The Swedish EPA (Naturv&#229;rdsverket) (agreement 2208-13-001) and Centre for Chemical Pesticides (CKB) are gratefully acknowledged for funding this project. We thank M&#228;rit Peterson, Henrik Jernstedt, Emma Gurnell and Elin Paulsson at the OMK-lab, SLU, for skillful assistance with analytical support and supply of pesticide standards.

1. Passive Sampler Design and Preparation
<ol>
	<li>Silicone rubber sheets
	<ol>
		<li>Cut the silicone rubber sheets (600 mm x 600 mm, 0.5 mm thick) into stripes of 2.5 mm x 600 mm and 2.5 mm x 314 mm using a stainless steel cutter and connect them using a stainless steel blind rivet (3.2 mm x 10 mm) with a rivet gun to obtain a total sampler stripe size of 2.5 mm x 914 mm (surface area = 457 cm2, sorbent mass = 15.6 g, volume = 22.9 cm3).</li>
	</ol>
	</li>
	<li>Place the silicone rubbers in an extraction chamber of a Soxhlet apparatus. Add 50 ml EA in the extraction chamber and add 250 ml EA and three boiling stones in a 500 ml round bottle flask.
	<ol>
		<li>Connect the extraction chamber with the bottle flask and a condenser. Clean the silicone rubbers by Soxhlet extraction for 96 hr at approximately 80 &#176;C, and dry them thereafter under gentle nitrogen gas.</li>
	</ol>
	</li>
	<li>Attach the silicone rubber stripe to a stainless steel spider sample holder by wrapping the silicone rubber stripe around the rods on the holder (Figure 1). Attach each end of the silicone rubber stripe to a rod on the holder using cable ties.</li>
</ol>
<img alt="Figure 1" src="/files/ftp_upload/54053/54053fig1.jpg" /> 
Figure 1. Schematic of silicone rubber. Passive sampler schematic for silicone rubber showing the attachment of the silicone rubber stripe to a stainless steel spider sample holder A) from the top and B) the side view. <a href="https://www.jove.com/files/ftp_upload/54053/54053fig1large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<ol start="2">
	<li>POCIS-A and POCIS-B
	<ol>
		<li>For POCIS-A, place 220 mg of HLB bulk sorbent (surface area = 1.78 x 106 cm2) between two 9.0 cm by 9.0 cm square polyethersulfone (PES) membranes (Figure 2).</li>
		<li>For POCIS-B, place 220 mg of a sorbent mixture (i.e., hydroxylated polystyrene-divinylbenzene resin (80%) and a carbonaceous adsorbent dispersed on a styrene divinylbenzene copolymer (20%)) (surface area = 2.82 x 106 cm2) between two PES membranes (Figure 2).</li>
		<li>Compress the sorbent and two PES between two stainless steel rings manually (inner &#216; = 5.4 cm) and secure it on a stainless steel sample holder (Figure 2).</li>
	</ol>
	</li>
</ol>
<img alt="Figure 2" src="/files/ftp_upload/54053/54053fig2.jpg" /> 
Figure 2. Schematic of passive sampler disks. Passive sampler schematic for POCIS A, POCIS B, SDB-RPS disk and C18 disk showing A) the assembling of the passive sampler using stainless steel rings, polyethersulfone (PES) membranes, and the receiving phase, and B) the assembling on a stainless steel sample holder. <a href="https://www.jove.com/files/ftp_upload/54053/54053fig2large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<ol start="3">
	<li>SDB-RPS disk and C18 disk
	<ol>
		<li>Place the SDB-RPS (surface area = 35 cm2, sorbent mass = 0.34 g, volume = 1.7 cm3) and C18 disks (surface area = 35 cm2, sorbent mass = 0.58 g, volume = 1.7 cm3) between two PES membranes (Figure 2). Compress the disks and two PES between two stainless steel rings manually (inner &#216; = 5.4 cm) and secure it on a stainless steel sample holder (Figure 2).</li>
	</ol>
	</li>
</ol>
2. Laboratory Uptake Experiments
NOTE: The Laboratory uptake experiments were performed to quantitatively characterize the uptake kinetics for 124 individual pesticides for five different passive sampler devices under controlled conditions.
<ol>
	<li>Conduct the uptake study in rectangular glass containers (each ~95 L): Tank 1) silicone rubber (n = 16), tank 2) POCIS-A (n = 16), POCIS-B (n = 16), and tank 3) SDB-RPS disk (n = 16), C18 disk (n = 16). Fill natural water into the three tanks.</li>
	<li>Perform all experiments at a constant water temperature (~20 &#176;C) and under turbulent water conditions (~10 cm sec-1) using two electric pumps attached to the wall on each side. Perform the experiments in the dark to minimize the effect of photodegradation.</li>
	<li>Spike each glass container with a pesticide standard mixture containing 124 pesticides using a glass syringe (c &#8776; 400 ng L-1 for individual pesticides in the water tank). Take out the passive samplers manually from the tanks, at time intervals of 5, 11, 20, and 26 days, to determine the sampling rates of the pesticides.</li>
	<li>Monitor the concentrations of the pesticides in each tank by collecting 100 ml water samples at day 0, 5, 11, 20, and 26. The analysis of the water samples is performed as described elsewhere21.
	<ol>
		<li>For quality control, expose blank samples to room air for 1 hr at day 0 and then store and treat them as real samples. Store all extracts as well as the 100 ml water samples collected from the tanks at -18 &#176;C until further analysis.</li>
	</ol>
	</li>
</ol>
3. Sample Extraction
<ol>
	<li>Silicone rubber
	<ol>
		<li>Prior to extraction, dry the silicone rubber stripe under a stream of high purity nitrogen gas.</li>
		<li>For gas chromatography-mass spectrometry (GC-MS) analysis, carry out the solid-liquid extraction using Soxhlet extraction22.
		<ol>
			<li>Place the silicone rubber into the Soxhlet extractor. Add 250 ml PE/ACE (50/50, v/v) and 3 boiling stones into the round bottle flask.</li>
			<li>Spike the silicone rubber with 100 &#181;l of an IS mixture (c = 5 ng ml-1) using a glass syringe. Add 50 ml PE/ACE (50/50, v/v) into the Soxhlet extractor. Switch on the heater and run the Soxhlet extraction for 19 hr and then switch off the heater.</li>
			<li>Concentrate the extracts by rotary evaporation followed by gentle nitrogen blow-down to 1 ml. Exchange the solvent to CH/ACE (90/10, v/v) by adding three times 1 ml CH/ACE (90/10, v/v) during the nitrogen blow-down to 1 ml.</li>
		</ol>
		</li>
		<li>For liquid chromatography&#8722;tandem mass spectrometry (LC-MS/MS) analysis, carry out the extraction using Soxhlet extraction22.
		<ol>
			<li>Place the silicone rubber into the Soxhlet extractor. Add 250 ml MeOH and 3 boiling stones into the round bottle flask and 50 ml MeOH into the Soxhlet extractor. Spike the silicone rubber with 100 &#181;l of an IS mixture (c = 5 ng ml-1) using a glass syringe.</li>
			<li>Switch on the heater and run the Soxhlet extraction for 19 hr and then switch off the heater. Concentrate the extracts by rotary evaporation followed by gentle nitrogen blow-down to 1 ml. Exchange the solvent to ACN by adding 1 ml ACN during the nitrogen blow-down to 1 ml.</li>
		</ol>
		</li>
	</ol>
	</li>
	<li>POCIS-A and POCIS-B
	<ol>
		<li>Open the POCIS sampler carefully and transfer the sorbent with ultrapure water using a funnel into a pre-cleaned empty polypropylene solid phase extraction (SPE) cartridge (6 ml) containing two polyethylene (PE) frits. Dry the sorbent by vacuum to remove water. Record the weight of the empty and packed SPE cartridge to control the weight of the sorbent material. Please note that different cartridges are used for GC-MS and LC-MS/MS analysis.</li>
		<li>Prior to elution, spike the sorbent with 100 &#181;l of an IS mixture (c = 5 ng ml-1) using a glass syringe. Elute POCIS-A and POCIS-B sorbents using 5 ml EA for GC-MS22.
		<ol>
			<li>Concentrate the extracts to 1 ml by gentle nitrogen blow-down. Exchange the solvent to CH/ACE (90/10, v/v) by adding three times 1 ml CH/ACE (90/10, v/v) during the nitrogen blow-down to 1 ml.</li>
		</ol>
		</li>
		<li>Elute POCIS-A and POCIS-B cartridges using 1.5 ml MeOH followed by 8 ml DCM/MeOH (80/20, v/v) for LC-MS/MS analysis22. Concentrate the extracts to 1 ml by gentle nitrogen blow-down. Exchange the solvent to ACN by adding 1 ml ACN during the nitrogen blow-down to 1 ml.</li>
	</ol>
	</li>
	<li>SDB-RPS and C18 disk
	<ol>
		<li>Transfer individual disks of SDB-RPS and C18 disk into a glass beaker and dry them under nitrogen gas. Spike the disks with 100 &#181;l of an IS mixture (c = 5 ng ml-1) using a glass syringe and sonicate them two times in a glass beaker at room temperature, first with 5 ml of EA for 10 min and then with 3 ml of EA for 10 min.</li>
		<li>Transfer both extracts into one glass tube, concentrate them to 2 ml by gentle nitrogen blow down, and split them into two 1 ml fractions (for GC-MS and LC-MS/MS analysis, respectively).</li>
		<li>Concentrate the extracts to 0.5 ml by gentle nitrogen blow-down and exchange the solvent to CH/ACE (90/10, v/v) for GC-MS analysis22. Concentrate the extracts to 0.5 ml by gentle nitrogen blow-down and exchange the solvent to ACN for LC-MS/MS analysis22.</li>
	</ol>
	</li>
</ol>
4. Water Samples
<ol>
	<li>Spike 20 ml water sample with 100 &#181;l of an IS mixture (c = 5 ng ml-1) using a glass syringe, add 3 ml of DCM, vortex for 3 min, and decant into a phase separator for GC-MS analysis 22.
	<ol>
		<li>After the two phases are separated, percolate the DCM phase into a glass tube. Repeat the extraction using 3 ml DCM, and rinse the tube with 2 ml DCM. Finally, concentrate the extracts to 0.5 ml by gentle nitrogen blow-down and exchange the solvent to CH/ACE (90/10, v/v).</li>
	</ol>
	</li>
	<li>Analyze the water samples using large volume injection, similar to the method described elsewhere by LC-MS/MS 21.</li>
</ol>
5. Instrumental Analysis
<ol>
	<li>GC-MS analysis
	<ol>
		<li>Perform the instrumental analysis of the CH/ACE extracts using GC-MS systems in electron ionization (EI) and negative chemical ionization (NCI) mode, respectively22.</li>
		<li>For the GC-MS method using EI, inject aliquots of 1 &#181;l with splitless injection method on a HP-5MS UI column (30 m, 0.25 mm inner diameter, 0.25 &#181;m film).</li>
		<li>For the GC-MS method using CI, inject aliquots of 3 &#181;l on a HP-5MS UI column (30 m, 0.25 mm inner diameter, 0.25 &#181;m film).</li>
	</ol>
	</li>
	<li>HPLC-MS/MS analysis
	<ol>
		<li>Perform the instrumental analysis of the ACN extracts using HPLC-MS/MS interfaced with an electrospray ionization source in negative ((-)ESI) and positive-ion mode ((+)ESI)22.</li>
		<li>For (+)ESI, dilute 100 &#181;l of the ACN extracts with 900 &#181;l ultrapure water adjusted to pH 5 using FA .</li>
		<li>For (-)ESI, dilute 100 &#181;l of the ACN extracts with 900 &#181;l solution of 1% FA in ultrapure water.</li>
		<li>For (+)ESI, use a binary gradient consisting of 2-propanol/methanol/10 mM ammonium formate (6/2/92, v/v/v) and MeOH at a flow rate of 0.3 ml min-1.</li>
		<li>For (-)ESI, use a binary gradient consisting of ACN/ultrapure water 0.1% HAc and ACN + 0.1% HAc at a flow rate of 0.3 ml min-1.</li>
		<li>Inject all samples using a large volume injection of 500 &#181;l using two online SPE columns (both 20 x 2 mm id and 20-25 &#181;m particle size), and an analytical column (C18, 100 x 3 mm, 3.5 &#181;m)21.</li>
	</ol>
	</li>
</ol>
6. Theory on Passive Sampling
NOTE: The uptake profile of the chemical to the passive sampler medium (PSM) is divided into three sections: Linear, curvilinear and equilibrium (Figure 3).
<img alt="Figure 3" src="/files/ftp_upload/54053/54053fig3.jpg" /> 
Figure 3. Passive sampler uptake curve. A) and C) uptake curve for the accumulated amount of acetamiprid and dimethoate, respectively, in the passive samplers (Nt) in ng absolute, and B) and D) water tank concentration of acetamiprid and dimethoate, respectively, in ng L-1. <a href="https://www.jove.com/files/ftp_upload/54053/54053fig3large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<ol>
	<li>Calculate the equivalent water volume (Veq L) for a passive sampler by dividing the accumulated amount of target compounds in the passive sampler after t days of exposure (N&#39;t, ng) by the concentration in the water phase using grab and time integrated active sampling (cw, ng L-1). 
	<img alt="Equation 1" src="/files/ftp_upload/54053/54053eq1.jpg" /> (1)</li>
	<li>Derive the sampling rate (RS, L day-1) from the linear uptake phase of the uptake profile, by taking the slope of Veq versus deployment time.</li>
	<li>Calculate the KPW (L kg-1) for individual pesticides using Eq. 2. 
	<img alt="Equation 2" src="/files/ftp_upload/54053/54053eq2.jpg" /> (2) 
	where mp is the sorbent mass per sampler (ng).</li>
	<li>In the linear uptake phase, calculate the TWA concentration of the analyte in water derived by the passive sampler (cTWA, ng L-1) using Eq. 3. 
	<img alt="Equation 3" src="/files/ftp_upload/54053/54053eq3.jpg" />&#160;(3) 
	where RS is the sampling rate (L day-1), and t is the deployment time (days).</li>
	<li>In the curvilinear phase, calculate cTWA using Eq. 4. 
	<img alt="Equation 4" src="/files/ftp_upload/54053/54053eq4.jpg" /> (4)</li>
	<li>In the equilibrium phase, calculate cTWA using Eq. 5. 
	<img alt="Equation 5" src="/files/ftp_upload/54053/54053eq5.jpg" /> (5)</li>
</ol>
&#160;&#160;&#160;
7. Statistical Data Analysis
<ol>
	<li>Test non-normal distribution of the data using a Shapiro-Wilk test23. Use non-parametric Spearman&#39;s rank correlation for KPW and RS vs physicochemical properties of the tested pesticides (Spearman&#39;s rho ranging from -1 to 1)24.</li>
</ol>

<ol>
	<li>Rodney, S. I., Teed, R. S., Moore, D. R. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Estimating+the+toxicity+of+pesticide+mixtures+to+aquatic+organisms:+A+review.">Estimating the toxicity of pesticide mixtures to aquatic organisms: A review.</a> Hum. Ecol. Risk Assess. 19 (6), 1557-1575 (2013).</li><li>Kreuger, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pesticides+in+stream+water+within+an+agricultural+catchment+in+southern+Sweden,+1990-1996.">Pesticides in stream water within an agricultural catchment in southern Sweden, 1990-1996.</a> Sci. Total Environ. 216 (3), 227-251 (1998).</li><li>Carlson, J. C., Challis, J. K., Hanson, M. L., Wong, C. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stability+of+pharmaceuticals+and+other+polar+organic+compounds+stored+on+polar+organic+chemical+integrative+samplers+and+solid-phase+extraction+cartridges.">Stability of pharmaceuticals and other polar organic compounds stored on polar organic chemical integrative samplers and solid-phase extraction cartridges.</a> Environ. Toxicol. Chem. 32 (2), 337-344 (2013).</li><li>Alvarez, D. 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=Development+of+a+passive,+in+situ,+integrative+sampler+for+hydrophilic+organic+contaminants+in+aquatic+environments.">Development of a passive, in situ, integrative sampler for hydrophilic organic contaminants in aquatic environments.</a> Environ. Toxicol. Chem. 23 (7), 1640-1648 (2004).</li><li>Vrana, B., 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+sampling:+An+effective+method+for+monitoring+seasonal+and+spatial+variability+of+dissolved+hydrophobic+organic+contaminants+and+metals+in+the+Danube+river.">Passive sampling: An effective method for monitoring seasonal and spatial variability of dissolved hydrophobic organic contaminants and metals in the Danube river.</a> Environ. Pollut. 184, 101-112 (2014).</li><li>Dougherty, J. A., Swarzenski, P. W., Dinicola, R. S., Reinhard, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Occurrence+of+herbicides+and+pharmaceutical+and+personal+care+products+in+surface+water+and+groundwater+around+Liberty+Bay,+Puget+Sound,+Washington.">Occurrence of herbicides and pharmaceutical and personal care products in surface water and groundwater around Liberty Bay, Puget Sound, Washington.</a> J. Environ. Qual. 39 (4), 1173-1180 (2010).</li><li>Mu&#241;oz, I., Mart&#236;nez Bueno, M. J., Ag&#252;era, A., Fern&#225;ndez-Alba, A. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Environmental+and+human+health+risk+assessment+of+organic+micro-pollutants+occurring+in+a+Spanish+marine+fish+farm.">Environmental and human health risk assessment of organic micro-pollutants occurring in a Spanish marine fish farm.</a> Environ. Pollut. 158 (5), 1809-1816 (2010).</li><li>Wille, 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=Rapid+quantification+of+pharmaceuticals+and+pesticides+in+passive+samplers+using+ultra+high+performance+liquid+chromatography+coupled+to+high+resolution+mass+spectrometry.">Rapid quantification of pharmaceuticals and pesticides in passive samplers using ultra high performance liquid chromatography coupled to high resolution mass spectrometry.</a> J. Chromatogr. A. 1218 (51), 9162-9173 (2011).</li><li>Poulier, G., 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=Estimates+of+pesticide+concentrations+and+fluxes+in+two+rivers+of+an+extensive+French+multi-agricultural+watershed:+application+of+the+passive+sampling+strategy.">Estimates of pesticide concentrations and fluxes in two rivers of an extensive French multi-agricultural watershed: application of the passive sampling strategy.</a> Environ. Sci. Pollut. Res. 22 (11), 8044-8057 (2015).</li><li>Moschet, C., Vermeirssen, E. L. M., Singer, H., Stamm, C., Hollender, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evaluation+of+in-situ+calibration+of+chemcatcher+passive+samplers+for+322+micropollutants+in+agricultural+and+urban+affected+rivers.">Evaluation of in-situ calibration of chemcatcher passive samplers for 322 micropollutants in agricultural and urban affected rivers.</a> Water Res. 71, 306-317 (2015).</li><li>Petty, J. D., 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=An+approach+for+assessment+of+water+quality+using+semipermeable+membrane+devices+(SPMDs)+and+bioindicator+tests.">An approach for assessment of water quality using semipermeable membrane devices (SPMDs) and bioindicator tests.</a> Chemosphere. 41 (3), 311-321 (2000).</li><li>Metcalfe, C. D., 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=Contaminants+in+the+coastal+karst+aquifer+system+along+the+Caribbean+coast+of+the+Yucatan+Peninsula,+Mexico.">Contaminants in the coastal karst aquifer system along the Caribbean coast of the Yucatan Peninsula, Mexico.</a> Environ. Pollut. 159 (4), 991-997 (2011).</li><li>Allan, I. 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=Field+performance+of+seven+passive+sampling+devices+for+monitoring+of+hydrophobic+substances.">Field performance of seven passive sampling devices for monitoring of hydrophobic substances.</a> Environ. Sci. Technol. 43 (14), 5383-5390 (2009).</li><li>Vrana, B., 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+sampling+techniques+for+monitoring+pollutants+in+water.">Passive sampling techniques for monitoring pollutants in water.</a> TrAC - Trend. Anal. Chem. 24 (10), 845-868 (2005).</li><li>Allan, I. J., Harman, C., Ranneklev, S. B., Thomas, K. V., Grung, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Passive+sampling+for+target+and+nontarget+analyses+of+moderately+polar+and+nonpolar+substances+in+water.">Passive sampling for target and nontarget analyses of moderately polar and nonpolar substances in water.</a> Environ. Toxicol. Chem. 32 (8), 1718-1726 (2013).</li><li>Escher, B. I., 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=Evaluation+of+contaminant+removal+of+reverse+osmosis+and+advanced+oxidation+in+full-scale+operation+by+combining+passive+sampling+with+chemical+analysis+and+bioanalytical+tools.">Evaluation of contaminant removal of reverse osmosis and advanced oxidation in full-scale operation by combining passive sampling with chemical analysis and bioanalytical tools.</a> Environ. Sci. Technol. 45, 5387-5394 (2011).</li><li>Pesce, S., Morin, S., Lissalde, S., Montuelle, B., Mazzella, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Combining+polar+organic+chemical+integrative+samplers+(POCIS)+with+toxicity+testing+to+evaluate+pesticide+mixture+effects+on+natural+phototrophic+biofilms.">Combining polar organic chemical integrative samplers (POCIS) with toxicity testing to evaluate pesticide mixture effects on natural phototrophic biofilms.</a> Environ. Pollut. 159 (3), 735-741 (2011).</li><li>Booij, K., Smedes, F., Van Weerlee, E. M., Honkoop, P. J. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Environmental+monitoring+of+hydrophobic+organic+contaminants:+The+case+of+mussels+versus+semipermeable+membrane+devices.">Environmental monitoring of hydrophobic organic contaminants: The case of mussels versus semipermeable membrane devices.</a> Environ. Sci. Technol. 40 (12), 3893-3900 (2006).</li><li>Harman, C., Allan, I. J., Vermeirssen, E. L. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Calibration+and+use+of+the+polar+organic+chemical+integrative+sampler-a+critical+review.">Calibration and use of the polar organic chemical integrative sampler-a critical review.</a> Environ. Toxicol. Chem. 31 (12), 2724-2738 (2012).</li><li>Jonker, M. T. O., Der Heijden, S. A. V. a. n., Kotte, M., Smedes, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantifying+the+effects+of+temperature+and+salinity+on+partitioning+of+hydrophobic+organic+chemicals+to+silicone+rubber+passive+samplers.">Quantifying the effects of temperature and salinity on partitioning of hydrophobic organic chemicals to silicone rubber passive samplers.</a> Environ. Sci. Technol. 49 (11), 6791-6799 (2015).</li><li>Jansson, C., Kreuger, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Multiresidue+analysis+of+95+pesticides+at+low+nanogram/liter+levels+in+surface+waters+using+online+preconcentration+and+high+performance+liquid+chromatography/tandem+mass+spectrometry.">Multiresidue analysis of 95 pesticides at low nanogram/liter levels in surface waters using online preconcentration and high performance liquid chromatography/tandem mass spectrometry.</a> J. AOAC Int. 93 (6), 1732-1747 (2010).</li><li>Ahrens, L., Daneshvar, A., Lau, A. E., Kreuger, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterization+of+five+passive+sampling+devices+for+monitoring+of+pesticides+in+water.">Characterization of five passive sampling devices for monitoring of pesticides in water.</a> J. Chromatogr. A. 1405, 1-11 (2015).</li><li>Royston, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Approximating+the+Shapiro-Wilk+W-test+for+non-normality.">Approximating the Shapiro-Wilk W-test for non-normality.</a> Stat. Comput. 2 (3), 117-119 (1992).</li><li>Gauthier, T. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Detecting+trends+using+Spearman's+rank+correlation+coefficient.">Detecting trends using Spearman's rank correlation coefficient.</a> Environ. Forensics. 2 (4), 359-362 (2001).</li><li>Morin, N., Mi&#232;ge, C., Coquery, M., Randon, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chemical+calibration,+performance,+validation+and+applications+of+the+polar+organic+chemical+integrative+sampler+(POCIS)+in+aquatic+environments.">Chemical calibration, performance, validation and applications of the polar organic chemical integrative sampler (POCIS) in aquatic environments.</a> TrAC - Trend. Anal. Chem. 36, 144-175 (2012).</li><li>. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Water+Quality+-+Sampling+-+Part+23:+Guidance+on+Passive+Sampling+in+Surface+Waters.">Water Quality - Sampling - Part 23: Guidance on Passive Sampling in Surface Waters.</a> ISO 5667-23:2011. , (2011).</li><li>Morin, N., Camilleri, J., Cren-Oliv&#233;, C., Coquery, M., Mi&#232;ge, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Determination+of+uptake+kinetics+and+sampling+rates+for+56+organic+micropollutants+using+"pharmaceutical"+POCIS.">Determination of uptake kinetics and sampling rates for 56 organic micropollutants using "pharmaceutical" POCIS.</a> Talanta. 109, 61-73 (2013).</li></ol>

The authors have nothing to disclose.

For quality control, as standard procedure, laboratory blanks, limits of detection (LOD), recoveries, and repeatability were examined23. A few pesticides were detected in the blank samples at low concentration levels. LODs were set as the value of the lowest point on the calibration curve which meets the criteria of a signal to noise ratio of 3. The average LODs were 8.0 pg absolute injected on column for silicone rubber, 1.7 pg absolute for POCIS-A, 1.6 pg absolute for POCIS-B, 3.0 pg absolute for SDB-RPS dis...

Pesticides are continuously introduced to the aquatic environment and may pose a risk to aquatic organisms1. Monitoring of pesticides in the aqueous environment is typically performed using grab sampling, however, this sampling technique does not fully account for temporal variations in concentrations due to fluctuations in flow or episodic inputs (e.g., precipitation, combined sewer overflows, sewage lagoon release)2,3. Thus, monitoring methods need to be improved for a better estimation of environmental risks associated with pesticides. Passive sampling allows continuous monitoring over an extended period of time with minimal infrastructure and low contaminant concentrations4,5.
Passive samplers have been shown to be a valuable tool for the monitoring in groundwater6, fresh water7-10, wastewater11 and marine waters12. Besides monitoring purposes13,14, passive samplers have also been used for non-target analysis15, toxicology testing16,17, and as an alternative to sediment- and biomonitoring18. Passive samplers accumulate chemicals continuously from water and provide time weighted average (TWA) concentrations14. The uptake of the contaminant depends on the sampling rate (RS) and passive sampler-water partition coefficient (KPW), which depends on the passive sampler design, sampler material, physicochemical properties of the contaminant, and environmental conditions (e.g., water turbulence, temperature)13,14,19,20.
The detailed video aims to show how to calibrate and apply passive samplers for pesticides in water. The specific objectives included i) to perform preparation, extraction and instrumental analysis for 124 individual pesticides using five different types of passive samplers, including silicone rubber, polar organic chemical integrative sampler (POCIS)-A, POCIS-B, SDB-RPS and C18 disk, ii) to assess RS and KPW for the pesticides in a laboratory uptake study, and iii) to demonstrate how to select the appropriate passive sampler of the target compound of interest and how to calculate TWA concentrations for the respective passive sampler.
Reference standards and passive sampler devices
Target compounds included 124 legacy and currently used pesticides including herbicides, insecticides and fungicides (Table 1). Internal standard mixture (IS mixture) included fenoprop (2,4,5-TP), clothianidin-D3, ethion and terbuthylazine-D5. Other used chemicals included methanol (MeOH), acetonitrile (ACN), acetone (ACE), dichloromethane (DCM), cyclohexane (CH), ethyl acetate (EA), petroleum ether (PE), 2-propanol, 25% ammonia solution, acetic acid (HAc) and formic acid (FA). Five different passive sampling devices were characterized, including silicone rubber, POCIS-A and POCIS-B, SDB-RPS, and C18 disk1,21.
Table 1. Passive sampler sampling rate (R&#39;S, L day-1), sampler-water partition coefficients (K&#39;PW, L kg-1) and equations (Eq.) used for the calculation of concentrations in field samples for individual pesticidesa. (Reprinted from Journal of Chromatography A, 1405, Lutz Ahrens, Atlasi Daneshvar, Anna E. Lau, Jenny Kreuger, Characterization of five passive sampling devices for monitoring of pesticides in water, 1-11, Copyright (2015), with permission from Elsevier.)22 <a href="https://www.jove.com/files/ftp_upload/54053/Table_1.xlsx" target="_blank">Please click here to download this file.</a>

<table><tbody><tr><td>Methanol</td><td>Merck Millipore</td><td>1.06035.2500</td><td></td></tr><tr><td>Acetonitrile</td><td>Merck Millipore</td><td>1.00029.2500&amp;nbsp;</td><td></td></tr><tr><td>Acetone</td><td>Merck Millipore</td><td>1.00012.2500</td><td></td></tr><tr><td>2-propanol</td><td>Merck Millipore</td><td>1.00272.2500</td><td></td></tr><tr><td>Dichloromethane</td><td>Merck Millipore</td><td>1.06054.2500</td><td></td></tr><tr><td>Ammoniak</td><td>Merck Millipore</td><td>1.05428.1000</td><td>Purity 25%</td></tr><tr><td>Formic acid</td><td>Sigma-Aldrich</td><td>94318-50ML-F</td><td>Purity ~98%</td></tr><tr><td>Ethyl acetate&amp;nbsp;</td><td>Sigma-Aldrich</td><td>31063-2.5L</td><td>for pesticide residue analysis</td></tr><tr><td>Petroleum ether&amp;nbsp;</td><td>Sigma-Aldrich</td><td>34491-4X2.5L</td><td>for pesticide residue analysis</td></tr><tr><td>Acetic acid&amp;nbsp;</td><td>Sigma-Aldrich</td><td>320099-500ML</td><td>Purity &amp;ge;99.7%</td></tr><tr><td>Cyclohexane&amp;nbsp;</td><td>Fisher Chemicals</td><td>C/8933/17</td><td>for residue analysis</td></tr><tr><td>Empty polypropylene SPE Tube with PE frits, 20 &amp;mu;m porosity, volume 6&amp;nbsp;ml</td><td>Supelco</td><td>57026</td><td></td></tr><tr><td>Empore SPE Disks, C&lt;sub&gt;18&lt;/sub&gt;, diam. 47&amp;nbsp;mm</td><td>Supelco</td><td>66883-U</td><td>Passive sampler</td></tr><tr><td>Empore SPE Disks, SDB-RPS (Reversed-Phase Sulfonate), diam. 47&amp;nbsp;mm</td><td>Supelco</td><td>66886-U&amp;nbsp;</td><td>Passive sampler</td></tr><tr><td>POCIS-A&amp;nbsp;</td><td>EST</td><td>POCIS-HLB</td><td>Passive sampler</td></tr><tr><td>POCIS-B</td><td>EST</td><td>POCIS-Pesticide&amp;nbsp;</td><td>Passive sampler</td></tr><tr><td>Polyethersulfone (PES) membranes</td><td>EST</td><td>PES</td><td></td></tr><tr><td>Silicone rubber sheet</td><td>Altec</td><td>03-65-4516</td><td>Passive sampler</td></tr><tr><td>Agilent 5975C</td><td>Agilent Technologies</td><td>5975C</td><td>GC-MS</td></tr><tr><td>HP-5MS UI</td><td>J&amp;amp;W Scientific</td><td>HP-5MS</td><td>Analytical column for GC-MS</td></tr><tr><td>Agilent 6460</td><td>Agilent Technologies</td><td>6460</td><td>HPLC-MS/MS</td></tr><tr><td>Strata C18&amp;ndash;E, 20 x 2 mm id and 20&amp;ndash;25 &amp;mu;m particle size</td><td>Phenomenex</td><td>Strata C18&amp;ndash;E</td><td>Online SPE column for LC-MS/MS</td></tr><tr><td>Strata X, 20 x 2 mm id and 20&amp;ndash;25 &amp;mu;m particle size</td><td>Phenomenex</td><td>Strata X</td><td>Online SPE column for LC-MS/MS</td></tr><tr><td>Zorbax Eclipse Plus C18</td><td>Agilent Technologies</td><td>Zorbax Eclipse Plus C18</td><td>Analytical column for LC-MS/MS</td></tr><tr><td>Isolute phase separator, 25 ml</td><td>Biotage</td><td>120-1907-E</td><td></td></tr><tr><td>Stainless steel blind rivet, 3.2x10&amp;nbsp;mm</td><td>Ejot &amp;amp; Avdel</td><td>951222</td><td></td></tr></tbody></table>

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).

Five different passive sampler techniques were compared for the uptake of 124 legacy and current used pesticides including silicone rubber (Figure 1), and POCIS A, POCIS B, SDB-RPS and C18 disk (Figure 2). The performance of the extraction method and instrumental analysis was optimized. The outcome of the laboratory uptake experiments can be used to calculate the R&#39;S and log K&#39;PW values (T...

Watch this Scientific Journal Video about Characterization and Application of Passive Samplers for Monitoring of Pesticides in Water at JoVE.com

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

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 ...

characterization-application-passive-samplers-for-monitoring

Research

JoVE Journal

Environment

9.4K Views.  Swedish University of Agricultural Sciences. A protocol about the characterization and application of five different passive sampling devices is presented.

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

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 ...

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.

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.

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

A Simple Method for Automated Solid Phase Extraction of Water Samples for Immunological Analysis of Small Pollutants

A new method for solid phase extraction (SPE) of environmental water samples is proposed. The developed prototype is cost-efficient and user friendly, and enables to perform rapid, automated and simple SPE. The pre-concentrated solution is compatible with analysis by immunoassay, with a low organic solvent content. A method is described for the extraction and pre-concentration of natural hormone 17&#946;-estradiol in 100 ml water samples. Reverse phase SPE is performed with octadecyl-silica sorbent and elution is done with 200 &#181;l of methanol 50% v/v. Eluent is diluted by adding di-water to lower the amount of methanol. After preparing manually the SPE column, the overall procedure is performed automatically within 1 hr. At the end of the process, estradiol concentration is measured by using a commercial enzyme-linked immune-sorbent assay (ELISA). 100-fold pre-concentration is achieved and the methanol content in only 10% v/v. Full recoveries of the molecule are achieved with 1 ng/L spiked de-ionized and synthetic sea water samples.

A protocol for the extraction and pre-concentration of estradiol from water samples by using an automated and miniaturized system is presented.

A new method for solid phase extraction (SPE) of environmental water samples is proposed. The developed prototype is cost-efficient and user friendly, and ...

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 ...

Protocols for Quantifying Transferable Pesticide Residues in Turfgrass Systems

Plant canopies in established turfgrass systems can intercept an appreciable amount of sprayed pesticides, which can be transferred through various routes onto humans. For this reason, transferable pesticide residue experiments are required for registration and re-registration by the United States Environmental Protection Agency (USEPA). Although such experiments are required, limited specificity is required pertaining to experimental approach. Experimental approaches used to assess pesticide transfer to humans including hand wiping with cotton gloves, modified California roller (moving a roller of known mass over cotton cloth) and soccer ball roll (ball wrapped with sorbent strip) over three treated turfgrass species (creeping bentgrass, hybrid bermudagrass and tall fescue maintained at 0.4, 5 and 9 cm, respectively) are presented. The modified California roller is the most extensively utilized approach to date, and is best suited for use at low mowing heights due to its reproducibility and large sampling area. The soccer ball roll is a less aggressive transfer approach; however, it mimics a very common occurrence in the most popular international sport, and has many implications for nondietary pesticide exposure from hand-to-mouth contact. Additionally, this approach may be adjusted for other athletic activities with limited modification. Hand wiping is the best approach to transfer pesticides at higher mowing heights, as roller-based approaches can lay blades over; however, it is more subjective due to more variable sampling pressure. Utility of these methods across turfgrass species is presented, and additional considerations to conduct transferable pesticide residue research in turfgrass systems are discussed.

Transferable pesticide residue experiments in turfgrass systems are integral components of human risk exposure assessments. Experimental approaches to measure transferable residues should be adjusted to the human interaction of interest and turfgrass system dynamics. Three transferable pesticide residue protocols are presented and the suitability across three turfgrass systems is discussed.

Plant canopies in established turfgrass systems can intercept an appreciable amount of sprayed pesticides, which can be transferred through various routes ...

Vegetated Treatment Systems for Removing Contaminants Associated with Surface Water Toxicity in Agriculture and Urban Runoff

Urban stormwater and agriculture irrigation runoff contain a complex mixture of contaminants that are often toxic to adjacent receiving waters. Runoff may be treated with simple systems designed to promote sorption of contaminants to vegetation and soils and promote infiltration. Two example systems are described: a bioswale treatment system for urban stormwater treatment, and a vegetated drainage ditch for treating agriculture irrigation runoff. Both have similar attributes that reduce contaminant loading in runoff: vegetation that results in sorption of the contaminants to the soil and plant surfaces, and water infiltration. These systems may also include the integration of granulated activated carbon as a polishing step to remove residual contaminants. Implementation of these systems in agriculture and urban watersheds requires system monitoring to verify treatment efficacy. This includes chemical monitoring for specific contaminants responsible for toxicity. The current paper emphasizes monitoring of current use pesticides since these are responsible for surface water toxicity to aquatic invertebrates.

This article summarizes the design attributes and the effectiveness of treatment systems that treat urban stormwater and agriculture irrigation runoff to remove pesticides and other contaminants associated with aquatic toxicity.

Urban stormwater and agriculture irrigation runoff contain a complex mixture of contaminants that are often toxic to adjacent receiving waters. Runoff may ...

Continuous Instream Monitoring of Nutrients and Sediment in Agricultural Watersheds

Pollutant concentrations and loads in watersheds vary considerably with time and space. Accurate and timely information on the magnitude of pollutants in water resources is a prerequisite for understanding the drivers of the pollutant loads and for making informed water resource management decisions. The commonly used &#34;grab sampling&#34; method provides the concentrations of pollutants at the time of sampling (i.e., a snapshot concentration) and may under- or overpredict the pollutant concentrations and loads. Continuous monitoring of nutrients and sediment has recently received more attention due to advances in computing, sensing technology, and storage devices. This protocol demonstrates the use of sensors, sondes, and instrumentation to continuously monitor in situ nitrate, ammonium, turbidity, pH, conductivity, temperature, and dissolved oxygen (DO) and to calculate the loads from two streams (ditches) in two agricultural watersheds. With the proper calibration, maintenance, and operation of sensors and sondes, good water quality data can be obtained by overcoming challenging conditions such as fouling and debris buildup. The method can also be used in watersheds of various sizes and characterized by agricultural, forested, and/or urban land.

With the advancement of technology and the rise in end-user expectations, the need and use of higher temporal resolution data for pollutant load estimation has increased. This protocol describes a method for continuous in situ water quality monitoring to obtain higher temporal resolution data for informed water resource management decisions.

Pollutant concentrations and loads in watersheds vary considerably with time and space. Accurate and timely information on the magnitude of pollutants in ...

Capturing Flow-weighted Water and Suspended Particulates from Agricultural Canals During Drainage Events

The purpose of this study is to describe the methods used to capture flow-weighted water and suspended particulates from farm canals during drainage discharge events. Farm canals can be enriched by nutrients such as phosphorus (P) that are susceptible to transport. Phosphorus in the form of suspended particulates can significantly contribute to the overall P loads in drainage water. A settling tank experiment was conducted to capture suspended particulates during discrete drainage events. Farm canal discharge water was collected in a series of two 200 L settling tanks over the entire duration of the drainage event, so as to represent a composite subsample of the water being discharged. Imhoff settling cones are ultimately used to settle out the suspended particulates. This is achieved by siphoning water from the settling tanks via the cones. The particulates are then collected for physico-chemical analyses.

Nutrients present in particulate form can contribute significantly to the overall loads in agricultural drainage waters. This study describes a novel method to capture flow-weighted water and suspended particulates from farm canal drainage over the entire duration of the drainage event.

The purpose of this study is to describe the methods used to capture flow-weighted water and suspended particulates from farm canals during drainage ...

Continuous Hydrologic and Water Quality Monitoring of Vernal Ponds

Vernal ponds, also referred to as vernal pools, provide critical ecosystem services and habitat for a variety of threatened and endangered species. However, they are vulnerable parts of the landscapes that are often poorly understood and understudied. Land use and management practices, as well as climate change are thought to be a contribution to the global amphibian decline. However, more research is needed to understand the extent of these impacts. Here, we present methodology for characterizing a vernal pond's morphology and detail a monitoring station that can be used to collect water quantity and quality data over the duration of a vernal pond's hydroperiod. We provide methodology for how to conduct field surveys to characterize the morphology and develop stage-storage curves for a vernal pond. Additionally, we provide methodology for monitoring the water level, temperature, pH, oxidation-reduction potential, dissolved oxygen, and electrical conductivity of water in a vernal pond, as well as monitoring rainfall data. This information can be used to better quantify the ecosystem services that vernal ponds provide and the impacts of anthropogenic activities on their ability to provide these services.

Understanding the ecosystem services and processes provided by vernal ponds and the impacts of anthropogenic activities on their ability to provide these services requires intensive hydrologic monitoring. This sampling protocol using in-situ monitoring equipment was developed to understand the impact of anthropogenic activities on water levels and quality.

Vernal ponds, also referred to as vernal pools, provide critical ecosystem services and habitat for a variety of threatened and endangered species. ...

Identifying Per- and Polyfluorinated Chemical Species with a Combined Targeted and Non-Targeted-Screening High-Resolution Mass Spectrometry Workflow

Historical and emerging per- and polyfluoroalkyl substances (PFASs) have garnered significant interest from the public and government agencies from the local to federal levels. The continuing evolution of PFAS chemistries presents a challenge to the environmental monitoring, where ongoing development of targeted methods necessarily lags the discovery of new chemical compounds. There is a need, therefore, to have forward-looking methodologies that can detect emerging and unexpected compounds, monitor these species over time, and resolve details of their chemical structure to enable future work in human health. To this end, non-targeted analysis by high-resolution mass spectrometry offers a broad base detection approach that can be combined with almost any sample preparation scheme and provides significant capabilities for compound identification after detection. Herein, we describe a solid-phase extraction (SPE) based sample concentration method tuned for shorter chain and more hydrophilic PFAS chemistries, such as per fluorinated ether acids and sulfonates, and describe analysis of samples prepared in this fashion in both targeted and non-targeted modes. Targeted methods provide superior quantification when reference standards are available but are intrinsically limited to expected compounds when performing analysis. In contrast, a non-targeted approach can identify the presence of unexpected compounds and provide some information about their chemical structure. Information about chemical features can be used to correlate compounds across sample locations and track abundance and occurrence over time.

Here, we present a protocol for the sequential targeted quantification and non-targeted analysis of fluorinated compounds in water by mass spectrometry. This methodology provides quantitative levels of known fluorochemical compounds and identifies unknown chemicals in related samples with semi-quantitative estimates of their abundance.

Historical and emerging per- and polyfluoroalkyl substances (PFASs) have garnered significant interest from the public and government agencies from the ...