Name: calibrated passive sampling - multi-plot field measurements of nh3 emissions with a combination of dynamic tube method and passive samplers
Uploaded: 2016-03-21T13:00:00
Description: Watch this Scientific Journal Video about Calibrated Passive Sampling - Multi-plot Field Measurements of NH3 Emissions with a Combination of Dynamic Tube Method and Passive Samplers at JoVE.com

The author is grateful to Dr. Marco Roelcke, Dr. Dirk Niekisch, Dr. Robert Quakernack, Dr. Kang Ni for their effort in developing and further development of this approach. Many thanks also to the field technicians Doris Ziermann and Jun Yang. The underlying investigations were supported by Deutsche Forschungsgemeinschaft, the Federal State Schleswig Holstein, EFRE grants of the European Union and SKW Piesteritz corp. as indicated in detail in the cited publications.

1. Experimental Design and General Operational Instructions
<ol>
	<li>Use comparatively large plots (12 m x 12 m or 9 m x 9 m) as compared to the sizes usually applied in replicated field trials (e.g. 3 m x 8 m) to avoid effects of uneven fertilizer distribution on ammonia emissions (Figure 2). Use square plot shapes to avoid effects of shifting wind directions on ammonia uptake by the samplers. Reduce drift of NH3 from one plot to the other to an acceptable degree by keeping a buff...

<ol>
	<li>Erisman, J. W., Bleeker, A., Hensen, A., Vermeulen, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Agricultural+air+quality+in+Europe+and+the+future+perspectives.">Agricultural air quality in Europe and the future perspectives.</a> Atmos. Environ. 42, 3209-3217 (2008).</li><li>Bremner, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Recent+research+on+problems+in+the+use+of+urea+as+a+nitrogen+fertilizer.">Recent research on problems in the use of urea as a nitrogen fertilizer.</a> Fert. Res. 42, 321-329 (1995).</li><li>Sutton, M. A., Oenema, O., Erisman, J. W., Leip, A., van Grinsven, H., Winiwarter, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Too+much+of+a+good+thing.">Too much of a good thing.</a> Nature. 472, 159-161 (2011).</li><li>Glibert, P. M., Harrison, J., Heil, C., Seitzinger, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Escalating+worldwide+use+of+urea+-+a+global+change+contributing+to+coastal+eutrophication.">Escalating worldwide use of urea - a global change contributing to coastal eutrophication.</a> Biogeochemistry. 77, 441-463 (2006).</li><li>Sommer, S. G., Schjoerring, J. K., Denmead, O. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ammonia+emission+from+mineral+fertilizers+and+fertilized+crops.">Ammonia emission from mineral fertilizers and fertilized crops.</a> Adv. Agron. 82, 557-622 (2004).</li><li>Jensen, L. S., et al., Sutton, M. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Benefits+of+nitrogen+for+food,+fibre+and+industrial+production.">Benefits of nitrogen for food, fibre and industrial production.</a> The European Nitrogen Assessment. , (2011).</li><li>Sommer, S. G., Hutchings, N. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ammonia+emission+from+field+applied+manure+and+its+reduction+-+invited+paper.">Ammonia emission from field applied manure and its reduction - invited paper.</a> Eur. J. Agron. 15, 1-15 (2001).</li><li>Shah, S. B., Westerman, P. W., Arogo, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Measuring+ammonia+concentrations+and+emissions+from+agricultural+land+and+liquid+surfaces:+A+review.">Measuring ammonia concentrations and emissions from agricultural land and liquid surfaces: A review.</a> J. Air Waste Manage. 56, 945-960 (2006).</li><li>Loubet, B., Cellier, P., Flura, D., Genermont, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+evaluation+of+the+wind-tunnel+technique+for+estimating+ammonia+volatilization+from+land:+Part+1.+Analysis+and+improvement+of+accuracy.">An evaluation of the wind-tunnel technique for estimating ammonia volatilization from land: Part 1. Analysis and improvement of accuracy.</a> J. Agr. Eng. Res. 72, 71-81 (1999).</li><li>Vandr&#233;, R., Kaupenjohann, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+Situ+Measurements+of+Ammonia+Emissions+from+Organic+Fertilizers+in+Plot+Experiments.">In Situ Measurements of Ammonia Emissions from Organic Fertilizers in Plot Experiments.</a> Soil Sci. Soc. Am. J. 62, 467-473 (1998).</li><li>Roelcke, M., Li, S. X., Tian, X. H., Gao, Y. J., Richter, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+situ+comparisons+of+ammonia+volatilization+from+N+fertilizers+in+Chinese+loess+soils.">In situ comparisons of ammonia volatilization from N fertilizers in Chinese loess soils.</a> Nutr. Cycling Agroecosyst. 62 (1), 73-88 (2002).</li><li>Pacholski, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Calibration+of+a+simple+method+for+determining+ammonia+volatilization+in+the+field+-+comparative+measurements+in+Henan+Province,+China.">Calibration of a simple method for determining ammonia volatilization in the field - comparative measurements in Henan Province, China.</a> Nutr. Cycling Agroecosyst. 74, 259-273 (2006).</li><li>Flesch, T. K., Harper, L. A., Powell, J. M., Wilson, J. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Inverse-dispersion+calculation+of+ammonia+emissions+from+Wisconsin+dairy+farms.">Inverse-dispersion calculation of ammonia emissions from Wisconsin dairy farms.</a> Trans. ASABE. 52, 253-265 (2009).</li><li>Gericke, D., Pacholski, A., Kage, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Measurement+of+ammonia+emissions+in+multi-plot+field+experiments.">Measurement of ammonia emissions in multi-plot field experiments.</a> Biosystems Eng. 108 (2), 164-173 (2011).</li><li>Quakernack, R., Pacholski, A., Techow, A., Herrmann, A., Taube, F., Kage, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ammonia+volatilization+and+yield+response+after+application+of+biogas+residues+to+energy+crops+in+a+coastal+marsh+of+Northern+Germany.">Ammonia volatilization and yield response after application of biogas residues to energy crops in a coastal marsh of Northern Germany.</a> Agric., Ecosyst. Environ. 160, 66-74 (2012).</li><li>Ni, K., Pacholski, A., Gericke, D., Kage, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Measurement+duration+required+for+determining+total+ammonia+losses+after+field+application+of+slurries+by+trail+hoses.">Measurement duration required for determining total ammonia losses after field application of slurries by trail hoses.</a> J. Agr. Sci. 151 (1), 34-43 (2013).</li><li>von Bobrutzki, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Field+inter-comparison+of+eleven+atmospheric+ammonia+measurement+techniques.">Field inter-comparison of eleven atmospheric ammonia measurement techniques.</a> Atmos. Meas. Tech. 3, 91-112 (2010).</li><li>Ni, K., Pacholski, A., Kage, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ammonia+volatilization+after+application+of+urea+to+winter+wheat+over+3+years+affected+by+novel+urease+and+nitrification+inhibitors.">Ammonia volatilization after application of urea to winter wheat over 3 years affected by novel urease and nitrification inhibitors.</a> Agric. Ecosyst. Environ. 197, 184-194 (2014).</li><li>Sintermann, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Are+ammonia+emissions+from+field-applied+slurry+substantially+over-estimated+in+European+emission+inventories.">Are ammonia emissions from field-applied slurry substantially over-estimated in European emission inventories.</a> Biogeosciences. 9, 1611-1632 (2012).</li><li>Mannheim, T., Braschkat, J., Marschner, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Measurement+of+ammonia+emission+after+liquid+manure+application.+2.+Comparison+of+the+wind+tunnel+and+the+IHF+method+under+field+conditions.">Measurement of ammonia emission after liquid manure application. 2. Comparison of the wind tunnel and the IHF method under field conditions.</a> J. Plant Nutr. Soil Sci. 158, 215-219 (1995).</li><li>Puchalski, M. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Passive+ammonia+monitoring+in+the+United+States:+Comparing+three+different+sampling+devices.">Passive ammonia monitoring in the United States: Comparing three different sampling devices.</a> Environ. Monit. 13 (11), 3156-3167 (2011).</li><li>Tang, Y. S., Cape, J. N., Sutton, M. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+and+types+of+passive+samplers+for+monitoring+atmospheric+NO2+and+NH3+concentrations.">Development and types of passive samplers for monitoring atmospheric NO2 and NH3 concentrations.</a> ScientificWorldJournal. 1, 513-529 (2001).</li></ol>

It was shown that the proposed method can be used to compare ammonia emissions from different fertilizer treatments in replicated field trials and to use the obtained statistically significant information from these measurements to improve management of N fertilizers. The quantity of emissions obtained by this approach has been validated in earlier studies by comparison with micrometeorological measurements13,15,16. In this paper, the quantitative validity of this approach was indirectly demonstrated by a clos...

Ammonia (NH3) is the only atmospheric trace gas predominantly (90%) emitted from agricultural sources in the EU. Although agriculture is also a major source (&#62;50% of EU emissions), these contribute only to about ~5% to the total of EU15 anthropogenic greenhouse gas emissions. In contrast, agricultural NH3 emissions are responsible for about 45% of emission-derived eutrophication, 31% of acidification and 12% fine dust formation within the EU151. In addition to detrimental effects to ecosystems and human health, nitrogen (N) loss by NH3 emission is an economic loss to farmers2. Nitrogen fertilizer is essential for the high rate of food production delivered by modern agriculture. Apart of the environmental damage, NH3 emissions thus, mean a considerable loss of nutrients, as NH3 is derived from fertilizer ammonium, in addition to nitrate the key mineral nitrogen species directly available to the plant governing crop growth processes and yield. Application of N fertilizers contributes &#8364;20-80 billion of profit per year for EU farmers but in turn it was estimated that NH3 released into the air from agriculture causes ~&#8364;50 billion in annual damage in the EU3. Therefore, reduction of NH3 emissions is essential for both decreasing the environmental effects and increasing the efficiency of the applied N.
In agriculture, NH3 is mainly emitted from animal houses, manure (slurries, anaerobic digestates (AD), solid manure) storage and management as well as manure field application. The propensity to emit NH3 differs depending on manure composition, e.g. dry matter content and manure pH. To some extent ammonium and amine based synthetic nitrogen fertilizers as urea and diammonium phosphate also contribute to NH3 emissions. Although calcareous ammonium nitrate (CAN) is the principal N fertilizer in many European countries, the use of granular urea has increased, and was second to CAN in Central and Western Europe in 20124. Urea is particularly popular in developing countries due to its advantages of a high N content, safety, and easy transportation and is the world&#39;s most important synthetic nitrogen fertilizer5. However, the increase of pH and surface soil NH4+-concentrations resulting from urea hydrolysis can result in high NH3 emissions. This can cause low N use efficiency, especially in alkaline soil or soil with low sorption capacity, which limits the use of urea fertilizer in Europe6,7.
Many studies on NH3 emission from organic and mineral fertilizer application and livestock housing have been performed in recent decades6, 8. Nevertheless, the research related to NH3 emissions after application of ammonia emitting fertilizers is still limited. This in particular applies to the relationship between ammonia emissions, fertilizer type used, site conditions and crop growth. Under ideal conditions this requires replicated field trials due to the variable response of crops to treatments which can only be validated in an experimental design including field replication for statistical testing.
Ammonia losses should therefore also be determined in replicated multi-plot field trials9, but the dominating ammonia loss methods yielding quantitative emissions (i.e. kg N/(ha*h)) require large field areas (micrometeorological methods), expensive equipment (wind tunnels) or in-field electrical power supply which make their application in replicated field trials difficult or impossible. In addition, specific settings of wind tunnels have been criticized with respect to the accuracy of obtained emission values10. Therefore, there is a strong need for an ammonia loss method to determine ammonia emissions in replicated field trials. This method could be used to help improve agricultural measures to reduce ammonia emissions based on statistically validated effects of site conditions, fertilizer type, application methods and crop development.
The basic idea of the new methodology, calibrated passive sampling, is to link a simple semi-quantitative measuring method for the measurement on many plots, with a quantitative method by simultaneous measurements with both methods on a few plots. Passive samplers modified compared to the design in the original publication11 are used as a semi-quantitative measurement method. The Dynamic-Tube Method (DTM)12, a calibrated dynamic chamber method, is employed to obtain a transfer coefficient, which converts the semi-quantitative losses of the passive sampler to quantitative losses (kg N ha-1). Due to the low air exchange rate in the chamber system uncalibrated emissions obtained from the DTM are about one order of magnitude lower than true emissions. However, this problem was overcome by a calibration equation which corrects the chamber fluxes depending on in-situ wind conditions13. These calibration equations can only be applied when chambers have the same internal headspace volume and design as those used in the calibration trials. Chambers can be directly inserted in soil or placed on soil rings. The latter prevent excessive disturbance of the soil and allows an almost airtight introduction of the chambers on dense grass swards or compacted soil. Moreover, the exact amount of fertilizer to be tested can be applied inside the soil rings. However, soil clods on the soil rings can also entail clamping between the chamber and the soil ring.
<img alt="Figure 1" src="/files/ftp_upload/53273/53273fig1.jpg" /> 
Figure 1: Simultaneous measurement with passive samplers and chamber method (DTM) in field plot. Passive sampler is located in the center of a square plot 0.15 m above soil/canopy. Measurements with DTM are made at least 2 locations within a plot per measurement date. Areas dedicated for harvest should not be affected by chamber and passive sampler measurement operations.
To derive the transfer coefficients measurements are carried out simultaneously on a small number of plots with both methods (Figure 1). It is important that they are applied with the same total measurement duration and that measurements are carried out at the same time (within 1 hr). The principle facilitating the application of a transfer coefficient for many plots is based on the fact that passive samplers placed in a homogeneous experimental field, with appropriate distance to obstacles disturbing the wind field as hedges, buildings etc. (at least 10 times, ideally 20 times of obstacle height)14, have the same NH3 absorption behavior under identical environmental conditions. So, for example, 50% lower emission on a plot would directly translate to 50% reduced ammonia uptake by a sampler solution. Therefore, a transfer coefficient used for scaling of acid trap values on a single plot can be used to scale the values of all acid traps used in the same field trial. Due to effects of varying environmental conditions (temperature, wind speed, surface roughness) on ammonia uptake efficiency of passive samplers11 the transfer coefficient has to be derived for each measurement campaign, respectively.
The general features of the two methods applied and the required design of field trials include 4 dynamic chambers placed onto the soil connected with Polytetrafluoroethylene (PTFE) tubing and ventilated by a bellows pump (DTM), passive samplers and large quadratic experimental plots with large buffer spaces for reducing the effect of NH3 drift between plots on the emission measurement on the actual plot.
The passive samplers are filled with dilute sulfuric acid (0.05 M H2SO4) and are placed in the center of the plots. The solution in the passive samplers continuously absorbs ammonia, and is replaced regularly depending on the expected intensity of the emissions. Simultaneously, NH3 fluxes are measured with the DTM on two treatment plots and a control plot at specific points in time. In contrast to wind tunnels, both methods combined in calibrated passive sampling have only very limited effects on soil moisture, soil temperature and rainfall which can affect ammonia emission losses very strongly6,8. While passive samplers are mounted 0.15 m above soil and canopy surface, without any effect on those variables, measurements with DTM chambers last only for about 5 min reducing potential chamber effects to a minimum.
Accurate results for NH4+ concentrations in the sampling solution can be obtained by measurements with ammonium-sensitive electrodes. Measurements with Continuous-Flow Auto Analyzers can be problematic as pH sensitive color reaction applied in these instruments can by hampered by the acidic pH of the sampling solution and chemicals used require modification. NH3 concentrations in the air passed through the chamber system of the DTM are instantaneously measured with indicator tubes. The measured NH3 concentrations are recorded on a data sheet after each measurement.
For DTM, NH3 fluxes (mg N/(m&#178; *h)) are calculated from measured NH3 concentrations and air flow rate through the 4 chamber system and the area covered by the chambers (Eq. 1, paragraph 2.5.1). The resulting un-calibrated fluxes (which underestimate the true emissions) are scaled to quantitative losses with a calibration equation (Eq. 2 and 3, see paragraph 2.5.1). Scaled cumulative NH3 losses (kg N/ha) of the DTM are calculated by averaging the fluxes between two subsequent measurement dates, multiplying this average flux with the duration of each interval, and adding-up all losses from all measurement intervals of a measurement campaign. Cumulative qualitative NH3 losses (ppm sum) from passive samplers are calculated by adding up collected NH4+-concentrations (ppm) on a plot within an experimental campaign. This is feasible because under identical volume and measurement temperatures, ppm values directly translate into captured amounts of ammonia. To scale these qualitative losses to quantitative losses the transfer coefficient (kg N/(ha *ppm)) is derived by relating cumulative final loss of the DTM (kg N ha-1) to the total sum of concentrations in the samplers measured on the same plots. This transfer coefficient is then used to convert semi-quantitative emissions from passive sampling to quantitative fluxes (e.g. kg N/ha) by multiplying the cumulative concentrations with the transfer coefficient.
Loss of water from the collectors through evaporation does not affect the absorption capacity but has to be corrected later for data analysis. Spilling of solution due to during strong winds has not been observed even in the coastal marshes of northern Germany. Decisive for a successful application of this approach is the identical design of all passive samplers applied in the field including identical position and height of placement within a plot. Several designs of passive samplers have been successfully applied in the past. This paper suggests one particular design which has proved reliable and easy to operate in field measurements. The presented approach has been extensively tested by comparison to standard ammonia loss methods (micrometeorological methods) in about 15 field trials confirming the quantitative validity of the procedure15,16 and an unbiased representation of the emissions dynamics17. The coefficient of determination (r&#178;) of calibrated fluxes compared to the micrometeorological measurements in the calibration study13 was 0.84, quite similar to the coefficient obtained by comparing ammonia sensors for measured atmospheric ammonia concentrations in a recent study18. The relative root-mean-square error of cumulative ammonia losses was 17%, also quite close to values obtained in other studies comparing micrometeorological measurements13. In the second validation where the proposed method was compared to micrometeorological measurements of ammonia emissions from organic slurries (5 separate trials), an r&#178; of 0.96 (slope of curve &#8776; 1) and a relative root-mean-square error of 5% was obtained for final cumulated ammonia emissions15. The method has proved sensitive in a 3 year field trial using different synthetic N fertilizers19. The application of this approach is restricted to average wind speeds &#8804;4 m/sec at 2 m height as the chamber method was only validated under those conditions 13,15,16.
A measurement campaign is defined as an experiment testing ammonia emissions after application of fertilizers on several plots lasting for several days, up to weeks. Each measurement campaign on a plot consists of several subsequent sampling intervals (passive sampler) or measurement dates (DTM). Sampling interval is defined as sequential duration of absorbance of emitted ammonia by a sampling solution. Measurement date is defined as sequential point in time at which DTM measurements are done on different plots used for deriving the transfer coefficient.

<table border="0" cellpadding="0" cellspacing="0" width="1019">
	<tbody>
		<tr height="42">
			<td height="42" style="height:42px;width:171px;">stainless steel Dr&#228;ger chamber + soil rings</td>
			<td style="width:327px;">Fa. Hofmann GmbH, Metallindustriewerk, Kiel, Germany</td>
			<td style="width:443px;">no number</td>
			<td style="width:80px;"></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:171px;">roofs and stainless steel rod for passive sampler</td>
			<td style="width:327px;">Fa. Hofmann GmbH, Metallindustriewerk, Kiel, Germany</td>
			<td style="width:443px;">no number</td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:171px;">ammonia electrode + bench</td>
			<td style="width:327px;">Thermo scientific</td>
			<td style="width:443px;">Cat. No. 9512BNWP or 951201</td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:171px;">ammonia electrode filling solution</td>
			<td style="width:327px;">Thermo scientific</td>
			<td style="width:443px;">Cat. No. 951202</td>
			<td></td>
		</tr>
		<tr height="80">
			<td height="80" style="height:80px;width:171px;">Ammonia calibration standards; 0.1 M ammonia chloride standard</td>
			<td style="width:327px;">Thermo scientific</td>
			<td style="width:443px;">Cat. No. 951006&#160;</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:171px;">Dr&#228;ger pumps</td>
			<td style="width:327px;">Draeger Safety AG&#38; Co Kg</td>
			<td style="width:443px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:171px;">Dr&#228;ger tubes</td>
			<td style="width:327px;">Draeger Safety AG&#38; Co Kg</td>
			<td style="width:443px;">types: 0.25/a; 2/a; 5/a</td>
			<td></td>
		</tr>
		<tr height="60">
			<td height="60" style="height:60px;width:171px;">acid resistant passive sampling bottles (Azlon bottle, HDPE)</td>
			<td style="width:327px;">Dunn Labortechnik GmbH</td>
			<td style="width:443px;">Cat.No.: BGE230P</td>
			<td></td>
		</tr>
		<tr height="60">
			<td height="60" style="height:60px;width:171px;">small vials (scintilation bottles PE 60 mm X 27 mm)</td>
			<td style="width:327px;">any laboratory store</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:171px;">PTFE tubing 7 mm x 1 mm WDG</td>
			<td style="width:327px;">any laboratory store</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:171px;">connectors PP Y-Form 6-7 mm</td>
			<td style="width:327px;">any laboratory store</td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

calibrated passive sampling - multi-plot field measurements of nh3 emissions with a combination of dynamic tube method and passive samplers

Agricultural ammonia (NH3) emissions (90% of total EU emissions) are responsible for about 45% airborne eutrophication, 31% soil acidification and 12% fine dust formation within the EU15. But NH3 emissions also mean a considerable loss of nutrients. Many studies on NH3 emission from organic and mineral fertilizer application have been performed in recent decades. Nevertheless, research related to NH3 emissions after application fertilizers is still limited in particular with respect to relationships to emissions, fertilizer type, site conditions and crop growth. Due to the variable response of crops to treatments, effects can only be validated in experimental designs including field replication for statistical testing. The dominating ammonia loss methods yielding quantitative emissions require large field areas, expensive equipment or current supply, which restricts their application in replicated field trials. This protocol describes a new methodology for the measurement of NH3 emissions on many plots linking a simple semi-quantitative measuring method used in all plots, with a quantitative method by simultaneous measurements using both methods on selected plots. As a semi-quantitative measurement method passive samplers are used. The second method is a dynamic chamber method (Dynamic Tube Method) to obtain a transfer quotient, which converts the semi-quantitative losses of the passive sampler to quantitative losses (kg nitrogen ha-1). The principle underlying this approach is that passive samplers placed in a homogeneous experimental field have the same NH3 absorption behavior under identical environmental conditions. Therefore, a transfer co-efficient obtained from single passive samplers can be used to scale the values of all passive samplers used in the same field trial. The method proved valid under a wide range of experimental conditions and is recommended to be used under conditions with bare soil or small canopies (&#60;0.3 m). Results obtained from experiments with taller plants should be treated more carefully.

In year 2014, a field trial was set up in the center of Denmark for testing the effects of several methods to reduce ammonia emissions after application of cattle slurry: incorporation with a rotary tiller, incorporation of acidified slurry and closed slot injection (injection of slurry in soil with subsequent coverage with soil). As a comparison with a high emission application technique and in particular for proper application of the chamber method trail hose application of slurry was also included. Altogether 24 plots were included in thi...

Watch this Scientific Journal Video about Calibrated Passive Sampling - Multi-plot Field Measurements of NH3 Emissions with a Combination of Dynamic Tube Method and Passive Samplers at JoVE.com

Calibrated Passive Sampling - Multi-plot Field Measurements of NH3 Emissions with a Combination of Dynamic Tube Method and Passive Samplers

Ammonia emissions are a major threat to the environment by eutrophication, soil acidification and fine particle formation and stem mainly from agricultural sources. This method allows ammonia loss measurements in replicated field trials enabling statistical analysis of emissions and of relationships between crop development and emissions.

Calibrated Passive Sampling - Multi-plot Field Measurements of NH3 Emissions with a Combination of Dynamic Tube Method and Passive Samplers

Agricultural ammonia (NH3) emissions (90% of total EU emissions) are responsible for about 45% airborne eutrophication, 31% soil acidification and 12% ...

The overall goal of this simple field in situ method is to quantify ammonia emissions from replicate plots in multi-plot field trials, facilitating statistical testing and identification of treatment effects. This method can help to answer key questions in the agronomic and agroecological field such as ammonia emmission quantification and abatement, determination of fertilizer use efficiency, and environmental assessment. The main advantage of this method is that it allows in situ quantification of ammonia emmisions in multi-plot field trials independent of electrical power supply.I will be demonstrating this procedure with Christian Wagner, a master's student from my laboratory. Use comparatively large plots as compared to the sizes usually applied in replicated field trials to avoid effects of uneven fertilizer distribution on ammonia emissions. Use square plot shapes to avoid effects of shifting wind directions on ammonia uptake by the samplers.Reduce drift of ammonia from one plot to the other by keeping a buffer area of one plot size between plots. Select two treatment plots and one control plot for simultaneous measurement with the dynamic tube method or DTM and passive sampler. Choose treatment plots with punitively high emissions giving a strong measurement signal.Following preparations as detailed in the text protocol, control measurement is made with the DTM on unfertilized control plots at the beginning and the end of each measurement date following a control, treatment, control sequence. Measure over three to six days to obtain reliable ammonia loss measurements for the timespan of a whole day by accounting for changing emissions due to varying temperatures and wind speeds. Make measurements at early morning, late morning, early afternoon, late afternoon, and shortly before sunset.To perform measurement, first rinse the DTM system with ammonia-free air by lifting the chambers to a height of about one meter above ground. Then, pump air through the polytetrafluoroethylene or PTFE tubing and chambers with a hand pump directly connected to the terminal PTFE tube of the chamber system. Press the DTM chambers directly into the ground to a depth of about 15 millimeters as marked by a rim at the chamber bottom.Alternatively, press the DTM chambers into soil rings. Make sure soil clods do not get lodged in between the soil ring and the chamber. Perform the first 20 preparatory pump strokes with a used low-concentration indicator tube to create quasi steady state conditions.Ammonia concentrations are indicated by a color change of the pH sensitive granules inside the tube, from dark yellow to bluish purple and can be read as long as the color change is within a scale printed on the tube. Choose the concentration range of the new indicator tube to be applied in the next measurement based on the information obtained from the observed color change of the used tube. Open a new indicator tube at both ends by breaking the heads off with the tube breaker installed on the pump case.Insert the indicator tube between the terminal PTFE tubing and the pump by pressing the tube ends into the PTFE tubing and the pump mouth. Insert the tube end with the lowest value on the scale printed on the tube into the PTFE tube and the end with the highest value into the pump mouth. Start pumping up to the default stroke number by pressing the OK button of the automatic pump or compressing the hand pump.Keep the pause between prepumping with the used tube and beginning of the actual measurement as short as possible. If a hand pump is used for measurements start the stopwatch simultaneously with the first stroke of the hand pump. Terminate the measurement when the standard stroke number is reached and the hand pump is fully relaxed.With relaxation of the hand pump after the terminal stroke is reached, terminate stopwatch measurement. Increase stroke number to a maximum of 50 strokes if the first line indication of the lowest value of the scale printed on the tube is not reached after the standard stroke number. After termination of the pumping use indicator tube readings only when at least the first line on the scale of an indicator tube is reached.Read the farthest color change on the tube from all sides as the line of coloring is often slightly slanted or uneven and record concentration value. Note the plot, date, time of measurement, number of strokes, and reading in PPM on the record sheet. Clean the rim of the chambers from sticking soil, manure, or fertilizer components with a clean paper towel.Then, lift the DTM system from the ground and flush as before. Make several measurements at different locations within a plot to increase the reliability of the measurements. Place passive samplers fastened to the steel rods in the center of the experimental plot at 0.15 meter height above the soil or canopy surface immediately after application of fertilizer to a plot.Hurry with the slurry fertilizer application tractor or system to install the sampler without delay. In case of dry soil, insert the steel rod into the soil with a hammer. Following placement of the passive samplers, walk to the passive sampler with a subdivided tray or bag with sorted filled acid vials for the first sampling interval.Put on gloves before handling the vials with acid solution. Take out the vial for the respective plot and sampling interval. Unscrew the bottle of the passive sampler and pour the 0.05 molar sulfuric acid solution from the vial into the mouth of the bottle.Then, screw the lid of the vial back on and return it to the tray or bag. To exchange the 0.05 molar sulfuric acid solution in a passive sampler after completion of a sampling interval carefully unscrew the passive sampler and cautiously route the solution between the windows through the discharge hole into the empty original vial. Refill the sampler through the bottle mouth with a new 0.05 molar sulfuric acid solution from the subsequent unused vial.Screw the lids on both vials with correct labeling. Fix the passive sampler to the rod by screwing it on the lid connected to the steel rod. Note plot number and filling time on the record sheet.Calculate the ammonia flexes as described in the text protocol. The results of a field trial for testing the effects of several methods to reduce ammonia emissions after application of cattle slurry compared to application with trail hoses is shown iIncluding incorporation with a rotary tiller, incorporation of acidified slurry, and closed slot injection. The method yielded highly significant differences between ammonia emissions with strongest loss reductions by application with closed slot injection or acidification with subsequent incorporation.These plots depict the differences between cumulative ammonia emissions after application of different urea fertilizers with and without addition of urease and nitrification inhibitors. Ammonia emission were strongly reduced by use of urease inhibitors independent of the use of nitrification inhibitors. Urea-only combined with nitrification inhibitors showed the highest emissions.The demonstrated method captures the strong effects of weather conditions on ammonia emissions from urea fertilizers and calcium ammonia nitrate as reflected in varying time courses and emissions levels at different application dates. Low temperatures and rainfall strongly reduce the emissions while high temperatures increased relative losses and the velocity. The effect of varying ammonia emissions on winter wheat grain nitrogen uptake, which can only be demonstrated in multi-plot field trials, is shown.Grain nitrogen uptake linearly decreased with ammonia emissions. Following this procedure also allows you to apply other methods like greenhouse gas, chamber measurements, soil sampling, plant sampling to determine agronomic efficiency and overall environmental sustainability. Thank you for watching this video and I wish you success in applying the proposed method.

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Integrated Field Lysimetry and Porewater Sampling for Evaluation of Chemical Mobility in Soils and Established Vegetation

Potentially toxic chemicals are routinely applied to land to meet growing demands on waste management and food production, but the fate of these chemicals is often not well understood. Here we demonstrate an integrated field lysimetry and porewater sampling method for evaluating the mobility of chemicals applied to soils and established vegetation. Lysimeters, open columns made of metal or plastic, are driven into bareground or vegetated soils. Porewater samplers, which are commercially available and use vacuum to collect percolating soil water, are installed at predetermined depths within the lysimeters. At prearranged times following chemical application to experimental plots, porewater is collected, and lysimeters, containing soil and vegetation, are exhumed. By analyzing chemical concentrations in the lysimeter soil, vegetation, and porewater, downward leaching rates, soil retention capacities, and plant uptake for the chemical of interest may be quantified. Because field lysimetry and porewater sampling are conducted under natural environmental conditions and with minimal soil disturbance, derived results project real-case scenarios and provide valuable information for chemical management. As chemicals are increasingly applied to land worldwide, the described techniques may be utilized to determine whether applied chemicals pose adverse effects to human health or the environment.

Field lysimetry and porewater sampling allow researchers to evaluate the fate of chemicals applied to soils and established vegetation. The goal of this protocol is to demonstrate how to install required instrumentation and collect samples for chemical analysis during integrated field lysimetry and porewater sampling experiments.

Potentially toxic chemicals are routinely applied to land to meet growing demands on waste management and food production, but the fate of these chemicals ...

Soil Sampling and Isolation of Entomopathogenic Nematodes (Steinernematidae, Heterorhabditidae)

Entomopathogenic nematodes (a.k.a. EPN) represent a group of soil-inhabiting nematodes that parasitize a wide range of insects. These nematodes belong to two families: Steinernematidae and Heterorhabditidae. Until now, more than 70 species have been described in the Steinernematidae and there are about 20 species in the Heterorhabditidae. The nematodes have a mutualistic partnership with Enterobacteriaceae bacteria and together they act as a potent insecticidal complex that kills a wide range of insect species.
Herein, we focus on the most common techniques considered for collecting EPN from soil. The second part of this presentation focuses on the insect-baiting technique, a widely used approach for the isolation of EPN from soil samples, and the modified White trap technique which is used for the recovery of these nematodes from infected insects. These methods and techniques are key steps for the successful establishment of EPN cultures in the laboratory and also form the basis for other bioassays that consider these nematodes as model organisms for research in other biological disciplines. The techniques shown in this presentation correspond to those performed and/or designed by members of S. P. Stock laboratory as well as those described by various authors.

Soil Sampling and Isolation of Entomopathogenic Nematodes Steinernematidae, Heterorhabditidae

Entomopathogenic nematodes are soil-inhabiting roundworms that parasitize a wide range of insects. We demonstrate sampling methods used for the isolation of these nematodes from the soil using two techniques: the insect baiting and the modified White trap, for the recovery of nematodes from soil samples and infected insect cadavers, respectively.

Entomopathogenic nematodes (a.k.a. EPN) represent a group of soil-inhabiting nematodes that parasitize a wide range of insects. These nematodes belong to ...

The Use of an Automated System (GreenFeed) to Monitor Enteric Methane and Carbon Dioxide Emissions from Ruminant Animals

Ruminant animals (domesticated or wild) emit methane (CH4) through enteric fermentation in their digestive tract and from decomposition of manure during storage. These processes are the major sources of greenhouse gas (GHG) emissions from animal production systems. Techniques for measuring enteric CH4 vary from direct measurements (respiration chambers, which are highly accurate, but with limited applicability) to various indirect methods (sniffers, laser technology, which are practical, but with variable accuracy). The sulfur hexafluoride (SF6)&#160;tracer gas method is commonly used to measure enteric CH4 production by animal scientists and more recently, application of an Automated Head-Chamber System (AHCS) (GreenFeed, C-Lock, Inc., Rapid City, SD), which is the focus of this experiment, has been growing. AHCS is an automated system to monitor CH4 and carbon dioxide (CO2) mass fluxes from the breath of ruminant animals. In a typical AHCS operation, small quantities of baiting feed are dispensed to individual animals to lure them to AHCS multiple times daily. As the animal visits AHCS, a fan system pulls air past the animal&#8217;s muzzle into an intake manifold, and through an air collection pipe where continuous airflow rates are measured. A sub-sample of air is pumped out of the pipe into non-dispersive infra-red sensors for continuous measurement of CH4 and CO2 concentrations. Field comparisons of AHCS to respiration chambers or SF6 have demonstrated that AHCS produces repeatable and accurate CH4 emission results, provided that animal visits to AHCS are sufficient so emission estimates are representative of the diurnal rhythm of rumen gas production. Here, we demonstrate the use of AHCS to measure CO2 and CH4 fluxes from dairy cows given a control diet or a diet supplemented with technical-grade cashew nut shell liquid.

The Use of an Automated System GreenFeed to Monitor Enteric Methane and Carbon Dioxide Emissions from Ruminant Animals

Accuracy and precision of the techniques used to measure methane emissions from ruminant animals are critically important for the success of greenhouse gas mitigation efforts. This manuscript describes the principles and operation of an automated system to monitor methane and carbon dioxide mass fluxes from the breath of ruminant animals.

Ruminant animals (domesticated or wild) emit methane (CH4) through enteric fermentation in their digestive tract and from decomposition of manure during ...

Characterization and Application of Passive Samplers for Monitoring of Pesticides in Water

Five different water passive samplers were calibrated under laboratory conditions for measurement of 124 legacy and current used pesticides. This study provides a protocol for the passive sampler preparation, calibration, extraction method and instrumental analysis. Sampling rates (RS) and passive sampler-water partition coefficients (KPW) were calculated for silicone rubber, polar organic chemical integrative sampler POCIS-A, POCIS-B, SDB-RPS and C18 disk. The uptake of the selected compounds depended on their physicochemical properties, i.e., silicone rubber showed a better uptake for more hydrophobic compounds (log octanol-water partition coefficient (KOW) &#62; 5.3), whereas POCIS-A, POCIS-B and SDB-RPS disk were more suitable for hydrophilic compounds (log KOW &#60; 0.70).

A protocol about the characterization and application of five different passive sampling devices is presented.

Five different water passive samplers were calibrated under laboratory conditions for measurement of 124 legacy and current used pesticides. This study ...

Clean Sampling and Analysis of River and Estuarine Waters for Trace Metal Studies

Most of the trace metal concentrations in ambient waters obtained a few decades ago have been considered unreliable owing to the lack of contamination control. Developments of some techniques aiming to reduce trace metal contamination in the last couple of decades have resulted in concentrations reported now being orders of magnitude lower than those in the past. These low concentrations often necessitate preconcentration of water samples prior to instrumental analysis of samples. Since contamination can appear in all phases of trace metal analyses, including sample collection (and during preparation of sampling containers), storage and handling, pretreatments, and instrumental analysis, specific care needs to be taken in order to reduce contamination levels at all steps. The effort to develop and utilize "clean techniques" in trace metal studies allows scientists to investigate trace metal distributions and chemical and biological behavior in greater details. This advancement also provides the required accuracy and precision of trace metal data allowing for environmental conditions to be related to trace metal concentrations in aquatic environments.
This protocol that is presented here details needed materials for sample preparation, sample collection, sample pretreatment including preconcentration, and instrumental analysis. By reducing contamination throughout all phases mentioned above for trace metal analysis, much lower detection limits and thus accuracy can be achieved. The effectiveness of "clean techniques" is further demonstrated using low field blanks and good recoveries for standard reference material. The data quality that can be obtained thus enables the assessment of trace metal distributions and their relationships to environmental parameters.

Special care using "clean techniques" is required to properly collect and process water samples for trace metal studies in aquatic environments. A protocol for sampling, processing, and analytical procedures with the aim of obtaining reliable environmental monitoring data and results with high sensitivity for detailed trace metal studies is presented.

Most of the trace metal concentrations in ambient waters obtained a few decades ago have been considered unreliable owing to the lack of contamination ...

Modification and Application of a Leaf Blower-vac for Field Sampling of Arthropods

Rice fields host a large diversity of arthropods, but investigating their population dynamics and interactions is challenging. Here we describe the modification and application of a leaf blower-vac for suction sampling of arthropod populations in rice. When used in combination with an enclosure, application of this sampling device provides absolute estimates of the populations of arthropods as numbers per standardized sampling area. The sampling efficiency depends critically on the sampling duration. In a mature rice crop, a two-minute sampling in an enclosure of 0.13 m2 yields more than 90% of the arthropod population. The device also allows sampling of arthropods dwelling on the water surface or the soil in rice paddies, but it is not suitable for sampling fast flying insects, such as predatory Odonata or larger hymenopterous parasitoids. The modified blower-vac is simple to construct, and cheaper and easier to handle than traditional suction sampling devices, such as D-vac. The low cost makes the modified blower-vac also accessible to researchers in developing countries.

Assessment of arthropod abundance in crops is critical for investigating population dynamics and species interactions. Here we describe the modification and application of a leaf blower-vac for suction sampling of arthropods in rice.

Rice fields host a large diversity of arthropods, but investigating their population dynamics and interactions is challenging. Here we describe the ...

Reliable Method for Assessing Seed Germination, Dormancy, and Mortality under Field Conditions

We describe techniques for approximating seed bank dynamics over time using Helianthus annuus as an example study species. Strips of permeable polyester fabric and glue can be folded and glued to construct a strip of compartments that house seeds and identifying information, while allowing contact with soil leachate, water, microorganisms, and ambient temperature. Strips may be constructed with a wide range of compartment numbers and sizes and allow the researcher to house a variety of genotypes within a single species, different species, or seeds that have experienced different treatments. As opposed to individual seed packets, strips are more easily retrieved as a unit. While replicate packets can be included within a strip, different strips can act as blocks or can be retrieved at different times for observation of seed behavior over time. We used a high temperature glue gun to delineate compartments and sealed the strips once the seed and tags identifying block and removal times were inserted. The seed strips were then buried in the field at the desired depth, with the location marked for later removal. Burrowing animal predators were effectively excluded by use of a covering of metal mesh hardware cloth on the soil surface. After the selected time interval for burial, strips were dug up and seeds were assessed for germination, dormancy and mortality. While clearly dead seeds can often be distinguished from ungerminated living ones by eye, dormant seeds were conclusively identified using a standard Tetrazolium chloride colorimetric test for seed viability.

Here we present a protocol for assessing seed survivorship, germination and dormancy under field conditions using buried, labeled seed strips and tetrazolium chloride (TZ) viability testing.

We describe techniques for approximating seed bank dynamics over time using Helianthus annuus as an example study species. Strips of permeable polyester ...

Implementation of Portable Emissions Measurement Systems (PEMS) for the Real-driving Emissions (RDE) Regulation in Europe

Vehicles are tested in controlled and relatively narrow laboratory conditions to determine their official emission values and reference fuel consumption. However, on the road, ambient and driving conditions can vary over a wide range, sometimes causing emissions to be higher than those measured in the laboratory. For this reason, the European Commission has developed a complementary Real-Driving Emissions (RDE) test procedure using the Portable Emissions Measurement Systems (PEMS) to verify gaseous pollutant and particle number emissions during a wide range of normal operating conditions on the road. This paper presents the newly-adopted RDE test procedure, differentiating six steps: 1) vehicle selection, 2) vehicle preparation, 3) trip design, 4) trip execution, 5) trip verification, and 6) calculation of emissions. Of these steps, vehicle preparation and trip execution are described in greater detail. Examples of trip verification and the calculations of emissions are given.

Implementation of Portable Emissions Measurement Systems PEMS for the Real-driving Emissions RDE Regulation in Europe

The European Commission has developed a Real-Driving Emissions (RDE) test procedure to verify pollutant emissions during real-world vehicle operation using the Portable Emissions Measurement Systems (PEMS). This paper presents the experimental procedures required by the newly-adopted RDE test.

Vehicles are tested in controlled and relatively narrow laboratory conditions to determine their official emission values and reference fuel consumption. ...

Production and Measurement of Organic Particulate Matter in a Flow Tube Reactor

Organic particulate matter (PM) is increasingly recognized as important to the Earth's climate system as well as public health in urban regions, and the production of synthetic PM for laboratory studies have become a widespread necessity. Herein, experimental protocols demonstrate approaches to produce aerosolized organic PM by &#945;-pinene ozonolysis in a flow tube reactor. Methods are described for measuring the size distributions and morphology of the aerosol particles. The video demonstrates basic operations of the flow tube reactor and related instrumentation. The first part of the video shows the procedure for preparing gas-phase reactants, ozonolysis, and production of organic PM. The second part of the video shows the procedures for determining the properties of the produced particle population. The particle number-diameter distributions show different stages of particle growth, namely condensation, coagulation, or a combination of both, depending on reaction conditions. The particle morphology is characterized by an aerosol particle mass analyzer (APM) and a scanning electron microscope (SEM). The results confirm the existence of non-spherical particles that have grown from coagulation for specific reaction conditions. The experimental results also indicate that the flow tube reactor can be used to study the physical and chemical properties of organic PM for relatively high concentrations and short time frames.

This paper describes the operation procedure for the flow tube reactor and related data collection. It shows the protocols for setting the experiments, recording data and generating the number-diameter distribution as well as the particle mass information, which gives useful information about chemical and physical properties of the organic aerosols.

Organic particulate matter (PM) is increasingly recognized as important to the Earth's climate system as well as public health in urban regions, and the ...

Wastewater Irrigation Impacts on Soil Hydraulic Conductivity: Coupled Field Sampling and Laboratory Determination of Saturated Hydraulic Conductivity

Since the early 1960s, an alternative wastewater discharge practice at The Pennsylvania State University has been researched and its impacts monitored. Rather than discharging treated wastewater to a stream, and thereby directly impacting the stream quality, the effluent is applied to forested and cropped land managed by the University. Concerns related to reductions in soil hydraulic conductivity occur when considering wastewater reuse. The methodology described in this manuscript, matching soil sample size with the size of the laboratory-based hydraulic conductivity measurement apparatus, provides the benefits of a relatively rapid collection of samples with the benefits of controlled laboratory boundary conditions. The results suggest that there may have been some impact of wastewater reuse on the soil&#39;s ability to transmit water at deeper depths in the depressional areas of the site. Most of the reductions in the soil hydraulic conductivity in the depressions appear to be related to the depth from which the sample was collected, and by inference, associated with the soil structural and textural differences.

Here we present a methodology which matches a soil sample size and a hydraulic conductivity measurement device to prevent the so-called wall flow along the inside of the soil container from being erroneously included in water flow measurements. Its use is demonstrated with samples collected from a wastewater irrigation site.

Since the early 1960s, an alternative wastewater discharge practice at The Pennsylvania State University has been researched and its impacts monitored. ...