EVALUATION OF TEMPORAL AND AGE-RELATED TRENDS OF CHEMICALLY AND BIOLOGICALLY GENERATED 2,3,7,8-TETRACHLORODIBENZO-p-DIOXIN EQUIVALENTS IN LAKE ONTARIO LAKE TROUT, 1977 TO 1993

Risks and Management of Dioxins and Dioxin-like Compounds in Baltic Sea Fish: An Integrated Assessment

“…The same goes for the individual dlPCBs and PCDD/Fs, as shown e.g. by Huestis et al (1997) for Lake Ontario trout. Sometimes the TEFs used have not been clearly indicated, and often absolute concentrations have not been reported, making it impossible to recalculate TEqs.…”

“…A levelling off of the declines may however occur at least for some parts of the population, as the rates of decline for also non-fish foods decrease. Such a development has been noted also in TEq levels in Great Lakes trout (Huestis et al 1997 …”

Caddis larvae (Trichoptera, Hydropsychidae) indicate delaying recovery of a watercourse polluted by pulp and paper industry

“…The use of PCBs was banned in many countries already in the 1970s and 1980s, and the production was ceased entirely in 1993 (AMAP 2000). Although the concentrations of these compounds have decreased in the effluents (Oikari & Holmbom 1996 and in the sediment since the 1970s and 1980s (Rappe et al 1987, Huestis et al 1997, Sanctorum et al 2011, hotspots still exist in many polluted watercourses and in the coastal areas (Breivik et al 2004, Verta et al 2007, Heimann et al 2011). Due to the persistence and toxic characteristics these chemicals are widely studied and still monitored in aquatic environment , Verta et al 2007).…”

“…While the worldwide pulp and paper industry has mostly used total chlorine free (TCF) or elemental chlorine free (ECF) bleaching methods since the early 1990s, this has largely decreased but not totally eliminated the formation of the PCDDs and PCDFs . Although the deposition of PCDDs and PCDFs to the sediments has decreased since 1980s (Huestis et al 1997), elevated concentrations in the surface sediment still exist in polluted watercourses and coastal areas ), and benthic animals may remarkably affect the fate of the chemicals accumulated in the sediments due to bioturbation, migration and trophic transfer (Reynoldson 1987). Regarding to PCBs, many countries banned their use already in the 1970s.…”

The H4IIE Cell Bioassay as an Indicator of Dioxin-like Chemicals in Wildlife and the Environment

“…The assumption of all of techniques for TCDD-EQ determination is that the test extract induces CYP1A1 through the same mechanism as the TCDD standard, and therefore simply acts as a dilution of TCDD (Finney, 1964;Villeneuve et al, 2000a). The method of ED50 comparison is frequently used for H4IIE cell bioassay data due to its simplicity (Jones et al, 1993a;Koistinen et al, 1997;Huestis et al, 1997). CYP1A1 activity is plotted versus the extract dose (semilog plot) and an appropriate regression model FIGURE 5.…”