Effects of calibration on L-THIA GIS runoff and pollutant estimation

Urbanization can result in alteration of a watershed's hydrologic response and water quality. To simulate hydrologic and water quality impacts of land use changes, the Long-Term Hydrologic Impact Assessment (L-THIA) system has been used. The L-THIA system estimates pollutant loading based on direct runoff quantity and land use based pollutant coefficients. The accurate estimation of direct runoff is important in assessing water quality impacts of land use changes. An automated program was developed to calibrate the L-THIA model using the millions of curve number (CN) combinations associated with land uses and hydrologic soil groups. L-THIA calibration for the Little Eagle Creek (LEC) watershed near Indianapolis, Indiana was performed using land use data for 1991 and daily rainfall data for six months of 1991 (January 1-June 30) to minimize errors associated with use of different temporal land use data and rainfall data. For the calibration period, the Nash-Sutcliffe coefficient was 0.60 for estimated and observed direct runoff. The calibrated CN values were used for validation of the model for the same year (July 1-December 31), and the Nash-Sutcliffe coefficient was 0.60 for estimated and observed direct runoff. The Nash-Sutcliffe coefficient was 0.52 for January 1, 1991 to December 31, 1991 using uncalibrated CN values. As shown in this study, the use of better input parameters for the L-THIA model can improve accuracy. The effects on direct runoff and pollutant estimation of the calibrated CN values in the L-THIA model were investigated for the LEC. Following calibration, the estimated average annual direct runoff for the LEC watershed increased by 34%, total nitrogen by 24%, total phosphorus by 22%, and total lead by 43%. This study demonstrates that the L-THIA model should be calibrated and validated prior to application in a particular watershed to more accurately assess the effects of land use changes on hydrology and water quality.     

Trophoblast-like cells sorted from peripheral maternal blood using flow cytometry: A multiparametric study involving transmission electron microscopy and fetal dna amplification

Three monoclonal antibodies (MAbs) against trophoblast (GB17, GB21, and GB25) and flow cytometry were used to sort trophoblast-like cells (TLCs) from peripheral blood of pregnant women. Sorted TLCs were processed for electron microscopy and fetal DNA amplification of the Y-specific sequences from mothers carrying male fetuses. At the ultra-structural level, most of the nucleated cells had the morphology of leucocytes, suggesting maternal contaminants, and we did not find the characteristic features of the free inter-villous trophoblast cells. Nevertheless, polymerase chain reaction (PCR) analysis showed an amplification of Y-specific sequences in two out of three samples of sorted TLCs. These results suggest that besides the maternal leucocytes, sufficient trophoblast nucleated fetal cells can be obtained using cell enrichment by sorting. This sensitive method holds promise for non-invasive prenatal diagnosis of fetal sex and if sufficient Y(positive) nuclei are found, for the diagnosis of selected numerical chromosome abnormalities.     

Disposal of Mine Wastes Containing Pb and Zn Near the Ocean: An Assessment of Associated Environmental Implications in the Arctic

The past two decades have witnessed an increase in the exploration for, and development of, mineral resources at Arctic latitudes. Such effort has resulted in the commencement of production at a number of different localities in close proximity to the ocean. Since proximity to a source of transportation for the conveyance of concentrates to the market is a primary requirement governing the economic decisions for the mine to proceed, it is logical that ore deposits near a coastline are primary targets for development.

Closely tied to coastal mining developments is the need to dispose of tailings and waste rock in the most economical manner. Prior to the advent of heightened public awareness and environmental concern, and the enactment of pollution legislation, disposal practices were largely based upon convenience. Currently, however, proposed disposal and operating practices receive closer scrutiny, with a view to providing adequate protection for aquatic resources and habitat. This paper summarizes some of the features of three Arctic mines, wastes from which enter the marine environment, and compares the disposal practices used at each to measures of environmental change as indicated by metal concentrations in various media.     

Environmental auditor qualifications: Meeting new,rigorous demands for quality audits

“Ah, Mr. Cahill, I wonder if you could come back to the auditor's team room. It seems one of your auditors has fallen asleep for the second time this week. I know you had a grueling trip getting here, but this is embarrassing to everyone”. So went an audit I led some time ago. It was not a fun experience, and it has left some scars. There has been much discussion lately in the profession about certifying environmental (health and safety) auditors against certain performance criteria. But how does one evaluate for such important measures as physical stamina?. This article discusses the qualifications that environmental auditors should have if they are to lead or conduct a quality audit. It becomes evident after reviewing these expectations that certifying auditors through a traditional written examination might ignore some of the most important skills an auditor should possess, especially in working with managers throughout an organization. Before certifying organizations progress too far down the restrictive written-exam road, they should determine how these other skills are to be assessed. No amount of book learning can overcome the drawbacks of a poor or combative interviewer or even an exhausted auditor.     

Soil nitrate nitrogen dynamics after biosolids application in a tobosagrass desert grassland

Dormant-season application of biosolids increases desert grass production more than growing season application in the first growing season after application. Differential patterns of NO3-N (plant available N) release following seasonal biosolids application may explain this response. Experiments were conducted to determine soil nitrate nitrogen dynamics following application of biosolids during two seasons in a tobosagrass [Hilaria mutica (Buckl.) Benth.] Chihuahuan Desert grassland. Biosolids were applied either in the dormant (early April) or growing (early July) season at 0, 18, or 34 dry Mg ha(-1). A polyester-nylon mulch was also applied to serve as a control that approximated the same physical effects on the soil surface as the biosolids but without any chemical effects. Supplemental irrigation was applied to half of the plots. Soil NO3-N was measured at two depths (0-5 and 5-15 cm) underneath biosolids (or mulch) and in interspace positions relative to surface location of biosolids (or mulch). Dormant-season biosolids application significantly increased soil NO3-N during the first growing season, and also increased soil NO3-N throughout the first growing season compared to growing-season biosolids application in a year of higher-than-average spring precipitation. In a year of lower-than-average spring precipitation, season of application did not affect soil NO3-N. Soil NO3-N was higher at both biosolids rates for both seasons of application than in the control treatment. Biosolids increased soil NO3-N compared to the inert mulch. Irrigation did not significantly affect soil NO3-N. Soil NO3-N was not significantly different underneath biosolids and in interspace positions. Surface soil NO3-N was higher during the first year of biosolids application, and subsurface soil NO3-N increased during the second year. Results showed that biosolids rate and season of application affected soil NO3-N measured during the growing season. Under dry spring-normal summer precipitation conditions, season of application did not affect soil NO3-N; in contrast, dormant season application increased soil NO3-N more than growing season application under wet spring-dry summer conditions.     

The Influence of Chironomus plumosus Larvae on Nutrient Fluxes and Phosphorus Fractions in Aluminum Treated Lake Sediment

One of the methods to diminish the internal phosphorus (P) loading is inactivation of P by aluminum (Al). After addition of Al to lake water an Al(OH)₃ floc is formed, which settles to the bottom and initially form a lid on the sediment surface. The effects of Chironomus plumosus larvae on sediment nutrient fluxes and P binding-sites in the sediment after addition of Al were tested. C. plumosus larvae were added to sediment cores in which sediment–water fluxes of nutrients were measured four times. After one month, the sediment was sectioned with depth and P fractions were measured by sequential chemical extraction. The chironomids created burrows through the Al layer which caused a significantly increased efflux of P from the Al treated sediment, because the P had only limited contact to the added Al. The chironomids also affected the P fractions in the sediment by their bioturbating activity. Thus, they caused increased Al concentrations in the upper part of the Al treated sediment. This created an enhanced contact between Al and P in the upper 7 cm of the sediment and, as a result, an increased binding of P to Al and a lowered porewater P. The DIP efflux is therefore expected to be lowered after the initial phase. Al had no effects on the nitrogen fluxes, but the chironomids enhanced the release, and decreased the release or increased the uptake by the sediments.     

Decision support systems for stored water quality: 2. An example application

The components of an environmental decision support system (EDSS) were outlined in Part 1 of this paper. Here, an example application is given using a range of data from the database in order to assess the utility of one specific model chosen from the modelbase: the one-dimensional thermal stratification model, EDD1. The model is applied to a range of lake types worldwide.     

Measuring bed shear stress along vegetated river beds using FST-hemispheres

The measurement of the bed shear stress along vegetated river beds is essential for accurately predicting the water level, velocity and solute and sediment transport fluxes in computational hydroenvironmental models. Details are given herein of an experimental and theoretical study to determine the bed boundary shear stress along vegetated river beds introducing a novel field measuring method, namely the FliessWasserStammtisch (FST)-hemispheres. Although investigations have been conducted previously for sedimentary channels using the FST-hemispheres, this preliminary study is thought to be the first time that such hemispheres have been used to investigate the bed shear stresses in vegetated channels. FST-hemispheres were first developed by Statzner and Müller [1989. Standard hemispheres as indicators of flow characteristics in lotic benthos research. Freshwater Biology 21, 445-459] to act as an integrated indicator of the gross hydrodynamic stresses present near the bed. Test and validation data were found to be at least of the same order of magnitude for the stresses predicted from literature for sedimentary channels, with this study establishing the commencement of a database of calibrated FST-hemisphere laboratory data for vegetated channel beds. In a series of experiments, depths ranging from 0.1 to 0.28m were considered, equating directly to comparable conditions in small rivers or streams. The results of this study provide a basis for enabling the FST-hemispheres to be used to evaluate the boundary shear stress for a wider range of applications in the future, including vegetated river beds.     

Prenatal prediction of childhood-onset spinal muscular atrophy (SMA) in Turkish families

Childhood-onset spinal muscular atrophy (SMA) is one of the most common neurodegenerative genetic disorders. SMN1 is the SMA-determining gene deleted or mutated in the majority of SMA cases. There is no effective cure or treatment for this disease yet. Thus, the availability of prenatal testing is important. Here we report prenatal prediction for 68 fetuses in 63 Turkish SMA families using direct deletion analysis of the SMN1 gene by restriction digestion. The genotype of the index case was known in 40 families (Group A) but unknown in the remaining 23 families (Group B). A total of ten fetuses were predicted to be affected. Eight of these fetuses were derived from Group A and two of these fetuses were from Group B families. Two fetuses from the same family in Group A had the SMNhyb1 gene in addition to homozygous deletion of the NAIP gene. One fetus from Group A was homozygously deleted for only exon 8 of the SMN2 gene, and further analysis showed the presence of both the SMN1 and SMNhyb1 genes but not the SMN2 gene. In addition, one carrier with a homozygous deletion of only exon 8 of the SMN1 gene was detected to have a SMNhyb2 gene, which was also found in the fetus. To our knowledge, these are the first prenatal cases with SMNhyb genes. Follow-up studies demonstrated that the prenatal predictions and the phenotype of the fetuses correlated well in 33 type I pregnancies demonstrating that a careful molecular analysis of the SMN genes is very useful in predicting the phenotype of the fetus in families at risk for SMA. Copyright © 2002 John Wiley & Sons, Ltd.