Ground-water quality and its relation to land use on Oahu, Hawaii, 2000-01

Shipping list no.: 2005-0044-P. "National Water-Quality Assessment Program." Includes bibliographical references (pages 55-57). Also available via Internet at the USGS web site. Address as of 01/07/05: http://water.usgs.gov/pubs/wri/wri034305/pdf/wri034305.pdf; current access available via PURL.Water quality in the main drinking-water source aquifers of Oahu was assessed by a one-time sampling of untreated ground water from 30 public-supply wells and 15 monitoring wells. The 384 square-mile study area, which includes urban Honolulu and large tracts of forested, agricultural, and suburban residential lands in central Oahu, accounts for 93 percent of the island’s groundwater withdrawals. Organic compounds were detected in 73 percent of public-supply wells, but mostly at low concentrations below minimum reporting levels. Concentrations exceeded drinking-water standards in just a few cases: the solvent trichloroethene and the radionuclide radon-222 exceeded Federal standards in one public-supply well each, and the fumigants 1,2-dibromo-3-chloropropane (DBCP) and 1,2,3-trichloropropane (TCP) exceeded State standards in three public-supply wells each. Solvents, fumigants, trihalomethanes, and herbicides were prevalent (detected in more than 30 percent of samples) but gasoline components and insecticides were detected in few wells. Most water samples contained complex mixtures of organic compounds: multiple solvents, fumigants, or herbicides, and in some cases compounds from two or all three of these classes. Characteristic suites of chemicals were associated with particular land uses and geographic locales. Solvents were associated with central Oahu urban-military lands whereas fumigants, herbicides, and fertilizer nutrients were associated with central Oahu agricultural lands. Somewhat unexpectedly, little contamination was detected in Honolulu where urban density is highest, most likely as a consequence of sound land-use planning, favorable aquifer structure, and less intensive application of chemicals (or of less mobile chemicals) over recharge zones in comparison to agricultural areas. For the most part, organic and nutrient contamination appear to reflect decades-old releases and former land use. Most ground water ages were decades old, with recharge dates ranging from pre-1940 to the present, and with most dates falling within the 1950s to 1980s time span. Several widely detected compounds were discontinued as long ago as the 1970s but have yet to be flushed from the ground-water system. Although large tracts of land in central Oahu have been converted from agriculture to residential urban use since the 1950s, water quality in the converted areas still more closely reflects the former agricultural land. It appears to be too early to detect a distinct water-quality signature characteristic of the newer urban use, although several urban turfgrass herbicides in use for just 10 years or so were detected in monitoring wells and may represent early arrivals of urban contaminants at the water table

Global net carbon exchange and intra-annual atmospheric CO2 concentrations predicted by an Ecosystem Process Model and Three-Dimensional Atmospheric Transport Model

A generalized terrestrial ecosystem process model, BIOME-BGC (for BIOME BioGeoChemical Cycles), was used to simulate the global fluxes of CO2 resulting from photosynthesis, autotrophic respiration, and heterotrophic respiration. Daily meteorological data for the year 1987, gridded to 1° by 1°, were used to drive the model simulations. From the maximum value of the normalized difference vegetation index (NDVI) for 1987, the leaf area index for each grid cell was computed. Global NPP was estimated to be 52 Pg C, and global Rh was estimated to be 66 Pg C. Model predictions of the stable carbon isotopic ratio 13C/12C for C3 and C4 vegetation were in accord with values published in the literature, suggesting that our computations of total net photosynthesis, and thus NPP, are more reliable than Rh. For each grid cell, daily Rh was adjusted so that the annual total was equal to annual NPP, and the resulting net carbon fluxes were used as inputs to a three-dimensional atmospheric transport model (TM2) using wind data from 1987. We compared the spatial and seasonal patterns of NPP with a diagnostic NDVI model, where NPP was derived from biweekly NDVI data and Rh was tuned to fit atmospheric CO2 observations from three northern stations. To an encouraging degree, predictions from the BIOME-BGC model agreed in phase and amplitude with observed atmospheric CO2 concentrations for 20° to 55°N, the zone in which the most complete data on ecosystem processes and meteorological input data are available. However, in the tropics and high northern latitudes, disagreements between simulated and measured CO2 concentrations indicated areas where the model could be improved. We present here a methodology by which terrestrial ecosystem models can be tested globally, not by comparisons to homogeneous-plot data, but by seasonal and spatial consistency with a diagnostic NDVI model and atmospheric CO2 observations

New Observations of the Interstellar Medium in the Lyman Break Galaxy MS 1512-cB58

We present the results of a detailed study of the interstellar medium of MS 1512-cB58, an L* Lyman break galaxy at z = 2.7276, based on new spectral observations obtained with the Echelle Spectrograph and Imager on the Keck II telescope at 58 km/s resolution. We focus in particular on the chemical abundances and kinematics of the interstellar gas and our main findings are as follows. Even at this relatively early epoch, the ISM of this galaxy is already highly enriched in elements released by Type II supernovae; the abundances of O, Mg, Si, P, and S are all about 2/5 of their solar values. In contrast, N and the Fe-peak elements Mn, Fe, and Ni are underabundant by a factor of about 3. Based on current ideas of stellar nucleosynthesis, these results can be understood if most of the metal enrichment in cB58 has taken place within the last 300 million years, the timescale for the release of N from intermediate mass stars. cB58 appears to be an example of a galaxy in the process of converting its gas into stars on a few dynamical timescales; quite possibly we are witnessing the formation of a galactic bulge or an elliptical galaxy. The energetic star formation activity has stirred the interstellar medium to high velocities of up to 1000 km/s. The net effect is a bulk outflow of the ISM at a speed of 255 km/s and at a rate which exceeds the star formation rate. It is unclear whether this gas will be lost or retained by the galaxy. We point out that the chemical and kinematic properties of cB58 are markedly different from those of most damped Lyman alpha systems at the same redshift.Comment: 38 pages, LaTeX, 9 Postscript Figures. Accepted for publication in the Astrophysical Journal. Sections 3.3 and 5.3 expanded, and two additional figures included, following referee's repor

The emission by dust and stars of nearby galaxies in the Herschel KINGFISH survey

Using new far-infrared imaging from the Herschel Space Observatory with ancillary data from ultraviolet (UV) to submillimeter wavelengths, we estimate the total emission from dust and stars of 62 nearby galaxies in the KINGFISH survey in a way that is as empirical and model independent as possible. We collect and exploit these data in order to measure from the spectral energy distributions (SEDs) precisely how much stellar radiation is intercepted and re-radiated by dust, and how this quantity varies with galaxy properties. By including SPIRE data, we are more sensitive to emission from cold dust grains than previous analyses at shorter wavelengths, allowing for more accurate estimates of dust temperatures and masses. The dust/stellar flux ratio, which we measure by integrating the SEDs, has a range of nearly three decades (from 10(-2.2) to 10(0.5)). The inclusion of SPIRE data shows that estimates based on data not reaching these far-IR wavelengths are biased low by 17% on average. We find that the dust/stellar flux ratio varies with morphology and total infrared (IR) luminosity, with dwarf galaxies having faint luminosities, spirals having relatively high dust/stellar ratios and IR luminosities, and some early types having low dust/stellar ratios. We also find that dust/stellar flux ratios are related to gas-phase metallicity ((log(f(dust)/f(*)) over bar) = -0.66 +/- 0.08 and -0.22 +/- 0.12 for metal-poor and intermediate-metallicity galaxies, respectively), while the dust/stellar mass ratios are less so (differing by approximate to 0.2 dex); the more metal-rich galaxies span a much wider range of the flux ratios. In addition, the substantial scatter between dust/stellar flux and dust/stellar mass indicates that the former is a poor proxy of the latter. Comparing the dust/stellar flux ratios and dust temperatures, we also show that early types tend to have slightly warmer temperatures (by up to 5 K) than spiral galaxies, which may be due to more intense interstellar radiation fields, or possibly to different dust grain compositions. Finally, we show that early types and early-type spirals have a strong correlation between the dust/stellar flux ratio and specific star formation rate, which suggests that the relatively bright far-IR emission of some of these galaxies is due to ongoing (if limited) star formation as well as to the radiation field from older stars, which is heating the dust grains

Spitzer IRAC Observations of Star Formation in N159 in the LMC

We present observations of the giant HII region complex N159 in the LMC using IRAC on the {\it Spitzer Space Telescope}. One of the two objects previously identified as protostars in N159 has an SED consistent with classification as a Class I young stellar object (YSO) and the other is probably a Class I YSO as well, making these two stars the youngest stars known outside the Milky Way. We identify two other sources that may also be Class I YSOs. One component, N159AN, is completely hidden at optical wavelengths, but is very prominent in the infrared. The integrated luminosity of the entire complex is L $\approx 9\times10^6$L$_{\odot}$, consistent with the observed radio emission assuming a normal Galactic initial mass function (IMF). There is no evidence for a red supergiant population indicative of an older burst of star formation. The N159 complex is 50 pc in diameter, larger in physical size than typical HII regions in the Milky Way with comparable luminosity. We argue that all of the individual components are related in their star formation history. The morphology of the region is consistent with a wind blown bubble $\approx 1-2Myr-old that has initiated star formation now taking place at the rim. Other than its large physical size, star formation in N159 appears to be indistinguishable from star formation in the Milky Way.Comment: 14 figure

Effect of rainfall timing and tillage on the transport of steroidhormones in runoff from manure amended row crop fields

Runoff generated from livestock manure amended row crop fields is one of the major pathways of hormone transport to the aquatic environment. The study determined the effects of manure handling, tillage methods, and rainfall timing on the occurrence and transport of steroid hormones in runoff from the row crop field. Stockpiled and composted manure from hormone treated and untreated animals were applied to test plots and subjected to two rainfall simulation events 30 days apart. During the two rainfall simulation events, detection of any steroid hormone or metabolites was identified in 8–86% of runoff samples from any tillage and manure treatment. The most commonly detected hormones were 17 _estradiol, estrone, estriol, testosterone, and _zearalenol at concentrations ranging up to 100–200 ng L−1. Considering the maximum detected concentrations in runoff, no more than 10% of the applied hormone can be transported through the dissolved phase of runoff. Results from the study indicate that hormones can persist in soils receiving livestock manure over an extended period of time and the dissolved phase of hormone in runoff is not the preferred pathway of transport from the manure applied fields irrespective of tillage treatments and timing of rainfall

The mouse deafness locus (dn) is associated with an inversion on chromosome 19

Recombination data for the mouse deafness locus (dn) on chromosome 19 are consistent with the presence of an inversion for which one of the breakpoints is between D19Mit14 and D19Mit96, a distance of less than 226 kb. Fluorescence in situ hybridization studies using a bacterial artificial chromosome on interphase (G1) nuclei provide additional support for the presence of an inversion. The dn gene is probably the orthologue of the human DFNB7/DFNB11 gene on chromosome 9. Copyright (C) 1998 Elsevier Science B.V

Effect of Composting on the Fate of Steroids in Beef Cattle Manure

In this study, the fate of steroid hormones in beef cattle manure composting is evaluated. The fate of 16 steroids and metabolites was evaluated in composted manure from beef cattle administered growth promotants and from beef cattle with no steroid hormone implants. The fate of estrogens (primary detected as estrone), androgens, progesterone, and the fusarium metabolite and implant a-zearalanol was monitored in manure compost piles. First-order decay rates were calculated for steroid half-lives in compost and ranged from 8 d for androsterone to 69 d for 4-androstenedione. Other steroid concentration data could not be fit to first-order decay models, which may indicate that microbial processes may result in steroid production or synthesis in composting systems. We demonstrate that composting is an effective strategy to remove steroid hormones from manure. Total steroid hormone removal in composted beef cattle manure ranged from 79 to 87%