Thus, TLVs should be treated as guidelines only and not as fixed standards. The recommended goal is to minimize chemical exposure in the work place as much as possible. TLVs are expressed in three ways: 1. Time-weighted average (TLV–TWA) designates the average concentration of a chemical to which workers may safely be exposed for 8 h per day and 5 days per week. 2. Short-term exposure limit (TLV–STEL) designates permissible exposure for no more than 15 min, and no more than four times per day, with at least 60-min intervals between exposures. 3. Ceiling concentrations (TLV–C) are concentrations that should not be exceeded at any time. How protective the TLVs are is being questioned. The 1990 report that analyzed the scientific underpinnings of the TLVs revealed that at the exposure at or below the TLV, only few cases showed no adverse effect (2). In some cases even 100% of those exposed were affected. On the other hand, there was a good correlation between the TLVs and the measured exposure occurring in the work place. Thus, it appears that the TLVs represent levels of contaminants that may be encountered in the work place, rather than protective thresholds. Biological exposure indices (BEIs) provide another way of looking at exposure to chemicals.

The activity of the Interdepartmental Commission for Maximum Admissible Concentrations and Intensities for Agents Harmful to Health in the Working Environment in 2018 and the work plan in 2019

2019 ◽  
Vol 35 (1(99)) ◽  
pp. 77-87
Author(s):  
Danuta Koradecka ◽  
Jolanta Skowroń
Keyword(s):  
Occupational Exposure ◽  
Working Environment ◽  
Concentration Limit ◽  
Exposure Limits ◽  
Limit Values ◽  
Maximum Admissible Concentration ◽  
Exposure Limit ◽  
Copper Mines ◽  
Interdepartmental Commission

In 2018 the Commission met at three sessions, during which 9 documentations for recommended exposure limits of chemical substances, were discussed. Moreover the Commission discussed on: a system for notifying entrepreneurs, employees and inspection bodies of proposals for new or verified binding values (for carcinogenic and mutagenic substances) or indicator values for harmful chemicals in the form of messages, rules for setting limit values for harmful to health chemicals in the working environment, a program to improve working conditions in copper mines of KGHM Polska Miedź SA. and the methodology for determining hygiene standards for active substances of cytostatics, taking into account the uncertainty factor "F". The Commission suggested to the Minister of Family, Labour and Social Policy the following changes in the list of MAC values: adaptation of the Polish list of maximum admissible concentration (MAC-NDS) to Directive 2019/130/EC of 31/1/2019 amending Directive 2004/37/EC on the protection of workers from the risks related to exposure to carcinogens or mutagens at work (these are: chloroethene, o-toluidine and 1,3-butadiene), adjusting the MAC-value for trimethylamine to the value included in the draft directive setting the fifth list of indicative occupational exposure limits, introducing changes in the list of the maximum admissible concentration of chemicals and dust harmful to health for the substances mentioned, introduce the following substances into the list of maximum admissible concentrations of chemical agents harmful to health: phenolphthalein (Carc. 1B), etoposide (Carc. 1B), fluorouracil (Muta. 1B, skin), 2-nitroanisole (Carc. 1B), N-nitrosodimethylamine (Carc. 1B). Four issues of the "Principles and Methods of Assessing the Working Environment" were published in 2018. The booklets included: 11 documentation of occupational exposure limit, 11 methods for the determination of chemical concentrations in the working environment, 4 articles, a report on the activities of the Interdepartmental Commission for MACs and MAIs in 2017 and the indexes of the documentations, methods and articles published between 2000-2018. Three sessions of the Commission are planned for 2019. MAC values for 10 chemicals substances will be discussed at these meetings. The Commission and the Group of Experts will continue to work on adapting the Polish list of the maximum admissible concentrations to: proposals for binding values for carcinogenic or mutagenic substances, proposed concentration limit values developed by the Committee for Risk Assessment (RAC) and work carried out at SCOEL.

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

2019 ◽  
Vol 35 (4(102)) ◽  
pp. 153-175
Author(s):  
Elżbieta Bruchajzer ◽  
Jadwiga Szymańska ◽  
Barbara Frydrych
Keyword(s):  
Occupational Safety ◽  
Animal Experiments ◽  
Genetic Material ◽  
Weighted Average ◽  
International Agency ◽  
Intragastric Administration ◽  
Exposure Limits ◽  
Limit Value ◽  
Short Term Exposure

Thioacetamide occurs in the form of colorless crystals with a characteristic smell of mercaptans. It was used in the past as a fumigant to prevent oranges from rotting, in rubber vulcanization and as a diesel stabilizer. It is currently used in a qualitative analysis as a source of hydrogen sulfide. According to information from the Central Register of Data on Exposure to Carcinogenic or Mutagenic Substances, Mixtures, Factors or Technological Processes in 2005-2016 from 486 to 1137 people were exposed to thioacetamide in Poland. Most of them were women. The LD50 value after intragastric administration of the compound to rats is 301 mg/kg. Thioacetamide is a strong hepatotoxic agent, its single dose caused hepatic necrosis. Administered repeatedly it induced liver damage, which was indicated by biochemical changes and cirrhosis. The effects of thioacetamide toxicity in chronic animal experiments indicated a relationship to exposure time. After chronic exposure of rats to thioacetamide in drinking water (at 0.03%, i.e., approximately 35 mg/kg/day) or in feed (0.5% in feed, i.e., approximately 28 mg/kg/day), hepatitis and local hepatic foci were noted after 4 months, these changes later intensified, and after 8–17 months chronic hepatitis, cirrhosis and cancer of the liver and bile ducts occurred. The results of mutagenicity and genotoxicity studies of thioacetamide are inconclusive. It can be assumed that the compound may damage genetic material in vivo after biotransformation to a highly hepatotoxic metabolite. The metabolism of thioacetamide by S-oxidation (mainly with the participation of CYP2E1) leads to the production of sulfoxide (TASO), and then to hepatotoxic, highly reactive sulfone (TASO2). The latter is of fundamental importance for the mechanism of toxic action of thioacetamide (by binding with hepatic macromolecules). Thioacetamide metabolites also induce oxidative stress. Because of neoplasms observed in chronic studies, International Agency for Research on Cancer (IARC) included thioacetamide in group 2B – agents probably carcinogenic to humans. According to the CLP classification, thioacetamide is a category-1B carcinogen with a "H350 – May cause cancer" note. The hepatotoxic effects of thioacetamide in rats after repeated administration were used as the basis for determining the maximum acceptable concentration (MAC; TLV-TWA – threshold limit value-time weighted average). A concentration of 1.5 mg/m3 was proposed as the MAC value. There are no bases to determine the short-term exposure limit (STEL) and the biological limit value (BLV). "Carc. 1B" marking is also proposed, as thioacetamide is a category-1B carcinogen. This article discusses the problems of occupational safety and health, which are covered by health sciences and environmental engineering.

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