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List of Chemical Substances
Published in T.S.S. Dikshith, and Safety, 2016
Pure dicofol is available as a white or gray powder or colorless solid crystals while the technical dicofol is a red-brown or amber viscous liquid with an odor like fresh-cut hay. Dicofol undergoes decomposition on burning or on contact with acids, acid fumes or bases, producing toxic and corrosive fumes including hydrogen chloride. Dicofol is a persistent OCP used as an acaricide and miticide. It is structurally similar to DDT. Dicofol is combustible and incompatible with strong oxidizing agents. It is soluble in most aliphatic and aromatic solvents and most common organic solvents, but practically insoluble in water and hydrolyzes in basic solution. It is used on a wide variety of fruit, vegetables, ornamental and field crops. Dicofol is manufactured from DDT. Dicofol is corrosive to some metals. It is used for foliar applications, mostly on cotton, apples, and citrus crops. Other crops include strawberries, mint, beans, peppers, tomatoes, pecans, walnuts, stonefruit, cucurbits, and non-residential lawns/ornamentals.
Concentrations, Sources and Ecological Risk of Organochlorine Pesticides in Urban Stream Sediments of Suzhou Industrial Park, China
Published in Soil and Sediment Contamination: An International Journal, 2022
Xiaoguo Wu, Qing Wang, Zijiao Yuan, Binbin He, Houqi Liu, Shanshan Wang
where x is the contribution rate of technical derived DDT, Rs is the ratio of o,p’-DDT/p,p’-DDT in the sediment samples. 1-x is the contribution rate of dicofol derived DDT. Seven sites with both o,p’-DDT and p,p’-DDT < MDL were excluded during the calculation (Table 2, these sites were labeled as NA in Table 2). There were 8 sites with only one DDT isomer > MDL, half of the MDL was assigned to the concentration value of undetected isomer during the calculation. This approximate calculation did not distort the results of source identification. For example, if o,p’-DDT < MDL, the calculated o,p’-DDT/p,p’-DDT would be very small (< 0.25), indicating there was no dicofol input. Conversely, p,p’-DDT < MDL would lead to a high ratio (> 7), indicating there was no technical DDT input (Zhang et al. 2018). Finally, the fractions of DDT from technical DDT were > 0.8 in 14/19 sites, = 0 in 4/19 sites, and = 0.4 in 1/19 site (Table 2). In summary, sediments of the SIP were mostly influenced by the usage of technical DDT, but the influence of the dicofol usage cannot be ignored either.
The Effect of Environmental Processes on the Isomeric Composition of DDT-related Compounds
Published in Soil and Sediment Contamination: An International Journal, 2019
S. Kucher, M. Ricking, J. Schwarzbauer
Due to the different stereo-chemical orientation of the chlorine atoms at the phenyl groups, the o,p’- and p,p’-isomers of DDX exhibit different physico-chemical properties. Accordingly, environmental processes, in particular biotic transformation and transfer between and within compartments, have different effects on the respective isomers. Consequently, changes and shifts in the relative isomeric composition of DDX in environmental samples can potentially act as indicators to track these processes and follow the environmental fate of DDX (Ricking and Schwarzbauer, 2012). However, to date, isomer-specific investigations mainly focused on the source apportionment of DDT in the environment. For example, based on the much higher o,p’-/p,p’-DDT ratio in dicofol compared to technical DDT (Di Muccio et al., 1988; Gillespie et al., 1994), a DDT pollution caused by technical DDT can be distinguished from that caused by dicofol (Qiu et al., 2005).
Distribution, sources and health risk assessment of DDT and its metabolites in agricultural soils in Zhejiang Province, China
Published in Environmental Technology, 2022
DDT produced in industry contains 75% p,p′-DDT and 15% o,p′-DDT, so the ratio of o,p′-DDT/p,p′-DDT is about 0.2 ([31]). In comparison, DDT is the raw material for the production of dicofol, and the content of o,p′-DDT in the dicofol is high. So the ratio of o,p′-DDT/p,p′-DDT is much higher than 0.2, which can be used to judge whether dicofol is introduced into the environment ([32]). In general, after long-term metabolic transformation, DDT degraded into DDE and DDD ([25]). Therefore, DDT-contaminated soil with historical residues has a higher content of DDE and DDD, and the value of (p,p′-DDE + p,p′-DDD)/p,p′-DDT is greater than 1, but in the new input polluted areas, the ratio is less than 1([1421]).