Technical Note: Field experiences using UV/VIS sensors for high-resolution monitoring of nitrate in groundwater

Huebsch, Manuela; Grimmeisen, Felix; Zemann, Moritz; Fenton, Owen; Richards, Karl G.; Jordan, Phillip; Sawarieh, Ali; Blum, Philipp; Goldscheider, Nico

doi:10.5194/hessd-11-12291-2014

Cited by 5 publications

(9 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Attributes such as the type, source and purpose of these data are itemised in Table 1. In addition, data from a perennial spring on site were examined previously by Huebsch et al (2015) (Fig 1). In summary, a pump house and lagoon (23 m 2 ), is equipped with a Corbett trapezoidal flume used to measure discharge from the lagoon with a calibrated water level recorder (Diver; 0.000 m to 10.000 m).…”

Section: Secondary Datasetsmentioning

confidence: 99%

“…In summary, a pump house and lagoon (23 m 2 ), is equipped with a Corbett trapezoidal flume used to measure discharge from the lagoon with a calibrated water level recorder (Diver; 0.000 m to 10.000 m). A double wavelength spectrophotometer (5 mm path length) sensor (NITRATAX plus sc, Hach Lange GmbH, Germany; Huebsch et al, 2015) measured NO 3 -N concentrations (0.000 to 25.000 mg L -1 ). Both instruments measured at a 15 minute resolution and were used to calculate NO 3 -N flux from 27 November 2011 to 25 March 2013.…”

Section: Secondary Datasetsmentioning

confidence: 99%

See 1 more Smart Citation

Integrated assessment of agricultural nutrient pressures and legacies in karst landscapes

Fenton

Mellander

Daly

et al. 2017

Agriculture, Ecosystems & Environment

Self Cite

View full text Add to dashboard Cite

Landscapes typically deemed at risk from leached losses of nitrogen (N) and phosphorus (P) are those with short subsurface hydrologic time lags. Due to the short time it takes nutrients to move from a source to an area of concern, such sites are deemed perfect to test the efficacy of programmes of measures as management changes. However, a small subset of these sites can retain nutrients in soil/subsoil layers, which in turn are leached and can be either attenuated (e.g. nitrate converted to gaseous forms or immobilised in soil and P can be mineralised) or mobilised over time. This biogeochemical time lag can have long lasting effects on water quality. In an intensive agricultural karst oxidised aquifer setting, the aim of this study was to improve understanding of P and N inputs, retention, attenuation and subsurface pathway distribution and to inform how similar sites can be managed in the future. This was undertaken for the present site by integrating existing secondary and new primary datasets for both N and P. Results showed that in the years pre-2000 slurry from an on-site integrated pig production unit had been applied at rates of 33 t ha-1 annually, which supplied approximately 136 kg ha-1 total N and approximately 26 kg ha-1 total P annually. This practice contributed to large quantities of N (Total N and NH 4-N) and elevated soil test P (Morgan extractable P), present to a depth of 1 m. This store was augmented by recent surpluses of 263 kg N ha-1 , with leached N to groundwater of 82.5 kg N ha-1 with only 2.5 kg N ha-1 denitrified in the aquifer thereafter. High resolution spring data showed greatest percentage loss in terms of N load from small (54-88%) and medium fissure pathways (7-21%) with longer hydrologic time lags, with smallest loads from either large fissure (1-13%) or conduit (1-10%) pathways with short hydrologic time lags (reaction time at the spring from onset of a rainfall event is within hours). Although soils were saturated in P and in mobile forms to 0.5 m, dissolved reactive P concentrations in groundwater remained low due to Ca and Mg limestone chemistry. Depletion of the legacy store with no further inputs (taking 25% of available mass of soil organic N as available in 1 m of soil/subsoil to be 75 kg N ha-1) would take approximately 50 years, with NO 3-N concentrations in the source area dropping to levels that could sustain groundwater NO 3-N concentrations below admissible levels within 9 years. Biogeochemical time lags (decades) are longer than hydrologic time lags on this site (months to years). Future management should target farm surpluses that maintain a legacy store at or below a soil organic N mass of ~ 20 kg N ha-1. Incorporation of biogeochemical and hydrologic time lag principles into future water quality regulations will provide regulators with realistic expectations when implementing policies.

show abstract

Section: Secondary Datasetsmentioning

confidence: 99%

Section: Secondary Datasetsmentioning

confidence: 99%

Integrated assessment of agricultural nutrient pressures and legacies in karst landscapes

Fenton

Mellander

Daly

et al. 2017

Agriculture, Ecosystems & Environment

Self Cite

View full text Add to dashboard Cite

show abstract

“…multiwavelength one (MWS) with PLSR resolution was carried out by Huebsch et al (2015) for groundwater monitoring. The findings were that the MWS offers more possibilities for calibration and error detection, but requires more expertise compared with the DWS.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

Direct DOC and nitrate determination in water using dual pathlength and second derivative UV spectrophotometry

et al. 2017

View full text Add to dashboard Cite

UV spectrophotometry is largely used for water and wastewater quality monitoring. The measurement/estimation of specific and aggregate parameters such as nitrate and dissolved organic carbon (DOC) is possible with UV spectra exploitation, from 2 to multi wavelengths calibration. However, if nitrate determination from UV absorbance is known, major optical interferences linked to the presence of suspended solids, colloids or dissolved organic matter limit the relevance of UV measurement for DOC assessment. A new method based on UV spectrophotometric measurement of raw samples (without filtration) coupling a dual pathlength for spectra acquisition and the second derivative exploitation of the signal is proposed in this work. The determination of nitrate concentration is carried out from the second derivative of the absorbance at 226 nm corresponding at the inflexion point of nitrate signal decrease. A short optical pathlength can be used considering the strong absorption of nitrate ion around 210 nm. For DOC concentration determination the second derivative absorbance at 295 nm is proposed after nitrate correction. Organic matter absorbing slightly in the 270-330 nm window, a long optical pathlength must be selected in order to increase the sensitivity. The method was tested on several hundred of samples from small rivers of two agricultural watersheds located in Brittany, France, taken during dry and wet periods. The comparison between the proposed method and the standardised procedures for nitrate and DOC measurement gave a good adjustment for both parameters for ranges of 2-100 mg/L NO3 and 1-30 mg/L DOC.

show abstract

“…4 In addition, broad-band ultraviolet/visible spectroscopy-based on-line probes for water monitoring have emerged. 5 These systems have been employed for complex water streams, e.g. with high turbidity, relying on sophisticated calibrations dedicated to each application.…”

Section: Introductionmentioning

confidence: 99%

“…with high turbidity, relying on sophisticated calibrations dedicated to each application. [5][6][7] Apart from these established techniques, infrared (IR) spectroscopy provides quantitative chemical information that can be obtained in reagent free measurements in real time. Ions like nitrate show strong and specific bands in the mid-IR spectrum.…”

Section: Introductionmentioning

confidence: 99%

A pocket-sized 3D-printed attenuated total reflection-infrared filtometer combined with functionalized silica films for nitrate sensing in water

Baumgartner

Freitag

Gasser

et al. 2020

Sensors and Actuators B: Chemical

View full text Add to dashboard Cite

Strong anion-exchange materials carry a positive charge that allows them to trap and concentrate anions while releasing other anions. Here, we introduced an ion exchange group into mesoporous silica films coated on attenuated total reflection (ATR) crystals to enrich nitrate from aqueous phase in the volume probed by the evanescent field. The ion-exchange and enrichment capabilities of the films were characterized using standard FTIR spectroscopy. Thereby fast analyte enrichment and full sensor recovery were observed. In addition, high enrichment factors of up to 1600 were achieved. After characterization, these coated ATR crystals were used in a dedicated ATR-IR filtometer comprising a Fabry-Pérot filter detector unit and a miniaturized thermal emitter with a footprint of only 80 mm × 120 mm × 70 mm. The filter covered the spectral region between 1250 -1800 cm -1 allowing for recording IR spectra of nitrate enriched into the mesoporous silica film. The sensor was calibrated using the Langmuir adsorption model as calibration function. From this, a limit of detection of 1.2 mg L -1 was derived for the ATR-IR filtometer.This emphasizes the high potential of functionalized mesoporous silica films combined with low-cost filtometers for portable water sensors.

show abstract

Technical Note: Field experiences using UV/VIS sensors for high-resolution monitoring of nitrate in groundwater

Cited by 5 publications

References 32 publications

Integrated assessment of agricultural nutrient pressures and legacies in karst landscapes

Integrated assessment of agricultural nutrient pressures and legacies in karst landscapes

Direct DOC and nitrate determination in water using dual pathlength and second derivative UV spectrophotometry

A pocket-sized 3D-printed attenuated total reflection-infrared filtometer combined with functionalized silica films for nitrate sensing in water

Contact Info

Product

Resources

About