Aroclor 1242

Aroclor 1248, Aroclor 1254, and Aroclor 1260. Quantitation is by comparison of chromatograms with standard concentrations of pure compounds treated in an identical manner. The phenoxy acid herbicides (2,4-dichlorophenoxy)acetic acid (2,4-D), sUvex, and (2,4,5-trichlorophenoxy)acetic acid (2,4,5-T) can be deterrnined by electron-capture detection after extraction and conversion to the methyl esters with BF.-methanol. The water sample must be acidified to pH <2 prior to extraction with chloroform. 

Commercial PCBs Toxic and Biochemical Effects. PCBs and related halogenated aromatic hydrocarbons ehcit a diverse spectmm of toxic and biochemical responses in laboratory animals dependent on a number of factors including age, sex, species, and strain of the test animal and the dosing regimen (single or multiple) (27—32). In Bobwhite and Japanese quad, the LC q dose for several different commercial PCB preparations ranged from 600 to 30,000 ppm in the diet the LC q values for mink that were fed Aroclors 1242 and 1254 were 8.6 and 6.7 ppm in the diet, respectively (8,28,33). The... 

Gravity settlers, basically of the type shown in Fig. 15-24 7, were used by Wilke et al. (UCRL-10625, 1963 UCRL-11182, 1964) to settle water and Aroclor (specific gravity, 1.36). The dispersion may... 

PCBs/alkylphenols Clophen A50 Aroclor 1242 Nonyl phenol Pentylphenol... 

Chemical Designations - Synonyms Aroclor Chlorinated biphenyl Halogenated waxes PCB Polychloropolyphenyls Chemical Formula (C,2H x)Clx-... 

G. M. Frame, A collaborative study of 209 PCB congeners and 6 Aroclor s on 20 different HRGC columns. Part 2. Semi-quantitative Aroclor congener distributions . Anal. Chem. 70 714-722(1997). 

Figure 13.1 Monitor (FID) (a) and analytical (ECD) (b) channel responses for PCB congeners in Aroclor 1254, showing selection of the six heart-cut events Frr-st columns, HT8 second columns, BPX5. Reprinted from Journal of High Resolution Chromatography, 19, R. M. Kinghorn et al., Multidimensional capillar-y gas chr omatography of polychlorinated biphenyl marker compounds , pp. 622-626, 1996, with per-mission from Wiley-VCH.

D. E. Schulz, G. Petiick and J. C. Duinker, Complete characterization of polycWoii-nated biphenyl congeners in commercial Aroclor and Clophen mixtures by multidimensional gas cliromatography-electi on capture detection. Environ. Sci. Technol. 23 852-859(1989). 

M.3 Polychlorinated biphenyls (PCBs) were once widely used industrial chemicals but were found to pose a risk to health and the environment. PCBs contain only carbon, hydrogen, and chlorine. Aroclor 1254 is a PCB with molar mass 360.88 g-mol. Combustion of 1.52 g of Aroclor 1254 produced 2.224 g of CO, and combustion of 2.53 g produced 0.2530 g of H20. How many chlorine atoms does an Aroclor 1254 molecule contain ... 

In this core, concentrations of PCBs (determined as Aroclor 1254 and 1260, by high resolution gas chromatography, electron capture detection and high resolution gas chromatography-low resolution mass spectrometry) were <30 ng and those of total DDT (p,p DDT + p,p DDD + p,p DDE) <5 ng g Campesan et al. (21) in 11 sediment samples from Valle di Brenta, determined by GC-ECD the following mean concentrations (ng gd.w.) ... 

Street JC, Sharma RP. 1975. Alteration of induced cellular and humoral immune responses by pesticides and chemicals of environmental concern Quantitative studies of immunosuppression by DDT, Aroclor 1254, carbaryl, carbofuran, and methyl parathion. Toxicol Appl Pharmacol 32 587-602. 

In a study with captive male American kestrels (Drouillard et al. 2001), birds were dosed with Aroclor-contaminated diet and the toxicokinetics of 42 PCB congeners contained therein was stndied. Those congeners that were most rapidly cleared contained vicinal meta-para hydrogen substituents on at least one phenyl ring. This provides further evidence for the importance of open (i.e., not substituted by chlorine) meta-para positions for metabolic attack, an issue that will be returned to in the next section (Section 6.2.3). 

There have been a nnmber of estimates of bioconcentration factors for total PCBs in aqnatic species following long-term exposure to PCB mixtures (EHC 140). Values for both invertebrates and hsh have been extremely variable, ranging from values below 1 to many thonsands. Bioaccnmnlation factors for birds and mammals for different Aroclors have indicated only limited degrees of bioaccumulation from food, for example, 6.6 and 14.8 for the whole carcasses of big brown bats Eptesicus fuscus) and white pelican (Pelecanus erythrorhynchos), respectively (see Environmental Health Criteria 140). 

The enrichment index, which is PCB congener as a percentage of total PCB in seabird depot fat/PCB as a percentage of total PCB in Aroclor 1260. 

PCB mixtures were once used for a variety of purposes, and came to cause widespread environmental pollution. Over 100 different congeners are present in commercial products such as Aroclor 1248 and Aroclor 1254. PCBs are lipophilic, stable, and of low vapor pressure. Many of the more highly chlorinated PCBs are refractory, showing very strong biomagnification with movement along food chains. 

Hansen, D.J., Parrish, P.R., and Forester, J. (1974). Aroclor 1016-Toxicity to and Uptake hy Estuarine Animals. Environmental Research 7, 363-373. 

Platonow, N.S. and Reinhart, B.S. (1973). Effects of polychlorinated biphenyls (Aroclor 1254) on chicken egg-production, fertility and hatchability. Canadian Journal of Comparative Medicine—Revue Canadienne De Medecine Comparee 37, 341-346. 

Fort DJ, Rayburn JR, DeYoung DJ, et al. 1991. Assessing the efficacy of an Aroclor 1254-induced exogenous metabolic activation system for FETAX. Drug Chem Toxicol 14 143-160. 

The hepatic microsomal a-hydroxylase activity for NPYR is inducible in rats by pretreatment with Aroclor, and in hamsters by pretreatment with Aroclor, 3-methylcholanthrene, phenobarbi-tal, and ethanol (10,15,19). In contrast, pretreatment of rats with 3-methylcholanthrene or phenobarbital causes no change or a slight decrease in microsomal NPYR o-hydroxylase activity (19). 

The rates of formation of these metabolites in liver microsomes from Aroclor pretreated rats is summarized in Table III. 

Liver microsomes from Aroclor 1254 pretreated rats were used. See Figure 2. 

Leonzio C, Monaci F. 1996. Multiresponse biomarker evaluation of interactions between mettiylmercury and Aroclor 1260 in quad. Ecotoxicology 5 365-376. 

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