Quantification of dioxin in the sieved fraction of river sediment

2005 ◽  
Vol 52 (9) ◽  
pp. 225-233 ◽  
Author(s):  
H. Ozaki ◽  
S. Taniguchi ◽  
R. Takanami ◽  
N. Shimomukai ◽  
T. Hamasaki ◽  
...  
Keyword(s):  
Grain Size ◽  
Organic Carbon ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
River Sediment ◽  
Contaminated Sediments ◽  
Total Carbon ◽  
Ignition Loss ◽  
Environment Agency ◽  
Nitrogen Contents

Dioxin pollution of aquatic sediments has been one of the important environmental problems in Japan. Grain size distribution and organic constituents may play important roles in dioxins contents in sediments, which have not been well investigated. This paper aims to quantify dioxins (PCDDs/Fs and co-PCBs) in sieved surface sediment fractions obtained from Kizu and Sumiyoshi Rivers in Osaka, Japan. The samples were prepared and analyzed following the ‘Manual of the Survey and Measurement of Dioxins in Sediment’ (Environment Agency of Japan, 2000). The results showed that TEQ concentrations of dioxins increased with decreasing grain size in sediment fractions. Sediment fractions with less than 20μm grain size showed the highest dioxin contents. Dioxins with five and six chlorine atoms dominated other congeners in less than 20μm fractions. The dioxin TEQ concentrations increased with total organic carbon (TOC), total carbon (TC), ignition loss (IL), total sulphur and nitrogen contents in the sediment fractions. Thus, reporting dioxin contents in sediments without considering grain size distribution may be erroneous, and conventional sedimentation and separation techniques might not be useful for treating contaminated sediments. This information can be useful for effective remediation of dioxin-contaminated sediments.

scholarly journals Mercury in Sediment Core Samples From Deep Siberian Ice-Rich Permafrost

2021 ◽  
Vol 9 ◽  
Author(s):  
Clara Rutkowski ◽  
Josefine Lenz ◽  
Andreas Lang ◽  
Juliane Wolter ◽  
Sibylle Mothes ◽  
...  
Keyword(s):  
Grain Size ◽  
Magnetic Susceptibility ◽  
Organic Carbon ◽  
Total Organic Carbon ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Total Nitrogen ◽  
The Arctic ◽  
Specific Magnetic Susceptibility ◽  
Shallow Soils

We determine Hg concentrations of various deposits in Siberia’s deep permafrost and link sediment properties and Hg enrichment to establish a first Hg inventory of late Pleistocene permafrost down to a depth of 36 m below surface. As Arctic warming is transforming the ice-rich permafrost of Siberia, sediment is released and increases the flux of particulates to the Arctic shelf seas through thawing coasts, lakeshores, and river floodplains. Heavy metals within soils and sediments are also released and may increasingly enter Arctic waters and the biological food chain. High levels of mercury (Hg) have been reported from shallow soils across the Arctic. Rapid thawing is now mobilizing sediment from deeper strata, but so far little is known about Hg concentrations in deep permafrost. Here, forty-one samples from sediment successions at seven sites and of different states of permafrost degradation on Bykovsky Peninsula (northern Yakutian coast) and in the Yukechi Alas region (Central Yakutia) were analyzed for Hg, total carbon, total nitrogen, and total organic carbon as well as grain-size distribution, bulk density, and mass specific magnetic susceptibility. We show average Hg concentrations of 9.72 ± 9.28 μg kg−1 in the deep sediments, an amount comparable to the few previous Arctic studies existing, and a significant correlation of Hg content with total organic carbon, total nitrogen, grain-size distribution, and mass specific magnetic susceptibility. Hg concentrations are higher in the generally sandier sediments of the Bykovsky Peninsula than in the siltier sediments of the Yukechi Alas. The ratio of Hg to total organic carbon in this study is 2.57 g kg−1, including samples with very low carbon content. We conclude that many deep permafrost sediments, some of which have been frozen for millennia, contain elevated concentrations of Hg and the stock of Hg ready to be released by erosion is of significance for the Arctic ecosystem. The Hg mobilized may accumulate on the way to or in the shallow sea, and where it enters into active biogeochemical cycles of aquatic systems it may concentrate in food webs. Our study highlights the need for better understanding Hg stocks and Hg release from permafrost.

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