Abstract Radon ( 222 Rn) has been highlighted by a number of authors as a significant public health concern. For example, it is the second most significant cause of lung cancer after tobacco smoking ( c. 1000–2000 and 21 000 deaths per year in the UK and USA, respectively), yet a very high proportion of the general public appears to be unaware of the risk. This chapter deals with topical radon issues, such as: radon in the workplace; radon in homes; exposure to radon during leisure activities; radon and water; measurement and monitoring; seasonal correction; remediation; cancer risks; cost–benefit analysis and cost-effectiveness; mapping; future policies; and further research. This assessment of the state of radon research is focused on the UK as an example of a country where radon has been on the governmental agenda since the late 1970s, but also highlights radon issues throughout the world in, for example, the USA, Europe and Asia.

The Paleocene–early Eocene interval is punctuated by a series of transient warming events known as hyperthermals that have been associated with changes in the carbon isotope composition of the ocean-atmosphere system. Here we present and discuss a detailed record of calcareous nannofossil and foraminiferal assemblages coupled with high-resolution geochemical, isotopic, and environmental magnetic records across the middle Ypresian at the Contessa Road section (Gubbio, Italy). This allows characterization of the Eocene Thermal Maximum 3 (ETM3, K or X) and recognition of four minor (I1, I2, J, L) hyperthermals. At the Contessa Road section, the ETM3 is marked by short-lived negative excursions in both δ 13 C and δ 18 O, pronounced changes in rock magnetic properties, and calcium carbonate reduction. These changes coupled with the moderate to low state of preservation of calcareous nannofossils and planktonic foraminifera, higher FI and agglutinated foraminifera values, along with a lower P/(P + B) ratio (P—planktonic; B—benthic) and coarse fractions provide evidence of enhanced carbonate dissolution during the ETM3. A marked shift toward warmer and more oligotrophic conditions has been inferred that suggests unstable and perturbed environmental conditions both in the photic zone and at the seafloor.

Abstract Central Skåne (Scania) in southern Sweden hosts evidence of extensive Jurassic volcanism in the form of mafic volcanic plugs and associated volcaniclastic deposits that entomb well-preserved macro-plant and spore–pollen assemblages. Palynological assemblages recovered from the Höör Sandstone are of Hettangian–Pliensbachian age and those from the overlying lahar deposits are dated as Pliensbachian–early Toarcian (?). Palynomorph assemblages from these units reveal significantly different ecosystems, particularly with respect to the gymnospermous components that represented the main canopy plants. Both palynofloras are dominated by osmundacean, marattiacean and cyatheacean fern spore taxa but, whereas the Höör Sandstone hosts abundant Chasmatosporites spp. pollen produced by plants related to cycadophytes, the volcanogenic deposits are dominated by cypress family pollen ( Perinopollenites ) with an understorey component rich in putative Erdtmanithecales (or possibly Gnetales), and collectively representing vegetation of disturbed habitats. Permineralized conifer wood attributed to Protophyllocladoxylon sp., belonging to plants that probably produced the abundant Perinopollenites grains, is abundant in the volcanigenic strata, and shows sporadic intraseasonal and multi-year episodes of growth disruption. Together with the relatively narrow but marked annual growth rings, and the annual and mean sensitivity values that span the complacent–sensitive domains, these features suggest growth within Mediterranean-type biomes subject to episodic disturbance.

Abstract Burning and evolving for over 50 years, the anthracite coal fire in Centralia, Pennsylvania, has provided researchers with an ideal environment to study how shallow coal fires affect surface vegetation, nutrients and soil, landscape subsidence, organisms, fire migration, as well as human health. Ten years ago, surface temperatures from some gas exhaust vents were measured to be between 456° and 540 °C, and the fire was recorded to be moving rapidly at a rate of 20–22 m/yr. However, the fire has changed considerably since that time. Today, the average annual temperature of surface exhaust vents is ~65 °C, and its rate of movement is nearly unperceivable. In light of the changing parameters of the fire, Centralia continues to provide an interesting environment in which to study the effects of a subsurface anthracite coal fire on the landscape. This field trip will examine the geologic structure of the region, the Buck Mountain coal succession, the geomorphic features produced by the fire, the environmental consequences related to the removal of natural resources like coal, how a government responds to regional environmental disasters like coal fires, and the legacy of a coal fire on a region. Over the past decade, this fire and its influence on the landscape have changed considerably. However, there are still many interesting things to learn from this fire and the surrounding region.

Abstract This guide accompanies a walking tour of sites where masonry was employed on or near the National Mall in Washington, D.C. It begins with an overview of the geological setting of the city and development of the Mall. Each federal monument or building on the tour is briefly described, followed by information about its exterior stonework. The focus is on masonry buildings of the Smithsonian Institution, which date from 1847 with the inception of construction for the Smithsonian Castle and continue up to completion of the National Museum of the American Indian in 2004. The building stones on the tour are representative of the development of the American dimension stone industry with respect to geology, quarrying techniques, and style over more than two centuries. Details are provided for locally quarried stones used for the earliest buildings in the capital, including Aquia Creek sandstone (U.S. Capitol and Patent Office Building), Seneca Red sandstone (Smithsonian Castle), Cockeysville Marble (Washington Monument), and Piedmont bedrock (lockkeeper’s house). Following improvement in the transportation system, buildings and monuments were constructed with stones from other regions, including Shelburne Marble from Vermont, Salem Limestone from Indiana, Holston Limestone from Tennessee, Kasota stone from Minnesota, and a variety of granites from several states. Topics covered include geological origins, architectural design considerations, weathering problems, and conservation issues.

Abstract Upper North Chickamauga Creek in Hamilton and Sequatchie Counties, Tennessee, is severely impacted by acid mine drainage (AMD) emanating from more than 15 abandoned coal mines in headwater tributaries. AMD is formed when pyrite and other sulfide minerals are exposed to air and water during coal mining. It is characterized by low pH (<2.8) and elevated concentrations of acidity, iron, aluminum, sulfate, and other pollutants. These attributes tend to be toxic to most aquatic life and result in reduced aesthetics and potential uses of the water. The North Chickamauga Creek Watershed Restoration Project is a multi-organizational effort to restore the upper 18 miles of the North Chickamauga Creek watershed to a level that will support a warm-water fishery. Several passive treatment systems (PTS) have been installed at abandoned mining sites in the North Chickamauga Creek watershed where AMD is generated and is flowing into surface waters. PTS is the engineered use of natural and enhanced geological, biological, chemical, and physical processes to prevent pollutant generation or to remove pollutants from aqueous discharges. PTS include technologies such as constructed wetlands, anoxic limestone drains, mine seals and flooding, successive alkalinity-producing systems, limestone trenches, and other components. During this field trip to the upper reaches of the North Chickamauga Creek watershed, we will visit several of the operational systems and observe untreated AMD. Participants will gain an understanding of how AMD is generated, its impacts and characteristics, and how it can be prevented or treated. This field trip requires extensive hiking over moderate slopes and sometimes vegetated terrain.

Abstract The 2005 removal of the 3.6-m-high Munroe Falls Dam from the middle Cuyahoga River, Ohio, provided an opportunity to assess dam removal channel-evolution models and to anticipate impacts from additional dam removals on the Cuyahoga River. Preremoval geomorphic and sedimentologic conditions were characterized. Monitoring of the river response to dam removal has continued for 5 yr. The dam removal lowered base level and increased flow velocity upstream of the former dam site. Postremoval, the initial channel response was rapid incision to the predam substrate, followed by rapid lateral erosion of the exposed impoundment fill. Four to nine months after removal, dewatering and vegetation of the exposed impoundment fill greatly reduced the rate of lateral erosion. For 2.5 yr post -removal, sandy bar forms were present upstream of the former dam, and sand was transported under all flow conditions of the year. Subsequently, the bed has become armored with gravel. Downstream of the former dam site, the channel aggraded with sand, causing flow to occupy meander bend chutes that had formerly only been active during high flow. A sandy deltaic feature has accumulated 3.3 km downstream in the impoundment created by the Le Fever Dam. The impacts of the Munroe Falls Dam removal are generally well described by published channel-evolution models with minor exceptions due to local geology and hydrology. The similarities between the Munroe Falls and Le Fever Dam impoundments suggest that this study can aid in understanding the impacts of the possible future removal of the Le Fever Dam.

Abstract In 1886, a large earthquake (∼M6.9–M7.3) rocked the Summerville-Charleston South Carolina area along the southeastern coast of North America. The largest east coast earthquake in North America, the earthquake caused massive damage to the cities and left ∼100 people dead. No surface rupture has ever been located; however, ongoing seismicity and damage from the 1886 earthquake has helped scientists to locate the active faults at depth and to identify potential surface offsets. The first day of the field trip will look at the damage from the earthquake as a means of understanding more about the mechanics of the earthquake. As the field trip moves into downtown Charleston, the damage will be examined as a proxy for how earthquakes cause buildings to fail and the type of damage a future earthquake could cause. The ongoing seismic activity along the suspected causal faults suggests that the earthquake risk in the Summerville-Charleston area remains high, and so the second day of the field trip will focus on the potential effects of a moderate to large earthquake in the region of the 1886 earthquake. One of the unique features of the Charleston-Summerville area is the high potential for widespread liquefaction and damage to the many bridges in the area. Therefore, Day 2 will focus on the potential for damage from a major earthquake on bridges and highly liquefiable sites by visiting a bridgeport area and then a barrier island. The visit to the barrier island highlights one of the main problems in Charleston in the event of an earthquake, the isolation of communities, with over 720 bridges and many more culverts in the area it is expected that people will be isolated in small communities for long periods of time.

Abstract Route 66 is among the most famous American highways of the middle twentieth century. A portion of the original Route 66 runs through southwestern Missouri, southeastern Kansas, and northeastern Oklahoma. This section of the road was intimately linked to the Tri-state region’s economic geology, namely mining lead and zinc as well as producing the fossil fuels—coal and natural gas—to smelt the ore. Mining began in the Tri-state district in the mid-nineteenth century and continued into the late twentieth century. An economic boom led to regional population growth and contributed to national development, but no environmental regulations existed during this period. The legacy of mining includes severe pollution, ruined communities, serious human-health issues, and devastated landscapes. Efforts now focus on protecting human health, reclamation of mined land, and remediation of water resources, led by federal and state agencies as well as universities and non-governmental organizations.

Conversion of upland forest and prairie vegetation to agricultural land uses, following Euro-American settlement in the Upper Mississippi River System, led to accelerated runoff and soil erosion that subsequently transformed channels, floodplains, and wetlands on bottomlands. Halfway Creek Marsh, at the junction of Halfway Creek and the Mississippi River on Wisconsin’s western border, is representative of such historical transformation. This marsh became the focus of a 2005–2006 investigation by scientists from the U.S. Geological Survey, the University of Wisconsin–Madison, and the U.S. Environmental Protection Agency, who used an understanding of the historical transformation to help managers identify possible restoration alternatives for Halfway Creek Marsh. Field-scale topographic surveys and sediment cores provided data for reconstructing patterns and rates of historical overbank sedimentation in the marsh. Information culled from historical maps, aerial photographs, General Land Office Survey notes, and other historical documents helped establish the timing of anthropogenic disturbances and document changes in channel patterns. Major human disturbances, in addition to agricultural land uses, included railroad and road building, construction of artificial levees, drainage alterations, and repeated dam failures associated with large floods. A volume of approximately 1,400,000 m 3 , involving up to 2 m of sandy historical overbank deposition, is stored through the upper and lower marshes and along the adjacent margins of Halfway Creek and its principal tributary, Sand Lake Coulee. The estimated overbank sedimentation rate for the entire marsh is ~3,000 m 3 yr ‒1 for the recent period 1994–2006. In spite of reduced surface runoff and soil erosion in recent years, this recent sedimentation rate still exceeds by ~4 times the early settlement (1846–1885) rate of 700 m 3 yr ‒1 , when anthropogenic acceleration of upland surface runoff and soil erosion was beginning. The highest rate of historical bottomland sedimentation occurred from 1919 to 1936, when the estimated overbank sedimentation rate was 20,400 m 3 yr ‒1 . This rate exceeded by nearly 30 times the 1846–1886 rate. Artificial levees were constructed along the upper reach of Halfway Creek in the marsh during the early twentieth century to restrict flooding on the adjacent bottomlands. Anomalously high overbank sedimentation rates subsequently occurred on the floodplain between the levees, which also facilitated more efficient transport of sediment into the lower marsh bottomland. Although overbank sedimentation rates dropped after 1936, corresponding to the widespread adoption of soil-conservation and agricultural best-management practices, the continuation of anomalously high overbank sedimentation between the levees led to increased bank heights and development of a relatively deep channel. The deep cross-section morphology is commonly mistaken as evidence of channel incision; however, this morphology actually resulted from excessive overbank sedimentation. The historical metamorphosis of the Halfway Creek channel and riparian wetlands underscores the importance of understanding the long-term history of channel and floodplain evolution when restoration of channels and riparian wetlands are under consideration. Sedimentation patterns and channel morphology for Halfway Creek Marsh probably are representative of other anthropogenically altered riparian wetlands in the Upper Mississippi River System and similar landscapes elsewhere.

Hydraulic gold-mining tailings produced in the late nineteenth century in the Sierra Nevada foothills of California caused severe channel aggradation in the lower Feather and Yuba Rivers. Topographic and planimetric data from historical accounts, maps, topographic surveys, vertical sections, aerial photographs, and LiDAR (light detection and ranging) data reveal contrasting styles of channel change and floodplain evolution between these two rivers. For example, levee cross-channel spacings up to 4 km along the lower Yuba River contrast with spacings <2 km on the larger Feather River. More than a quarter billion cubic meters of hydraulic-mining sediment were stored along the lower Yuba River, and the wide levee spacing was intentionally maintained during design of the flood-control system to minimize delivery of sediment to navigable waters downstream. Consequently, the lower Yuba floodplain has a multithread high-water channel system with braiding indices >12 in some reaches. Some of the larger of these channels remain clearly visible on aerial photographs and LiDAR imagery in spite of intensive agricultural leveling. Narrow levee spacings on the Feather River were designed to encourage transport of mining sediment downstream and keep the channel clear for navigation. Levee spacings on the lower Feather River reached a minimum near the turn of the twentieth century, when floodplain widths were reduced at several constricted reaches to <250 m. Historical data indicate that the general channel location of the lower Yuba River had stabilized by the end of the nineteenth century, whereas substantial channel avulsions began later and continued into the twentieth century on the lower Feather River. The striking contrasts in channel change between the Yuba and Feather Rivers are due, at least in part, to different river-management strategies, although the Yuba River received much more sediment. Early river engineering of these channels represented the first efforts at integrated river-basin management west of the Mississippi, so the observed long-term effects are instructive. Modern river management should consider how the disturbance factors in these channels and the imprint of early river management affect the modern morphologic stability and sediment-production potential of the channel and floodplain.

This paper deals with channel evolution over the past 200 yr in 12 selected streams in northern and central Italy and aims at reconstructing the evolutionary trends (e.g., trends of channel width and bed elevation) and understanding the causes of channel adjustments. The selected streams have been studied using various sources and methods (historical maps, aerial photographs, topographic surveys, and geomorphological surveys). The selected rivers have undergone almost the same processes in terms of temporal trends; however, the magnitude of adjustments varies according to several factors, such as original channel morphology. Initially, river channels underwent a long phase of narrowing (up to 80%) and incision (up to 8–10 m), which started at the end of the nineteenth century and was intense from the 1950s to the 1980s. Then, over the last 15–20 yr, channel widening and sedimentation, or bed-level stabilization, have become the dominant processes in most of the rivers. Different human interventions have been identified as the causes of channel adjustments in Italian rivers (sediment mining, channelization, dams, reforestation, and torrent control works). Such interventions have caused a dramatic alteration of the sediment regime, whereas effects on channel-forming discharges have seldom been observed. Some notable implications for river management and restoration are (1) the state of rivers before major human disturbances and channel adjustments can rarely be taken as a reference, as at present rivers are far from their pristine condition; and (2) sediment management is and will be a key issue in such fluvial systems.

The South Platte and Republican River basins provide examples of historical channel changes on the western Great Plains. Flow regulation and diversion caused substantial channel narrowing and vegetation encroachment along larger, perennial rivers that head in the Rocky Mountains. Intensive groundwater pumping has reduced the volume and longitudinal connectivity of refuge pools along smaller intermittent or ephemeral channels that head on the plains. A case study from the Pawnee National Grassland of Colorado illustrates the dynamics of intermittent streams, as well as measures that can be taken to protect and restore refuge pools along these streams. The implications of channel change, and the need to protect and rehabilitate rivers, are less widely recognized for smaller rivers of the western Great Plains than for the larger, perennial rivers. Our objectives in this chapter are to provide a regional context for understanding changes in smaller plains rivers during the past century by reviewing the diversity of channel types and historical changes in the western Great Plains, and to briefly explore the dynamics of smaller plains rivers and the challenges to preserving these riverscapes.

Streamflow on the North Fork Cache La Poudre River, a tributary of the South Platte River in north-central Colorado, has been modified by impoundments for a century. A proposed expansion of the largest reservoir on the North Fork, Halligan Reservoir, presents an opportunity to modify dam operation to achieve environmental flows that sustain the river ecosystem while augmenting municipal water supplies. Over the past century, decreases in flood-related disturbances have resulted in reduced bed scouring through sediment transport and significant shifts in community composition and population structure of the dominant woody species present along the North Fork. We propose a four-step method to characterize environmental flows that maintain sediment mobility and riparian vegetation composition and structure. Our environmental flow standards explicitly address the fundamental role of sediment in creating and maintaining riparian habitat. Environmental flows to transport bedload are lower magnitude, higher frequency events (2 yr recurrence interval) that serve many in-channel functions, whereas environmental flows directed at riparian vegetation respond over longer time scales to high magnitude, lower frequency events (10 yr and 25 yr floods). Field evidence suggests the need for a 10 yr flood to saturate over-bank areas and exclude xeric species near the channel. Managed 25 yr floods serve as a target flow for generating canopy gaps, creating regenerative habitat, enhancing biogeochemical processes, maintaining habitat heterogeneity, and possibly disrupting the coarse bed-surface layer and scouring pools to maintain fish overwinter habitat within the North Fork. Where field evidence is lacking, selection of target flows can be guided by daily discharge exceedence values.

Volcanic features are common on geologically active earthlike planets. Megascale or “super” eruptions involving >1000 Gt of magma have occurred on both Earth and Mars in the geologically recent past, introducing prodigious volumes of ash and volcanic gases into the atmosphere. Here we discuss felsic (explosive) and mafic (flood lava) supereruptions and their potential atmospheric and environmental effects on both planets. On Earth, felsic supereruptions recur on average about every 100–200,000 years and our present knowledge of the 73.5 ka Toba eruption implies that such events can have the potential to be catastrophic to human civilization. A future eruption of this type may require an unprecedented response from humankind to assure the continuation of civilization as we know it. Mafic supereruptions have resulted in atmospheric injection of volcanic gases (especially SO 2 ) and may have played a part in punctuating the history of life on Earth. The contrast between the more sustained effects of flood basalt eruptions (decades to centuries) and the near-instantaneous effects of large impacts (months to years) is worthy of more detailed study than has been completed to date. Products of mafic supereruptions, significantly larger than known from the geologic record on Earth, are well preserved on Mars. The volatile emissions from these eruptions most likely had global dispersal, but the effects may not have been outside what Mars endures even in the absence of volcanic eruptions. This is testament to the extreme variability of the current Martian atmosphere: situations that would be considered catastrophic on Earth are the norm on Mars.

Abstract The 1980 eruption of Mount St. Helens caused instantaneous landscape disturbance on a grand scale. On 18 May 1980, an ensemble of volcanic processes, including a debris avalanche, a directed pyroclastic density current, voluminous lahars, and widespread tephra fall, abruptly altered landscape hydrology and geomorphology, and created distinctive disturbance zones having varying impacts on regional biota. Response to the geological and ecological disturbances has been varied and complex. In general, eruption-induced alterations in landscape hydrology and geomorphology led to enhanced stormflow discharge and sediment transport. Although the hydrolog-ical response to landscape perturbation has diminished, enhanced sediment transport persists in some basins. In the nearly 30 years since the eruption, 350 million (metric) tons of suspended sediment has been delivered from the Toutle River watershed to the Cowlitz River (roughly 40 times the average annual preeruption suspended-sediment discharge of the Columbia River). Such prodigious sediment loading has wreaked considerable socioeconomic havoc, causing significant channel aggradation and loss of flood conveyance capacity. significant and ongoing engineering efforts have been required to mitigate these problems. The overall biological evolution of the eruption-impacted landscape can be viewed in terms of a framework of survivor legacies. Despite appearances to the contrary, a surprising number of species survived the eruption, even in the most heavily devastated areas. With time, survivor “hotspots” have coalesced into larger patches, and have served as stepping stones for immigrant colonization. The importance of biological legacies will diminish with time, but the intertwined trajectories of geophysical and biological successions will influence the geological and biological responses to the 1980 eruption for decades to come.

Westhampton Beach is located between two stabilized inlets (Shinnecock and Moriches Inlets) on a barrier island on the south shore of Long Island, New York. Increasing beach erosion in the 1970s prompted a request for construction of a groin field to trap sand and restore the beach. The U.S. Army Corps of Engineers developed a plan for the groin field, and their recommendation was to sequentially build the groins up drift (eastward toward Shinnecock Inlet) using standard project design. However, in the late 1970s, local community pressure forced the U.S. Army Corps of Engineers, contrary to project design, to construct the groins down drift (westward) toward Moriches Inlet. The aim was to restore the eastern, more commercial, part of Westhampton Beach first. Financial limitations in 1972 suspended the project before its completion. Unfortunately, this set the stage for serious problems because the groin field was meant to operate as a completed project, and major problems developed soon after project termination. As a result, severe erosion and multiple washovers occurred west of the last groin. The major nor'easter of 1992 breached the island and destroyed many homes. The U.S. Army Corps of Engineers, in an emergency operation, dredged offshore sand and filled the breaches before they widened too much for effective closure. The subsequent litigation among the homeowners, the county, and the state spread over a number of years. A final settlement was reached on 31 October 1994. However, in a time of sea-level rise on a developed barrier island between two stabilized inlets, more people and bigger structures have now been put in peril.

Abstract The commercial development of Utah’s state rock, coal, by the Union Pacific and Denver and Rio Grande Western railroads began in the late 1800s. Ninety-five percent of the coal produced in Utah today is used to generate electricity, and recent developments in coal-bed methane characterization and extraction are promising for the state’s economy . The Emery coalfield in central Utah consists of sediments deposited along the western margin of the Cretaceous Western Interior Seaway and subsequently deformed during the Laramide orogeny and Basin and Range deformation. The coal-field contains important methane and bituminous deposits in the Ferron Sandstone Member of the Cretaceous Mancos Shale . Ferron coal beds exposed on the northwest-dipping western flank of the San Rafael Swell have been burning for decades. The collapse of strata overlying the Ferron as a consequence of burning provides conduits for the circulation of oxygen, thereby promoting the smoldering that can be observed today. Dating clinker in the Emery coalfield would provide useful information about the timing of certain geologic events in Utah on a local and perhaps regional scale . Federal agencies and laws help safeguard coal mining in the United States today. The environmental effects of Utah’s natural burning and mine-related coal fires are unknown. However, such fires elsewhere are responsible for pollution, including acid rain, and they are responsible for a variety of human diseases .

Abstract Human activities impact an estimated 98% of rivers in the United States. This chapter summarizes impacts associated with pioneer societies, commercial activities, and public works. In pioneer societies, individuals or small groups undertake activities such as timber harvest, agriculture, or navigation improvements. Nineteenth-century placer mining of gold along rivers of California's Sierra Nevada is used as a case study. Commercial activities are conducted by groups of people seeking profit through industry, commerce, or agriculture. Commercial activities impacted rivers much more extensively than most activities of pioneer societies. Impacts to water quality, and particularly the U.S. Geological Survey National Water Quality Assessment (NAWQA) program, provide a case study. Results from the 1991–1995 NAWQA program indicate that approximately half the sites sampled in urban areas have surface-water contamination exceeding levels at which adverse biological effects can occur in aquatic biota. Public works such as dam and levee construction undertaken by local and federal governmental agencies caused massive alteration of river systems. Channelization is used as a case study of the impacts of public works on rivers; more than 56,000 km of waterways were channelized by the Corps of Engineers and the Soil Conservation Service after 1940. The net effect of human activities in the United States has been to disconnect rivers from adjacent hillslopes, floodplains, and valley bottoms, underlying hyporheic and groundwater zones, and from headwaters and downstream processes. Because a connected river is a functioning ecosystem, rather than simply a canal for moving water and sediment, disconnection simplifies and impoverishes the ecosystem. This has resulted in widespread loss of biological diversity in rivers of the United States.