Influence of Humic Substance in Solids on the Measurement of Oxygen-Consuming Organics of the Yellow River

Abstract

ABSTRACT. The Yellow River has a high content of solids. The influence of solids on the measurement of oxygen-consuming organics (OCOs) such as chemical oxygen demand (COD Mn ) has aroused attentions in recent years. However, no research about effects of humic substance in solids on the determination of COD Mn has been reported. Experiments have been carried out to study the influence of humic substance in solids (Loess soil) on COD Mn in this research. Several significant results have arisen from the study. (1) The total COD Mn of water sample including liquid and solid phases increased significantly with the increase of solid content; the COD Mn of liquid phase of water sample under pre-treatment with acid (LPUPA) also increased significantly with the increase of solid content while that without pre-treatment did not increased significantly. (2) With the increasing of solid content, the total BOD 5 of water sample increased much slower than the total COD Mn and the COD Mn of LPUPA. (3) The humic substances in solids contributed greatly to the total COD Mn of water sample. When the solid contents were 7.5 and 15.0 g/L, the humic substances in solids accounted for 15.9% and 17.1% of the total COD Mn of water sample, respectively; fulvic acid-one of the main compositions of humic substance-contributed to 23.6% and 46.3% of the COD Mn of LPUPA, respectively. (4) The humic substances can hardly be biologically oxidized under natural conditions, the COD Mn of LPUPA and the total COD Mn of water sample exaggerates the oxygen-consuming organic contamination of the Yellow River. Therefore, COD Mn was not suitable for being regarded as a parameter reflecting the pollution degree of OCOs in river water with a high solid content.

Reconstructed long-term time series of phytoplankton primary production of a large shallow temperate lake: the basis to assess the carbon balance and its climate sensitivity

“…J. Komárková-Legnerová to Limnothrix redekei (Nõges et al, 2010a;Tuvikene et al, 2010); (3) chemical oxygen demand COD Mn , a common proxy for dissolved organic matter (DOM), was significantly lower in the period 1968-1977 compared with that in 1998-2008 and had a highly significant increasing trend within both periods (Tuvikene et al, 2010). Potassium permanganate, a much milder oxidizer compared to the more often used potassium dichromate, is highly sensitive to variations in dissolved organic matter, including humic substances (Xia et al, 2005). A correlations analysis between limnological variables in 102 Estonian lakes (Milius & Starast, 1999) found the strongest correlation among all analysed 14 variables between COD Mn and water colour (r = 0.97) that allows using COD Mn as a proxy for water colour.…”

ESTIMATION CODMN IN GUANGZHOU SECTION OF PEARL RIVER BASED ON GF-1 IMAGES

“…Despite the different band response of satellite sensors, the most important reason is that the CODMn is a synthetical index rather than a certain substance like Chl-a. It refers to the amount of oxygen consumed when the organic matter in a given volume of water is chemically oxidized to CO2 and H2O by permanganate (Xia, 2005). And this organic matter is constructed with organic particulate matter and dissolved organic matter in any proportions.…”