Geochronology of priority pollutants in a sedimentation area of the rhine river

Abstract

Eight sediment cores were taken from Lake Ketelmeer, a sedimentation area of the Rhine River, located in the central part of The Netherlands. Priority pollutants (eight metals, six planar and mono‐ortho polychlorinated biphenyls, seven polychlorinated dibenzo‐p‐dioxins, 10 polychlo‐rinated dibenzofurans, and eight polycyclic aromatic hydrocarbons) were determined in all or in a selected number of cores. Present‐day and historical levels of pollutants since the late 1930s were established through the use of radionuclide time tracers (137Cs, 134Cs) and area‐specific geological time markers. Postdepositional redistribution of pollutants and possible transformations were evaluated by analyzing sediment top‐layer samples that were taken in 1972. Disappearance in the anaerobic sediment was observed for several chlorinated biphenyls, dioxins, and furans, Disappearance of the chlorinated compounds may be caused by microbial dechlorination reactions in the anaerobic lake sediment. For the persistent metals and polycyclic aromatic hydrocarbons, as well as for the somewhat changed concentrations of chlorinated aromatics, trends in the concentration profiles during the last five decades are described. Rather low concentrations of almost all studied chlorinated compounds were observed in the early 1940s. These low levels were in contrast to the metal and PAH concentrations, which were already high in the late 1930s and were lowered during the second world war. For all studied compounds, maximum concentrations were found between 1955 and 1975. Cadmium and nickel levels remained high until 1980. The highly toxic 2,3,7,8‐tetrachlo‐rodibenzo‐p‐dioxin reached concentrations up to 400 ng/kg in the mid‐1960s. Recently deposited sediments showed lower pollutant levels. The levels of lead, arsenic, and all studied PAHs were the lowest observed in the past five decades.

Long-term Developments in Ecological Rehabilitation of the Main Distributaries in the Rhine Delta: Fish and Macroinvertebrates

“…However, water quality data from the river Rhine are very scarce from the period before 1965. Analysis of dated sediment layers in the forelands have shown to be a helpful tool in reconstructing pollution history with heavy metals and organic micropollutants (Klink, 1989;Beurskens et al, 1993).…”

Environmentally Relevant Properties of All 209 Polychlorinated Biphenyl Congeners for Modeling Their Fate in Different Natural and Climatic Conditions

“…[60][61][62][63][64][65][66][67][68][69][70][71][73][74][75] The dominating degradation process of PCBs in air and in pristine surface waters was found to be photolysis and in solids (soil/plants and sediments) biodegradation. UVinduced degradation (reduction to hydrogen) of ortho-chlorines of PCBs was generally fastest and para-chlorine loss the next fastest in the atmosphere, in surface water, and on solid surfaces.…”

“…As well, the biodegradation rate in water is 10 to 20 times slower than the biodegradation rate Kb in solid surface layers of soil, plants, and sediment. [61][62][63][64][65][66][67][68][69][70][71][72] For fate modeling, we used estimates of the degradation rates in water for photolysis Kp/15 and for biodegradation Kb/15. The hydrolysis rate (Kh) in water is very slow related to photolysis and biodegradation, thus it has no observable influence on the total rate and half-life estimates (in eqs 27 to 30)…”

“…[68][69][70][71] Degradation rates R(i)/h -1 and half-lives HL(i)/h of the chemical in the four compartments (i ) 1 to 4) are needed for fate prediction. 3,8,9 On the basis of field observations and molecular structure, approximate R(i) and HL(i) values are estimated by eqs 27 to 30.…”

Polychlorinated‐dibenzo‐p‐dioxins and dibenzofurans (PCDD/Fs) in dated environmental samples, and their connection to known sources

“…Useful data should cover a reasonable period of more than 30-40 years, and consist of congener sums [32]; seven sediment discs Lake Huron, l-12cm, Core 4, US [C] [33]; two sediment discs Lake Windermere 1988-92,1946-50, UK [C] [34]; three sediment discs Morecambe Bay, 0,14,28 cm, Irish Sea [C] [35]; two sediment discs Green Lake, 1988, 1943 US [C] [36]; three sediment discs Siskiwit Lake 0-0.5, 5-6 and 8-9 cm, US [37]; three sediment discs Lake Ketelmeer, 1945Ketelmeer, ,1965Ketelmeer, ,1985 [I] [38]; three average sediment, Hudson River 1990-91 (five recent discs), 1952-82 (five max. discs), 1907-24 (three deep discs), US [C] [39]; seven sediment discs Lake Constance 1949-1973, Germany [C] [40]; fourteen sediment discs Lake Constance (Core B) 1993-1895, Germany [C] [41].…”