Sediment disruption

Below the sediments disrupted by cultivation, a unit (Unit A) was found that was about 120 cm thick and that contained a disorderly mixture (almost an inverse time sequence) of Roman, Pharaonic, and Predynastic sherds. The next 15 cm or so was a clay-rich Nile silt (Unit B) in which there was a normal ceramic sequence with sherds dating from about 300 B.C. to about 2500 B.C. Table I describes the typical core sample. The layers of sediments were compacted and, in some cases, partially hardened by a calcareous cement, but in all cases, the samples could be easily crumbled. 

Sediment Disruption Due to Construction of Bunkers, Ground Fortification and... 

Gutleb, A.C., Schriks, M., and Mossink, L. et al. (2007). A synchronized amphibian metamorphosis assay as an improved tool to detect thyroid hormone disturbance by endocrine disrupters and apolar sediment extracts. Chemosphere 70, 93-100. 

Roach, A. and Harte, F. (2008). Disruption and sedimentation of casein micelles and casein micelle isolates under high-pressure homogenization. Innovative Food Sci. Emerg. Technol. 9,1-8. 

Unconsolidated or weakly consolidated sediments sometimes collapse around the well screen before the filter pack can be installed. This phenomenon is called formation collapse . Formation collapse can occur as a result of the inherently unstable nature of certain sediments or the disruptive nature of the drilling process. Formation collapse is most common below the water table. Although steps can be taken to minimize the amount of collapse, it may not be entirely preventable. The groundwater monitoring plan may need to accept natural formation material as the filter pack for some or all of the screen section. Well development activities (see Section 2.1.6) can be designed to maximize the effectiveness of the formation collapse materials as a filter pack. 

Ecologically, copper is a trace element essential to many plants and animals. However, high levels of copper in soil can be directly toxic to certain soil microorganisms and can disrupt important microbial processes in soil, such as nitrogen and phosphorus cycling. Copper is typically found in the environment as a solid metal in soils and soil sediment in surface water. There is no evidence that biotransformation processes have a significant bearing on the fate and transport of copper in water. 

Heavy metals and to some extent their derivatives are among the indestructible pollutants that are neither subject to bacterial attack nor other breakdown or degradation processes and are thus permanent additions to the environment.12 14 Accordingly, their concentrations most often exceed the permissible levels normally found in the environment soil, water ways, and sediments, ending up in the food chains. Following these events, heavy metals and/or their derivatives accumulate in the plant and animal life where they profoundly disrupt biological processes, causing various... 

Bioturbation Disruption of sediment layers by activity of living organisms... 

The sustainable management of sediments, in addition to water, soil and sludge environmental matrices, in relation to surfactant regulations, is also an important and relevant issue. The US EPA has recently shown concern regarding the levels of surfactants in sediments and has thus released a Draft Contaminated Sediment Science Plan. In this draft, recommendations for the development of analytical methods and evaluations of the toxicity and risk assessment of Emerging endocrine disrupters like APEOs and their metabolites in sediment samples are outlined. 

A Discharge regime A Flow pattern ATurbidity/sediment transport A Temperature regime + Longitudinal disruption + Lateral disruption + Vertical disruption Destruction of ecotones A Instream structures A Habitat features + Habitat fragmentation... 

Sedimentation and siltation can have a number of harmful effects on the environment. For example, as sediments accumulate in a river, stream, harbor, hay, or other body of water, they may disrupt transportation on the water and limit its use for swimming, hshing, boating, and other recreational activities. In some bodies of water, dredging has become a virtually nonstop operation in order to keep them open to shipping and other commercial and recreational operations. The U.S. Army Corps of Engineers alone dredges more than 78 million cubic yards (60 million cubic meters) of sediment each year at an annual cost of nearly 200 million. 

---