Effects of hydrodynamic conditions and temperature on polar organic chemical integrative sampling rates

Abstract

The effects of changing hydrodynamic conditions and changing temperatures on polar organic chemical integrative sampler (POCIS) sampling rates (R ) were investigated for 12 crop protection chemicals. Exposure concentration was held constant in each laboratory experiment, and flow velocities were calculated from measured mass transfer coefficients of the water boundary layer near the surface of POCIS devices. At a given temperature R generally increased by a factor of 2 to 5 between a stagnant condition and higher flow velocities (6-21 cm/s), but R for most compounds was essentially constant between the higher flow velocities. When temperature was varied between 8 and 39 °C for a given flow condition, R increased linearly. In general, R increased by a factor of 2 to 4 and 2 to 8 over this temperature range under flow and stagnant conditions, respectively. An Arrhenius model was used to describe the dependence of POCIS sampling rates on temperature. Adjustments of R for temperature did not fully explain observed differences between time-weighted average concentrations of atrazine determined from POCIS and from composite water sampling in a field setting, suggesting that the effects of other competing factors still need to be evaluated. Environ Toxicol Chem 2018;37:2331-2339. © 2018 SETAC.

Validation of the Application of a Polar Organic Chemical Integrative Sampler (POCIS) in Non-steady-state Conditions in Aquatic Environments

“…The values of R s at 1500 rpm were higher than those at 400 rpm. This tendency is consistent with the findings of several previous studies [5,11,12,[22][23][24][25][26]. In general, the mass transfer of chemicals from water to sorbent under low flow conditions is governed by the water boundary layer.…”

“…Conversely, the water turbulence prevalent under high flow conditions decreases the thickness of the water boundary layer. However, at some point, which is reported to be approximately 6 cm/s [25], an increase in turbulence no longer affects the sampling rate [23]. The flow velocities in the 1 L glass beaker under 400 rpm and 1500 rpm were calculated to be 1.0 cm/s and 18 cm/s, respectively ( Table 2).…”

Experimental Estimation of 44 Pharmaceutical Polar Organic Chemical Integrative Sampler Sampling Rates in an Artificial River under Various Flow Conditions

“…A greater increase in sampling rates was observed between flow velocities V 0 to V 1 (Supplemental Data, Figure S3), because on average sampling rates increased by a factor of 3 between stagnant ( V 0 ) and flow condition V 1 . Djomte et al (2018) found that sampling rates increased by a factor of 2 to 5 between stagnant and flow conditions. For these same authors (Djomte et al 2018), pesticide sampling rates remained constant over the range of velocities from 6 to 21 cm/s.…”

“…Djomte et al (2018) found that sampling rates increased by a factor of 2 to 5 between stagnant and flow conditions. For these same authors (Djomte et al 2018), pesticide sampling rates remained constant over the range of velocities from 6 to 21 cm/s. We made the same observation: the sampling rates of pharmaceuticals slightly increased between flow velocities 2 to 3 and 6 to 7 cm/s and then again between 6 to 7 and 20 cm/s, by an average factor of 1.1 ± 0.4 and 1.4 ± 0.2, respectively.…”

“…Calibration experiments spanned a wide range of conditions, some of which were far from being environmental conditions, for example, compound concentrations from 10 to 10 000 ng/L, various matrices (such as wastewater, tap water, ultrapure water, or sea water), temperature and agitation modes adopted to induce water flow velocity (such as magnetic, flow system, quiescent), and the design and volumes of the laboratory‐scale pilot. For example, calibrations may be conducted in a beaker filled with 1 to 4.5 L of water (Alvarez et al 2004; Jones‐Lepp et al 2004; Matthiessen et al 2006; Arditsoglou and Voutsa 2008; Martínez Bueno et al 2009; Kohoutek et al 2010; Bartelt‐Hunt et al 2011; Rujiralai et al 2011; Thomatou et al 2011; Charlestra et al 2012; Amdany et al 2014; Magi et al 2018), or in a small tank filled with 2 to 10 L (Alvarez et al 2007; MacLeod et al 2007; Togola and Budzinski 2007; Li et al 2010a; Bayen et al 2014; Di Carro et al 2014; Metcalfe et al 2014; Martínez Bueno et al 2016; Miller et al 2016), 20 to 50 L (Hernando et al 2005; Zhang et al 2008; Bailly et al 2013; Morin et al 2013; Vallejo et al 2013; Belles et al 2014a; Djomte et al 2018), 50 to 100 L (Mazzella et al 2007; Lissalde et al 2011; Fauvelle et al 2012; Ahrens et al 2015; Poulier et al 2015), or 250 to 1400 L (Harman et al 2008; Belles et al 2014b; Kaserzon et al 2014) of water. Less frequently, calibrations are conducted in laboratory‐scale pilots with channels containing a large volume of water, on the order of 120 L (Li et al 2010b), 480 L (Vermeirssen et al 2012), or as much as 113 000 L (Lotufo et al 2018).…”