Assessment of the Environmental Effects Associated with Wooden Bridges Preserved with Creosote, Pentachlorophenol, Or Chromated Copper Arsenate

Assessment of the Environmental Effects Associated with Wooden Bridges Preserved with Creosote, Pentachlorophenol, Or Chromated Copper Arsenate
Author: Kenneth M. Brooks
Publisher:
Total Pages: 108
Release: 2000
Genre: Wood preservatives
ISBN:

Timber bridges provide an economical alternative to concrete and steel structures, particularly in rural areas with light to moderate vehicle traffic. Wooden components of these bridges are treated with chromated copper arsenate type C (CCA), pentachlorophenol, or creosote to prolong the life of the structure from a few years to many decades. This results in reduced transportation infrastructure costs and increased public safety. However, the preservative used to treat the wooden components in timber bridges is lost to the environment in small amounts over time. This report describes the concentration of wood preservatives lost to adjacent environments and the biological response to these preservatives as environmental contaminants. Six bridges from various states were examined for risk assessment: two creosote treated bridges, two pentachlorophenol-treated bridges, and two CCA-treated bridges. In all cases, the largest bridges located in biologically active environments associated with slow-flowing water were selected to represent worst-case analyses. Sediment and water column concentrations of preservative were analyzed upstream from, under, and downstream from each bridge. The observed levels of contaminant were compared with available regulatory standards or benchmarks and with the quantitative description of the aquatic invertebrate community sampled from vegetation and sediments. Pentachlorophenol- and creosote-derived polycyclic aromatic hydrocarbons (PAHs) were not observed in the water near any of the selected bridges. However, low levels of PAHs were observed in the sediments under and immediately downstream from these bridges. Pentachlorophenol concentrations did not approach toxicological benchmarks. Sediment concentrations of naphthalene, acenaphthylene, and phenanthrene exceeded the probable effect level. Metal levels at the bridges treated with CCA were less than predicted effect levels, in spite of questionable construction practices. Adverse biological effects were not observed in the aquatic invertebrate community or laboratory bioassays conducted on water and sediments sampled at each of the bridges. Results of this study reveal the need to follow the construction information found in Best Management Practices for the Use of Treated Wood In Aquatic Environments published by Western Wood Preservers Institute. Regulatory benchmarks used in risk assessments of this type need to be indexed to local environmental conditions. The robust invertebrate communities associated with slow-moving streams over soft bottoms were not susceptible to the concentrations of PAHs that would be expected to affect more sensitive taxa, which typically are located in faster moving water over hard bottoms. Contaminants released from timber bridges into these faster systems (where more sensitive taxa are located) are significantly diluted and not found at biologically significant levels.

Assessment of the Environmental Effects Associated with Wooden Bridges Preserved with Creosote, Pentachlorophenol, Or Chromated Copper Arsenate

Assessment of the Environmental Effects Associated with Wooden Bridges Preserved with Creosote, Pentachlorophenol, Or Chromated Copper Arsenate
Author: Kenneth M. Brooks
Publisher:
Total Pages: 100
Release: 2001-12
Genre:
ISBN: 9780756716929

Timber bridges provide an economic alternative to concrete & steel structures, particularly in rural areas. Wooden components of these bridges are treated with chromated copper arsenate type C (CCA), pentachlorophenol, or creosote to prolong the life of the structure. However, these preservatives are lost to the environment in small amounts over time. This report describes the concentration of wood preservatives lost to adjacent environments & the biological response to these preservatives as environmental contaminants. Six bridges from various states were examined for risk assessment. Includes: previous treated-wood assess.; materials & methods. Photos & maps.

Identification of Research Needs Related to Highway Runoff Management

Identification of Research Needs Related to Highway Runoff Management
Author: Marie Venner
Publisher: Transportation Research Board
Total Pages: 175
Release: 2004
Genre: Road drainage
ISBN: 0309088151

Introduction -- Department of Transportation research preferences -- Review of published literature and potential research needs -- Summary of identified research gaps and needs -- Master bibliography -- Appendixes.

Treatment Wetlands

Treatment Wetlands
Author: Robert H. Kadlec
Publisher: CRC Press
Total Pages: 1048
Release: 2008-07-22
Genre: Nature
ISBN: 1420012517

Completely revised and updated, Treatment Wetlands, Second Edition is still the most comprehensive resource available for the planning, design, and operation of wetland treatment systems. The book addresses the design, construction, and operation of wetlands for water pollution control. It presents the best current procedures for sizing these syste

Field Evaluation of Timber Preservation Treatments for Highway Applications

Field Evaluation of Timber Preservation Treatments for Highway Applications
Author: Jake J. Bigelow
Publisher:
Total Pages: 110
Release: 2007
Genre: Bridges
ISBN:

Timber material repair and replacement cost for timber bridges is a considerable expense to highway agencies in Iowa, especially to county road departments. To address these needs, the objectives of this investigation was to study the field effectiveness of various treatment alternatives used on Iowa roadway projects and to determine if the current specifications and testing are adequate for providing proper wood preservation. To satisfy the research needs, the project scope involved a literature review, identification of metrics, questionnaire survey of Iowa counties, on site inspections, and a review of current specifications and testing procedures. Based on the preservative information obtained, the following general conclusions were made: Copper naphthenate is recommended as the plant-applied preservative treatment for timber bridges. Best Management Practices should be followed to ensure quality treatment of timber materials. Bridge maintenance programs need to be developed and implemented. The Iowa Department of Transportation specifications for preservative treatment are the regulating specification for bridges constructed with state or federal funding in Iowa and are also recommended for all other bridges.