Rivers, toxic substances

Keywords Biota, FR Yugoslavia, The Danube River, Toxic substances. War destruction... 

Monsanto. 1978. TSCA sect. 8(d) submission 40-7859047. A study of variables effecting the river die-away test. Special study 1978. Washington, D.C. Office of Toxic Substances, U.S. Environmental Protection Agency. EPA Doc Control No. OTS 84003A... 

The WFD, so far, has identified 33 priority hazardous pollutants (PHS), for which Environmental Quality Standards (EQS) have been set. To some extent, these EQS can be met through the establishment of emission control measures. These PHS may originate from several different sources and activities. The main sources of toxic substances to water bodies in Europe may be categorised as agriculture, sewage treatment plants, urban runoff, industry, contaminated lake/ river sediment, soils and landfills. Input via atmospheric transport and deposition has also been identified as an important source both far from and close to source areas. Many of the PS are today banned in Europe, but due to their persistence they are still present in the environment [30]. 

Hellawell JM. 1988. Toxic substances in rivers and streams. Environmental Pollution 50 61-85. 

The identification and quantitation of potentially toxic substances in the environment requires the application of sophisticated analytical techniques. Ideally, these should exactly identify each of several hundred compounds present in very complex mixtures even though each species may have an environmental concentration of less than a part per billion. The most generally useful and widely employed analytical tool which meets these requirements is gas chromatography mass spectrometry (GCMS). In this paper, we will briefly review sample isolation methods which are used with GCMS and present two case studies on the organic compounds in industrial wastewaters and river systems which demonstrate these and other principles. 

The above equation describes how the concentration of the toxic substance in river water varies as a function of time and distance x from the spill. The solution is simple and a spreadsheet program can carry out the calculations. Figure 3-27 shows the pollutant distribution in the river as a function of distance downstream after some specific times. The diagram indicates where the toxic substance has moved to at a specific time. 

Suppose there was a major spill of 600 kg of a toxic chemical (that can dissolve In water) in a river that is 20 m wide and 3 m deep. The local government of a city 180 km downstream from the spill site asks you to evaluate the water quality (whether it can be piped into the city water supply) in the river next to the city as a function of time. Suppose water flow rate is 2 m/s and width and depth of water of the river are constant. Assume an eddy diffusivity of 10 m /s. You find from ERA guidelines that the maximum tolerable concentration of the toxic substance for drinking water is 0.01 ppb. 

To reduce the inflow of toxic substances into basin waters efficiently, the Corporation required information on which effluents posed the greatest hazard to the river. While chemical data on many of the effluents were available, their diverse composition was difficult to interpret in terms of hazard potential. Moreover, hazard is not only linked to chemical composition of an effluent, but also on the toxic effects it can have on a variety of freshwater organisms. Adverse effects on biota are also influenced by the volume of wastewater discharged at different times of the year. Hence, the Corporation searched for a cost-effective approach, based on ecotoxicological principles, to rank the various effluents (there are several hundred sources), in terms of their toxic loading, so that subsequent efforts (such as clean up actions) could be prioritized. 

The Niagara River has been a focus since 1987 as a major source of environmental contaminants. Both the U.S. and Canadian environmental agencies have made rigorous efforts to reduce pollution of toxic substances. Further, the EPA and New York State Department of Environmental Conservation identified 26 U.S. hazardous sites. The Niagara River Toxic Management Plan (NRTMP) has named several toxic chemicals, 10 of which are considered of major concern (Table 1-1). 

The importance of waste reduction through the use of a chemical catalyst can be exemplified by the use of yV-methylimidazole as a catalyst in the leaching step of gold extraction from ores in the mining industry. Cyanide, a toxic substance that poses a major health threat, has traditionally been used for these processes. A sample case is the 1999 leak in a Rumanian facility from a cyanide storage tank into the Rhine River that killed thousands of fish. 

Kralingen, Netherlands [83] Surface water Meuse River Coagulation Sedimentation Ozonation Dual layer filtration Carbon filtration Safety chlorination Protection against periodic taste/odor and toxic substances Removal of THM s produced by chlorination Removal of matter produced by or unsuccessfully removed by ozonation Particle size 0.8 mm Bed deptli 4 m Bed diameter 6 m Volume per filter 116 m" Contact time 12 min. 

One common example of qualitative analysis is the examination of the conditions of a particular environment. Farmers, for example, may have soil samples examined for mineral content to determine any necessary steps for producing a better crop yield. Qualitative analysis is also employed in detecting the presence of pollutants in rivers or other bodies of water, or in the land or air. Those who use water from wells may periodically have those wells tested for toxic substances such as lead. Again, although most people only see the results of the analysis as a positive or negative finding for some chemical or element, the rigorously developed procedures of qualitative analysis have still been applied. 

Macroinvertebrates have been used as indicators for the quality of rivers for many decades in Europe and elsewhere (Mancini, 2006). Historically, the emphasis of macroinvetebrate assessment methods has been on the effects of organic pollution, but it is clear that this quality element can also be used effectively for detecting the effects of other pressures, including hydromorphological alterations, acidification and perhaps also toxic substances. The history, principal approaches and available methods for river monitoring and assessment based on macroinvertebrates in the context of the WFD were recently reviewed extensively by De Pauw et al. (2006), and will not be further discussed here. 

The focal areas of this book have relatively minor relationships to the primary formation of the Earth s crust which has caused a certain distribution of the chemical elements. They mainly deal with products of the alteration of the crust in geologic processes. We can presently still observe the weathering of solid rocks, the erosion of mountain ridges, and the transport of eroded materials as suspended and dissolved constituents in river and rain water, in ice and wind. In-situ weathering forms soils, and soils are the basis of food production for human nutrition. Therefore, soUs need special protection against the impact of toxic substances (see Part I, Chapters 4 and 5). 

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