Effects of Sewage Sludges Contaminated with Polychlorinated Dibenzo-p-dioxins, Dibenzofurans, and Biphenyls on Agricultural Soils

Abstract

The fate of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and polychlorinated biphenyls (PCBs) in sewage sludges after agricultural application was analyzed. This study was based on the experiments designed for two soils with different agronomical characteristics after applying different rates of sewage sludge. The concentrations of PCDDs, PCDFs, and PCBs in soils were determined before and after the application of sewage sludges, and a general increase was observed with the applied rate, especially in the case of the PCDDs. The values of sludge-treated areas were 1.2-11.6 times higher than the respective values of the noncontaminated areas. Changes observed in the ratio between PCDD and PCDF levels and in the isomeric distribution also suggest the influence of the sewage sludge on the soil. The values of sludgetreated areas were compared with the limits proposed in Germany for agricultural and horticultural land uses. The results of the soil investigation showed that, in the case of an initial soil with low contamination, the final soil did not exceed the limit; but, in the case of an initial soil with considerable contamination, the final soil exceed the limit, which restricts the cultivation of certain vegetables.

A comparison of TEQ contributions from PCDDs, PCDFs and dioxin-like PCBs in sewage sludges from Catalonia, Spain

“…The ratio R TEQ PCDD/TEQ PCDF was calculated, and the values ranged between 0.5 and 1.4, with a mean value of 1.0. Generally, sewage sludge samples are characterized by a R TEQ PCDD/TEQ PCDF >1 (Eljarrat et al, 1997 and1999). However, from the eight samples analysed in our study, four presented a R TEQ PCDD/TEQ PCDF <1.…”

“…Regarding the PCB levels, the results obtained in this study were compared with those obtained in previous studies (Pauné et al, 1994;Eljarrat et al, 1997). Eljarrat et al …”

“…The contamination of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in sewage sludge is well documented. Analytical results have been reported from the United States (Tiernan et al, 1997), Germany (Gihr et al, 1991;Hagenmaier et al, 1992), Sweden (Broman et al, 1990), the United Kingdom (Sewart et al, 1995) and Spain (Eljarrat et al, 1997 and1999).…”

“…A further objective was to compare the PCB, PCDD and PCDF levels in these sludges with results obtained from samples taken in the 80s (Eljarrat et al, 1997 and1999) in order to detect temporal trends.…”

Remediation Technologies of Ash and Soil Contaminated by Dioxins and Relating Hazardous Compounds.

“…Besides that, sewage sludge which has been often used as fertilizer also contains PCDD/Fs. 5) Actually, it is pointed out that sewage sludge is a secondary source of PCDD/Fs to the environment. Its origins of the PCDD/Fs may be attributed to several different sources such as atmospheric deposition, transformation of chlorinated organic precursors, like chlorophenols, during treatment of wastewater and industrial dumps from textile, pulp and paper industries.…”