REGIONAL AND FUNCTIONAL DISAGGREGATION OF THE COTTON INDUSTRY IN A NATIONAL INPUT-OUTPUT MODEL

Crop Production/Industries,

Using deuterated PAH amendments to validate chemical extraction methods to predict PAH bioavailability in soils

Validating chemical methods to predict bioavailable fractions of polycyclic aromatic hydrocarbons (PAHs) by comparison with accumulation bioassays is problematic. Concentrations accumulated in soil organisms not only depend on the bioavailable fraction but also on contaminant properties. A historically contaminated soil was freshly spiked with deuterated PAHs (dPAHs). dPAHs have a similar fate to their respective undeuterated analogues, so chemical methods that give good indications of bioavailability should extract the fresh more readily available dPAHs and historic more recalcitrant PAHs in similar proportions to those in which they are accumulated in the tissues of test organisms. Cyclodextrin and butanol extractions predicted the bioavailable fraction for earthworms (Eisenia fetida) and plants (Lolium multiflorum) better than the exhaustive extraction. The PAHs accumulated by earthworms had a larger dPAH:PAH ratio than that predicted by chemical methods. The isotope ratio method described here provides an effective way of evaluating other chemical methods to predict bioavailability

Geology of Sierra Del Carmen, West Texas and Mexico: A General Geologic Framework to Support Mapping of Biologic (Botanical) Resources

The purpose of this study is to provide geologic base maps to support the mapping of biological (botanical) resources in the Sierra del Carmen, Coahuila, Mexico, and adjacent areas in Big Bend National Park, Brewster County, Texas. Sierra del Carmen, which generally trends north-northwestward, includes the eastern part of Big Bend National Park and extends southerly into adjacent Coahuila. The range, which is within the Chihuahuan Desert, rises abruptly from the desert floor and has topographic relief that exceeds 2,000 m. The terrain is rugged, and the range is marked by numerous narrow and steep-sided canyons and valleys. The stratigraphic framework of the range is one aspect that controls the distribution of vegetation throughout the area. In general, different rock types can weather into soils of different composition, and the rocks and soils may contain different amounts of moisture. Thus, different plant species may be associated with specific rock lithologies. Geologic structures such as faults, folds, and fracture zones control the position of the rock units and influence landforms, drainage directions, and canyon development. Structures may also influence the concentration and retention of surface moisture. The geologic map of this region is intended to assist other scientists, students, and interested visitors in understanding the geology of this fascinating area and in interpreting the influence of the geologic framework on related sciences. The map emphasizes bedrock and surficial units that can be important controls on the distribution of plant communities.Bureau of Economic Geolog

Regional Geologic Setting of the Eagle Flat Study Area, Hudspeth County, Texas

The Eagle Flat study area lies near the eastern limit of the Basin and Range geologic province in Trans-Pecos Texas. The geologic features of the region record a long history of geologic events. By describing the regional geologic setting, we can place the Eagle Flat study area within a larger context, and the significance of the site-specific investigations can be more properly understood. In general, the discussions are arranged chronologically, from oldest to youngest; each characterizes the regional geologic framework and describes how the proposed site at Faskin Ranch fits within that geologic setting. The oldest rocks in the region are metamorphosed Precambrian sedimentary and igneous rocks. Precambrian rocks crop out about 6 miles (9 km) east of the proposed repository site and are extensively exposed in the hills in the northeast part of the study area and in the Carrizo Mountains east of the Eagle Flat study area. Precambrian rocks are also present in isolated occurrences on the northeast flank of the Eagle Mountains, southeast of the site, on the Diablo Plateau, and in the Franklin Mountains, and in New Mexico. In northeastern Chihuahua, Precambrian rocks are present in limited outcrops but are known primarily from deep exploratory drilling. The Precambrian rocks show evidence of sedimentation, magmatism, metamorphism, and deformation before deposition of overlying Paleozoic and younger strata. The greater depth of burial of Precambrian rocks in Chihuahua is interpreted to be partly a manifestation of Precambrian faulting and subsidence associated with a wide northwest-trending zone that parallels the Rio Grande. This zone, the Texas Lineament, broadly trends through the study area and locally coincides with younger geologic structures.Bureau of Economic Geolog

Summary Report for the 2002-2003 STATEMAP Project: Geological Mapping to Support Improved Database Development and Understanding of Urban Corridors and Critical Aquifers of Texas

This Texas STATEMAP project involves geologic mapping of a portion of the Seymour aquifer of North-Central Texas (Fig. 1). The "Geologic Map of Seymour Aquifer Deposits, Vernon, Texas, 30 x 60 Minute Quadrangle," the deliverable for this 2002-2003 contract year, addresses groundwater-resource issues related to the aquifer. The map and related geologic data are intended for a diverse audience, including geologists, hydrologists, engineers, students, and laypersons. Uses include (a) identifying aquifer recharge boundaries, (b) characterizing attributes and variations within the aquifer strata, and (c) providing information necessary for land-use activities such as locating landfills and other waste-disposal sites. The map and related geologic data can also be used with Seymour aquifer information to analyze the aquifer's groundwater flow and response to pumpage and recharge for future water-management decisions. The aquifer has been an important source of water for irrigation, municipal pumpage, and industrial and livestock use in the area.Bureau of Economic Geolog