نتایج جستجو برای: sediment threshold

تعداد نتایج: 158501  

Journal: :The Science of the total environment 2014
Ryan L Perroy Colin S Belby Cody J Mertens

Legacy lead (Pb) contamination from sport shooting activities is a well-known hazard. Assessing the risk this contamination presents to the environment and public health requires a detailed understanding of its spatial distribution, yet our knowledge in this area is limited, especially for wetland shooting ranges. In this study, we analyzed 1351 sediment samples from 456 surficial (0-5 cm) loca...

Journal: :Environmental toxicology and chemistry 2002
Young-Cheol Cho Roger C Sokol G-Yull Rhee

The kinetics of polychlorinated biphenyl (PCB) dechlorination by Hudson River (New York, USA) sediment microorganisms were investigated using Aroclor 1242 at 10 concentrations ranging from 0 to 900 ppm (0-11.2 micromol Cl/g sediment). The time course of PCB dechlorination and population growth were determined by congener-specific analysis and the most-probable-number technique, respectively, ov...

2010
JACK LEWIS

Automated data collection is essential to effectively measure suspended sediment loads in storm events, particularly in small basins. Continuous turbidity measurements can be used, along with discharge, in an automated system that makes real-time sampling decisions to facilitate sedi­ ment load estimation. The Turbidity Threshold Sampling method distributes sample collection over the range of r...

Journal: :Journal of hazardous materials 2010
John E Weinstein Kevin D Crawford Thomas R Garner Alan J Flemming

Screening-level ecological and human health assessments were performed for polycyclic aromatic hydrocarbon (PAH) contamination in the sediments of 19 stormwater detention ponds located in coastal South Carolina. For ecological screening benchmarks, we used threshold and probable effect concentrations (TEC and PEC) derived from consensus-based sediment quality guidelines for individual PAH analy...

2015
A. N. Papanicolaou

The objective of the present research is to explore the causes of microventing, a phenomenon generally occurring in cohesive sediments during their deposition and consolidation. Microvents are characterized by volcano-like formations, remnants of the expulsion of fluid and sediment along a vertical channel through the sediment layer. The size of these vent formations ranges from the order of mi...

2013
LINDA H. KALNEJAIS RICHARD P. SIGNELL

The release of particulate-phase trace metals due to sediment resuspension has been investigated by combining erosion chamber experiments that apply a range of shear stresses typically encountered in coastal environments with a shear stress record simulated by a hydrodynamic model. Two sites with contrasting sediment chemistry were investigated. Sediment particles enriched in silver, copper, an...

2014
Nicholas P. Webb Gregory S. Okin Shannon Brown

Representation of surface roughness effects on aeolian sediment transport is a key source of uncertainty in wind erosion models. Drag partitioning schemes are used to account for roughness by scaling the soil entrainment threshold by the ratio of shear stress on roughness elements to that on the vegetated land surface. This approach does not explicitly account for the effects of roughness confi...

Journal: :Journal of environmental quality 2011
Richard A Wildman Lincoln F Pratson Michael DeLeon Janet G Hering

Lake Powell is a large reservoir in Utah and Arizona that has experienced large changes in water level during a recent drought. As a first step in assessing the connection between hydrologic and chemical changes at Lake Powell, we characterized the particle size and solid-phase bulk concentrations for 31 elements and 25 minerals in sediment from the inflow region and some shoreline locations by...

Journal: :Chemosphere 2007
A R R Péry V Ducrot A Geffard J Garric

Sediment characteristics are well known to interfere with toxicity, mainly through differences in terms of bioaccumulation. Here, with chironomids exposed to zinc in an artificial and a field sediment, we investigated the differences of zinc accumulation and of effects on the life cycle, at individual and population level. We used biology and energy-based modeling to analyze the data at all the...

2005
J. L. FLORSHEIM J. F. MOUNT C. R. CONSTANTINE

The state of the science of lowland river floodplain restoration reflects the relatively new and experimental nature of large river floodplain rehabilitation efforts. Based on results of a case study of floodplain restoration at the lowland Cosumnes River, California, we present a geomorphic monitoring and adaptive assessment framework that addresses the need to inform and utilize scientific kn...

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