PCDE nitro

In addition to hydroxy-PCDEs, nitro- and aminoderivatives of PCDEs could be possible sources of PCDEs in the environment. Nitrofen is prepared by base-catalyzed condensation of 2,4-dichlorophenol (2,4-DCP) with l-chloro-4-nitrobenzene [30]. PCDEs have not been detected in 2,4-DCP and 2,4,5-TCP [37] but, in theory, just as the occurrence of PCDE by-products in chlorophe-nols is most likely due to the condensation of chlorophenols, the condensation of 2,4-dichlorophenol during the manufacture of nitrofen might lead to the formation of PCDEs. Aminofen is produced from nitrofen by catalytic reduction [4],... 

Many herbicides are nitro-PCDEs such as nitrofen and DNP [28,29]. Different diphenyl ether herbicides are presented in Table 3. The use of nitrofen, 2,4-di-chloro-4 -nitro-diphenyl ether, was restricted to crops without detectable residues at harvest in the 1980s, since it has caused neonatal deaths in rats [30]. A aminoderivative of PCDEs, Aminofen, is an intermediate in the chemical industry and has been used in the manufacture of herbicides Illoxan and Diclofop-methyl [4]. Amino-PCDEs are also impurities of Eulan WA New that contains... 

Nitro-trifluoromethyl-PCDEs and hydroxy-trifluoromethyl-PCDEs have been detected as impurities in 3-trifluoromethyl-4-nitrophenol (TFM), which is a field formulation of a lampricide [32]. This lampricide has been applied to protect salmonids from sea lampreys in streams since the 1950s. 

More information is needed on teratogenicity of PCDEs as well as the role of thyrotoxicity in the developmental toxicity of PCDEs [104], Teratogenicity caused by nitro-PCDEs has been suggested to involve alterations in thyroid hormone status [87] and transient alterations in maternal thyroid status might affect development of the fetus [143], Effects of PCDEs after prenatal exposure have been similar to those of PCBs [104]. 

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