River sediments, PCDD

TCP), and pentachlorophenol (PCP), in order of abundance. Minor amounts of other trichlorophenols and dichlorophenols may also be present, as well as recalcitrant polychlorinated phenoxyphenols (PCPPs) and PCDD/Fs as impurities [75, 76]. In Finland, approximately 30,000 tons of CP products were used between 1934 and 1988, when they were banned because of their potential toxicity to humans and the environment [77, 78]. The careless manufacturing and application of wood preservatives together with the lack of suitable waste disposal caused massive contamination of river sediments and sawmill sites. For example, the river Kymijoki in southern Finland was identified as the largest source of dioxins accumulating in fish in the entire Baltic area. Similar products were used in other European countries, especially Nordic countries with a large forestry industry, such as Sweden [79]. 

Rappe C, Andersson R, Bonner M, Cooper K, Fiedler H, Howell F, Kulp SE, Lau C (1997) PCDDs and PCDFs in Soil and River Sediment Samples from a Rural Area in the United States of America. Chemosphere 34 1297... 

Prange JA, Gaus C, Papke O, Muller JF (2002) Investigations into the PCDD Contamination of Topsoil, River Sediments and Kaolinite Clay in Queensland, Australia. Chemosphere 46 1335... 

The fractional contribution of the major PCDD and PCDF congeners to their respective total concentrations in Niagara River sediments in Table 3 is shown in Fig. 9. Despite large variations in concentration among sites, the PCDF pattern is remarkably similar along the river. The major congeners are OCDF,... 

Fig. 9 Fractional contribution of major PCDD and PCDF congeners to E-PCDDs and E-PCDFs concentrations in Niagara River sediments in 2000 (Table 3). Adapted from Richman [38]...

Within classical POPs, chlorinated compounds are the most relevant, standing out are PCBs, PCDDs and PCDFs. However, among the emerging POPs, different brominated compoimds have attracted the most scientific interest during the last decade. This work will focus on the most relevant chlorinated and brominated organic pollutants in river sediments. 

Gotz R, P Friesel, K Roch, O Papke, M Ball, M, A Lis (1993) Polychlorinated-/ -dioxins PCDDs, dibenzofu-rans PCDFs, and other chlorinated compounds in the River Elbe results on bottom sediments and fresh sediments collected in sedimentation chambers. Chemosphere 27 105-111. 

Secondary sources of PCDD/PCDFs, their reservoirs, are those matrices where they are already present, either in the environment or as products. Product reservoirs include PCP-treated wood, PCB-containing transformers and sewage sludge, compost and liquid manure, which can be used as fertilizers in agriculture and gardens. Reservoirs in the environment are, for example, landfills and waste dumps, contaminated soils (mainly from former chemical production or handling sites), and contaminated sediments (especially in harbours and rivers with industries discharging directly to the waterways). 

Based on information by Fu et al. [219], other reactions include trans-chlorinations (migration of chlorine from PCDD to organic matter) and polymerizations, which have not been quantified. In spiked sediments from the Hudson and Passaic Rivers and sediment microorganisms, lesser-chlorinated products accounted for 10-15% of the decrease in octa-CDD. Hepta-, tetra-, tri-, and 2-mono-CDD congeners tend to dominate the dechlorination pattern [432, 433]. The microbial dechlorination sequence of octa-CDD is provided in Fig. 29 [432], which distinguishes a pathway via... 

Hallett and Brooksbank [39] quote an internal Environment Canada report in which water and suspended sediment samples from the Niagara River were sometimes found to contain measurable concentrations of various PCDD/F homologs. PCDD concentrations were < 1.4 pgL-1 in one or two out of six samples, however, five or six samples contained OCDD concentrations up to 3.6pgL-1. TeCDF concentrations were very high in one sample, 156pgL-1 four out of six samples had PnCDF concentrations up to 317 pg L-1. PCDD/Fs were detected in suspended sediments more frequently, up to 2530 pg L-1 of OCDF. TeCDDs were not detected in any sample at unknown detection limits. 

Fig. 7 PCDD/F homolog profiles in urban air particulates and surface sediments sampled from mid-Lake Michigan (1982), lower Lake Huron (1975, 1981), eastern Lake Erie (1981, 1983), and western Lake Ontario (1983) near the Niagara River mouth. Reproduced with permission from Czuczwa and Hites [20]. Concentrations of OCDD are given in the upper right hand corner (ppt = ngkg-1 dw)...

Table 2 Concentrations of PCDD/Fs in sediments (ngkg 1 dw) at various sites along the Saginaw River in the mid-1990s...

Table3 Concentrations (ngkg 1 dw) of PCDD/Fs in sediments near various sources of contamination along the US side of the Niagara River in 2000...

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