Streams eutrophication

Hynes HBN (1969) The enrichment of streams. Eutrophication causes, consequences, correctives. National Academy of Sciences, Washington, DC, USA, pp 188-196... 

Oxidation half-lives predicted by one compartment model t,/2 = 38 h in stream, eutrophic pond or lake and oligotrophic lake based on peroxy radical concentration of 10-9 M (Smith et al. 1978) aquatic fate rate k = 5 x 103 M-1 s-1 with t,/2 = 38 h (Callahan et al. 1979) ... 

Surface water half-life for all processes, except for dilution t,/2 = 0.5 h in stream, eutrophic lake and pond and t,/2 = 600 h in oligotrophic lake, based on transformation and transport of quinoline predicted by the one-compartment model (Smith et al. 1978) ... 

Note that the maintenance of water quaUty and hence stream standards are not static, but subject to change with the municipal and industrial environment. For example, as the carbonaceous organic load is removed by treatment, the detrimental effect of nitrification in the receiving water increases. Eutrophication may also become a serious problem in some cases. These considerations require an upgrading of the required degree of treatment. 

Water pollution Deposited material or percolate escapes either by surface run-off or by underground movement, threatening streams, rivers, aquifers or the sea Direct poisoning or eutrophication... 

Gucker B, Pusch M (2006) Regulation of nutrient uptake in eutrophic lowland streams. Limnol Oceanogr 51 1443-1453... 

The Ebro watershed has a large surface area (85,000 km2) and a complex drainage network (a total of 347 streams). The Ebro is a relatively well known river from the point of view of the biological communities composition. Studies exist on the aquatic fauna and flora [3]. However, the functional activity of the river is largely unknown, mostly because of its complexity and associated technical difficulties. This chapter provides a state-of-the art of the who is who in the biological communities in the river, as well as considerations about the threats imposed by habitat deterioration, eutrophication, pollution and species invasions, and indicates the current gaps that still exist in the knowledge of the river. 

It is also necessary to treat noncarbon-based pollutants. We mentioned nitrogen and phosphorus as possible targets for biological remediation. Nitrogen is present in wastewater streams as ammonia. Conventional methods convert the ammonia to nitrate. Under normal circumstances, the conversion is sufficient. However, excessive amounts of nitrates contribute to the eutrophication of lakes and ponds. In these cases, a second class of organism is used to convert the nitrates to nitrogen gas. 

Estimates of denitrification rates range from 54 to 345 xmol/m2 per hour in streams with high rates of organic matter deposition, 12 to 56 xmol/m2 per hour in nutrient-poor oligotrophic lakes, and 42 to 171 xmol/m2 per hour in eutrophic lakes (62). Rudd et al. (64) reported an increase in the rate of denitrification from less than 0.1 to over 20 xmol/m2 per hour in an oligotrophic lake when nitric acid was added in a whole-lake experimental acidification. This result suggests that freshwater denitrification may be limited by N03" availability. In deep muds of slow-flowing streams, the process can effectively reduce N03" concentrations in... 

Eutrophication. Thus far N has been discussed in terms of its prominence as an acidic anion (i.e., as N03 ). As in terrestrial ecosystems, inorganic forms of N also act as nutrients in aquatic systems, and a possible consequence of chronic N loss from watersheds is the fertilization of lakes and streams. Establishing a link between N deposition and the eutrophication of aquatic systems depends on a determination that the productivity of the system is limited by N availability and that N deposition is a major source of N to the system. In many cases the supply of N from deposition is minor when compared to other anthropogenic sources, such as pollution from either point or nonpoint sources. 

Cyanobacterial (Blue-Green Bacteria) Toxins. Cyanobacterial poisonings were first recognized in the late 1800s. Human poisonings are rare however, kills of livestock, other mammals, birds, fish, and aquatic invertebrates are common. It is caused by a variety of biotoxins and cytotoxins, including anatoxin, microcystin, and nodularin produced by several species of cyanobacteria, including Anabaena, Aphanizomenon, Nodularia, Oscillatoria, and Microcystis. The main contamination problems include all eutrophic freshwater rivers, lakes, and streams. 

A builder is a compound that removes calcium and magnesium ions normally present in water, and, as a result, reduces the concentration of surfactants required to carry out the detergent action. Currently, the builder mainly used in practice is sodium tripolyphosphate. However, phosphates are plant nutrients and provoke eutrophication in lakes and streams which receive municipal wastewater contaminated with detergent residuals. Consequently, the use of phosphates in detergents has been restricted. 

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