Standing Bodies of Water

Estuaries constitute another type of body of water, consisting of arms of the ocean into which streams flow. The mixing of fresh- and saltwater gives estuaries unique chemical and biological properties. Because they are the breeding grounds of much marine life, the preservation of estuaries is very important for the health of the biosphere. 

The chemistry and biology of Earth s vast oceans are unique because of their high salt content, their great depth, and other factors. Oceanographic chemistry is a discipline in its own right. The environmental problems of the oceans have increased greatly in recent years because of the release of pollutants to oceans, oil spills, and increased utilization of natural resources from oceans. 

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The dominant transport process from water is volatilization. Based on mathematical models developed by the EPA, the half-life for M-hexane in bodies of water with any degree of turbulent mixing (e.g., rivers) would be less than 3 hours. For standing bodies of water (e.g., small ponds), a half-life no longer than one week (6.8 days) is estimated (ASTER 1995 EPA 1987a). Based on the log octanol/water partition coefficient (i.e., log[Kow]) and the estimated log sorption coefficient (i.e., log[Koc]) (see Table 3-2), ii-hexane is not expected to become concentrated in biota (Swann et al. 1983). A calculated bioconcentration factor (BCF) of 453 for a fathead minnow (ASTER 1995) further suggests a low potential for -hcxanc to bioconcentrate or bioaccumulate in trophic food chains. 

A seiche in a body of water is a standing wave oscillation of the water surface with the natural frequency of oscillation for that water body. It is normally observed in completely enclosed water bodies such as lakes and inland seas. Thus, when a long wave traverses the water body it is reflected from the end and the interference with the original wave results in a standing wave pattern. However, if a body of water such as a bay or estuary is open at one end, reflection may still occur at the open end and produce standing waves. 

Evaporation and Evaporative Fractionation of Water. Evaporation from standing water bodies is the principal fractionation mechanism in most hydrological systems. Evaporative isotopic enrichment is a function of numerous factors (e.g., temperature, salinity, and relative humidity) that cause considerable variation in the lsO/ ieO and D/H ratios of natural surface waters. Craig and Gordon (22) evaluated isotopic effects on precipitation and evaporation in the ocean-atmosphere system. Much of what was developed in that work is directly applicable to the freshwater systems discussed here. 

Isotopic fractionation resulting from evaporation from standing water bodies can be described in terms of equilibrium and nonequilibrium fractionation effects. Equilibrium fractionation occurs when the isotopic composition of the evaporated water or lake evaporate is in thermodynamic equilibrium with the lake water (23). Equilibrium fractionation, however, can occur only when the water vapor in the air mass above the lake is 100% saturated. The process of equilibrium isotopic fractionation is described by Raleigh fractionation. The isotopic composition of water vapor in equilibrium with liquid water at any time is given by... 

Ecological conditions (affecting the life of a plant or animal) related to lakes and other bodies of fresh standing water or (more widely) all inland water. Volume 2(9). 

Its implementation is easy in small countries due to centralization of management and ease of surveillance of this new form of accreditation by a national accreditation body. Due to the long-standing establishment of validation of food microbiological methods in some countries, the beginning of validation of water microbiological methods, and establishment of European standards for the validation of food microbiological test methods (Microval project), the flexible-scope type of accreditation must be adapted to certain national requirements, but could prove less complex than the standard requirements. 

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