In Expt. 1, dried shoot tissue was sent for nutrient analysis at the Service Testing and Research Laboratory (STAR) Laboratory, The Ohio State University (Wooster, OH, USA). Plant tissue of two experimental blocks were pooled for analysis, giving three replicates of each of the following treatments: MM at 5, 10, 20, 40 g⋅L^–1 and FP and HP at 20 mL⋅L^–1. Plant tissue was ground and then digested using an automated microwave digestion system (Discover SP-D; CEM, Matthews, NC, USA). The total concentration of the nutrients—phosphorus (P), potassium (K), aluminum (Al), boron (B), calcium (Ca), Cu, Fe, Mg, Mn, molybdenum (Mo), sodium (Na), sulfur (S), and Zn—was measured by inductively coupled plasma (ICP) emission spectrometry (Agilent 5110 ICP-OES; Agilent Technologies, Santa Clara, CA, USA) (Isaac and Johnson 1985). The concentration of total N was measured by combustion using a Vario Max Cube Carbon-Nitrogen Analyzer (Elementar Americas, Mt. Laurel, NJ, USA).

For TP concentrations, unfiltered water samples were analyzed using ICP (Agilent Technologies, Santa Clara, CA) following persulfate digestion at Service Testing and Research (STAR) Laboratory. A Tukey’s honestly significant difference (HSD) statistical test was used for multiple comparisons and t-test for pairwise comparison in the nutrient concentrations collected across this study. All the analyses were assessed relative to a 5 % significance level.

The dried latex was analyzed for elemental composition by inductively coupled plasma spectroscopy (ICP) by The Ohio State University’s Service Testing and Research Laboratory. Dried latex samples from different experiments also were similarly analyzed for elemental composition.

Several habitat variables were sampled at each transect (0m, 15 m, 30 m) within each reach to serve as covariates in our study. During each survey, water depth (cm) was a mean of six values measured each season at two points per transect positioned left and right of the thalweg. Three 250-mL water samples were collected seasonally (winter and summer of each year), one from each transect (0m, 15 m, 30 m) of each reach. Samples were measured for total nitrogen (TN; mg N/L), total phosphorus (TP; mg P/L), nitrate (mg NO3 -N/L), ammonia (mg NH3 -N/L), and orthophosphate (mg PO4 -P/L) at the Ohio Agricultural Research and Development Center Service Testing and Research Lab (STAR Lab, Wooster, Ohio).

Plant leaf and fruit nutrient analysis was conducted at Ohio State University’s Service, Testing, and Research (STAR) laboratory (Wooster, OH, USA). Total concentrations of plant essential elements (P, K, Ca, Mg, S, Al, B, Cu, Fe, Mn, Mo, Na, and Zn) were determined by microwave digestion with HNO3 followed by inductively coupled plasma (ICP) emission spectrometry according to Jones et al. (1991). Nitrate nitrogen in plant tissue samples was determined by a potentiometric method according to Baker and Smith (1969). Total nitrogen in plant tissue samples was determined by the Dumas method according to the Association of Official Analytical Chemists (AOAC International, 2000).

To obtain crude protein levels, ground oat samples were sent to the Service Testing and Research (STAR) Laboratory at The Ohio State University. The Dumas combustion method (AOAC 992.23) was applied to all samples to quantify nitrogen content. These results were multiplied by a nitrogen conversion factor of 5.83, as recommended by the USDA, to obtain crude protein (Jones, 1931). Due to the limited resources, crude protein analysis was done on a single representative sample.

Forages and concentrate samples were analyzed for DM, CP, ADF, NDF, and EE by wet chemistry methods (Cumberland Valley Analytical Services, Waynesboro, PA). Forages, concentrate, serum, and hoof trimmings were analyzed for mineral content by Inductively Coupled Plasma Spectrophotometry (Service Testing and Research Laboratory, Wooster, OH).

For the dried DMD and hydrochar, total carbon and nitrogen contents were determined by an elemental analyzer (Elementar Vario Max CNS, Mt. Laurel, NJ, USA) and all testes were carried out in triplicates. Meanwhile, a complete suite of elements (a total of 28, as listed in Table 3), was analyzed using microwave-assisted nitric acid digestion followed by ICP-OES (Agilent 5110, USA) [31]. The analysis was carried out at the Service Testing and Research (STAR) Laboratory, Wooster, OH, USA. All samples were digested twice and each digested sample was measured twice for replication.

Subsamples of the forages, concentrates, and composited refusals were dried at 55°C for 72 h to determine DM. Dried samples were ground to pass through a 1-mm sieve (Wiley mill; Arthur H. Thomas Co.) and analyzed for DM at 100°C overnight, OM (method 942.05, AOAC International, 2000), NDF with heat-stable α-amylase and sodium sulfite (Ankom200 Fiber Analyzer; Ankom Technology Corp.), starch (Weiss and Wyatt, 2000), FA (Jenkins, 2010), and minerals (Service Testing and Research Laboratory, OARDC, Wooster, OH) using inductively coupled plasma emission spectroscopy (Isaac and Johnson, 1985).

Flower corollas were collected on the day of flower opening (non-senescing) and the last day of flower senescence (senescing). The samples were dried in a forced air-drying oven set at 60°C, ground into a powder that could pass a 2-mm sieve, and sent to the Service Testing and Research (STAR) Lab (The Ohio State University, Wooster, OH, United States) for nutrient analysis. Total nitrogen (N) was analyzed using a Vario Max combustion analyzer (Elementar Americas, Ronkonkoma, NY, United States) following the Dumas combustion method (Sweeney, 1989). Plant tissue was digested using an automated microwave digestion system (Discover SP-D, CEM, Matthews, NC, United States). The concentrations of other mineral nutrients including phosphorus (P) were determined using an inductively coupled plasma spectrometer (Agilent 5110 ICP-OES, Agilent Technologies, Santa Clara, CA, United States; Isaac and Johnson, 1985).

A total of 0.25–0.5 g of each filter paper + suspended sediment subsample was digested according to EPA Method 3051A at The Ohio State University Service Testing and Research Laboratory (STAR Lab) for analysis on an Agilent 5110 ICP-OES for the elements: Al, As, B, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Mo, Na, Ni, P, Pb, S, Sb, Se, Si, Sr, Tl, V, and Zn.

Samples were then ground so that the vegetation could pass through a 2 mm sieve and sent to The Ohio State University Service Testing and Research (STAR) lab for nutrient analysis. The STAR lab analyzed all macrophyte samples for a major suite of elements (including phosphorus) by performing a nitric/perchloric acid digestion and then using an Agilent 5110 ICP-OES for sample analysis. Nitrogen composition was determined by the STAR lab using a VARIO Max Cube Carbon-Nitrogen Analyzer. Biofilm was not removed from the macrophytes and, thus, nutrient concentrations include algal growth on the emergent vegetation sampled.

Nutrient samples were collected coincident with fish samples at each study reach at 5–7 locations. Sub-samples from each reach were composited by reach and were refrigerated before submission to The Ohio State University’s Service Testing and Research (STAR) Laboratory for analysis of total nitrogen (N; mg L−1) and total phosphorus (P; mg L−1) within 24 h of collection. Total N and P were analyzed using flow injection analysis (Latchat Quick Chem 8500 Flow Injection Analyzer, Hach Company, Loveland, Colorado).

Samples were then analyzed for pH, organic matter (as LOI), percent carbon (C), percent N, aluminum (Al3+), iron (Fe3+), sulfur (S2−), NO3−, and STP (as Mehlich III) using standard methods by the Service Testing and Research (STAR) Lab at The Ohio State University (Wooster, OH).

Samples were air-dried indoors at room temperature, ground and passed through a Number 10 sieve. They were then packaged and shipped to the Service Testing and Research (STAR) Lab of The Ohio State University in Wooster, OH, for analyses.

To determine the soil fertility at planting and at harvest, samples were taken from each of the eight corn mesocosms and at the reference farm. Samples were taken at the time of planting (May 5, 2020 for reference farm, June 6, 2020 for mesocosms) and at harvest (Sept. 25, 2020 for mesocosms, Oct. 7, 2020 for reference farm). Plant-available P and K were determined via Mehlich 3 analysis (Mehlich, 1984), while NH4 and NO3 were determined via 2 m KCl extraction (Mulvaney, 1996). The mass of elemental nitrogen available to plants was then estimated by multiplying the NH4 values for each sample by (14/18) and the NO3 values by (14/62), then summing the results. Critical Mehlich 3 concentrations for corn agriculture were found in the literature to serve as a benchmark by which to evaluate sample test results.

NO3− or K+ ISEs, commonly used in laboratories and hospitals to measure NO3− or K+, were used to quantify the ppm of NO3− or K+ in the leachate. Nutrient Recipe base input samples and leachate output after uptake were cross-referenced once via the Service Testing and Research lab at Ohio State University and found to match up with calculated recipe input quantities and ISE quantified values (data not shown).

We collected six mineral soil cores (15 cm deep × 2 cm diameter) from each site and combined them at the site level to create a composite sample for analysis of metal and micronutrient concentrations via nitric acid digestion (conducted by The Ohio State University’s Service Testing and Research Laboratory). Metal and micronutrient information from the composite soil sample provides a snapshot of contaminant levels at one timepoint but does not provide information about temporal or spatial variability of contaminants (Carter & Gregorich, 2008).

Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) analysis were conducted at Service Testing and Research Laboratory (STAR Lab) at the Ohio State University Wooster campus (Wooster, OH). Agilent 5110 ICP-OES Dual view model (Agilent Corp., Santa Clara, CA, USA) was used to determine metal contaminants in Rakı samples. The metals were quantified using the calibration models for each metal at a wavelength of 228 nm (As), 324 nm (Cu), 220 nm (Pb) and 206 nm (Zn), following a method modified from Budzynska et al. (2018).

Leaching solutions were analyzed by inductively coupled plasma spectrometry (ICP). Palm oil digestions and all leaching solution ICP measurements were conducted by the Service Testing and Research Laboratory (Ohio Agricultural Research and Development Center – Ohio State University) on an Agilent 5110 ICP spectrometer (Agilent Technologies, Santa Clara, CA, USA). Instrument detection limits for all elements are noted in footnotes to the data tables. Blanks and spiked acetic acid samples were used to verify analytical performance. Recovery of lead from spiked acetic acid samples was 104.4% of the expected value. Stability of acetic acid extraction solutions during storage was confirmed by reanalysis of solutions and no differences were observed.

Plant tissue nutrient analysis was conducted using samples of the shoot of ‘Standard’ arugula (6 plants per treatment) at Ohio State University’s Service, Testing, and Research (STAR) laboratory (Wooster, OH, USA) to investigate the variations in nutrient uptake under different EC levels. Total concentrations of plant-essential elements (P, K, Ca, Mg, S, Al, B, Cu, Fe, Mn, Mo, Na, and Zn) were determined by microwave digestion with HNO3 followed by inductively coupled plasma (ICP) emission spectrometry according to Jones [28]. Nitrate nitrogen in plant tissue samples were determined by the NO3-N cadmium reduction method [29]. Total nitrogen in plant tissue samples were determined by the Dumas method according to Association of Official Analytical Chemists [30].

All ashed shrimp and fish feed samples were analyzed at the Ohio State University STAR Lab for the elements: Al, As, B, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Mo, Na, Ni, P, Pb, S, and Sb on the ICP-OES. Results for As, Be, Cd, and Co were omitted because all values were below method detection limit (MDL). 0.4–0.5 g. subsamples of shrimp/fish feed ash were dissolved in 15 mL HNO3, and then samples were filtered at 0.45 μm and diluted 10-fold before running on an Agilent 5110 ICP-OES.

All water-quality measurements were made concurrently at each site between ~08:00 and 12:00. These samples were then sent to The Ohio State University’s Service Testing and Research Laboratory (Wooster, Ohio, USA) for analysis of total phosphorus (P; mg/L), total nitrogen (N; mg/L), phosphate (PO4; mg/L), nitrate (NO3; mg/L), ammonia (NH3; mg/L), total dissolved solids (TDS; mg/L), and total Hg (ppt).

A suite of chemical water-quality variables associated with urbanization in the stream channel (Meyer et al., 2005; Walsh et al., 2005; Vietz et al., 2016) were selected and measured at each study site twice annually (mid-late May and mid-late July, 2014–2018). Nine 250-mg water samples were collected at each study site, one sample each at both stream edges and the thalweg at the upstream, middle and downstream sections each reach. These samples were sent to The Ohio State University’s Service Testing and Research Laboratory (Wooster, OH, USA) for analysis of mercury (Hg; ppt), phosphate (mg l-1), nitrate (mg l-1), ammonia (mg l-1), total phosphorus (mg l-1) and total nitrogen (mg l-1).

Leaching solutions were analyzed by inductively coupled plasma spectrometry(ICP). ICP measurements were carried out by the Service Testing and Research Laboratory (Ohio Agricultural Research and Development Center –Ohio State. University) on a Prodigy Dual View ICP spectrometer (Teledyne Leeman Labs, Hudson, NH, USA). Blanks and spiked samples were used to verify analytical performance. In addition, stability of extraction solutions during storage was confirmed by reanalysis of solutions and no differences were observed. 

Each soil was screened through a 2-mm sieve and then mixed thoroughly before selected soil properties were measured (Table 1). Soil pH was measured using a 1:1 ratio of soil to deionized water (Watson and Brown, 1998), soil texture by the hydrometer method (Day, 1965), total C and N using high temperature combustion (Nelson and Sommers, 1996), Bray P-1 by the method of Frank et al. (1998), and exchangeable bases (Ca, K, and Mg) by extraction with 1 M NH4OAC (Warncke and Brown, 1998).The materials applied as soil treatments were crop (corn) residues, gypsum, and glucose. Corn residues were collected from the field and dried in an oven at 60 °C before being ground to pass a 2 mm mesh sieve. Glucose and gypsum were obtained. 

Feeds were also analyzed for minerals by Service Testing and Research Laboratory (Ohio Agricultural Research and Development Center, Wooster) using inductively coupled plasma emission spectroscopy (Isaac and Johnson, 1985) after microwave digestion with nitric acid (Jones et al., 1991). 

Distance from the river, PAR, soil characteristics (pH, percent moisture, and nutrient analysis), slope, and aspect were recorded at each site. PAR measurements were taken in late April during the peak growing season (Apogee Instruments, Logan, UT), as close to noon as possible on a cloudless day. In April 2016, two 15-cm soil cores were also taken from each quadrat; soil moisture content was measured for each sample in the lab. Soil texture (particle-size analysis) was also investigated using the hydrometer method (Gee and Bauder 1979). Nutrient analyses involving phosphorus, potassium, calcium, magnesium, CEC, pH, lime test index (a measure of reserve acidity), and total nitrogen were performed by the STAR laboratory at the Ohio State University. Due to additional costs associated with testing, nitrate nitrogen levels were only assessed for every other quadrat along the transect. 

Soil samples were collected from the surface 20 cm of all plots in the fall following crop harvest but prior to broadcast and chisel tillage incorporation of any P and K fertilizer. Seven to 10, 2.5-cm diam. soil cores were sampled between planted rows, composited, air-dried, and sieved (<2 mm). The Service Testing and Research Laboratory at the Ohio Agricultural Research and Development Center (Wooster, OH) conducted soil test P (Bray-P1; Frank et al., 1998), soil pH (Thomas, 1996), cation exchange capacity (CEC), and ammonium acetate-extractable K, Ca, and Mg (Warncke and Brown, 1998) every year except when soils were not sampled in 2007 and 2009 (Wood County), 2007 (Clark County), and 2011 (all three county sites). Table 1 provides the initial soil characterization for each site. 

Another subsample was sent to Ohio State University’s Service, Testing, and Research Laboratory for standard analyses, including pH, available Bray (no.1) phosphorus, cation exchange capacity, exchangeable potassium, calcium, and magnesium. Soil moisture also was calculated for each sample. 

Sample Type: Soil 

Link 

Plant samples were analyzed by the OARDC Service Testing and Research Lab at the Ohio State University, Wooster, Ohio. Total concentrations of major elements (P, K, Ca, Mg, S, Al, B, Cu, 17 Fe, Mn, Mo, Na, and Zn) of plant materials were determined with Inductively Coupled Plasma (ICP) Emission Spectrometry after digestion with HNO3 according to Baker and Smith (1969). NO3 –N of plant materials was determined by potentiometric method according to Isaac and Johnson (1985). 

To account for influences of nutrient concentration on emergent insect production, we collected six 250-mL water samples for total nitrogen (N) and phosphorus (P) measurements from each reach: three samples collected laterally across the channel at evenly spaced intervals at the upstream and three at the downstream end of each reach (six samples total). Samples were collected once during the mid-point of the study at low flow (late July 2012). 

Proximate analysis was carried out on experimental diets and on fish whole bodies after 62 days of feeding. Prior to analysis, whole body fish (5/tank) were dehydrated via freeze-drying (<200 mT, −4 °C for 48 h). The difference in sample weight before and after drying were used to calculate moisture content using the following equation; percent moisture content = ((initial weight –final weight) * 100)/ initial weight. After drying, fish samples were manually ground, and protein and ash analysis was performed on dry ground samples following standard procedures (AOAC, 2002). 

Acknowledgements 

Proximate analysis of experimental diets and fish bodies was carried out in coordination with the Ohio Agricultural Research and Development Center Service Testing and Research Lab 

We germinated sunflowers variety ‘Dwarf Sunspot’ individually in thoroughly wetted, peat-based growing medium and transplanted seedlings once they produced their first pair of true leaves into pots containing either contaminated or control soil. Transplanted seedlings (14–19 day post germination) in their respective soil contamination treatments were randomly assigned a location in the greenhouse maintained at 22/ 20 °C, 16/8 h day/night. Plants were watered daily to maintain approximately 35% water holding capacity and were fertilized once during this growing period at a rate of 150 ppm (Peters Professional 20–10-20 General Purpose, Everris). Dwarf Sunspot sunflowers generally produce a single flower head, and once this flower head formed but before it opened, we covered the flower head with a tightly woven mesh bag (1 gal paint strainer) to exclude access to the flower head by pollinators and other insects in the greenhouse. We measured plant height at 49 days after planting (5 days before the start of the field experiment). Soil from plants not used in the field experiments (n = 8 per soil contamination treatment) was air dried and analyzed for Pb by the Service Testing and Research Lab at the Ohio Agricultural Research and Development Center.