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Results for “Environmental Science and Technology - Water”

Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

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At least 361 records · Page 20Linked to original sources
USGS2002

Satellite-aided evaluation of population exposure to air pollution

The Clean Air Act Amendments of 1977 set schedules for states to implement regional, spatial assessments of air quality impacts. Accordingly, the U.S. Environmental Protection Agency recently published guidelines for quantifying population exposure to adverse air quality impact by using air quality and population data by census tracts. Our research complements the EPA guidelines in that it demonstrates the ability to determine population exposure to air pollution through computer processing that utilizes Landsat satellite-derived land use information. Three variables-a 1985 estimate of total suspended particulates for 2-km 2 grid cells, Landsat-derived residential land cover data for 0.45-ha cells, and population totals for census tracts-were spatially registered and cross-tabulated to produce tabular and map products illustrating relative air quality exposure for residential population by 2-km 2 cells. It would cost $20,000 to replicate our analysis for an area similar in size to the 4000-km 2 Portland area. Once completed, the spatially fine, computer-compatible air quality and population data are amenable to the timely and efficient generation of population-at-risk tabular and map information on a continuous or periodic basis.

Oregon↗
USGS2008

Molecular and structural characterization of dissolved organic matter from the deep ocean by FTICR-MS, including hydrophilic nitrogenous organic molecules

Dissolved organic matter isolated from the deep Atlantic Ocean and fractionated into a so-called hydrophobic (HPO) fraction and a very hydrophilic (HPI) fraction was analyzed for the first time by Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) to resolve the molecular species, to determine their exact masses, and to calculate their molecular formulas. The elemental composition of about 300 molecules was identified. Those in the HPO fraction (14C age of 5100 year) are very similar to much younger freshwater fulvic acids, but less aromatic and more oxygenated molecules are more frequent. This trend continues toward the HPI fraction and may indicate biotic and abiotic aging processes that this material experienced since its primary production thousands of years ago. In the HPI fraction series of nitrogenous molecules containing one, two, or three nitrogens were identified by FTICR-MS. Product ion spectra of the nitrogenous molecules suggest that the nitrogen atoms in these molecules are included in the (alicyclic) backbone of these molecules, possibly in reduced form. These mass spectrometric data suggest that a large set of stable fulvic acids is ubiquitous in all aquatic compartments. Although sources may differ, their actual composition and structure appears to be quite similar and largely independent from their source, because they are the remainder of intensive oxidative degradation processes. ?? 2008 American Chemical Society.

Environmental Science & Technology↗
USGS2008

A biodynamic understanding of dietborne metal uptake by a freshwater invertebrate

Aquatic organisms accumulate metals from dissolved and particulate phases. Dietborne metal uptake likely prevails in nature, but the physiological processes governing metal bioaccumulation from diet are not fully understood. We characterize dietborne copper, cadmium, and nickel uptake by a freshwater gastropod (Lymnaea stagnalis) both in terms of biodynamics and membrane transport characteristics. We use enriched stable isotopes to trace newly accumulated metals from diet, determine food ingestion rate (IR) and estimate metal assimilation efficiency (AE). Upon 18-h exposure, dietborne metal influx was linear over a range encompassing most environmental concentrations. Dietary metal uptake rate constants (kuf) ranged from 0.104 to 0.162 g g -1 day-1, and appeared to be an expression of transmembrane transport characteristics. Although kuf values were 1000-times lower than uptake rate constants from solution, biodynamic modeling showed that diet is the major Cd, Cu, and Ni source in nature. AE varied slightly among metals and exposure concentrations (84-95%). Suppression of Cd and Cu influxes upon exposure to extreme concentrations coincided with a 10-fold decrease in food IR, suggesting that feeding inhibition could act as an end point for dietary metal toxicity in L. stagnalis.

Environmental Science & Technology↗
USGS2008

Bioaccumulation of pharmaceuticals and other anthropogenic waste indicators in earthworms from agricultural soil amended with biosolid or swine manure

Analysis of earthworms offers potential for assessing the transfer of organic anthropogenic waste indicators (AWIs) derived from land-applied biosolid or manure to biota. Earthworms and soil samples were collected from three Midwest agricultural fields to measure the presence and potential for transfer of 77 AWIs from land-applied biosolids and livestock manure to earthworms. The sites consisted of a soybean field with no amendments of human or livestock waste (Site 1), a soybean field amended with biosolids from a municipal wastewater treatment plant (Site 2), and a cornfield amended with swine manure (Site 3). The biosolid applied to Site 2 contained a diverse composition of 28 AWIs, reflecting the presence of human-use compounds. The swine manure contained 12 AWIs, and was dominated by biogenic sterols. Soil and earthworm samples were collected in the spring (about 30 days after soil amendment) and fall (140−155 days after soil amendment) at all field sites. Soils from Site 1 contained 21 AWIs and soil from Sites 2 and 3 contained 19 AWIs. The AWI profiles at Sites 2 and 3 generally reflected the relative composition of AWIs present in waste material applied. There were 20 AWIs detected in earthworms from Site 1 (three compounds exceeding concentrations of 1000 µg/kg), 25 AWIs in earthworms from Site 2 (seven compounds exceeding concentrations of 1000 µg/kg), and 21 AWIs in earthworms from Site 3 (five compounds exceeding concentrations of 1000 µg/kg). A number of compounds that were present in the earthworm tissue were at concentrations less than reporting levels in the corresponding soil samples. The AWIs detected in earthworm tissue from the three field sites included pharmaceuticals, synthetic fragrances, detergent metabolites, polycyclic aromatic hydrocarbons (PAHs), biogenic sterols, disinfectants, and pesticides, reflecting a wide range of physicochemical properties. For those contaminants detected in earthworm tissue and soil, bioaccumulation factors (BAF) ranged from 0.05 (galaxolide) to 27 (triclosan). This study documents that when AWIs are present in source materials that are land applied, such as biosolids and swine manure, AWIs can be transferred to earthworms.

Environmental Science & Technology↗