Increases in the polychlorinated dibenzo-p-dioxin and -furan content of soils and vegetation since the 1840s

Abstract

Archived soil samples (0-23 cm, plough layer depth) collected from the same semirural plot in southeast England between 1846 and 1986 have been analyzed for polychlorinated (tetra to octa) dibenzo-p-dioxins and -furans (PCDD/Fs). Atmospheric deposition will have been the major source of PCDD/Fs to the site over this time. PCDD/Fs were present in all the samples, and concentrations started to increase around the turn of the century, rising from 31 to 92 ng of £PCDD/Fs (kg of soil)"1 between 1893 and 1986. Unwashed bulked herbage samples from 1960-1970 and the 1980s contained 96 and 85 ng of £PCDD/F kg"1 respectively, compared to 12 ng of £PCDD/F kg'1 in a sample from 1880-1990. Average ^PCDD/F net rates of increase in the soil over the last century were calculated as ca. 190 ng m"2 year'1. It is suggested that the increases in soil and herbage PCDD/Fs observed this century at Rothamsted are representative of those likely for agricultural systems in many industrialized regions. The possible changing sources of PCDD/Fs to the environment are discussed in the context of the concentration trends and congener-specific observations.

Prediction of the retentions of polybrominated dibenzo-p-dioxins (PBDDs) by using the retentions of polychlorinated dibenzo-p-dioxins (PCDDs)

“…Like PCDD/Fs, they also appear to be resistant to chemical transformations and have low biological degradation rate (Buchert and Ballschmiter, 1986;Norwood et al, 1989;Hagenmair et al, 1992;Wenning et al, 1992;Fletcher and McKay, 1993). They have been found in rivers, lakes and ground water, soil, as well as in¯y ash (Kjeller et al, 1991;Wenning et al, 1993).…”

Quantitative relationship between chromatographic retentions and molecular structures of polychlorinated dibenzo-p-dioxins (PCDDs)

“…They have been found in rivers, lakes and ground water, soil, as well as in¯y ash (Hagenmair et al, 1992). PCDD/F are persistent environmental pollutants, that bioaccumulate throughout the food chain and may pose a serious health risk to humans and animal species (Buchert and Ballschmiter, 1986;Norwood et al, 1989;Kjeller et al, 1991;Wenning et al, 1992;Fletcher and McKay, 1993;Wenning et al, 1993). In general the most toxic PCDDs and PCDFs are known to be the congeners with 2,3,7,8 chlorine substitutents for determination of toxic equivalents (TE), so PCDDs with 1,2, or 3 Cls will be of less concern.…”

A new method of predicting of gas chromatographic retention indices for polychlorinated dibenzofurans (PCDFs)

“…They are resistant to chemical transformations and have low biological degradation (Mackay and Paterson, 1981;Buchert and Ballschmiter, 1986;Norwood et al, 1989;Hagenmair et al, 1992;Wenning et al, 1992;Fletcher and Mckay, 1993). And they have been found in rivers, lakes and ground water, soil, and¯y ash (Kjeller et al, 1991;Wenning et al, 1993).…”