Concentration models for dissolved nitrogen nutrients from non-point sources in potomac estuary

1991 ◽  
Vol 33 (4) ◽  
pp. 335-349
Author(s):  
Su-zan Yeh ◽  
Chu-fa Tsai ◽  
Robert E. Ulanowicz ◽  
Larry W. Douglass
Keyword(s):  
Point Sources ◽  
Dissolved Nitrogen ◽  
Nitrogen Nutrients ◽  
Potomac Estuary

Separation of Point and Diffuse Loads of Pollutants Using Monitoring Data of Rivers

1993 ◽  
Vol 28 (3-5) ◽  
pp. 165-175 ◽  
Author(s):  
H. Behrendt
Keyword(s):  
Heavy Metals ◽  
Reasonable Agreement ◽  
River System ◽  
Point Sources ◽  
New Method ◽  
Monitoring Data ◽  
Diffuse Sources ◽  
Dissolved Nitrogen ◽  
Lead And Zinc ◽  
Cadmium Lead

The results of a new method for estimating point and diffuse loads of rivers from analysis of monitoring data are presented (immission approach). The estimated point source loads of dissolved nitrogen, total phosphorus, and the heavy metals, cadmium, lead and zinc were compared with the loads of existing inventories. The diffuse loads of these pollutants were compared with estimations calculated on the basis of area related loads of the main diffuse sources (emission approach). Reasonable agreement was obtained in these comparisons, thus demonstrating the utility of the new method as a tool for analyzing point sources and diffuse loads of pollutants to a river system from analysis of monitoring data.

scholarly journals Long-term dynamics in nutrients, chlorophyll a and water quality parameters in the Lagoon of Venice

2020 ◽  
Vol 84 (3) ◽  
pp. 215 ◽  
Author(s):  
Francesco Acri ◽  
Federica Braga ◽  
Fabrizio Bernardi Aubry
Keyword(s):  
Global Climate ◽  
Quality Parameters ◽  
Climate Trends ◽  
Lagoon Of Venice ◽  
Anthropogenic Pressures ◽  
Ecosystem Research ◽  
Future Studies ◽  
Dissolved Nitrogen ◽  
Nitrogen Nutrients

Since 1997, CNR-ISMAR has been collecting monthly hydrochemical and phytoplankton data in the northern and central basins of the Lagoon of Venice. The data have been part of the International Long-Term Ecosystem Research (LTER) database since 2007, helping to fill a gap in lagoon environmental studies. Analysing our time series (1998-2017), we were able to observe a rise in water temperature due to climate trends, a reduction in trophic status mainly due to the lower input of inorganic dissolved nitrogen nutrients and an increase in transparency and dissolved oxygen related to the increased biomass of macrophytes (macroalgae and seagrasses). Finally, a reduction in phytoplankton biomass and an accompanying increase in seagrass and macroalgal cover were observed. Present and future studies will help to evaluate the ways in which the Lagoon of Venice ecosystem responds to anthropogenic pressures and global climate change.

Resistance Monitor and Control for Vacuum Evaporation of Metals and Carbon

1976 ◽  
Vol 34 ◽  
pp. 572-573
Author(s):  
Russell L. Steere ◽  
Eric F. Erbe ◽  
J. Michael Moseley
Keyword(s):  
Electronic Device ◽  
Point Sources ◽  
High Contrast ◽  
Variable Resistor ◽  
Quality Of Results ◽  
Low Contrast ◽  
Evaporation Source ◽  
And Control ◽  
At Will

We have designed and built an electronic device which compares the resistance of a defined area of vacuum evaporated material with a variable resistor. When the two resistances are matched, the device automatically disconnects the primary side of the substrate transformer and stops further evaporation.This approach to controlled evaporation in conjunction with the modified guns and evaporation source permits reliably reproducible multiple Pt shadow films from a single Pt wrapped carbon point source. The reproducibility from consecutive C point sources is also reliable. Furthermore, the device we have developed permits us to select a predetermined resistance so that low contrast high-resolution shadows, heavy high contrast shadows, or any grade in between can be selected at will. The reproducibility and quality of results are demonstrated in Figures 1-4 which represent evaporations at various settings of the variable resistor.

EVALUATION OF MOUNTAIN AREA AS NON-POINT SOURCE OF NITROGEN FOR SETO INLAND SEA: THE NORTHERN SHIKOKU REGION, JAPAN

2017 ◽  
Author(s):  
Shohei Morisawa ◽  
Shohei Morisawa ◽  
Yukio Komai ◽  
Yukio Komai ◽  
Takao Kunimatsu ◽  
...  
Keyword(s):  
Average Concentration ◽  
Point Sources ◽  
Seto Inland Sea ◽  
Mountain Streams ◽  
Unit Load ◽  
Mountain Areas ◽  
Mountain Area ◽  
The Seto Inland Sea ◽  
Unit Load Method ◽  
Important Position

The northern Shikoku region is located in the Western part of Japan and faces towards the Seto Inland Sea. The forest area, which is one of the non-point sources in the Seto Inland Sea watershed, occupies 75% of the land use in the watershed of the northern Shikoku region. The amount of loadings of nutrients and COD in the Seto Inland Sea has been estimated by the unit load method but actually the data has not been investigated. It is however, necessary to know the real concentration of nitrogen in mountain streams to evaluate the role which is the mountain area plays as non-point sources. Therefore, more water samples of mountain streams in the watershed need to be taken and the concentrations of nitrogen analyzed. The mountain streams in the northern Shikoku area were investigated from April, 2015 to November, 2015. The number of sampling sites was 283, in addition to the past data by Kunimatsu et al. The average concentration of nitrate nitrogen in Ehime, Kagawa, and Tokushima was 0.61mg/L, 0.78mg/L and 0.34mg/L, respectively. The environmental standard range for nitrogen in the Seto Inland Sea is from between less than 0.2mg/L and less than 1mg/L. Therefore, the average concentration of nitrogen in these regions was over category II, and those of mountain streams in Kagawa Prefecture exceeded category III. About 20% of mountain streams were more than 1mg/L. It has become clear that mountain areas occupy an important position as non-point sources for the Seto Inland Sea.

Nitrogen and phosphorus in the Vistula River, Poland -- changes from source to mouth

1994 ◽  
Vol 30 (5) ◽  
pp. 177-186 ◽  
Author(s):  
Karin Sundblad ◽  
Andrzej Tonderski ◽  
Jacek Rulewski
Keyword(s):  
Central Region ◽  
Northern Region ◽  
Point Sources ◽  
Nutrient Loss ◽  
Phosphorus Concentration ◽  
Nitrogen And Phosphorus ◽  
Concentration Data ◽  
Diffuse Sources ◽  
Vistula River ◽  
South Central

Nitrogen and phosphorus concentration data representing samples collected once a month for nine months at 13 locations along the Vistula River are considered in a preliminary discussion of the sources of the nutrients transported to the Baltic Sea. Concentrations in relation to flow data indicated substantial differences between subbasins. Based on those differences, on the area-specific nutrient loss for a six-month period and on the wastewater discharge in each subbasin, four regions could be recognized in the river basin: i) the southern region with a large impact of point sources, ii) the south central region, where diffuse sources seemed to be of major importance, iii) the north central region with a combined effect of point and diffuse sources, and retention in two reservoirs, iv) the northern region where point sources seemed to be the dominating source, at least for phosphorus. Our results illustrate the importance of differences in phosphorus retention between the basins. Long-term retention along the course of the river, particularly in the two reservoirs, must be estimated to allow proper source apportionment in the Vistula basin. Concentration decreases in the Wloclawek Reservoir varied between 44 and 68% for P, and 11 to 37% for N, in the months with significant retention. In some months, however, concentrations increased, indicating a release of nutrients.

UV-disinfection of treated wastewater: possible effects on surface waters

1994 ◽  
Vol 29 (12) ◽  
pp. 255-266 ◽  
Author(s):  
T. Gschlößl
Keyword(s):  
Uv Irradiation ◽  
Wastewater Treatment Plants ◽  
Technological Development ◽  
Research Work ◽  
Treatment Plant ◽  
Pilot Project ◽  
Point Sources ◽  
Treated Wastewater ◽  
Bathing Water Directive ◽  
Flowing Waters

UV-irradiation as an effective method of diminishing germs in the outlet of wastewater treatment plants was studied in a half-scale pilot-project sponsored by the State of Bavaria/BRD for a period of 3 years. Technical, physical and biological parameters capable of influencing this process were examined. The possibility to improve the hygienic and also the ecological structure of receiving waters was put to discussion. Possible effects of formed bypproducts upon the water biocoenosis of rivers were pointed out. The results demonstrated that UV-irradiation can diminish the number of germs in the outlet of a treatment plant to an extent which is sufficient to guarantee the maintenance of the bacteriological and presumably also the virological values set by the EC Bathing Water Directive. Nevertheless the UV-treatment process requires further technological development and research work concerning i.e. the improvement of hydraulic conditions, coat-forming on the quartz sleeves of the lamps, photochemical forming of by-products, after-growth and effects upon the localised benthic flora and fauna of the receiving water. It has to be stressed that a significant improvement of the bacteriological structure of flowing waters is only attainable, if the influx from non-point sources can be reduced simultaneously.

Evaluation and Avoidance of False Alarm by Controlling Rhine Water with Continuously Working Biotests

1994 ◽  
Vol 29 (3) ◽  
pp. 207-209 ◽  
Author(s):  
H. Puzicha
Keyword(s):  
Warning System ◽  
Point Sources ◽  
Trophic Levels ◽  
River Rhine ◽  
Wide Range ◽  
River Test ◽  
Continuous Working ◽  
Range Of Variation ◽  
Contaminant Load ◽  
Rhine Water

Effluents from point sources (industries, communities) and diffuse inputs introduce pollutants into the water of the river Rhine and cause a basic contaminant load. The aim is to establish a biological warning system to detect increased toxicity in addition to the already existing chemical-physical monitoring system. To cover a wide range of biocides, continuous working biotests at different trophic levels (bacteria, algae, mussels, water fleas, fishes) have been developed and proved. These are checked out for sensitivity against toxicants, reaction time, validity of data and practical handling under field conditions at the river. Test-specific appropriate methods are found to differentiate between the normal range of variation and true alarm signals.

Water Quality Prognosis and Cost Analysis of Pollution Abatement Measures in the Rhine Basin (The River Rhine Project: Ever)

1994 ◽  
Vol 29 (3) ◽  
pp. 95-106
Author(s):  
Alfred P. Benoist ◽  
Gerard H. Broseliske
Keyword(s):  
Water Quality ◽  
Pollution Abatement ◽  
Point Sources ◽  
Management Tool ◽  
River Rhine ◽  
Priority Pollutants ◽  
Rhine Basin ◽  
Frame Work ◽  
Water Quality Objectives ◽  
Calculation Models

For priority pollutants, the international Rhine Action Programme (RAP) aims to meet the quality objectives for the Rhine, set by the International Rhine Commission (IRC), by the year 2000. An assessment must be carried out to define additional measures exceeding best available technology (BAT) for point sources and best environmental practice (BEP) for diffuse sources for those priority pollutants still violating the quality objectives of the Rhine after implementing BAT and BEP only. To carry out the required assessments, an excessive amount of work and money is needed, including the application of sophisticated calculation models. For prioritizing reasons, the Institute for Inland Water Management and Waste Water Treatment (RIZA) initiated a project called EVER, which was conducted by DHV Water BV. EVER is the abbreviation of the Dutch equivalent for Effective Distribution of Emission Reductions (Effective Verdeling van Emissie Reducties). The aim of this project is to carry out a first and crude evaluation of the impact of abatement measures (BAT and BEP), as set by the IRC for the period 1985-1995. For those pollutants still showing a violation of the quality objectives for the Rhine in the year 1995, a range finding method is used, to predict the costs and impact of abatement measures exceeding BAT and BEP on the water quality of the Rhine. So, EVER is a management tool to prioritize the work to be done within the frame-work of the IRC, triggering the application of e.g. sophisticated calculation models for a selected number of priority pollutants. In EVER, the prognosis of the reduction of specific discharge rates for approximately forty priority pollutants is given for twelve sub-catchment areas for the year 1995. This prognosis is used to predict concentrations at eight international monitoring locations in the Rhine basin, using the discharges and concentrations of the year 1985 as a reference. The predicted concentrations for the year 1995 are compared with the (preliminary) water quality objectives as set by the IRC. The results indicate, that for six of the selected pollutants the number of available data is too small for sound predictions. Fifteen of the selected pollutants will satisfy the water quality objectives in 1995. Twenty (half) of the selected pollutants will still violate the quality objectives at several monitoring locations. These twenty pollutants are the basis for priorities to be set within the frame-work of the IRC for phase 3 (1995-2000) of the RAP. For these pollutants, additional abatement measures exceeding BAT and BEP are selected in EVER for the manageable groups of sources (anthropogenic non-point sources, industrial sources and municipal sources). Each measure is analyzed separately for costs and effectiveness. Finally the results of this project are integrated into a matrix system which will enable us to select the most effective mix of pollution abatement measures at the lowest costs. The result of the selected additional measures exceeding BAT and BEP shows that 17 pollutants will still violate the quality objectives.

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