Streams freshwater studies

HUGHES J M (2007) Constraints on recovery nsing molecnlar methods to study connectivity of aquatic biota in rivers and streams. Freshwater Biology, 52,616-631. 

The operating costs entail raw material costs and effluent treatment costs. Only scenarios 1 and 3, i.e. fixed outlet concentration with and without reusable water storage, are considered. The additional information provided for the case study pertains to the mass ratios between raw material streams and freshwater. In process 1, 1 kg of water (aqueous phase) is required to wash 3 kg of raw material stream (organic phase) to the desired specification. In process 2, 1 kg of water is required for every 2 kg of raw material stream. These requirements are dictated by mass transfer. 

Freshwater macroinvertebrates were comparatively sensitive to diazinon (Table 16.7). Results of large-scale experimental stream studies (Arthur et al. 1983) showed that dose levels of 0.3 pg diazinon/L caused a five- to eightfold reduction in emergence of mayflies and caddisflies within 3 weeks. After 12 weeks, mayflies, damselflies, caddisflies, and amphipods were absent from benthic samples. Elevated (and catastrophic) drift of stream invertebrates was also documented in diazinon-treated streams, especially for amphipods, leeches, and snails (Arthur et al. 1983). Shortterm tests of 5-h duration with rotifers (Brachionus calyciflorus) show a 50% reduction in feeding... 

In a study involving several contaminated freshwater streams in New Jersey Pinelands, Ross and Sherrell [8] have used CFF, with a 10 kDa (ca. 3 nm) cutoff, to separate the filtrate (<0.45 pm) into colloidal and truly dissolved fractions in freshwater systems. The colloidal fraction,/cou, was calculated by difference ... 

The study of Alpine aquatic environments began in the early 19th century, but only since the early 1990s has scientific interest intensified on these freshwater habitats. Most of these studies have been conducted in the Southern Alps, Swiss Alps and Central Austrian Alps, and included lakes, springs and streams above 2,000 m asl. 

In 1947, Patrick established a new department of limnology (the study of lakes, ponds, and streams) at the academy, a department that is now known as the Patrick Center for Environmental Research. The purpose of the department has been to study the structure and function of freshwater ecosystems, including rivers, lakes, and wetlands, along with the impact of human activities on these systems. Patrick served as curator of the center and chair of the Department of Limnology at the academy for more than decades. In 2003, at the age of 94, she still held the titles of Senior Scientist and Francis Boyer Chair of Limnology at the academy. 

Much of the unintentional release will be into wastewater or waste stream and therefore wastewater treatment plants, waste incineration plants, and landfills will be important sources for ENM release into water and air. The removal of ENMs from wastewater has to date been only poorly studied [ 38], but it can be expected that at least part of the ENMs in wastewater will be discharged into freshwaters. Very little is known to date about the behavior of ENMs in waste incineration plants and leaching from landfills [39]. 

The body of flatworms (phylum Platyhehninthes) consists of two external cell layers (endoderm and ectoderm) with a third layer between. A distinct excretory system is present. In addition to a nerve net resembling that of the Cnidaria, there are a cerebral ganglion and distinct eyes. One large group of flat-worms, the planaiians (typically about 15 mm in length, Fig. 1-14), inhabit freshwater streams. They are said to be the simplest creatures in which behavior can be studied. 

Gypsum is a relatively inert by-product of wet process acid production. However, it may pose an environmental problem to wet process acid operations simply because some 5 to 7 tonnes are produced for each tonne of phosphoric acid (100% basis). Years ago, disposal by some facilities was simply into the nearest watercourse via a slurry pipeline. However, with the realization that even inactive suspended solids in freshwater streams can have severe smothering and siltation effects on both water quality and the diversity of stream life, this practice has been largely discontinued. Use of the gypsum for wallboard manufacture has been studied [54], and is used where supplies of natural gypsum are scarce, such as in the U.S. [55, 56]. Application of... 

Shown in Fig. 9.9 are water-composition ranges for some humid-climate streams (in New Jersey), a dilute, freshwater lake (Lake Huron) and lake-bottom muds from the Great Lakes (Sutherland 1970), and deep-soil moisture from Pennsylvania (Sears 1976 Sears and Langmuir 1982). Lake Huron and the Delaware River are dilute, humid-climate waters. They both plot near the kaolinite-gibbsite boundary. Their composition can be described as water dominated. In other words, their chemistries are controlled chiefly by dilution with fresh rainfall and runoff, not by reactions with geological materials. In a study of acid rain (water-dominated) control of soil moisture and ground-water chemistry of a sandy aquifer in Denmark, Hansen and Postma (1995) found that pore waters were close to equilibrium with gibbsite and supersaturated with kaolinite (Fig. 9.9). Precipitation pH = 4.34 at the site, and log([K+]/lH+]) = -0.95. 

Studies of the atmospheric input of chemicals to the open ocean have also been increasing lately. For many substances a relatively small fraction of the material delivered to estuaries and the coastal zone by rivers and streams makes its way through the near shore environment to open ocean regions. Most of this material is lost via flocculation and sedimentation to the sediments as it passes from the freshwater environment to open sea water. Since aerosol particles in the size range of a few micrometers or less have atmospheric residence times of one to several days, depending upon their size distribution and local precipitation patterns, and most substances of interest in the gas phase have similar or even longer atmospheric residence times, there is ample opportunity... 

Our studies indicated rapid photolysis of trichlorophenol, di-chlorophenol, and pentachlorophenol in both distilled and estuarine water. We can compare our results of pentachlorophenol with those of other investigators who have studied the photolysis of this compound in both fresh and marine waters O, 17-20). The photolysis rate constant kp for pentachlorophenol in a freshwater stream was 0.29 hr ( 1/2 2.4 hr) at 3.8 cm in the summer ( W), while we found a kp of 0.37 hr ( 1/2 " 2 hr, light hours) at a depth of 3.0 cm in the summer (Table I). The half-life of pentachlorophenol in a 1 m deep freshwater pond was 1.5 to 3 days (17) while in 5.5 m deep marine mesocosm the half-life was 22 days (18). Using lamps to simulate sunlight the pentachlorophenol in surface seawater was found to have a half-life of 2.4 hr. ( 5), Thus our rate constant and half-life for pentachlorophenol photolysis was similar to one determined by others in surface waters. Due to attenuation of light by substances in the water longer half-lives, i.e., days rather than hours, are found for pentachlorophenol when distributed throughout the water column. 

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