NITRATE CONCENTRATIONS IN KARST SPRINGS IN AN EXTENSWELY GRAZED AREA1

ABSTRACT: The impact on water quality by agricultural activity in karst terrain is an important consideration for resource management within the Appalachian Region. Karst areas comprise about 18 percent of the Region's land area. An estimated one-third of the Region's farms, cattle, and agricultural market value are located on karst terrain. Nitrate concentrations were measured in several karst springs in Southeastern West Virginia in order to determine the impact of animal agriculture on nitrate pollution of the karst ground water system. Karst basins with 79, 51, 16, and 0 percent agriculture had mean nitrate concentrations of 15.8, 12.2, 2.7, and 0.4 mg/l, respectively. A strong linear relationship between nitrate concentration and percent agricultural land was shown. Median nitrate concentration increased about 0.19 mg l^-1 per percent increase in agricultural land. Weather patterns were also found to significantly affect the median nitrate concentrations and the temporal variability of those concentrations. Lower nitrate concentrations and lower temporal variability were observed during a severe drought period. It was concluded that agriculture was significantly affecting nitrate concentrations in the karst aquifer. Best management practices may be one way to protect the ground water resource.     

THE IMPACT OF STOCKWATERING PONDS (STOCKPONDS) ON RUNOFF FROM LARGE ARIZONA WATERSHEDS1

ABSTRACT: Major water rights adjudications involving the Little Colorado River Basin and Gila River Basin are presently underway within Arizona. Water resource managers are faced with the prospect of evaluating and regulating tens of thousands of water diversions and uses. Stockponds comprise a large percentage of the total number of water diversions within these basins. Water balance studies conducted on the Little Colorado River watershed above Lyman Lake and on the Gila River watershed above Solomon, Arizona, indicate that the impact of stockponds on the water available to downstream users is insignificant when compared to total watershed production. Considering that there are an estimated 25,000 stockponds in the Gila River basin alone, rigorous case-by-case investigations and stringent regulation of individual stockponds may be impractical and unwarranted. Therefore, stock-pond claims within the context of the general adjudication process may be effectively handled by partial summary judgment, thereby allowing the court to concentrate on major water users and water rights issues.     

Analysis of heavy metals in foliage near a modern refuse incinerator

Heavy metals such as cadmium and lead are typically found at high levels in fly ash from refuse incinerators. In two earlier studies it was found that such heavy metals on grass or tree foliage in the vicinity of old refuse incinerators with relatively low stacks and limited or no emission control devices showed a high degree of correlation between diminishing foliar concentration and the logarithm of sampling distance from the incinerator. In the study reported here of the concentration of cadmium and lead on foliage near a modern refuse incinerator with a high stack and efficient emission controls, the foliar concentrations of the metals showed no significant diminution with sampling distance from the incinerator. Factors affecting heavy metal emissions from refuse incinerators and contamination of nearby areas are discussed.     

Modeling transport and deposition of contaminants to ecosystems of concern: a case study for the Laurentian Great Lakes

Transfer efficiency (TE) is introduced as a model output that can be used to characterize the relative ability of chemicals to be transported in the environment and deposited to specific target ecosystems. We illustrate this concept by applying the Berkeley-Trent North American contaminant fate model (BETR North America) to identify organic chemicals with properties that result in efficient atmospheric transport and deposition to the Laurentian Great Lakes. By systematically applying the model to hypothetical organic chemicals that span a wide range of environmental partitioning properties, we identify combinations of properties that favor efficient transport and deposition to the Lakes. Five classes of chemicals are identified based on dominant transport and deposition pathways, and specific examples of chemicals in each class are identified and discussed. The role of vegetation in scavenging chemicals from the atmosphere is assessed, and found to have a negligible influence on transfer efficiency to the Great Lakes. Results indicate chemicals with octanol-water (K(ow)) and air-water (K(aw)) partition coefficients in the range of 10(5)-10(7) and 10(-4)-10(-1) combine efficient transport and deposition to the Great Lakes with potential for biaccumulation in the aquatic food web once they are deposited. A method of estimating the time scale for atmospheric transport and deposition process is suggested, and the effects of degrading reactions in the atmosphere and meteorological conditions on transport efficiency of different classes of chemicals are discussed. In total, this approach provides a method of identifying chemicals that are subject to long-range transport and deposition to specific target ecosystems as a result of their partitioning and persistence characteristics. Supported by an appropriate contaminant fate model, the approach can be applied to any target ecosystem of concern.     

Persistence and runoff losses of 3 herbicides and chlorpyrifos from a corn field in the Lake Balaton watershed of Hungary

Corn is intensively cultivated in western Hungary in the basin of Lake Balaton, one of the most important water resources in eastern Europe. Pesticide runoff was measured in 1996 and 1997 from a typical corn field near Zalaegerszeg, Hungary, which drains into the Zala River, an important water source of Lake Balaton. Three herbicides, namely atrazine, acetochlor, and propizochlor, and the insecticide chlorpyrifos were applied to bare soil in a field with 5% slope and soil and runoff water pesticide concentrations were monitored. In 1997, a rainfall-runoff simulation experiment was conducted on a small sub-plot in order to measure pesticide runoff under reasonable worst-case conditions. Under natural rainfall almost all losses occurred in a large runoff event in 1996 one month after application in which 3% of atrazine and 1% of acetochlor was transported off the field. Propizochlor and chlorpyrifos losses in the same event were much lower: 0.2% and <0.01%, respectively, because of these chemicals' shorter persistence times in near-surface soil. The rainfall simulation produced only trace amounts of losses even though 4.1 cm was applied in 2 hours; the soil was extremely dry and only 0.2 cm runoff occurred containing less than 0.01% of all chemicals applied. The results suggest that intensive use of corn herbicides, which have been found to result in widespread contamination of water resources elsewhere, may be expected to have the same impact in the Balaton watershed depending on the amounts and intensities used in the basin.     

Does male harassment of females contribute to reproductive synchrony in the grey seal by affecting maternal performance?

We investigated the possibility that male harassment of lactating females differed in relation to time of birth in the grey seal, Halichoerus grypus, on Sable Island, Nova Scotia. This was done by comparing the frequency of male disturbances, maternal performance and pup growth for females that either gave birth during the peak of the pupping season or after the peak. Of the females, 58% gave birth in a 7-day period near the beginning of the pupping period, when the operational sex ratio was 2–4 females per male. Late in the pupping period the operational sex ratio reversed to about 1 female for every 2 males. The relative frequency of disturbances by males was significantly greater for late-pupping mothers than for peak-pupping ones (1.9 vs. 1.4 encounters/h). Females that gave birth late also were disturbed by males 3 times more often than females that gave birth during the peak (3.4 vs. 1.1 % of observation time). Late-pupping mothers spent 22% less time suckling (4.0 vs. 5.1 % of observation time), had 30% slower growing pups (1.7 vs. 2.4 kg/d), and weaned pups that were 16% lighter (45.6 vs. 54.0 kg). The effect of birth time on pup mass gain and weaning mass was not attributable to factors such as maternal mass, pup birth mass or pup sex. We conclude that the reduced maternal performance is likely the result of the increased male harassment. As reduced weaning mass can lead to reduced juvenile survival, male harassment may have contributed to the enhanced reproductive synchrony in this species.     

RELATION OF PHYSICAL AND MINERALOGICAL PROPERTIES TO STREAMBANK STABILITY1

ABSTRACT. Alluvial streambank materials from nine unstable and six stable reaches showed little variation in physical and mineralogical properties. The bulk density of all the samples was so similar that they could be considered from the same population. Particle size distributions showed that the clay fractions were slightly, but significantly, higher for the stable reaches. The mineralogy of all samples was also quite similar. The sand-sized grains of the stable areas were less rounded than those of the unstable areas. This somewhat angular shape of the grains may have produced an interlocking between grains that added stability to the bank material. Also, clay coatings on the sand-sized grains from the stable areas may have caused cementation between grains that also strengthened the material.     

The effect of suspended particles coated by humic acid on the toxicity of pharmaceuticals, estrogens, and phenolic compounds

The sorption characteristics of 10 organic chemicals, categorized as pharmaceuticals, estrogens and phenols, onto synthetic suspended particle (i.e., alumina) coated with humic acid were investigated according to their octanol-water partition coefficient (K(ow)). Chemical analyses were performed with gas chromatography and mass spectrometry (GC/MS) and high performance liquid chromatography (HPLC). The effects of particles on the toxicity reduction were evaluated using bioassay tests, using Daphnia magna and Vibrio fisheri for phenols and pharmaceuticals, and the human breast cancer cell MCF-7 for estrogens. Sorption studies revealed that 22 and 38% of octylphenol and pentachlorophenol, respectively, were removed by suspended particle, whereas 2,4-dichlorophenol was not removed, which was directly proportional to the logK(ow) value. Similar to the sorption tests, suspended particles significantly reduced the acute toxicities of octylphenol and pentachlorophenol to D. magna and V. fisheri (p<0.01), but there was no significant difference in the toxicity of 2,4-dichlorophenol to D. magna (p=0.8374). Pharmaceuticals, such as ibuprofen, gemfibrozil and tolfenamic acid, showed no discernible sorption to the suspended particle, with the exception of diclofenac, which revealed 11% sorption. For estrogens, such as estrone, 17beta-estradiol and 17alpha-ethynylestradiol, the results indicated no reduction in the sorption test. This may be attributed to the polar interaction by functional groups in sorption between pharmaceuticals and estrogens and suspended particles. In the bioassays, presence of suspended particles did not significantly modify the toxicity of pharmaceuticals (regardless of their K(ow) values) to D. magna, V. fisheri or E-screen.     

New postcrania of Deccanolestes from the Late Cretaceous of India and their bearing on the evolutionary and biogeographic history of euarchontan mammals

Extant species of the supraordinal mammal clade Euarchonta belong to the orders Primates, Scandentia, or Dermoptera. The fossil record of euarchontans suggests that they underwent their initial radiation during the Paleocene (65–55 million years ago) in North America, Eurasia, and Africa. The time and place of origin is poorly resolved due to lack of definitive fossils of euarchontan stem taxa. We describe a fragmentary humerus and two fragmentary ulnae from the latest Cretaceous of India that bear significantly on this issue. The fossils are tentatively referred to Deccanolestes cf. hislopi due to their small size and the fact that Deccanolestes is the only eutherian dental taxon to have been recovered from the same locality. The new fossils are used to evaluate the existing behavioral hypothesis that Deccanolestes was arboreal, and the competing phylogenetic hypotheses that Deccanolestes is a stem eutherian versus a stem euarchontan. The humerus resembles those of euarchontans in possessing a laterally keeled ulnar trochlea, a distinct zona conoidea, and a spherical capitulum. These features also suggest an arboreal lifestyle. The ulnar morphology is consistent with that of the humerus in reflecting an arboreal/scansorial animal. Detailed quantitative comparisons indicate that, despite morphological correlates to euarchontan-like arboreality, the humerus of Deccanolestes is morphologically intermediate between those of Cretaceous “condylarthran” mammals and definitive Cenozoic euarchontans. Additionally, humeri attributed to adapisoriculids are morphologically intermediate between those of Deccanolestes and definitive euarchontans. If adapisoriculids are euarchontans, as recently proposed, our results suggest that Deccanolestes is more basal. The tentative identification of Deccanolestes as a basal stem euarchontan suggests that (1) Placentalia began to diversify and Euarchonta originated before the Cretaceous–Tertiary boundary and (2) the Indian subcontinent, Eurasia, and Africa are more likely places of origin for Euarchonta than is North America.     

Collectivism,propensity to trust and self-esteem as predictors of organizational citizenship in a non-work setting

This study examined organizational citizenship of residents in a housing cooperative setting where roles were not influenced by traditional employee–employer work relationships. Results demonstrate that the individual differences of collectivism and propensity to trust predicted organizational citizenship (assessed six months later). In addition, organizational-based self-esteem fully mediated the effects of collectivism and propensity to trust on organizational citizenship, and tenure moderated the trust—self-esteem relationship. We discuss the implications of these results given the changing nature of work and the increasing importance of non-work organizations. Copyright © 2000 John Wiley & Sons, Ltd.