我国内陆流域各类水体中天然放射性核素浓度

1985年～1989年由新疆、甘肃、青海、西藏、内蒙古、陕西、宁夏等省、自治区环境监测站(研究所)对内陆流域各类水体中U、Th、~(226)Ra、~(40)K浓度进行调查,由调查的29条内陆河、23个湖泊、15座水库、55处井泉和34个自来水的统计结果表明,流域内各水体中U和~(40)K浓度的平均值与同期调查的黄河水系同类水体的浓度相近,明显高于长江水系,与全国同类水体相比亦属偏高。Th和~(226)Ra的平均浓度与全国同类水体的浓度相近,甘、新内陆区浓度较低。调查发现,一些咸水湖、井水和自来水中U、~(226)Ra,或~(40)K浓度异常偏高。     

应用藻类的污染指数评价乌鲁木齐水体的水质

通过对乌鲁木齐地区几个水体中浮游植物的调查,根据浮游植物的群落结构、数量、优势种和污染指数来评价这些水体的水质。     

Forms of Nitrogen (NO 3 - -N; NO 2 - -N and NH 2 CONH 2 -N) and their relations to A.O.U. in the Indian coastal waters of Arabian Sea

The distribution of three important dissolved forms of nitrogen, viz. nitrate, nitrite and urea in the surface and bottom water samples collected from 27 selected hydrographic profiles, in the Arabian Sea, along the west coast of India is described. Of the three forms, nitrate concentrations were the highest and comparatively higher concentrations were observed in the bottom water. Decomposition of organic matter resulting in the release of the thermodynamically stable nitrogen species, i.e. nitrate, may be the major factor resulting in higher nitrate concentrations at these depths, where the water is also characterized by low values of dissolved oxygen and temperature. The significant positive correlation between A.O.U. and nitrate of the bottom water samples emphasizes the role of oxidative decomposition of organic matter which plays an active role in reducing the oxygen concentrations below the theoretical values since at this depth ( , 200 m) the net production is taken to be zero. This is also evidenced by the negative correlation of nitrate with dissolved oxygen and temperature, for the bottom samples.     

FORMS OF NITROGEN (NO 3 - -N; NO 2 - -N AND NH 2 CONH 2 -N) AND THEIR RELATIONS TO A.O.U. IN THE INDIAN COASTAL WATERS OF ARABIAN SEA

The distribution of three important dissolved forms of nitrogen, viz. nitrate, nitrite and urea in the surface and bottom water samples collected from 27 selected hydrographic profiles, in the Arabian Sea, along the west coast of India is described. Of the three forms, nitrate concentrations were the highest and comparatively higher concentrations were observed in the bottom water. Decomposition of organic matter resulting in the release of the thermodynamically stable nitrogen species, i.e. nitrate, may be the major factor resulting in higher nitrate concentrations at these depths, where the water is also characterized by low values of dissolved oxygen and temperature. The significant positive correlation between A.O.U. and nitrate of the bottom water samples emphasizes the role of oxidative decomposition of organic matter which plays an active role in reducing the oxygen concentrations below the theoretical values since at this depth ( ≈200 m) the net production is taken to be zero. This is also evidenced by the negative correlation of nitrate with dissolved oxygen and temperature, for the bottom samples.     

The Influence of Trace Elements on Environment; Distribution of Thallium in Fluids of Volcanic Areas

During weathering of igneous rocks thallium can be readily mobilized as TI⁺ in aqueous phase and picked up by plants. In this way it can reach the alimentary cycle of both livestock and humans. Since the toxicity of thallium is well-established, an analytical procedure for its determination is optimized in order to contribute to the knowledge of TI⁺ distribution in specific environments. The analytical method is applied to fluid phase samples from Vulcano island (Italy) and from other volcanic areas.     

Water quality in the Red Sea coastal waters (Egypt): Analysis of spatial and temporal variability

In order to provide a background picture of the water quality of the Egyptian Red Sea a number of hydrological and chemical parameters have been measured bimonthly in 2000. Few data are available on this area, which is apparently subjected to an increasing human impact due to recreational (swimming and diving), industrial (mainly phosphate shipping and industry) and fishing/harbor activities. The results of the present study indicate that changes in the salinity and pH were not significant with highly oxygenated seawaters. The levels of suspended solids (as total suspended matter, TSM) and chlorophyll-a (Chl-a) were generally low and showed an homogeneous distribution in the study region. The ratio of chlorophyll-a to total suspended matter concentrations increased between November and March and decreased from May to September. Chlorophyll-a was significantly correlated with transparency and total suspended matter concentrations in July, September and November. Nitrogen, phosphorus and reactive silicate concentrations were generally low, and allowed classifying the Egyptian Red Sea coastal water as oligotrophic to mesotrophic. The middle region of the study area, which was located between Safaga and Qusair displayed relatively high phosphate contents when compared with other coastal areas. The high values of N:P ratios indicate that PO 4 -P is the limiting factor for phytoplankton growth in the Red Sea coastal waters, with the possible exception of the middle region. Significant relationships were found between chlorophyll-a concentrations and nutrient levels in different sampling periods. Spatial distribution patterns of the studied variables revealed that productivity of the Red Sea coastal waters is mostly controlled by phosphate concentrations, salinity, temperature and dissolved oxygen.     

Mercury Pollution in the Surface Environment of a Volcanic Area

The mercury content has been determined in samples of fumarolic gases, phreatic waters, soil and vegetation collected at Vulcano, Aeolian Islands, Italy. Volcanic activity is demonstrated as a source of natural mercury pollution whose extent has been evaluated here by studying the contribution of different components of the surface environment. The possible influences for living organisms are examined.     

厦门海域春夏季微型浮游动物对浮游植物的摄食压力初探

应用稀释法对厦门海域浮游植物生长率(k)和微型浮游动物的摄食率(g)进行了估算。结果显示：5月,西海域18测站k、g分别为2．41、0．78d^-1;南部海域27测站分别为2．43、1．32d^-1。8月18测站k、g分别为3．00、2．90d^-1;27测站分别为1．94、0．91d^-1。说明厦门海域作为典型的亚热带港湾,具有高的k、g值。分粒级研究结果显示：8月,18测站微型浮游动物对微型浮游植物(Micro)具摄食偏好;而27测站微型浮游动物对Micro和Nano级的摄食率相近。应用流式细胞技术研究18测站微微型真核浮游植物的k、g,结果表明：春季,生长率和摄食率分别为2．00、1．02d^-1;夏季分别为1．52、0．96d^-1。     

Contribution of Nitrogen Species to the Surface Aquifers of Volcanic Areas: The Island of Vulcano (Italy)

Ammonium and nitrate concentrations have been investigated in water samples from the wells in the island of Vulcano, (Italy). Systematic observations, extended over a period of five years, have verified different trends in the changing concentrations of both species. Nitrate ion is considered as contributed to the unconfined upper ground aquifer by the surface environment, while for ammonium ion a deep origin appears more likely. Significant changes in the activity of the volcanic system appear to affect the distribution of ammonium only, while nitrate levels do not display any important variation.     

"南海贻贝观察":广东沿海牡蛎体中Zn含量水平及其变化趋势

为了了解广东沿海重要养殖水域Zn含量水平变化趋势,1989～1997年间实施"南海贻贝观察"计划对广东12个地点牡蛎体的Zn含量进行了连续监测.广东沿海牡蛎体Zn含量范围为50.4×10-6～768×10-6,总平均值为245×10-6,总体上属清洁～微污染水平.牡蛎体Zn含量的海域分布格局呈珠江口海区＞粤东海区≥粤西海区.1989～1991年,广东沿海牡蛎体Zn含量呈上升趋势,此后略微下降,1994～1997年间牡蛎体Zn含量虽有波动,但年际间没有明显差异.