Chemical Uptake Research Articles

Modeling plant uptake of organic contaminants by root vegetables: The role of diffusion, xylem, and phloem uptake routes

The uptake of organic contaminants by root vegetables involves diffusion, transport by xylem and phloem saps, degradation, and volatilization. To understand the role of uptake and elimination routes in the bioconcentration modeling of organic contaminants, a two-compartment uptake model (root and leaf compartments) was proposed. The results showed that for the root compartment, logarithm values of bioconcentration factors (log BCF, the concentration ratio between plant tissues and soil) of chemicals fell within a narrow range when the logarithm of octanol-water partition coefficient (log KOW) was less than 3.0, whereas log BCF values decreased rapidly with increasing log KOW values when log KOW was greater than 3.0. This is because the diffusion route had a significant impact on the root uptake of chemicals, wherein the first-order rate constant dropped rapidly for high-lipophilicity chemicals, resulting in very low log BCF values. For the leaf compartment, chemicals with moderate lipophilicity (log KOW of 3.0–4.0) had the highest simulated log BCF values. This is because moderate log KOW values generated the highest transpiration stream concentration factors (TSCFs, the concentration ratio between xylem or phloem saps and water), resulting in high uptake efficiency of chemicals by leaves. Furthermore, we improved the uptake model by considering the surface-deposition route for pesticides (foliar spray), and the simulation results indicated that this uptake route cannot be neglected for lipophilic compounds. Although the simulations agreed with an experimental study and some reported data, future studies should focus on factors, such as plant physiology (plant varieties, periderm effects and compositions of xylem and phloem saps) and environmental conditions (soil properties and weather conditions), to improve the plant uptake model.

The Economics of Irrigation Water: Empirical Evidence from the Awash River Basin, Ethiopia

Using primary data collected from Ethiopia’s Awash River basin, we study the economics of irrigation water for smallholder farmers. We estimate the impact of irrigation water on gross margin and chemical fertilizer uptake. Our results show that irrigation water has a statistically significant and positive effect on the profitability of crops and chemical fertilizer uptake. We also generate qualitative data on irrigation water returns by producing various crops in the different parts of the basin. In addition, we present the intensity of irrigation water used for various crops in the different parts of the basin as reported by farmers. In doing so, we offer some qualitative evidence on the economic trade-offs involved in irrigation water use at farm and basin levels. The policy implications of the findings are discussed.

Orychophragmus violaceus-maize rotation increases maize productivity by improving soil chemical properties and plant nutrient uptake

Appropriate use of cover crops and crop rotation in agriculture can contribute to food security and sustainable production. However, the impacts of Orychophragmus violaceus ( O. violaceus ) as rotation cover crop in maize on soil physicochemical properties and crop nutrient uptake have rarely been verified and quantified via field studies. With a conventional wheat ( Triticum aestivum L.)-maize ( Zea mays L.) rotation used as a control, a field experiment was conducted on the North China Plain in 2017–2018 and 2018–2019 to evaluate the dynamic variations in soil chemical properties and maize agronomic indexes and the impacts on maize nutrient uptake and yield under continuous maize and O. violaceus -maize rotation. We observed that rotation of O. violaceus with maize positively impacts soil chemical properties and subsequent maize productivity. Compared to those in the wheat-maize rotation, the mean contents of soil organic matter (SOM), soil alkali–hydrolyzable nitrogen (SAN), soil available phosphorus (SAP), and soil available potassium (SAK) in the O. violaceus -maize rotation increased by 8%, 11%, 13% and 18%, respectively, within the 0–60 cm soil layer, thereby increasing the maize N and P uptake and yield at maturity. According to correlation analysis and path model results, the most powerful direct factor affecting the maize yield was plant nutrient uptake rather than biomass accumulation. The O. violaceus -maize rotation was superior to the wheat-maize rotation and continuous maize in term of SOM, SAN, plant agronomic indexes, and maize nutrient uptake and yield. Overall, O. violaceus -maize is a reasonable rotation system for use on the North China Plain and provides new insight into the mechanisms and processes underlying crop yield and nutrient uptake. • O. violaceus -maize greatly increased soil organic matter and soil available nitrogen. • The maize nutrients uptake was increased at maturity in O. violaceus -maize system. • Replacing wheat or fallow field with O. violaceus increased maize yield by 8%−12%. • The relationship between soil chemical property and maize yield was quantified.

Special Thai Oolong Tea: Chemical Profile and In Vitro Antidiabetic Activities.

Special Thai oolong tea is oolong tea (Camellia sinensis (L.) Kuntze) steamed with selected Thai botanical drugs. Oolong tea steamed with ginger (Zingiber officinale), lemongrass (Cymbopogon citratus), and celery (Anathallis graveolens L.) is called eternity tea (EN), whereas peaceful rest (PR) tea is made of oolong tea leaves steamed with Indian gooseberry (Phyllanthus emblica), Turkey berry (Solanum torvum), and wild betel leaf bush leaves (Piper sarmentosum). Oolong tea is known for its numerous biological activities including antidiabetic properties. However, the effect of the additional botanical drugs on the biological activities of special oolong teas has not yet been explored. From the results, the PR extract exhibited the best activity in the in vitro assays relevant to antidiabetic properties such as chemical antioxidant, anti-inflammation, anti-adipogenesis, enzyme inhibition, and glucose uptake and consumption. The UHPLC-QTOF-MS/MS profiles of PR and EN extracts indicated chemical profiles different from oolong tea. For instance, gingerdiol and gingerol were detected in EN, whereas piperettine I was detected in PR. Therefore, it was inferred that among the three tea extracts, the additional compounds in PR contributed to good activities compared to oolong and EN. It is also important to highlight that the PR extract inhibited glucose uptake and consumption by adipocytes and skeletal muscles at concentrations of 500 and 100 μg/ml, respectively, as well as metformin activity (p < 0.05). Findings from this study support the antidiabetic potential of PR tea.

Impacts of agricultural waste and NPK fertilizers on soil chemical properties, production and phosphorus uptake of sweet corn plants on ultisol soil

Ultisol soil is classified as a marginal terrain with a low productivity level. Thus, this research aims to determine the most fitting biochar material and the effects of NPK fertilizer regarding the chemical properties of Ultisol soil that are analyzed on the production and phosphorus uptake of sweet corn plants. The materials used for the biochar consist of agricultural waste. This research utilized factorial randomized block design which was repeated three times. Factor number one consisted of three types of biochar: rice husk, corncob, and coconut shell. Factor number two was made up of NPK fertilizer which consisted of three dosages: without NPK, 2 g pot-1, and 4 g pot-1. This research was conducted on December 2019 up to March 2020. Research shows that there was no interaction between biochar types and NPK fertilizer, whether on the chemical properties of Ultisol soil, growth parameter, and production nor phosphorus uptake of the sweet corn plants. Corncob biochar was better than other types in affecting the chemical properties of Ultisol soil, production, root dry weight and phosphorus uptake by the sweet corn plants. Application of 4 g pot-1 NPK fertilizer was the best for almost all observation parameters.

Engineering a cultivation strategy for higher lipid accretion and biodiesel production by the marine microalga Picochlorumsoloecismus

Microalgal-derived biofuels are currently paving the way towards sustainable and green energy generation. The current study targets to bring in multiway novelties in this direction through generating substantial biomass and lipid yields in a single cultivation cycle, lower experimental time, less chemical utilization and enhanced biodiesel quality. It also ensures higher cost-effectivity, mass applicability and promising annual outcomes. In the present work, a marine microalga Picochlorum soloecismus was subjected to an extensive range of macronutrient stresses to elevate its storage lipids. Amongst all the factors studied, 4 best parameters, i.e., concentrations of NaCl and nitrate, initial culture pH, and incubation period were optimized and a modified medium called Optimized ASN (Artificial Seawater Nutrient) was developed. This resulted in 3.4- and 5.3-fold higher lipid content and productivity, reduction in the experimental time from 18 days to 9 days alongside a diminution of 350- and 25-fold in the requirements of chemicals - NaCl and NaNO3. The reduction in chemical uptake consequently lowered the medium cost by 16-fold. The biomass loss after optimization was almost insignificant and a single-phase cultivation cycle presented 2.8-fold higher lipid productivity than a two-phase cycle. The biodiesel properties were validated with the mandatory biodiesel standards. At a pilot-scale projection, the optimized medium approximated annual lipid productivity of 19.5 t ha−1 yr−1 generated through 35 annual cultivation cycles. Eventually, the medium was tested on 10 different freshwater and marine microalgae where the positive response showed by all the strains proved its suitability as an efficient lipid promoting culture medium with mass applicability.

Non-target and suspect-screening analyses of hydroponic soybeans and passive samplers exposed to different watershed irrigation sources

Water scarcity increases the likelihood of irrigating food crops with municipal wastewater that may pose potential dietary risks of regulated and non-regulated organic chemical uptake to edible plant tissues. Only a few studies have used high resolution mass spectrometry (HRMS) to assess the uptake of chemicals of concern into food crops. This study used non-target and suspect-screening analyses to compare total chemical features, tentatively identified chemicals (TICs), and EPA ToxCast chemicals in soybean plants and passive samplers exposed to five different irrigation sources that were collected from an agricultural watershed during mild drought conditions. Secondary-treated municipal wastewater effluent, two surface waters, two ground waters, and deionized municipal tap water were used for two hydroponic experiments: soybean roots and shoots and Composite Integrative Passive Samplers (CIPS) harvested after fourteen days of exposure and soybeans after fifty-six days. CIPS were sealed in separate glass amber jars to evaluate their efficacy to mimic chemical features, TICs, and ToxCast chemical uptake in plant roots, shoots, and beans. Total soybean biomass and water use were greatest for tap water, municipal wastewater, and surface water downstream of the municipal wastewater facility relative to groundwater samples and surface water collected upstream of the wastewater facility. ToxCast chemicals were ubiquitous across watershed irrigation sources in abundance, chemical use category, and number. Wastewater-exposed soybeans had the fewest extractable TICs in plant tissues of all irrigation sources. More ToxCast chemicals were identified in CIPS than extracted from irrigation sources by solid phase extraction. ToxCast chemicals in beans and CIPS were similar in number, chemical use category, and log Kow range. CIPS appear to serve as a useful surrogate for ToxCast chemical uptake in beans, the edible food product.

Human Toxicological Impacts in Life Cycle Assessment of Circular Economy of the Built Environment: A Case Study of Denmark

The circular economy has become an important topic in the building industry, and life cycle assessment (LCA) is often used to quantify its benefits. Through chemical analysis, this article demonstrates that the current LCA is not yet well-adapted to assess the circular economy of building materials and components. It is shown that current inventory data and models are insufficient because they do not consider the uptake and emission of chemicals during use, the migration of chemicals within the value chain across the multiple phases in the circular economy, and because current characterization models lack a large fraction of the potentially emitted chemicals from said uptake and emission identified in the tested building material samples. Thus, it is shown that impacts relevant for LCA in the circular economy of buildings remain unaddressed because they are currently either omitted in the LCA that covers a limited number of impact indicators, or are ostensibly covered in the LCA covering a full set of indicators but missed due to inadequate characterization models. To ameliorate this, a definition of embedded toxicity and its relationship to the toxicological footprint is presented and a method for measurement is proposed, illustrating how assessing embedded toxicity can yield information for facilitating safe building-material reuse. Finally, a suggestion for the improvement of life cycle impact assessment methods is proposed.

Investigations of the Chemical Distribution in Sorbitol and Citric Acid (SorCA) Treated Wood—Development of a Quality Control Method on the Basis of Electromagnetic Radiation

Recent studies showed treatments with sorbitol and citric acid (SorCA) to significantly improve the dimensional stability and biological durability of wood. The industrialization of this process requires a quality control (QC) method to determine if the fixated chemicals are homogenously distributed within the piece of wood, which is essential for uniform material performance. Therefore, the objective of this work was to evaluate the use of common electromagnetic radiation-based methods to determine the degree of modification in SorCA-treated wood. Both Fourier transform infrared (FTIR) spectroscopy and near-infrared (NIR) spectroscopy have been used to create rough calibrations for the weight percent gain (WPG) prediction models. The FTIR measurements resulted in a high linear correlation between the band area ratio (BAR) and the WPG (R2 = 0.93). Additionally, a partial least square (PLS) regression of NIR spectroscopic data resulted in a model with a high prediction power (R2 = 0.83). Furthermore, X-ray density profiling emerged as a simple alternative for the QC by showing a gradient of modification chemicals inside the sample and differences in chemical uptake between earlywood and latewood. Overall, it can be concluded that the results from FTIR, NIR and X-ray densitometry can serve as indicators of impregnation chemical distribution in SorCA-modified wood.

Chemically Functionalized Polysaccharide-Based Chelating Agent for Heavy Metals and Nitrogen Compound Remediation from Contaminated Water

The aim of this research was to develop chemically functionalized polysaccharide-based chelating materials with unique heavy metal and nitrogen compound absorptive properties from cellulose, butane tetracarboxylic acid (BTCA), and chitosan. The BTCA was incorporated onto cellulose through an esterification reaction in the presence of sodium phosphate dibasic dihydrate as catalyst and then cross-linked with chitosan. The effect of BTCA concentration, modification time, and temperature on the carboxylic acid content percentage of modified cellulose was analyzed. Furthermore, modified cellulose was cross-linked with chitosan to produce water-insoluble chelating materials for heavy metals and nitrogen compound remediation from contaminated water. Characterization of the modified cellulose and its water-insoluble chelating foam materials including chemical, structural, heavy metals, and nitrogen compound uptake analyses. The modified cellulose–chitosan foam can absorb up to 8.91–66.45 mg/g arsenic, 6.57–29.1 mg/g mercury, 10–75.6 mg/g lead, 10–45.47 mg/g cadmium, and 6.45–21.2 mg/g selenium when the foam was treated with 100–1000 ppb contaminated water. The heavy metal uptake of modified cellulose–chitosan foam in contaminated water was significantly greater than modified cellulose, cellulose, and commercial metal-chelating agent PuroliteFerrIX A33E. The interesting thing is that only 0.2gram foam material is enough to decrease of 1liter arsenic concentration from 100 to 11 ppb, which meets the EPA standards. However, the modified cellulose–chitosan foam also can absorb about 0.2 g/g ammonium nitrate, 0.14 g/g ammonium chloride, and 0.29 g/g ammonia when it was treated with 0.1% nitrogen compound contaminated water. The modified cellulose and modified cellulose–chitosan foam was characterized with TGA, DSC, FTIR, and SEM, confirming the cross-linking of the materials.

Ameliorated Marginal Peat: Soil Chemical Characteristics, NPK Uptake and Potential Rice Yield

Ameliorated Marginal Peat: Soil Chemical Characteristics, NPK Uptake and Potential Rice Yield

Determination of In Vivo Biotransformation Kinetics Using Early-Time Biota Concentrations.

Technical challenges have hampered the characterization of biotransformation kinetics-a critical link in understanding and predicting the toxicokinetics and ecotoxicology of organic compounds. A shortcut approach to characterize the in vivo biotransformation rate constant (kM ) with incomplete pathway or metabolite details was proposed. The value of kM can be derived as , with fPC (t) being the molar equivalent fraction of the parent compound (PC) at an early time t in both constant exposure and decay source chemical uptake scenarios. The approximation-based kM values agreed well with kM values derived from rigorous fitting or toxicokinetic modeling (n = 42, root mean square error = 0.30) with accuracy exceeding those of typical toxicokinetic or partitioning models. The method is accurate when sampling time is adequately resolved (i.e., t < ln(2)/kM ) but will likely produce biased kM values with improper time-averaging. The approximate equation yields consistent theoretical expectations for fast and slow biotransformation reactions and is fully compatible with standard bioaccumulation and toxicity testing protocols. The simplification strategy circumvents statistical complications and numerical issues inherent in regressing or modeling the toxicokinetics of multimetabolite systems and may be adapted to similar problems at other physiological scales or ecotoxicological contexts. The method can help advance interspecies comparison of chemical metabolism and support the development of in vitro-in vivo extrapolations and in silico models needed for building next-generation ecological and health risk-assessment practices. Environ Toxicol Chem 2022;41:148-158. © 2021 SETAC.

Intake and Uptake of Chemicals Upon Use of Various Tobacco/Nicotine Products: Can Users be Differentiated by Single or Combinations of Biomarkers?

Summary With increasing use of new generation tobacco/nicotine products (TNPs) instead or in addition to conventional cigarettes (CCs), the question arises, whether the user of these new TNPs and CCs can be distinguished on the basis of their exposure in terms of intake and uptake of specific chemicals. For this purpose, the exposure to chemicals for users of 5 product types including CCs, HNB (heat-not-burn products), electronic cigarettes (ECs), oral tobacco products (OT, with the focus on snus), nicotine replacement therapy (NRT) products (only nicotine gum (NG) was considered in this study) was evaluated on the basis of published data. For both intake and biomarker-based uptake, 4 relative exposure levels with the assigned values from 1 (lowest exposure) to 4 (highest exposure) were defined resulting in exposure level patterns. Unique single-biomarker-based exposure levels were found for smokers (11 chemicals), vapers (1 chemical) and non-users (NU, 1 chemical). A few selected biomarkers (usually with relative levels of 3–4) were found to be sufficient for unequivocal differentiation of one user/NU group from the other 5 groups. The impact of dual-product use is also briefly discussed. [Contrib. Tob. Nicotine Res. 30 (2021) 167–198]

Soil and plant contamination by potentially toxic and emerging elements and the associated human health risk in some Egyptian environments.

The aim of this work was to assess the origins, mobility, bioavailability and potential health risks of V, Cr, Co, As, Se, Mo, Cd, Sn and Sb, which are not sufficiently studied in the terrestrial environment of Egypt. This has been carried out by employing a combination of chemical fractionation, plants uptake, mathematical modeling and risk assessment approaches on a wide range of soils and plants sampled from industrial, urban and agricultural locations across Egypt. The contents of As, Cd, Sn and Sb were elevated in the soils of some urban and industrial locations within Cairo, although their soil geo-accumulation (Igeo) indices remained ≤ 2, indicating only moderate contamination. Selenium showed moderate to heavy contamination levels (Igeo up to 4.7) in all sampling locations, and Sb was highly elevated (Igeo = 7.1; extreme contamination) in one industrial location. Therefore, Se was the most important contributor to the pollution load followed by Sb and Cd. Both principle component analysis (of total content) and geochemical fractionation (by sequential extraction) suggested that V, Cr and Co are mostly of geogenic origin, while Se and Sb contents appear to be highly influenced by anthropogenic inputs. The most mobile and bioavailable element was Cd with a large non-residual fraction in all soils (76% of total Cd). The bio-concentration factors of Cd in leafy and fruiting plants were 50 times larger than other elements (except Mo) indicating preferential systematic plant uptake of Cd. Risk assessment models showed an overall low noncarcinogenic and carcinogenic risks to the population of Egypt due to the studied elements with only a few anomalies.

Cancer microcell initiation and determination

BackgroundCancer remains one of the leading causes of death worldwide, despite the possibilities to detect early onset of the most common cancer types. The search for the optimal therapy is complicated by the cancer diversity within tumors and the unsynchronized development of cancerous cells. Therefore, it is necessary to characterize cancer cell populations after treatment has been applied, because cancer recurrence is not rare. In our research, we concentrated on small cancer cell subpopulation (microcells) that has a potential to be cancer resistance source. Previously made experiments has shown that these cells in small numbers form in specific circumstances after anticancer treatment.MethodsIn experiments described in this research, the anticancer agents’ paclitaxel and doxorubicin were used to stimulate the induction of microcells in fibroblast, cervix adenocarcinoma, and melanoma cell lines. Mainly for the formation of microcells in melanoma cells. The drug-stimulated cells were then characterized in terms of their formation efficiency, morphology, and metabolic activity.ResultsWe observed the development of cancer microcells and green fluorescent protein (GFP) transfection efficiency after stress. In the time-lapse experiment, we observed microcell formation through a renewal process and GFP expression in the microcells. Additionally, the microcells were viable after anticancer treatment, as indicated by the nicotinamide adenine dinucleotide hydrogen phosphate (NADPH) enzyme activity assay results. Taken together, these findings indicate that cancer microcells are viable and capable of resisting the stress induced by anticancer drugs, and these cells are prone to chemical substance uptake from the environment.ConclusionMicrocells are not only common to a specific cancer type, but can be found in any tumor type. This study could help to understand cancer emergence and recurrence. The appearance of microcells in the studied cancer cell population could be an indicator of the individual anticancer therapy effectiveness and patient survival.

Core-shell architecture of Ni-Co MOF wrapped by a heterogeneous FeBTC@PPy layer for high-performance EMI shielding

High-performance EMI shielding of a core-shell nanocomposite of Ni-Co MOF (core) wrapped by a heterogeneous layer of FeBTC MOF and polymeric polypyrrole (PPy) (shell) named Ni-Co/FeBTC@PPy is reported. Herein, the spherical structure Ni-Co MOF was firstly prepared and employed as nucleation sites for polymerization of pyrrole monomer utilizing FeCl3 as an in situ oxidant. Surprising, ionic iron not only played the role of oxidizing agent in the polymerization but was also able to interact with the 1,3,5-benzenetricarboxylate (BTC) organic linker existing in the frame of Ni-Co MOF to generate a new metallic MOF named FeBTC. The simultaneous formation of FeBTC@PPy in the one step polymerization inadvertently enriched both the variety of chemical components and uptake of the specific surface area to the productive nanocomposite. The as-synthesized Ni-Co/FeBTC@PPy nanocomposite displayed its best shielding efficiency at a weight ratio of 1:3 of Ni-Co MOF: pyrrole monomer, with a maximum shielding SET value of 34.1 dB compared to its value of 20.5 dB and 4 dB for the individual components of PPy and Ni-Co MOF, respectively. The sustainable EM attenuation property of Ni-Co/FeBTC@PPy can be ascribed mainly to dielectric loss along with interfacial polarization, multiple internal reflection, and multiple scattering.

Crop Establishment Methods and Integrated Nutrient Management Improve: Part II. Nutrient Uptake and Use Efficiency and Soil Health in Rice (Oryza sativa L.) Field in the Lower Indo-Gangetic Plain, India

Rice, the predominant food crop in India, is being grown traditionally with improper plant nutrient management mostly under the flooded situation. Recent advancement in research on crop science focuses on water-saving rice technologies for maximization in crop and water productivity under the backdrop of a shrinking water resource base for ensuring environmental and agricultural sustainability. Under this situation, an experiment was conducted in two consecutive years in a split-plot design keeping rice cultivation methodologies, viz., aerobic culture, System of Rice Intensification (SRI), and conventional flooded culture in main plots and integrated plant nutrient management (INM) treatments in sub-plots. The experiment was aimed at understanding the effects of different rice production systems and INM on nutrient content, uptake, and use efficiency. The change in soil quality parameters was also studied to understand the impact of crop establishment methods (CEM) and INM options. Significant reduction (p ≤ 0.05) in nutrient uptake and use efficiency was observed under aerobic culture compared to SRI and flooded method, although aerobic culture showed the highest physiological nitrogen use efficiency. Post-harvest available Fe status was significantly lower in aerobic rice (mean 10.39 ppm) compared to other crop establishment technologies; however, Zn status was higher in aerobic rice over the flooded situation. Although available potassium was not affected due to rice cultivation methods, available nitrogen and phosphorus status were influenced remarkably. Soil microbial quality was improved in aerobic rice in comparison to flooded rice. SRI proved to be the most efficient rice establishment method for enhancement in nutrient uptake, use efficiency, and enrichment of soil chemical and microbiological quality. Irrespective of crop culture, integrated plant nutrition in rice improved the nutrient uptake, use efficiency, and soil quality parameters. The study revealed that, under the alluvial soils of the Indo-Gangetic Plains of Eastern India, SRI can be considered as a water-saving rice production method. The method can also improve nutrient uptake, efficiency, and soil quality parameters if proper INM is adopted.

Exposure to oxybenzone from sunscreens: daily transdermal uptake estimation.

Fugacity, the driving force for transdermal uptake of chemicals, can be difficult to predict based only on the composition of complex, non-ideal mixtures such as personal care products. Compare the predicted transdermal uptake of benzophenone-3 (BP-3) from sunscreen lotions, based on direct measurements of BP-3 fugacity in those products, to results of human subject experiments. We measured fugacity relative to pure BP-3, for commercial sunscreens and laboratory mixtures, using a previously developed/solid-phase microextraction (SPME) method. The measured fugacity was combined with a transdermal uptake model to simulate urinary excretion rates of BP-3 resulting from sunscreen use. The model simulations were based on the reported conditions of four previously published human subject studies, accounting for area applied, time applied, showering and other factors. The fugacities of commercial lotions containing 3-6% w/w BP-3 were ~20% of the supercooled liquid vapor pressure. Simulated dermal uptake, based on these fugacities, are within a factor of 3 of the mean results reported from two human-subject studies. However, the model significantly underpredicts total excreted mass from two other human-subject studies. This discrepancy may be due to limitations in model inputs, such as fugacity of BP-3 in lotions used in those studies. The results suggest that combining measured fugacity with such a model may provide order-of-magnitude accurate predictions of transdermal uptake of BP-3 from daily application of sunscreen products.

Multisite Calibration of a Microporous Polyethylene Tube Passive Sampler for Quantifying Drugs in Wastewater

Passive sampling approaches to monitor licit and illicit drugs of concern in wastewater shows promise as a supplementary sampling technique to grab sampling when conventional composite autosampling may not be possible. Recent studies have assessed the applicability of passive sampling at a single wastewater treatment plant (WWTP). However, it remains unknown whether a single-site calibration can be applied to other WWTPs. This study evaluated the in situ calibration of microporous polyethylene tube passive samplers (MPTs) against simultaneously collected composite samples for 22 different WWTPs. Samples were analyzed for methylamphetamine, amphetamine, hydroxycotinine, cotinine, benzoylecgonine, 3,4-methylenedioxymethamphetamine, and noroxycodone. Estimated rates of chemical uptake (sampling rates) were calculated using the mass accumulated in the samplers, the concentration measured in composite samples, and the duration of deployment. The estimated sampling rates were consistent between WWTPs (>90% within a factor of two) and ranged from 5 mL day-1 (amphetamine) to 9 mL day-1 (noroxycodone). The samplers were effective at estimating analyte concentrations, with 77% of results having a normalized difference to 24 h composite samples of below 30%. Our study suggests that MPT passive samplers provide a tool for the spatiotemporal monitoring of drug use where automated integrative sampling techniques may not be feasible.

Passive sampler designed for per‐ and polyfluoroalkyl substances using polymer‐modified organosilica adsorbent

AbstractA passive sampler designed to measure per‐ and polyfluoroalkyl substances (PFAS) was evaluated to determine chemical uptake rates under a variety of conditions. The sampler design is simple and robust, using organosilica modified with cross‐linked amine polymer in an high density polyethylene housing retained with polypropylene mesh. The addition of amine groups as a weak ion‐exchange resin in combination with Cu2+ was designed to promote binding of short‐chain PFAS. A five‐fold improvement in perfluorobutanoic acid adsorption was measured when Cu2+ was added to the polyethylenimine polymer. The samplers showed an integrated response to all analytes tested except for short‐chain PFAS. Sampling rates of PFAS analytes from simulated groundwater were on average 10 mL/day at flow rates of 0.038–1.9 cm/min. Relatively low variability in sampling rate was observed over the range of laboratory tested conditions (representing common conditions in environmental waters) including elevated ionic strength, sulfate concentration, and humic acid content.Article Impact StatementMeasuring per‐ and polyfluoroalkyl substances in environmental samples is important for monitoring. Passive samplers can offer practical advantages for making measurements.