Heavy metal discharges into Shasta Lake and Keswick reservoirs on the upper Sacramento River, California; a reconnaissance during low flow

Outmigration survival of acoustic-tagged, hatchery-origin, late-fall-run Chinook salmon (Oncorhynchus tshawytscha) smolts from the Sacramento River was estimated for 5 years (2007–2011) using a receiver array spanning the entire outmigration corridor, from the upper river, through the estuary, and into the coastal ocean. The first 4 years of releases occurred during below-average river flows, while the fifth year (2011) occurred during above-average flows. In 2011, overall outmigration survival was two to five times higher than survival in the other 4 years. Regional survival estimates indicate that most of the improved survival seen in 2011 occurred in the riverine reaches of the outmigration corridor, while survival in the brackish portions of the estuary did not significantly differ among the 5 years. For the 4 low-flow years combined, survival rate in the river was lower in the less anthropogenically modified upper reaches; however, across all regions, survival rate was lowest in the brackish portion of the estuary. Even in the high-flow year, outmigration survival was substantially lower than yearling Chinook salmon populations in other large rivers. Potential drivers of these patterns are discussed, including channelization, water flow, and predation. Finally, management strategies are suggested to best exploit survival advantages described in this study.

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A polymer – zeolite composite for mixed metal removal from aqueous solution

Water Science & Technology ◽

10.2166/wst.2021.057 ◽

2021 ◽

Author(s):

Merve Yıldız Yiğit ◽

Esra Sultan Baran ◽

Çiğdem Kıvılcımdan Moral

Keyword(s):

Heavy Metals ◽

Heavy Metal ◽

Metal Uptake ◽

Metal Removal ◽

Low Cost ◽

Heavy Metal Removal ◽

Heavy Metal Concentration ◽

Low Flow ◽

Zeolite Composite ◽

Multiple Heavy Metals

Abstract Heavy metals become inevitable pollutants that are toxic to life. Lots of treatment methods are available; adsorption is a cheap option. Metals are mostly found as mixtures in wastewaters. Taking this into account, a natural composite adsorbent aims to remove multiple heavy metals (Pb2+, Cu2+, Cd2+). Alginate was combined with clinoptilolite to form alginate – clinoptilolite (A–C) beads. First, factors influencing the removal efficiency of metals were investigated. Then, continuous column experiments were performed to evaluate the real application potential of the adsorbent. A–C beads preferably adsorbed Pb2+. Batch experiments showed metal uptake reached equilibrium after 24 hours and kinetics were compatible with the first-order. Also, pH values near neutral levels were observed to increase heavy metal removal. On the other hand, adsorption equilibrium was well described by the Langmuir model for Cu2+ and Cd2+ and by the Freundlich model for Pb2+. The highest heavy metal uptake was calculated as 2,145 mg /g A–C beads for Pb2+. Continuous column operations were suggested to apply low flow rates (<2 mL/min) and heavy metal concentration (<10 mg/L) for effectiveness. A–C beads can be a good candidate for mixed heavy metal removal composed of environmentally friendly and low-cost materials.

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Impacts of Low Flows on Heavy Metal concentrations in Turag River Bangladesh

Journal of Environmental Science and Natural Resources ◽

10.3329/jesnr.v10i2.39032 ◽

2018 ◽

Vol 10 (2) ◽

pp. 177-182

Author(s):

MA Rahman ◽

SH Rahman ◽

MAZ Chowdhury ◽

Z Fardous

Keyword(s):

Heavy Metals ◽

Heavy Metal ◽

Health Status ◽

Natural Resources ◽

Water Flow ◽

Low Flow ◽

Contamination Level ◽

Ecological Health ◽

Heavy Metal Concentrations ◽

Standard Limit

Water flow is a vital requirement of a river to secure ecological health status. We investigated the low flow of Turag River and its effect on the heavy metals concentration. Generally, the water of the river flowed very less from January to May. The reverse result was found from June to October. Keeping in mind this fact, eight different heavy metals were statistically analyzed. We observed that during low flow season five heavy metals surpass the standard limit for irrigation. Considering irrigation standard, the order of contamination level was: Mn > Cd > Pb > Fe > Cr > Ni > Zn > Cu in low flow season. Therefore, it is necessary to maintain moderate flow in the river system.J. Environ. Sci. & Natural Resources, 10(2): 177-182 2017

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Risk assessment of heavy metal pollution in water, sediment and plants in the Nile River in the Cairo region, Egypt

Oceanological and Hydrobiological Studies ◽

10.1515/ohs-2020-0001 ◽

2020 ◽

Vol 49 (1) ◽

pp. 1-12 ◽

Cited By ~ 2

Author(s):

Afify D.G. Al-Afify ◽

Amaal M Abdel-Satar

Keyword(s):

Risk Assessment ◽

Heavy Metal ◽

Ecological Risk ◽

Metal Pollution ◽

Heavy Metal Pollution ◽

Eichhornia Crassipes ◽

Anthropogenic Sources ◽

Low Flow ◽

Ceratophyllum Demersum ◽

Nile River

AbstractSamples of water, sediment and two native plants (Eichhornia crassipes and Ceratophyllum demersum), collected seasonally from eight sites, were analyzed to investigate the level of contamination with metals (Fe, Mn, Ni, Co, Zn, Cu, Cr, Pb and Cd) in the Nile River in the Cairo region, using heavy metal pollution and contamination indices in the case of water, and the geoaccumulation index, the pollution load index, the enrichment factor and the potential ecological risk factor in the case of sediment. The results clarified that the levels of metals among three compartments were in order: sediments > plants > water. The Nile water in Cairo is not critically polluted by the studied metals and the metal pollution index for most sites does not exceed the critical limit (< 100). Sediment samples showed a clear accumulation of Mn, Ni and Cd when compared with benchmarks cited by the Environmental Protection Agency (EPA), especially during low flow seasons. The contribution of Cd to the ecological risk assessment was about 80%, while the contribution of Ni was about 10%, reflecting that these elements originated primarily from anthropogenic sources. Eichhornia crassipes and Ceratophyllum demersum have a higher accumulation capacity for Mn, Cu and Fe compared to the other studied metals.

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Complementary Z-Contrast Imaging and Digital Image Processing

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100118394 ◽

1985 ◽

Vol 43 ◽

pp. 304-305

Author(s):

K. N. Colonna ◽

G. Oliphant

Keyword(s):

Image Processing ◽

Heavy Metal ◽

Digital Image Processing ◽

Digital Image ◽

Biological Tissue ◽

Biological Imaging ◽

Tissue Preparation ◽

Contrast Imaging ◽

Imaging Tool ◽

Z Contrast

Harmonious use of Z-contrast imaging and digital image processing as an analytical imaging tool was developed and demonstrated in studying the elemental constitution of human and maturing rabbit spermatozoa. Due to its analog origin (Fig. 1), the Z-contrast image offers information unique to the science of biological imaging. Despite the information and distinct advantages it offers, the potential of Z-contrast imaging is extremely limited without the application of techniques of digital image processing. For the first time in biological imaging, this study demonstrates the tremendous potential involved in the complementary use of Z-contrast imaging and digital image processing.Imaging in the Z-contrast mode is powerful for three distinct reasons, the first of which involves tissue preparation. It affords biologists the opportunity to visualize biological tissue without the use of heavy metal fixatives and stains. For years biologists have used heavy metal components to compensate for the limited electron scattering properties of biological tissue.

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Recent Progress In High-Resolution Shadowing For Biological Transmission Electron Microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100181300 ◽

1990 ◽

Vol 48 (1) ◽

pp. 510-511 ◽

Cited By ~ 1

Author(s):

Heinz Gross ◽

Katarina Krusche ◽

Peter Tittmann

Keyword(s):

Heavy Metal ◽

High Resolution ◽

Freeze Drying ◽

Atmospheric Conditions ◽

Vacuum Equipment ◽

Transmission Electron ◽

Gas Atmosphere ◽

Gas Molecules ◽

Residual Gas ◽

Backing Layer

Freeze-drying followed by heavy metal shadowing is a long established and straight forward approach to routinely study the structure of dehydrated macromolecules. Very thin specimens such as isolated membranes or single macromolecules are directly adsorbed on C-coated grids. After rapid freezing the grids are transferred into a suitable vacuum equipment for freeze-drying and heavy metal shadowing.To improve the resolution power of shadowing films we introduced shadowing at very low specimen temperature (−250°C). To routinely do that without the danger of contamination we developed in collaboration with Balzers an UHV (p≤10-9 mbar) machine (BAF500K, Fig.2). It should be mentioned here that at −250°C the specimen surface acts as effective cryopump for practically all impinging residual gas molecules from the residual gas atmosphere.Common high resolution shadowing films (Pt/C, Ta/W) have to be protected from alterations due to air contact by a relatively thick C-backing layer, when transferred via atmospheric conditions into the TEM. Such an additional C-coat contributes disturbingly to the contrast at high resolution.

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