Heavy metal concentrations in water and surface sediments of ...

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It was found that Ruppia maritima was capable of simultaneously absorbing two kinds of nitrogen sources such as ammonia and nitrate in the reclaimed water.
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CHINESE JOURNAL OF GEOCHEMISTRY

Vol. 25 (Suppl.) 2006

wastewater. The contents of nitrogen and phosphorus of Ruppia maritima varied with the season. The most contents of nitrogen and phosphorus in the tissue ofRuppia maritima were up to 5.042% and 0.956%, respectively. It was observed that the community of Ruppia maritima was replaced gradually by the community of Potamogeton pectinatus in the coastal scenic watercourse of reclaimed wastewater from April 2004 to October 2005. The stable isotope technique was used to trace nitrogen by Ruppia maritima absorbed in water at laboratory. It was found that Ruppia maritima was capable of simultaneously absorbing two kinds of nitrogen sources such as ammonia and nitrate in the reclaimed water. The accumulation of nitrogen from ammonia (615NH4-N) and from nitrate (61sNO3-N) showed the logarithm and exponential relations with time, respectively. Higher nutrient loading in the coastal reclaimed wastewater may be a reason why the community ofRuppia maritima declines.

Key words

reclaimed wastewater; Ruppia maritima; biomass; nutrient; seasonal variation

Heavy metal concentrations in water and surface sediments of Maharlou Lake, SE of Shiraz, Iran

Farid Moore, Guiti Forghani Tehrani, Afshin Qishlaqi, Fatemeh Rastmanesh Farid Moore, Guiti Forghani Tehrani, Afshin Qishlaqi, Fatemeh Rastmanesh, Iran

The main objective of this study is to evaluate trace metal distribution and identify their sources in the Maharlou Lake. Trace metals (Cr, Co, Ni, Cu, Zn, Cd, Pb) and major elements (A1, Ca, Fe, K, Mg, Mn, Na, P) were investigated in water and surface sediments. There was a negative relationship between the depth of water and heavy metal concentration. Metal concentrations in water and sediment samples show a high variability and decrease in this order: AI>Fe>Ni>Co>Pb>Zn>Cu>Mn>Cd. In the northern parts of the lake, especially at the inflow of drains and the Khoshk River of Shiraz City, metal concentrations are higher in both water and sediment samples. In order to assess the heavy metal enrichment in sediment samples, trace metal concentrations were normalized for A L Except for Mn, all metals are enriched relative to average crust and average sedimentary rocks. Also, the results showed that stations located at the northern coast of the lake, have higher enrichment factors (EF) than the other stations. The results of this study showed that the Khoshk River and other drains are the main pollutant sources of the Maharluo Lake.

Key words

Maharluo Lake; trace metal; enrichment factor; pollutant source; Iran

Hydrologic and hydraulic characteristics of the Yellow River and impact of flow and sediment diversion

Dong WANG1, Shaoming PAN2, Jichun W - U 1, Qingping ZHU 3, Chang LIU 1 1Department of Earth Sciences, Nanjing University, Nanjing 210093, China 2 The Key Lab of Ministry of Education of Coast & Island Development, Nanfing University, Nanfing 210093, China 3 The YellowRiver Conservancy Committee of Ministry of WaterResources, Zhengzhou 450003, China

In the history, the Yellow River nurtured Chinese civilization. It is respected as the "ancestor of the four large rivers in China" and praised as "the mother fiver of China". At the same time, the Yellow River is regarded as "the misery of China" and considered as the most complex river hard to control in the world. Today, the Yellow River is also one large river greatly influenced by human activities in the world. The safety of the Yellow River, particularly flood control, is always the most important issue for governing and developing the country. Great achievements have been made after many years of efforts for controlling the Yellow River. However, since the nineties of 20 century, some new problems occurred, such as sharp reduction of flux to sea, dry rivercourse, worsen environment, etc. Rapidly shrinking riverbed and two-level perched stream are disadvantageous to flood safety especially. The new concepts and new practices are urgently needed to control the river. Therefore, the Yellow River Conservancy Committee of Ministry of Water Resources had continuously carried out flow and sediment diversion each year from 2002 to 2005. To timely probe into the new issues produced after flow and sediment diversion, and in order to deepen the understanding of rules for the Yellow River's water and sediment and provide reference and experience to the researchers for other large rivers, five hydrologic and hydraulic characteristics of the Yellow River, such as lack of water, much of sediment, different resources of water and sediment, inconsistency between water and sediment and frequency of sink switching and route changing, are described. Flow and sediment diversion of the Yellow River is also reviewed. Under flow and sediment diversion, which is a kind of new and more direct and