At each site, five soil samples to a depth of 10 cm were collected using a cylinder of 7 cm diameter, sieved with 2 mm mesh, and dried. Soil pH was measured in a 1:5 (w:v) water suspension with a Hach HQ40D meter (ISO 10390). Total nitrogen (N) was determined using the Kjeldahl method. Soil was digested in H2SO4 with Kjeltabs (K2SO4 + CuSO4•5H2O; Tecator Digestor Auto, FOSS, Hilleroed, Denmark), followed by distillation on a FOSS Tecator Kjeltec 2300 Analyzer Unit. Total organic carbon (Corg) and total C were determined with a dry combustion analyzer Leco RC-612 (ISO 10694). P-Olsen was measured with an ion chromatograph (Dionex ICS-1100, Thermo Fisher Scientific) following soil extraction with 0.5 M NaHCO3. In order to determine total K, Mg, Ca, Zn, Cd, and Pb concentrations, ground samples were digested in hot concentrated HClO4 (FOSS Tecator Digestor Auto) at 288 – 292 °C. The extracted elements were analyzed by flame or graphic atomic absorption spectrometry (Varian AA280FS, AA280Z, Agilent Technologies, Santa Clara, USA). The results were ascertained using certified reference soil material CRM048-050 (RTC). Bioavailable fractions of Zn, Cd and Pb were assessed using the Diffussive Gradients in Thin-films (DGT) technique, following Dietrich et al. (2021) (link).
Hq40d meter
Manufactured by HACH
Sourced in United States
The HQ40D meter is a portable, multi-parameter water quality instrument designed for field and laboratory use. It is capable of measuring various water quality parameters, including pH, conductivity, dissolved oxygen, and temperature. The HQ40D provides accurate and reliable measurements to help users assess water quality.
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Lab products found in correlation
Varian aa 280 fs, by Agilent Technologies (1 mentions)
Dionex ics 1100, by Thermo Fisher Scientific (1 mentions)
Toc vcpn analyzer, by Shimadzu (1 mentions)
La 950, by Horiba (1 mentions)
Eclipse e200, by Nikon (1 mentions)
Turbidimeter, by HACH (1 mentions)
Ics 1100, by Thermo Fisher Scientific (1 mentions)
Rc 612, by Leco (1 mentions)
Digestor auto, by Foss (1 mentions)
Sc 144 dr, by Leco (1 mentions)
Kjeltec 2300 analyzer unit, by Foss (1 mentions)
5 protocols using hq40d meter
1
Comprehensive Soil Characterization Protocol
2
Limnological Water Quality Assessment
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Temperature (Tw), pH and dissolved oxygen (O2) were measured in situ with a Hach Lange HQ40D meter. Total nitrogen (TN) was determined using a TOC-VCPN analyzer (Shimadzu), phosphate-phosphorus (P-PO43−) and chlorophyll a spectrophotometrically (Aquamate, Thermo Spectronic) using filtered samples of water following reaction with ammonium molybdate and hot extraction with ethanol, respectively. Total phosphorus (TP) was determined analogously, but in non-filtered and mineralized (H2SO4 and peroxodisulfate) samples of water. Trophic status of the water was approximated by reference to Carlson Indexes (TSITP and TSIChla) (Carlson, 1977 (link)).
3
Activated Sludge Process Characterization
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DO was measured using an HQ40D meter (Hach, Loveland, CO, USA). The SVI, Vzs, MLSS, MLVSS, as well as the SOURs were analyzed according to standard methods (Baird and Bridgewater, 2017 ). The gluocose and ammonia chloride equivalent to 100 mg L − 1 COD and 30 mg L − 1 NH3—N were added as the sole electron donors in SOURCOD and SOURN tests, respectively. The in-situ OUR in each chamber was measured without external electron donor addition. The 5 min and 30 min SVI were measured using a standard 2 L settlemeter and recorded as SVI5 and SVI30, respectively. COD and ammonia concentrations were analyzed using TNTplus® 820 and TNTplus® 840 vials in a spectrophotometer (Hach, Loveland, CO, USA). The ammonia and sCOD samples were measured with the filtrate from 0.45 μm syringe filters (EZFlow®, Old Saybrook, CT, USA). The particle size distribution was determined using a particle size analyzer (Horiba, LA-950, Kyoto, Japan). A microscope (Nikon Eclipse, E200, NY, USA) was utilized for sludge morphology imaging.
4
Environmental Factors Affecting Water Quality
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Every time a sample was collected, metadata were also collected. Specifically, data on dissolved oxygen levels, pH, conductivity, and water temperature were measured in-field using a Hach HQ40d meter (Loveland, CO, United States); turbidity was measured in the laboratory using a turbidimeter (Hach). Flow rate in NY was measured 6 inches below the water surface using a flow meter (Global Water Instrumentation Inc., Cordova, CA, United States), while surface flow was estimated in AZ using the float method described in Gore (Gore, 2006 ). Meteorological data were obtained from the weather station3 ,4 ,5 closest to each site; the mean distance of the stations to the sites was 8.9 km (range = 0.4–25.5 km). Data were downloaded for the entire growing season in each state. Avg., min., and max. air temperature, avg. relative humidity, avg. solar radiation, and avg. wind speed were calculated for 0–1, 0–2, 0–3, 0–4, and 0–5 days before sample collection (BSC). Total rainfall was calculated using non-overlapping time periods (i.e., 0–1, 1–2, 2–3, 3–4, and 4–5 days BSC). Since no rain fell in Arizona during the time periods considered, rainfall factors were only included in downstream analyses when E. coli levels or pathogen detection in New York was the outcome.
5
Comprehensive Soil Characterization Protocol
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Soil samples were sieved (2 mm mesh) and divided into three parts that were then either dried for chemical analyses, frozen at -20 °C for phospholipid fatty acid (PLFA) analysis, or kept moist at 4 °C for the other microbial analyses. Dry weight was measured after drying overnight at 105 °C. Maximum waterholding capacity (WHC) was assessed using a gravimetric method. Soil texture was determined through a combination of sieving and sedimentation (ISO 11277 1998) . Soil pH was measured in 1:5 (w:v) water suspensions (ISO 10390 1994) with a Hach Lange HQ40D meter. Organic C was determined with a Leco RC-612 and total S with a Leco SC-144 DR dry combustion analyzer. Total N was determined by Kjeldahl method; soil was digested in H 2 SO 4 with Kjeltabs (K 2 SO 4 + CuSO 4 •5H 2 O; Foss Tecator Digestor Auto) followed by distillation on a Foss Tecator Kjeltec 2300 Analyzer Unit. The available (Olsen) P was measured with an ion chromatograph (Dionex ICS-1100) following soil extraction with 0.5 M NaHCO 3 (Olsen et al. 1954, modified) .
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