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Full-Text Articles in Physical Sciences and Mathematics

Medium-Term Impacts Of Grassland And Forestry Integration On The Environmental Performance Of A New Zealand Pastoral System, Michael B. Dodd, A. O. Hughes, Grant M. Rennie Feb 2024

Medium-Term Impacts Of Grassland And Forestry Integration On The Environmental Performance Of A New Zealand Pastoral System, Michael B. Dodd, A. O. Hughes, Grant M. Rennie

IGC Proceedings (1997-2023)

At the IGC in 2008, we presented a paper outlining a project that aimed to improve the economic and environmental performance of a New Zealand hill country pastoral catchment farm system. This project was undertaken by engaging a wide group of sector stakeholders in visioning, modelling, planning and implementing significant land use change within a 296-hectare pastoral farm. In recognition of developing sectoral views of agricultural sustainability, the major changes involved pine afforestation, livestock production intensification, protection of waterways and indigenous bush restoration. The report in 2008 outlined the positive impacts on key farm systems and water quality performance indicators …


Implementation, Participation And Evaluation Of A Voluntary Water Quality Protection Program For Grazingland Owners And Managers, Mel R. George, J. M. Harper, S. R. Larson, R. E. Larsen, N. K. Mcdougald, D. J. Lewis Aug 2023

Implementation, Participation And Evaluation Of A Voluntary Water Quality Protection Program For Grazingland Owners And Managers, Mel R. George, J. M. Harper, S. R. Larson, R. E. Larsen, N. K. Mcdougald, D. J. Lewis

IGC Proceedings (1997-2023)

In 1990, California's range livestock industry began working with the state's water quality regulatory agency to develop a voluntary producer participation programme to protect water quality on privately owned grazinglands. In 1995 they implemented a voluntary programme of surface water protection supported by extension education and technical assistance conducted by University of California and USDA Natural Resources Conservation Service. Past studies have shown that education programmes are crucial to voluntary pollution control programmes in agriculture (EPA 1990) and that ranchers will change grazing management practices in response to extension education programmes (Richards and George 1996). The objective of this project …


Effect Of Long-Term Nutrient Management Strategies For Pastures On Phosphorus In Surface Runoff And Soil Quality, G. L. Mullins, J. P. Fontenot, G. A. Alloush, G. Johnson, D. G. Boyer, V. G. Allen, G. Scaglia Aug 2023

Effect Of Long-Term Nutrient Management Strategies For Pastures On Phosphorus In Surface Runoff And Soil Quality, G. L. Mullins, J. P. Fontenot, G. A. Alloush, G. Johnson, D. G. Boyer, V. G. Allen, G. Scaglia

IGC Proceedings (1997-2023)

Manure, whether mechanically applied or deposited by grazing animals, has been associated with increased risk of non-point source pollution, especially phosphorus. This is especially true in areas where the industry, especially poultry, has been concentrated in geographical areas that are grain deficient, resulting in a reliance on imported grain for poultry feed. Intensification has resulted in the production of large quantities of poultry manure, within relatively small geographical areas. Surplus litter is typically land applied as a nutrient source or used as an animal feed. The objective of this project was to evaluate the effects of long-term nutrient management strategies …


Riparian Management In Intensive Grazing Systems For Improved Biodiversity And Environmental Quality: Productive Grazing, Healthy Rivers, S. R. Aarons, M. Jones-Lennon, P. Papas, N. Ainsworth, F. Ede, J. Davies Jun 2023

Riparian Management In Intensive Grazing Systems For Improved Biodiversity And Environmental Quality: Productive Grazing, Healthy Rivers, S. R. Aarons, M. Jones-Lennon, P. Papas, N. Ainsworth, F. Ede, J. Davies

IGC Proceedings (1997-2023)

Within high rainfall intensive grazing systems of southern Victoria, riparian zones are often degraded due to vegetation clearing, stock access and inappropriate farm management. Streams in these landscapes often have poor water quality and reduced biodiversity due to degraded terrestrial and aquatic ecosystems. Improved management of riparian zones depends on developing tools and practices for integration into productive grazing systems. This paper describes the approaches used and the tools developed in the 'Productive Grazing, Healthy Rivers: Improving riparian and in-stream biodiversity' project


Riparian Management In Intensive Grazing Systems For Improved Biodiversity And Environmental Quality: Productive Grazing, Healthy Rivers, S. R. Aarons, M. Jones-Lennon, P. Papas, N. Ainsworth, F. Ede, J. Davies Mar 2023

Riparian Management In Intensive Grazing Systems For Improved Biodiversity And Environmental Quality: Productive Grazing, Healthy Rivers, S. R. Aarons, M. Jones-Lennon, P. Papas, N. Ainsworth, F. Ede, J. Davies

IGC Proceedings (1997-2023)

Within high rainfall intensive grazing systems of southern Victoria, riparian zones are often degraded due to vegetation clearing, stock access and inappropriate farm management. Streams in these landscapes often have poor water quality and reduced biodiversity due to degraded terrestrial and aquatic ecosystems. Improved management of riparian zones depends on developing tools and practices for integration into productive grazing systems. This paper describes the approaches used and the tools developed in the ‘Productive Grazing, Healthy Rivers: Improving riparian and in-stream biodiversity’ project.


Understanding Livestock Grazing Impacts: A Decision Support Tool To Develop Goal-Oriented Grazing Management Strategies, S. J. Barry, K. Guenther, G. Hayes, R. Larson, G. Nader, M. Doran Feb 2023

Understanding Livestock Grazing Impacts: A Decision Support Tool To Develop Goal-Oriented Grazing Management Strategies, S. J. Barry, K. Guenther, G. Hayes, R. Larson, G. Nader, M. Doran

IGC Proceedings (1997-2023)

Managing grasslands in the western United States has become much more complex over the last few decades. A century ago the goal was to survive as a livestock producer, and grassland management involved using forage effectively and overcoming obstacles such as predators and shortages of water and feed. Today the successful grassland manager also needs to consider the diversity and health of the ecosystem as a whole. Livestock grazing can negatively and/or positively affect riparian areas, sensitive plants, and endangered wildlife. Since the impact on a specific factor will vary depending on the timing, intensity and class of livestock grazed, …


Stakeholder Perceptions Of Microplastics Management In Oregon, Maya A. Hurst-Mayr May 2022

Stakeholder Perceptions Of Microplastics Management In Oregon, Maya A. Hurst-Mayr

Student Research Symposium

There is currently no federal policy in the United States that specifically addresses microplastics (MPs) pollution. However, states are beginning to act on this issue; California’s SB 1422 initiates measurement of MPs in drinking water resources and Senate Bill 1263 requires the state to adopt a strategy to reduce the ecological impact of MPs in marine ecosystems. Other West Coast states like Oregon and Washington are expected to follow California’s example. It is important to know what the actors who are a part of shaping MPs policy in Oregon would see as barriers and opportunities to doing so. We conducted …


Water Quality In Terms Of Metals During Flooding In Two Ecosystems Of The Conchos Watershed, Mexico: Rangeland‐Forest And Urban Areas, H. Rubio, J. Jiménez, K. Wood, M. Gutierrez Nov 2020

Water Quality In Terms Of Metals During Flooding In Two Ecosystems Of The Conchos Watershed, Mexico: Rangeland‐Forest And Urban Areas, H. Rubio, J. Jiménez, K. Wood, M. Gutierrez

IGC Proceedings (1997-2023)

No abstract provided.


Impacts Of Grazing Management On Cattle Distribution And Non‐Point Source Pollution From Pastures In The Central United States, M. Haan, J. Russell, D. Bear, D. Morrical Nov 2020

Impacts Of Grazing Management On Cattle Distribution And Non‐Point Source Pollution From Pastures In The Central United States, M. Haan, J. Russell, D. Bear, D. Morrical

IGC Proceedings (1997-2023)

No abstract provided.


Grassland And Water Resources: Recent Trends And Future Challenges In Temperate Zones, Benoît Marc Oct 2020

Grassland And Water Resources: Recent Trends And Future Challenges In Temperate Zones, Benoît Marc

IGC Proceedings (1997-2023)

No abstract provided.


The North Wyke Farm Platform: A New Uk National Capability For Research Into Sustainability Of Agricultural Temperate Grassland Management, Phil J. Murray, Bruce A. Griffith, Robert J. Orr, Martin S. A. Blackwell, Jane M. B. Hawkins, S. Peukert Apr 2020

The North Wyke Farm Platform: A New Uk National Capability For Research Into Sustainability Of Agricultural Temperate Grassland Management, Phil J. Murray, Bruce A. Griffith, Robert J. Orr, Martin S. A. Blackwell, Jane M. B. Hawkins, S. Peukert

IGC Proceedings (1997-2023)

The North Wyke Farm Platform is a new UK National Capability that will enable studies that can be closely monitored and controlled under different land-use options at the farm-scale. As a Biotechnology and Biological Sciences Research Council-funded National Capability, the Farm Platform provides centralised scientific facilities including core data (field and water chemistry, water flow rates, greenhouse gas emissions from soils, livestock and agronomic data, and farm management records). Access to the Farm Platform for experimental work or to data will be available to other research users and collaborators. This shared approach will enhance the depth and breadth of information …


Mediating Socio-Political Barriers To Water Quality Improvement In Surface Water On Grazed Wildlands, Tipton D. Hudson Apr 2020

Mediating Socio-Political Barriers To Water Quality Improvement In Surface Water On Grazed Wildlands, Tipton D. Hudson

IGC Proceedings (1997-2023)

Acute and growing social and legal conflict over regulation of non-point source pollution in Washington State has hampered proactive efforts to improve water quality in streams dominated by grazed watersheds. Livestock farmers caught in the conflict over water quality experience legal risk, reduced quality of life, and financial risk. Nonpoint source pollution is “pollution that is not released through pipes but rather originates from multiple sources over a relatively large area”. This diffuse pollution is notoriously difficult to regulate. Because causality is often not definable, coercing behavior is problematic, and most efforts to address nonpoint source (NPS) pollution rely on …


Rehabilitating Degraded Frontage Soils In Tropical North Queensland, Trevor J. Hall Feb 2020

Rehabilitating Degraded Frontage Soils In Tropical North Queensland, Trevor J. Hall

IGC Proceedings (1997-2023)

The extensive tropical grasslands of north Queensland are grazed by beef cattle and provide a significant proportion of the water flowing into the Great Barrier Reef (GBR) lagoon. Soil sediments and nutrients eroding from the grazing lands of the Burdekin and Fitzroy catchments in north-east Queensland contributes to reduced water quality in the GBR lagoon. Degraded and eroded D-condition bare areas and eroding gullies in grazing lands provide a disproportionate amount of soil and nutrient losses from predominately native pasture grasslands used for cattle grazing. Rehabilitating these degraded areas will help improve water quality flowing onto the reef.

Rehabilitation methods …


Short-Term Organic Carbon Release And Chlorine Disinfectant Decay For Cross-Linked Polyethylene (Pex) Plumbing Pipes, Miriam Tariq, Christian J. Ley, Maryam Salehi, Andrew J. Whelton Aug 2018

Short-Term Organic Carbon Release And Chlorine Disinfectant Decay For Cross-Linked Polyethylene (Pex) Plumbing Pipes, Miriam Tariq, Christian J. Ley, Maryam Salehi, Andrew J. Whelton

The Summer Undergraduate Research Fellowship (SURF) Symposium

The use of cross-linked polyethylene (PEX) plumbing pipes has grown in popularity for residential applications. However, PEX pipes can leach organic materials into water that can enable biofilm growth, cause off-tastes and -odors, and may react with disinfectants to form disinfection by-products (DBP). Varied manufacturing processes that are applied to create PEX pipes add to the complexity of understanding organic materials released. In this study, organic carbon release from three PEX pipe brands was monitored for up to five days using a series of stagnation periods. Seven stagnation periods of 1, 2, 4, 8, 24, 72, and 120 hours were …


Past, Present, And Future Water Quality In Lake Union/Ship Canal, Elliott Bay, And The Duwamish Estuary And The Benefits Of Combined Sewer Overflow Control And Other Projects, Jim Simmonds Apr 2018

Past, Present, And Future Water Quality In Lake Union/Ship Canal, Elliott Bay, And The Duwamish Estuary And The Benefits Of Combined Sewer Overflow Control And Other Projects, Jim Simmonds

Salish Sea Ecosystem Conference

To help protect regional water quality, in 2012 King County initiated a study to review the impacts of combined sewer overflows (CSOs) and other sources of pollution to inform the region of the benefits of CSO control. King County’s Water Quality Assessment and Monitoring Study (Study) explored water quality in Lake Union/Ship Canal, Elliott Bay, and the Duwamish Estuary, where the County is planning projects to reduce the frequency of CSOs to an average of one untreated overflow per site per year over a 20-year moving average. Reducing CSO frequency to this degree is known as CSO “control” and is …


Nitrogen Inventory In The Nooksack-Fraser Transboundary Watershed, Jiajia Lin, Jana Compton, Jill Baron, Chris Clark, Donna Schwede, Shabtai Bittman, David Hooper, Barb Carey, Peter Homann, Hanna Winter, Peter Kiffney, Nichole Embertson, Heather Mackay, Robert Black, Gary Bahr Apr 2018

Nitrogen Inventory In The Nooksack-Fraser Transboundary Watershed, Jiajia Lin, Jana Compton, Jill Baron, Chris Clark, Donna Schwede, Shabtai Bittman, David Hooper, Barb Carey, Peter Homann, Hanna Winter, Peter Kiffney, Nichole Embertson, Heather Mackay, Robert Black, Gary Bahr

Salish Sea Ecosystem Conference

The Nooksack-Fraser transboundary area (2639 km2) is home to communities with a strong base in farming, fisheries and outdoor recreation. Water quality issues impact parts of this area, where sewage effluent and animal waste are potential sources of both fecal coliform bacteria (FCB) and nitrogen (N) in the environment. Excessive nitrogen loading can lead to eutrophication in coastal areas, and nitrate contamination of groundwater. The Nooksack-Fraser Transboundary Nitrogen (NFT-N) project was developed to determine the sources and fates of N in the watershed using data on energy use, transportation, fertilization, wastewater treatment plants, livestock operations, wildlife and more. This project …


Impact Of Septic Systems In Drayton Harbor Water Quality, Jennifer Hayden Apr 2018

Impact Of Septic Systems In Drayton Harbor Water Quality, Jennifer Hayden

Salish Sea Ecosystem Conference

Septic systems are personal wastewater treatment systems for rural properties. Over 3,000 septic systems exist in the Drayton Harbor watershed. Septic systems that are not maintained properly can create problems for homeowners, negatively impact water quality, and pose a public health threat. Whatcom County Health Department (WCHD) began implementing a septic system operation and maintenance (O&M) program in 2008 in the Drayton Harbor watershed when most of Drayton Harbor was classified as Prohibited for shellfish harvesting due to elevated fecal coliform bacteria levels. The local health officer’s designation of Drayton Harbor as a Marine Recovery Area in 2008 allowed WCHD …


Nooksack Tribe Collaborative Teaming To Address Shellfish Harvest Closures In Drayton Harbor, Oliver Grah, Jezra Beaulieu Apr 2018

Nooksack Tribe Collaborative Teaming To Address Shellfish Harvest Closures In Drayton Harbor, Oliver Grah, Jezra Beaulieu

Salish Sea Ecosystem Conference

The Nooksack Indian Tribe reservation is located at the foot of the North Cascades Mountains, near Deming, WA, and approximately 13 miles east of Bellingham and the Salish Sea. Drayton Harbor is part of the Salish Sea and is the Tribe’s traditional shellfish gathering area. Drayton Harbor is also an important shellfish gathering and production area for commercial and recreational uses. The Harbor has been under a TMDL for fecal coliform bacteria for more than 10 years for non-compliance with state water quality standards. Although re-opened to year-round harvest in late 2016, Drayton Harbor’s shellfish have been subjected to various …


Engaging The Community In Drayton Harbor's Comeback Story, Betsy Peabody Apr 2018

Engaging The Community In Drayton Harbor's Comeback Story, Betsy Peabody

Salish Sea Ecosystem Conference

During the 1980 and 1990s, bacterial contamination in Drayton Harbor resulted in bay-wide closures of tribal, commercial and recreational shellfish harvest. In 2001, Puget Sound Restoration Fund partnered with local shellfish farmer extraordinaire Geoff Menzies to launch the Drayton Harbor Community Oyster Farm. With Geoff at the helm, the community farm invigorated a 20+ year community-wide effort to restore 810 acres of growing area to Approved harvest status in 2016. At the outset, seeding oysters in a bay prohibited to harvest, and involving volunteers in oyster farming, was a gamble. But the vision was that if people became immersed in …


Raising The Standards For Water Quality Objectives In Burrard Inlet: Interaction Between Public, Ecological And Cultural Values Through Indigenous-Provincial Collaboration, Anuradha Rao, Bridget Doyle, John Konovsky, Patrick Lilley Apr 2018

Raising The Standards For Water Quality Objectives In Burrard Inlet: Interaction Between Public, Ecological And Cultural Values Through Indigenous-Provincial Collaboration, Anuradha Rao, Bridget Doyle, John Konovsky, Patrick Lilley

Salish Sea Ecosystem Conference

Water Quality Objectives (WQOs) in British Columbia set limits within which various parameters should remain to enable sensitive uses of water bodies. The current WQOs for Burrard Inlet are more than 25 years old and do not reflect current science, all pollutants of concern or a complete understanding of uses and values, for example uses of particular importance to First Nations. As part of its work to implement the Burrard Inlet Action Plan, Tsleil-Waututh Nation is leading an initiative with the Province of BC to update the Burrard Inlet WQOs. One goal in doing so is to ensure that ecological …


Changes To Washington State's Recreational Use Criteria And Implications For Surface Waters, Bryson Finch, Chad Brown Apr 2018

Changes To Washington State's Recreational Use Criteria And Implications For Surface Waters, Bryson Finch, Chad Brown

Salish Sea Ecosystem Conference

Washington State’s surface water quality standards set limits on pollution in lakes, rivers, and marine waters in order to protect beneficial uses, such as swimming and fishing. Washington State Department of Ecology has recently announced a rulemaking to update recreational use criteria (RUC). Recreational use criteria are intended to protect human health while enjoying water-related activities. Recreational use criteria are based on bacterial indicators rather than direct measurements of pathogens. Washington’s current bacterial indicator, fecal coliform, was removed from the Environmental Protection Agency’s (EPA) recommendations in 1986. The EPA is now requiring states update their RUC to the new bacterial …


How Did Large Scale Climate Anomalies Impact 2015 Phytoplankton Blooms In Puget Sound?, Juhi Lafuente, Christopher Krembs, S. L. Albertson, Allison Brownlee, Julia Bos, Laura Hermanson, Mya Keyzers Apr 2018

How Did Large Scale Climate Anomalies Impact 2015 Phytoplankton Blooms In Puget Sound?, Juhi Lafuente, Christopher Krembs, S. L. Albertson, Allison Brownlee, Julia Bos, Laura Hermanson, Mya Keyzers

Salish Sea Ecosystem Conference

The Washington State Department of Ecology has been routinely monitoring marine water quality throughout the Puget Sound since 1973. An established historic baseline from 1999 to 2008 allows us to examine how water quality varies year to year as a result of both natural and human influences. The recent large scale climate anomaly, the Blob, impacted this region when a mass of warm water entered Puget Sound in fall 2014. In conjunction with higher than normal air temperatures, patterns of estuarine circulation and stratification were regionally altered in Puget Sound. Changes to these physical patterns affect ecosystem functions starting at …


Long-Term Water Quality Trend Analysis In The Lone Tree Creek Watershed And Surrounding Marine Waters, Shannon Buckham, Nicole Casper Apr 2018

Long-Term Water Quality Trend Analysis In The Lone Tree Creek Watershed And Surrounding Marine Waters, Shannon Buckham, Nicole Casper

Salish Sea Ecosystem Conference

The Lone Tree Creek watershed is located on the Reservation of the Swinomish Indian Tribal Community (SITC) and is an important area both ecologically and culturally. Lone Tree Creek and the surrounding Skagit Bay nearshore environment provide important salmon and shellfish habitats, as well as recreation areas, and therefore have been the focus for ongoing research since 1997. Water quality parameters in the creek, lagoon, and two bay sites have been monitored since the late 1990s and early 2000s, and an additional pocket estuary site was added to monitoring efforts in 2007. This study used Mann-Kendall analysis to determine how …


Social And Economic Impacts Of A 2017 Oyster-Transmitted Norovirus Outbreak In Hammersley Inlet, Puget Sound, Marisa Nixon Apr 2018

Social And Economic Impacts Of A 2017 Oyster-Transmitted Norovirus Outbreak In Hammersley Inlet, Puget Sound, Marisa Nixon

Salish Sea Ecosystem Conference

Hammersley Inlet in Washington State is a highly productive growing area for oysters, with at least 34 different commercial shellfish growers operating in its tidelands. The oysters in Hammersley Inlet provide an important source of income, employment and recreation for surrounding Mason County. In early spring 2017, Hammersley Inlet was implicated in a shellfish-transmitted norovirus outbreak that resulted in growing area closures and recalls, significantly impacting small, local shellfish farmers. From its initial illness investigation, Washington State Department of Health (DOH) was unable to identify a point pollution source responsible for the outbreak, and some shellfish producing parcels remained closed …


Water Quality Effects Of Fish Habitat Restoration At Lone Tree Creek, Nicole Casper, Shannon M. Buckham Apr 2018

Water Quality Effects Of Fish Habitat Restoration At Lone Tree Creek, Nicole Casper, Shannon M. Buckham

Salish Sea Ecosystem Conference

Lone Tree Creek is located on the Swinomish Indian Tribal Community (SITC) Reservation. The creek’s watershed includes pocket estuary habitat, discharges over shellfish beds, an important resource for the Swinomish People, and flows into northern Skagit Bay. In 2006, extensive creek restoration replaced culverts, restored tidal influence to the pocket estuary, and planted riparian buffers, successfully restoring rearing habitat for juvenile Chinook salmon. Beyond fish habitat benefits, SITC wanted to assess long-term restoration effects on creek water quality and its associated pocket estuary, lagoon and bay. Water quality monitoring for conventional parameters and bacteria spanned 1997-2016 (10 years pre- and …


Quantitative Biomonitoring Of Water Quality For Pops Using Freshwater Mussels, Ken G. Drouillard Aug 2015

Quantitative Biomonitoring Of Water Quality For Pops Using Freshwater Mussels, Ken G. Drouillard

21st International Conference on Environmental Indicators (ICEI 2015)

No abstract provided.


The Phosphorus Paradox: Productive Agricultural And Water Quality, Andrew N. Sharpley Aug 2015

The Phosphorus Paradox: Productive Agricultural And Water Quality, Andrew N. Sharpley

21st International Conference on Environmental Indicators (ICEI 2015)

No abstract provided.


Phytoplankton Ecology: Algal Assemblages In Correlation With Water Quality In High Elevation Lakes, North Cascades, Wa, Anna Nakae May 2015

Phytoplankton Ecology: Algal Assemblages In Correlation With Water Quality In High Elevation Lakes, North Cascades, Wa, Anna Nakae

Scholars Week

High- elevation lakes are unique ecosystems that are exposed to extreme environmental conditions and, as a result, are relatively simple systems in which changes can be detected. Phytoplankton communities within these systems are of interest because can be greatly influenced by the chemical components of the surrounding environment. This relationship allows phytoplankton assemblages to act as bioindicators that can give a greater insight into the water characteristics of lakes and vice versa. For this research, seven lakes were studied: Terminal, Upper Bagley, Lower Bagley, Heather Meadows Pond, Sunrise , Picture and Highwood. All seven are located in the headwaters watershed …


Monitoring Water Quality On Tributary Inflows To Lake Mead And On A Transect Of The Overton Arm, Jorge Arufe, Robert Burrows Jan 2009

Monitoring Water Quality On Tributary Inflows To Lake Mead And On A Transect Of The Overton Arm, Jorge Arufe, Robert Burrows

Lake Mead Science Symposium

The USGS, in cooperation with the NPS and BOR (Bureau of Reclamation), is collecting water quality data to determine the temporal changes and spatial distributions of natural and anthropogenic compounds entering the Overton Arm of Lake Mead. These efforts and others already underway on the lake by BOR, USGS, and SNWA will aid in the development of a reservoir model of the lake. The effects of the flood flows on the water quality of the Overton Arm are largely unknown and necessary for model development and verification.

Water quality physical parameters are continuously monitored near the mouth of the Virgin …


History Of Contaminant Inputs Into Lake Mead Derived From Sediment Cores, Michael R. Rosen, Peter C. Van Metre, David Alvarez, Kathy R. Echols, Steven L. Goodbred Jan 2009

History Of Contaminant Inputs Into Lake Mead Derived From Sediment Cores, Michael R. Rosen, Peter C. Van Metre, David Alvarez, Kathy R. Echols, Steven L. Goodbred

Lake Mead Science Symposium

Assessing the changes in contaminant inputs (both organic and inorganic) over time is important in determining sources and sinks of these inputs. Variations in contaminant input were assessed in four sediment cores taken in 1998 from three different parts of Lake Mead (two from Las Vegas Bay and one from Overton Arm and Virgin Basin). Sediments were analyzed for major and trace elements, radionuclides, and organic compounds. Anthropogenic contaminant concentrations are greatest in Las Vegas Bay reflecting inputs from the Las Vegas urban area, although concentrations are low compared to sediment quality guidelines and to other USA lakes. One exception …