Decomposition of monoalkyl dithiocarbamates

Joris, Serge J.; Aspila, Keijo I.; Chakrabarti, Chuni L.

doi:10.1021/ac60288a004

Cited by 65 publications

(52 citation statements)

References 17 publications

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“…Repulsion between the fractional positive charge developed on N and C leads to cleavage of N-C bond forming dialkyl amine and CS 2 . [21] DMDTC and CS 2 are mainly responsible for the hepatotoxicity. [4] The probable pathway for the fate of DMDTC in acidic conditions is shown in Figure 4.…”

Section: Identification Of Degradation Products For Tomato Fruit (T 1mentioning

confidence: 99%

Identification of degradation products of thiram in water, soil and plants using LC-MS technique

Gupta

Rani

Kumar

et al. 2012

Journal of Environmental Science and Health, Part B

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In order to evaluate the deleterious effects of exposure to pesticides on a target population, a comprehensive study on their degradation in the various segments of ecosystem under varying environmental conditions is needed. In view of this, a study has been carried out on the metabolic pathways of thiram, a dithiocarbamate fungicide, in a variety of matrices namely water and soil under controlled conditions and plants in field conditions. The identification of degradation products was carried out in samples collected at various time points using LC-MS. The degradation products identified can be rationalized as originating by a variety of processes like hydrolysis, oxidation, N-dealkylation and cyclization. As a result of these processes the presence of some metabolites like dimethyl dithiocarbamate, bis(dimethyl carbamoyl) disulphide, bis(dimethyl dithiocarbamoyl) trisulphide and N-methyl-amino-dithiocarbamoyl sulphide was observed in all the cases. However, some different metabolites were observed with the change in the matrix or its characteristics such as cyclised products 2(N, N-dimethyl amino)thiazoline carboxylic acid and 2-thioxo-4-thiazolidine were observed only in plants. The investigations reflect that degradation initiates with hydrolysis, subsequently oxidation/dealkylation, followed by different types of reactions. The pathways seem to be complex and dependent on the matrices. Dimethyl dithiocarbamate and oxon metabolites, which are more toxic than parent compound, seem to persist for a longer time. Results indicate persistence vis-a-vis toxicity of pesticide and its metabolites and also provide a data bank of metabolites for forensic and epidemiological investigations.

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Section: Identification Of Degradation Products For Tomato Fruit (T 1mentioning

confidence: 99%

Identification of degradation products of thiram in water, soil and plants using LC-MS technique

Gupta

Rani

Kumar

et al. 2012

Journal of Environmental Science and Health, Part B

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“…The thickness of the arrows indicates the relative importance of each reaction in the m ouse (Jowa et al, 1992). Similar reactions occur nonenzym atically in aqueous solutions (Joris et al, 1970).…”

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confidence: 88%

“…SMD spontaneously (nonenzymatically) and rapidly breaks down in aqueous environments both in vitro and in vivo. There are two competitive pathways that form either carbon disulfide and methylamine, or hydrogen disulfide and MITC (Joris et al, 1970) (Figure 1). FIGURE 1.…”

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confidence: 99%

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Role of Decomposition Products in Sodium Methyldithiocarbamate-Induced Immunotoxicity

El²,

Db³

et al. 1996

Journal of Toxicology and Environmental Health

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Sodium methyldithiocarbamate (SMD) is a widely used agricultural agent that causes immunological changes in B6C3F1 mice. The most prominent effects of SMD include a decrease in thymus weight and percentage of CD4+CD8+ thymocytes, an increase in spleen weight, an increase in the percentage of neutrophils in the blood, a decrease in the percentage of lymphocytes in the blood, and a decrease in natural killer (NK) cell activity in the spleen. The mechanism by which SMD causes these changes is unknown, and the relative importance of the parent compound and its decomposition products is not known. In addition, it is not known if these effects are unique to mice, or if other mammals are affected similarly. This prompted the present investigation of the major decomposition product of SMD, methylisothiocyanate (MITC), and two minor products, methylamine and carbon disulfide, in mice. Equimolar dosages of methylamine and carbon disulfide caused minimal immunological changes, and these changes were not characteristic of those noted for SMD. In contrast, MITC significantly decreased thymus weight and cellularity and changed peripheral white blood cell populations in a manner similar to that noted for an equimolar dosage of SMD. However, MITC did not significantly affect NK cell activity or increase spleen weight. Thus, MITC is probably responsible for some of the immunological changes noted in SMD-treated mice. The remaining changes are not produced by MITC, methylamine, or carbon disulfide. Thus, it is likely that the parent compound or a synergistic action of the parent compound with one or more of the decomposition products is responsible for these remaining changes (increased spleen weight and decreased splenic NK cell activity). Data are also presented that indicate that SMD-induced thymic atrophy occurs in rats as well as mice and that the dosage required to decrease thymus weight by 50% is lower for rats than for mice. Investigations of other mammals are needed to indicate SMD's potential as a human immunotoxicant and to compare the role of MITC in the immunotoxic effects of SMD in different species.

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“…Ecological issues Toxic to aquatic organisms, non-target plants, and microbes in soil in pure solutions, so it is apparent that they do not require enzymatic catalysis (Joris et al, 1970). However, in soil an average of 92% of metam sodium decomposes to methylisothiocyanate within a few hours .…”

Section: Regulationsmentioning

confidence: 99%

Toxicology of Metam Sodium

Pruett¹,

Myers²,

Keil³

2001

Journal of Toxicology and Environmental Health Part B: Critical Reviews

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Metam sodium is the third most commonly used agricultural pesticide (by weight) in the U.S. A spill of 19,000 gallons of metam sodium into the Sacramento River in 1991 clearly demonstrated that a major uncontrolled release can have adverse ecological and human health effects. Furthermore, this incident revealed that estimates of Reference Exposure Levels for the major breakdown product of metam sodium (methylisothiocyanate, MITC) were reasonable with regard to the induction of discomfort. In fact, the irritant properties of MITC seem to account for many of the most commonly reported symptoms in this incident. However, neurotoxicity may also account for some of these symptoms. There is evidence that metam sodium can act as a contact sensitizer in humans, inducing allergic dermatitis. It also may exacerbate or induce respiratory allergy (asthma). The ecological impact of routine use of metam sodium is not clear, but adverse effects on non-target plants have been inferred from modeling studies, and adverse effects on soil microbes have been observed. These issues deserve further study. Human health effects of occupational or routine environmental exposure to metam sodium are not known, but there is limited evidence for immunological (hypersensitivity) and developmental effects as well as irritation and associated symptoms. Animal studies suggest a potential for immunological, developmental, carcinogenic, and atherogenic effects. Metam sodium and some of its breakdown products have a wide variety of molecular and cellular actions that could explain the health effects noted here. However, further studies are needed to relate specific molecular or cellular actions to specific health effects.

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Decomposition of monoalkyl dithiocarbamates

Cited by 65 publications

References 17 publications

Identification of degradation products of thiram in water, soil and plants using LC-MS technique

Identification of degradation products of thiram in water, soil and plants using LC-MS technique

Role of Decomposition Products in Sodium Methyldithiocarbamate-Induced Immunotoxicity

Toxicology of Metam Sodium

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