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Toxicology
Published in W. David Yates, Safety Professional’s Reference and Study Guide, 2020
The organophosphate and N-methyl carbamate insecticides cause the accumulation of acetylcholine at nerve endings by poisoning the acetylcholinesterase enzyme. In carbamate poisoning, the inhibition of the enzyme is rapidly reversible, and the workers are often improved by the time of arrival at the clinic or emergency room. Organophosphates can irreversibly bind to the enzyme so that normal enzyme activity can only be restored after the cells synthesize new acetylcholinesterase. This process takes up to 60 days. The primary route of occupational exposure is through the skin. Some of the health effects associated with pesticides are diarrhea, urination, miosis, bradycardia, emesis, lacrimation and salivation, secretions, and sweating. The primary route of occupational exposure is through the skin.24
Respiratory and Cardiovascular Responses
Published in Alan G. Heath, Water Pollution and Fish Physiology, 2018
The ventilatory change may be proportional to the dose even at very low levels. Bishop and McIntosh (1981) report a good correlation between the threshold for an increase in cough frequency in water containing cadmium and the maximum acceptable toxicant concentration (MATC) obtained by growth and reproduction studies. A similar type of correlation with the MATC was seen with coughing of rainbow trout in water containing aluminum (Ogilvie and Stechey, 1983) and ventilation frequency of bluegill immersed in surfactant solutions (Maki, 1979). Thus, these responses could be a useful method for estimating water quality criteria, providing it is recognized by the investigators that not all substances cause changes in ventilation. For example, in tests on DDT, dieldrin, and methyl carbamate with rainbow trout, only DDT gave useful results with the ventilatory response. The other two pesticides produced no response until clearly lethal concentrations were used (Lunn et al., 1976). More recently, Carlson (1990) found that malathion caused no ventilatory response in bluegill whereas carbaryl, another acetylcholinesterase inhibitor like malathion, caused hyperventilation but only at fairly high concentrations. It should also be realized that the initial response to some chemicals may be lost after about a day of continuous exposure so measurements taken at only one time interval of exposure could be misleading.
Toxicology
Published in W. David Yates, Safety Professional’s, 2015
The organophosphate and N-methyl carbamate insecticides cause accumulation of acetylcholine at nerve endings by poisoning the acetylcholinesterase enzyme. In carbamate poisoning, the inhibition of the enzyme is rapidly reversible, and the workers are often improved by the time of arrival at the clinic or emergency room. Organophosphates can irreversibly bind to the enzyme so that normal enzyme activity can only be restored after the cells synthesize new acetylcholinesterase. This process takes up to 60 days. The primary route of occupational exposure is through the skin. Some of the health effects associated with pesticides are diarrhea, urination, miosis, bradycardia, emesis, lacrimation and salivation, secretions, and sweating. The primary route of occupational exposure is through the skin.24
Impact of a Non-Formal Environmental Education Program on safe handling of pesticides among Mexican subsistence farmers: a participatory pilot study
Published in Human and Ecological Risk Assessment: An International Journal, 2021
Belén Madeline Sánchez-Gervacio, José Legorreta-Soberanis, Ramón Bedolla-Solano, José Luis Rosas-Acevedo, Rafael Valencia-Quintana, Ana Laura Juárez-López, Sergio Paredes-Solís
In order to reduce the harmful effects of pesticides, Mexico has tried to regulate their use by creating laws which include General Law of Ecological Balance and Environmental Protection (Diario Oficial de la Federación (DOF) 2012), General Law for the Prevention and Integral Management of Waste (Diario Oficial de la Federación (DOF) 2018) and the Official Mexican Standard NOM-052-SEMARNAT-2005 (Diario Oficial de la Federación (DOF) 2006). However, as these laws are largely unknown to farmers (García and Rodríguez 2012), in rural communities there is very limited impact of these laws on the adverse effects of pesticides (Sankoh et al. 2016; Zhang et al. 2016). Pesticides prohibited in other countries due to high degree of toxicity are still used in Mexico; notable among them are. 1,1′-dimethyl-4,4′-bipyridyl dichloride (Paraquat), O, O-diethyl-O-4 -nitro-phenylthiophosphate (Paration), diethyl 2 - [(dimethoxyphosphorothioyl) sulfanyl] butanedioate (Malathion), 2-acetic acid; isopropylamine salt of N (-phosphonomethyl) glycina (Glyphosate) (Pérez et al. 2013) and 2,3-dihydro-2,2-dimethyl-7-benzofuranyl-methyl carbamate (Furadan) (Bejarano et al. 2017).
Advances in state-of-art valorization technologies for captured CO2 toward sustainable carbon cycle
Published in Critical Reviews in Environmental Science and Technology, 2018
Shu-Yuan Pan, Pen-Chi Chiang, Weibin Pan, Hyunook Kim
Carbamates (RNH−COOR) are being used for production of pesticides, germicides, pharmaceuticals, and other organic chemicals. Important carbamate compounds include aromatic carbamates such as methyl N-phenyl carbamate (MPC), as well as alkyl carbamates such as methyl carbamate (MC), ethyl carbamate (EC), and butyl carbamate (BC). From the green chemistry point of view, CO2 can be used to generate the carbamates from amines and alcohols, which is considered as an environmentally benign route. At an ambient temperature and pressure, CO2 can easily combine with amines to form the corresponding carbamic acids. If alcohols are used as the alkyl source, however, the subsequent dehydrative condensation to carbamates proceeds slowly (Ion et al., 2008). Thus, an excess amount of a dehydrant is often used to overcome the equilibrium limitation.
An insight on the different synthetic routes for the facile synthesis of O/S-donor carbamide/thiocarbamide analogs and their miscellaneous pharmacodynamic applications
Published in Journal of Sulfur Chemistry, 2023
Faiza Asghar, Bushra Shakoor, Babar Murtaza, Ian S. Butler
Lee et al. [33] examined the most extensively employed carbamate protective groups in their study, comprising methyl carbamate, Boc, Fmoc, etc. The urea derivatives were synthesized in good to outstanding yield after 2–5 h at room temperature as a result of reaction of carbamates with an excess of piperindine and trimethylaluminum (amine/metal/carbamate ratio 3:2.5:1). The rate of conversion was exceedingly slow when using t-butyl carbamate (Boc), as perceived by TLC; but, when heated to 50°C, the reaction was completed in 1.5 h. The only example in these studies is the Fmoc-protected aniline that produced a low yield (34%) of the target product. The relatively low yield was ascribed to the strong lability of the Fmoc group to piperidine [33].