Diazotrophy modulates cyanobacteria stoichiometry through functional traits that determine bloom magnitude and toxin production.

Harmful cyanobacterial blooms are an increasing threat to water quality. The interactions between two eco-physiological functional traits of cyanobacteria, diazotrophy (nitrogen (N)-fixation) and N-rich cyanotoxin synthesis, have never been examined in a stoichiometric explicit manner. We explored how a gradient of resource N:phosphorus (P) affects the biomass, N, P stoichiometry, light-harvesting pigments, and cylindrospermopsin production in a N-fixing cyanobacterium, Aphanizomenon. Low N:P Aphanizomenon cultures produced the same biomass as populations grown in high N:P cultures. The biomass accumulation determined by carbon, indicated low N:P Aphanizomenon cultures did not have a N-fixation growth tradeoff, in contrast to some other diazotrophs that maintain stoichiometric N homeostasis at the expense of growth. However, N-fixing Aphanizomenon populations produced less particulate cylindrospermopsin and had undetectable dissolved cylindrospermopsin compared to non-N-fixing populations. The pattern of low to high cyanotoxin cell quotas across an N:P gradient in the diazotrophic cylindrospermopsin producer is similar to the cyanotoxin cell quota response in non-diazotrophic cyanobacteria. We suggest that diazotrophic cyanobacteria may be characterized into two broad functional groups, the N-storage-strategists and the growth-strategists, which use N-fixation differently and may determine patterns of bloom magnitude and toxin production in nature.

Effects of Environmentally Relevant Concentration Exposure Profiles on Polar Organic Chemical Integrative Sampler (POCIS) Sampling Rates.

Polar organic chemical integrative sampler (POCIS) is a passive sampling device that offers many advantages over traditional discrete sampling methods, but quantitative time-weighted average (TWA) concentrations rely heavily on the robustness of sampling rates. The effects of changing chemical concentration exposures on POCIS sampling rates and its ability to operate in an integrative regime were investigated for 12 pesticides across a range of environmentally relevant concentrations. In five independent 21-day experiments, POCIS devices were exposed to these compounds at constant concentrations ranging from 3 to 60 µg/L and multiple pulsed concentrations with maximum peaks ranging from 5 to 150 µg/L (TWA concentrations = 3 to 92 µg/L). For the 21-day exposures to constant and pulsed concentrations, there were no significant differences in the POCIS sampling rates between corresponding TWA concentrations. Similarly, there was no significant effect on POCIS ability to operate in an integrative regime. However, loss of linearity was visible for some replicates when exposed to higher pulsed concentrations over an extended period. Modeling and Freundlich isotherms did not predict sorbent saturation, but the extraction and reconstitution protocol likely contributed to atrazine dissolution and subsequent underestimation of sorbed chemical mass when HLB adsorption exceeded 400 µg.

Assessment of mosquitofish (Gambusia affinis) health indicators in relation to domestic wastewater discharges in suburbs of Houston, USA.

Personal care products, pharmaceuticals, and other contaminants of emerging concern (CECs) in domestic wastewater treatment plant (WWTP) effluents can impact aquatic organisms. Health indicators were compared for mosquitofish (Gambusia affinis) collected above and below WWTP discharges from five streams in suburban areas of the Houston metropolitan area, Texas, USA. Specimens were evaluated for reproductive, morphological, and histological indicators. Several indicators revealed significant spatial and temporal variation; however, possibly because of their mobility, fish collected upstream and downstream of wastewater treatment plants did not reveal consistent trends based on the endpoints examined. CEC concentrations in water samples from stream reaches below WWTP discharges were quantified for the first time in the Houston Metropolitan area. The 18 CECs detected in stream water had concentrations lower than values currently reported to impact fish. Future research should examine caged fish at each site and fish collected over longer stream reaches that receive successive discharges from WWTP and stronger CEC gradients.

Enantiomer-specific in vitro biotransformation of select pharmaceuticals in rainbow trout (Oncorhynchus mykiss).

The occurrence of pharmaceuticals in the environment represents a challenge of emerging concern. Many pharmaceuticals are chiral compounds; however, few studies have examined the relative toxicity of pharmaceutical enantiomers to wildlife. Further, our understanding of stereospecific pharmacokinetics remains largely informed by research on humans and a few well-studied laboratory test animals, and not by studies conducted with environmentally relevant species, including fish. The objective of this study was to investigate whether rainbow trout display stereospecific in vitro metabolism of three common chiral pharmaceuticals. Metabolism by trout liver S9 fractions was evaluated using a substrate depletion approach, which provides an estimate of intrinsic hepatic clearance (CL(IN VITRO,INT)). No biotransformation was observed for rac-, R-, or S-fluoxetine. Ibuprofen, including both enantiomers and the racemic mixture, appeared to undergo slow metabolism, but the resulting substrate depletion curves did not differ significantly from those of inactive controls. Contrary to relative clearance rates in humans, S(-)-propranolol was more rapidly cleared than the R(+)-enantiomer. This work demonstrates that relative clearance rates and the effects of racemic mixtures in trout could not have been predicted based on human data. Additional research describing species differences and exploring tools for species extrapolation in biomedical and environmental studies is needed.

The effects of salinity and N:P on N-rich toxins by both an N-fixing and non-N-fixing cyanobacteria.

Freshwater ecosystems are experiencing increased salinization. Adaptive management of harmful algal blooms (HABs) contribute to eutrophication/salinization interactions through the hydrologic transport of blooms to coastal environments. We examined how nutrients and salinity interact to affect growth, elemental composition, and cyanotoxin production/release in two common HAB genera. Microcystis aeruginosa (non-nitrogen (N)-fixer and microcystin-LR producer; MC-LR) and Aphanizomenon flos-aquae (N-fixer and cylindrospermopsin producer; CYN) were grown in N:phosphorus (N:P) 4 and 50 (by atom) for 21 and 33 days, respectively, then dosed with a salinity gradient (0 - 10.5 g L-1). Both total MC-LR and CYN were correlated with particulate N. We found Microcystis MC-LR production and release was affected by salinity only in the N:P 50 treatment. However, Aphanizomenon CYN production and release was affected by salinity regardless of N availability. Our results highlight how cyanotoxin production and release across the freshwater - marine continuum are controlled by eco-physiological differences between N-acquisition traits.

Occurrence of pharmaceuticals and personal care products in German fish tissue: a national study.

German Environment Specimen Bank (GESB) fish tissue samples, collected from 14 different GESB locations, were analyzed for 15 pharmaceuticals, 2 pharmaceutical metabolites, and 12 personal care products. Only 2 pharmaceuticals, diphenhydramine and desmethylsertraline, were measured above MDL. Diphenhydramine (0.04-0.07 ng g(-1) ww) and desmethylsertraline (1.65-3.28 ng g(-1) ww) were measured at 4 and 2 locations, respectively. The maximum concentrations of galaxolide (HHCB) (447 ng g(-1) ww) and tonalide (AHTN) (15 ng g(-1) ww) were measured at the Rehlingen sampling site in the Saar River. A significant decrease in HHCB and AHTN fish tissue concentrations was observed from 1995 to 2008 at select GESB sampling sites (r(2) = 0.69-0.89 for galaxolide and 0.89-0.97 for tonalide with p < 0.003). Galaxolide and tonalide fish tissue concentrations in Germany were ∼19× and ∼28× lower, respectively, as compared to fish tissue concentrations measured in a United States nationwide PPCP study conducted in 2006. Proximity of the sampling locations to the upstream wastewater treatment plant discharging point and mean annual flow at the sampling location were found to significantly predict galaxolide and tonalide fish tissue concentrations (HHCB: r(2) = 0.79, p = 0.021 and AHTN: r(2) = 0.81, p = 0.037) in Germany.

Comparative Analysis of RNA-Extraction Approaches and Associated Influences on RT-qPCR of the SARS-CoV-2 RNA in a University Residence Hall and Quarantine Location.

Wastewater-based epidemiology (WBE) provides an early warning and trend analysis approach for determining the presence of COVID-19 in a community and complements clinical testing in assessing the population level, even as viral loads fluctuate. Here, we evaluate combinations of two wastewater concentration methods (i.e., ultrafiltration and composite supernatant-solid), four pre-RNA extraction modifications, and three nucleic acid extraction kits using two different wastewater sampling locations. These consisted of a quarantine facility containing clinically confirmed COVID-19-positive inhabitants and a university residence hall. Of the combinations examined, composite supernatant-solid with pre-RNA extraction consisting of water concentration and RNA/DNA shield performed the best in terms of speed and sensitivity. Further, of the three nucleic acid extraction kits examined, the most variability was associated with the Qiagen kit. Focusing on the quarantine facility, viral concentrations measured in wastewater were generally significantly related to positive clinical cases, with the relationship dependent on method, modification, kit, target, and normalization, although results were variable-dependent on individual time points (Kendall's Tau-b (τ) = 0.17 to 0.6) or cumulatively (Kendall's Tau-b (τ) = -0.048 to 1). These observations can support laboratories establishing protocols to perform wastewater surveillance and monitoring efforts for COVID-19.

Sustaining University Operations During the COVID-19 Pandemic.

Colleges and universities around the world engaged diverse strategies during the COVID-19 pandemic. Baylor University, a community of ˜22,700 individuals, was 1 of the institutions which resumed and sustained operations. The key strategy was establishment of multidisciplinary teams to develop mitigation strategies and priority areas for action. This population-based team approach along with implementation of a "Swiss Cheese" risk mitigation model allowed small clusters to be rapidly addressed through testing, surveillance, tracing, isolation, and quarantine. These efforts were supported by health protocols including face coverings, social distancing, and compliance monitoring. As a result, activities were sustained from August 1 to December 8, 2020. There were 62,970 COVID-19 tests conducted with 1435 people testing positive for a positivity rate of 2.28%. A total of 1670 COVID-19 cases were identified with 235 self-reports. The mean number of tests per week was 3500 with approximately 80 of these positive (11/d). More than 60 student tracers were trained with over 120 personnel available to contact trace, at a ratio of 1 per 400 university members. The successes and lessons learned provide a framework and pathway for similar institutions to mitigate the ongoing impacts of COVID-19 and sustain operations during a global pandemic.

Sunlight concurrently reduces Prymnesium parvum elicited acute toxicity to fish and prymnesins.

Prymnesium parvum continues to spread globally, producing harmful algal blooms that release toxins known to cause fish kills. While previous work has identified possible P. parvum toxin(s) (e.g., prymnesins, fatty acids, fatty acid amides) and investigated treatment strategies targeted at minimizing cell abundance, studies examining efficacy of treatment approaches to remove toxins are lacking. To understand influences of sunlight on toxins stability and toxicity to fish, acutely toxic P. parvum cultures were exposed to three light scenarios (lab dark control, field dark, and field light) and then evaluated for acute toxicity to fish and prymnesins abundance. Previous work showed acute toxicity to fathead minnow larvae was ameliorated after 2 h of sunlight exposure, and results observed herein found an identical trend. Acute toxicity disappeared in light exposed filtrate, but filtrate exposed to 35 °C without sunlight remained acutely toxic to fish. Additionally, six prymnesins were identified through high-resolution mass spectrometry and abundance corresponded to acute toxicity levels. Prymnesins were present at the highest level in filtrate that was acutely toxic but diminished in filtrate that was exposed to light and correspondingly ameliorated acute toxicity to fish. These findings suggest prymnesins are responsible for measured acute toxicity and are photo-labile, which represents an important implication for treatment strategies.

Differential influences of (±) anatoxin-a on photolocomotor behavior and gene transcription in larval zebrafish and fathead minnows.

BACKGROUND: Though anatoxin-a (antx-a) is a globally important cyanobacterial neurotoxin in inland waters, information on sublethal toxicological responses of aquatic organisms is limited. We examined influences of (±) antx-a (11-3490 µg/L) on photolocomotor behavioral responses and gene transcription associated with neurotoxicity, oxidative stress and hepatotoxicity, in two of the most common alternative vertebrate and fish models, Danio rerio (zebrafish) and Pimephales promelas (fathead minnow). We selected environmentally relevant treatment levels from probabilistic exposure distributions, employed standardized experimental designs, and analytically verified treatment levels using isotope-dilution liquid chromatography tandem mass spectrometry. Caffeine was examined as a positive control. RESULTS: Caffeine influences on fish behavior responses were similar to previous studies. Following exposure to (±) antx-a, no significant photolocomotor effects were observed during light and dark transitions for either species. Though zebrafish behavioral responses profiles were not significantly affected by (±) antx-a at the environmentally relevant treatment levels examined, fathead minnow stimulatory behavior was significantly reduced in the 145-1960 µg/L treatment levels. In addition, no significant changes in transcription of target genes were observed in zebrafish; however, elavl3 and sod1 were upregulated and gst and cyp3a126 were significantly downregulated in fathead minnows. CONCLUSION: We observed differential influences of (±) antx-a on swimming behavior and gene transcription in two of the most common larval fish models employed for prospective and retrospective assessment of environmental contaminants and water quality conditions. Sublethal responses of fathead minnows were consistently more sensitive than zebrafish to this neurotoxin at the environmentally relevant concentrations examined. Future studies are needed to understand such interspecies differences, the enantioselective toxicity of this compound, molecular initiation events within adverse outcome pathways, and subsequent individual and population risks for this emerging water quality threat.

Nitrogen form, concentration, and micronutrient availability affect microcystin production in cyanobacterial blooms.

Harmful algal blooms (HABs) are increasing in magnitude, frequency, and duration caused by anthropogenic factors such as eutrophication and altered climatic regimes. While the concentrations and ratios of nitrogen (N) and phosphorus are correlated with bloom biomass and cyanotoxin production, there is less known about how N forms and micronutrients (MN) interact to regulate HABs and cyanotoxin production. Here, we used two separate approaches to examine how N and MN supply affects cyanobacteria biomass and cyanotoxin production. First, we used a Microcystis laboratory culture to examine how N and MN concentration and N form affected the biomass, particulate N, and microcystin-LR concentration and cell quotas. Then, we monitored the N, iron, molybdenum, and total microcystin concentrations from a hypereutrophic reservoir. From this hypereutrophic reservoir, we performed a community HAB bioassay to examine how N and MN addition affected the biomass, particulate N, and microcystin concentration. Microcystis laboratory cultures grown in high urea and MN conditions produced more biomass, particulate N, and had similar C:N stoichiometry, but lower microcystin-LR concentrations and cell quotas when compared to high nitrate and MN conditions. Our community HAB bioassay revealed no interactions between N concentration and MN addition caused by non-limiting MN background concentrations. Biomass, particulate N, and microcystin concentration increased with N addition. The community HAB amended with MN resulted in greater microcystin-LA concentration compared to non-MN amended community HABs. Our results highlight the complexity of how abiotic variables control biomass and cyanotoxin production in both laboratory cultures of Microcystis and community HABs.

Effect of varying feedstock-pretreatment chemistry combinations on the formation and accumulation of potentially inhibitory degradation products in biomass hydrolysates.

A variety of potentially inhibitory degradation products are produced during pretreatment of lignocellulosic biomass. Qualitative and quantitative interrogation of pretreatment hydrolysates is paramount to identifying potential correlations between pretreatment chemistries and microbial inhibition in downstream bioconversion processes. In the present study, corn stover, poplar, and pine feedstocks were pretreated under eight different chemical conditions, which are representative of leading pretreatment processes. Pretreatment processes included: 0.7% H(2)SO(4), 0.07% H(2)SO(4), liquid hot water, neutral buffer solution, aqueous ammonia, lime, lime with oxygen pressurization, and wet oxidation. Forty lignocellulosic degradation products resulting from pretreatment were analyzed using high performance liquid chromatography in combination with UV spectroscopy or tandem mass spectrometry detection (HPLC-PDA-MS/MS) and ion chromatography (IC). Of these compounds, several have been reported to be inhibitory, including furfural, hydroxymethyl furfural, ferulic acid, 3,4-dihydroxybenzaldehyde, syringic acid among others. Formation and accumulation of monitored compounds in hydrolysates is demonstrated to be a function of both the feedstock and pretreatment conditions utilized.

Effects of suspended sediment on POCIS sampling rates.

Effects of chemical uptake onto polar organic chemical integrative samplers (POCIS) exposed to total suspended solid (TSS) sediment concentrations of 0 and 3600 ppm were investigated for 12 pesticides at constant concentration, temperature, and flow velocity. The effects of sediment exposure on POCIS uptake were negligible for compounds with polyethersulfone-water partition coefficients greater than three (i.e., log KPESW > 3). However, significant effects were observed for 3 of 12 compounds tested, and the maximum effect was an approximate 4-fold increase in sampling rate for the sediment experiment relative to the control. Effects of sediment on the pesticide distribution between polyethersulfone (PES) membranes and Oasis HLB sorbent were also investigated. The fraction of pesticide accumulated on PES membranes was relatively low for most compounds and ranged from 0 to 33%. In contrast, four compounds with higher affinity for PES accumulated preferentially on the membranes (fraction ranging from 64 to 96%), suggesting that a sampling rate derived from the additive contribution of membrane extraction and the more typical extraction of analytes from HLB sorbent would improve the sensitivity of sampling rate estimations for these compounds. However, for these same compounds, the combined sampling rate, Rs (HLB + PES), was considerably more susceptible to a sediment effect than the traditional sampling rate determination, relying solely on extraction from HLB sorbent.

Periphyton, bivalves and fish differentially accumulate select pharmaceuticals in effluent-dependent stream mesocosms.

Pharmaceuticals and other ionizable contaminants from municipal wastewater treatment plant effluent can bioaccumulate in fish, particularly in effluent dominated and dependent systems in semi-arid and arid regions. However, invertebrate bioaccumulation of these compounds has been less studied. Using municipal wastewater effluent as source water in outdoor stream mesocosms to simulate effluent-dependent lotic systems, we examined bioaccumulation of several widely-used pharmaceuticals including acetaminophen (nonsteroidal anti-inflamatory), caffeine (stimulant), carbamazepine (anti-epileptic), diltiazem (calcium channel blocker), diphenhydramine (anti-histamine), fluoxetine (anti-depressant), norfluoxetine (anti-depressant metabolite), and sertraline (anti-depressant) in freshwater clams (Corbicula fluminea), periphyton and stoneroller minnows (Campostoma anomalum), a commonly studied grazer in stream ecology, during a replicated outdoor stream mesocosm study at the Baylor Experimental Aquatic Research facility. Target analytes were determined in tissues, source effluent and stream water by isotope dilution LC-MS/MS. After an 8-day uptake period, clams accumulated a number of pharmaceuticals, including acetaminophen, carbamazepine, diltiazem, diphenhydramine, fluoxetine, norfluoxetine and sertraline with maximum concentrations reaching low µg/kg. We observed uptake rates in clams for acetaminophen at 2.8 µg/kg per day, followed by diphenhydramine (1.2 µg/kg per day) and carbamazepine (1.1 µg/kg per day). Caffeine, carbamazepine, diltiazem and diphenhydramine were measured in periphyton. Diphenhydramine was the only compound detected in all matrices, where bioaccumulation factors (BAFs) were elevated in bivalves (1631 ± 589 L/kg), compared to stoneroller minnows (247 ± 84 L/kg) and periphyton (315 ± 116 L/kg). Such BAF variability across multiple biological matrices highlight the need to understand bioaccumulation differences for ionizable contaminants among freshwater biota, including threatened and endangered species (e.g., unionids), commercially important bivalves (e.g., estuarine and marine bivalves), and fish.

Suspect and non-target screening of acutely toxic Prymnesium parvum.

Harmful algal blooms (HABs) are increasing in frequency, magnitude, and duration around the world. Prymnesium parvum is a HAB species known to cause massive fish kills, but the toxin(s) it produces contributing to this acute toxicity to fish have not been confirmed. In the present study, a 2 × 2 factorial design was employed to examine influences of salinity (2.4 or 5 ppt) and nutrient limitation (f/2 or f/8) on P. parvum acute toxicity to fish and produced molecules. Acute toxicity (LC50) of these cultures, following a 48-h mortality assay, ranged from 10,213 to 96,816 cells mL-1. Non-targeted analysis was performed using liquid chromatography high-resolution mass spectrometry (LC-HRMS) to investigate compounds contributing to the differential toxicological responses. When P. parvum elicited toxicity to fish, suspect screening confirmed the presence of several prymnesins, and the peak area of PRM-A (3 Cl; prymnesin2aglycone) was significantly (p < 0.05) and positively related to acute toxicity. In addition, a non-targeted approach to highlighting peaks that differ between two chemical fingerprints was developed, termed a relative difference plot, and used to search for peaks co-varying with P. parvum induced acute toxicity to fish. Several peaks were highlighted along with the prymnesins identified through suspect screening when acute toxicity to fish was observed.

Pharmaceutical uptake kinetics in rainbow trout: In situ bioaccumulation in an effluent-dominated river influenced by snowmelt.

Whether seasonal instream flow dynamics influence bioaccumulation of pharmaceuticals by fish is not well understood, specifically for urban lotic systems in semi-arid regions when flows are influenced by snowmelt. We examined uptake of select pharmaceuticals in rainbow trout (Oncorhynchus mykiss) caged in situ upstream and at incremental distances downstream (0.1, 1.4, 13 miles) from a municipal effluent discharge to East Canyon Creek in Park City, Utah, USA during summer and fall of 2018. Fish were sampled over 7-d to examine if uptake occurred, and to define uptake kinetics. Water and fish tissues were analyzed via isotope dilution liquid chromatography tandem mass spectrometry. Several pharmaceuticals were consistently detected in water, fish tissue and plasma, including carbamazepine, diphenhydramine, diltiazem, and fluoxetine. Pharmaceutical levels in water ranged up to 151 ng/L for carbamazepine, whereas the effluent tracer sucralose was consistently observed at low µg/L levels. During both summer and fall experiments at each of three downstream locations from effluent discharge, rainbow trout rapidly accumulated these pharmaceuticals; tissue levels reached steady state conditions within 24-96 h. Spatial and temporal differences for pharmaceutical levels in rainbow trout directly corresponded with surface water exposure concentrations, and uptake kinetics for individual pharmaceuticals did not vary among sites or seasons. Such observations are consistent with recent laboratory bioconcentration studies, which collectively indicate inhalational exposure from water governs rapid accumulation of ionizable base pharmaceuticals by fish in inland surface waters.

Low dissolved oxygen increases uptake of a model calcium channel blocker and alters its effects on adult Pimephales promelas.

Human population growth accompanied with urbanization is urbanizing the water cycle in many regions. Urban watersheds, particularly with limited upstream dilution of effluent discharges, represent worst case scenarios for exposure to multiple environmental stressors, including down the drain chemicals (e.g., pharmaceuticals) and other stressors (e.g., dissolved oxygen (DO)). We recently identified the calcium channel blocker diltiazem (DZM) to accumulate in fish plasma exceeding human therapeutic doses (e.g., Cmin) in coastal estuaries impaired due to nonattainment of DO water quality standards. Thus, we examined whether DO influences DZM uptake by fish, and if changes in DO-dependent upatke alter fish physiological and biochemical responses. Low DO (3.0 mg DO/L) approximately doubled diltiazem uptake in adult fathead minnows relative to normoxic (8.2 mg DO/L) conditions and were associated with significant (p < 0.05) increases in fish ventilation rate at low DO levels. Decreased burst swim performance (Uburst) of adult fathead minnows were significantly (p < 0.05) altered by low versus normal DO levels. DO × DZM studies reduced Uburst by 13-31% from controls, though not significantly (p = 0.06). Physiological responses in fish exposed to DZM alone were minimal; however, in co-exposure with low DO, decreasing trends in Uburst appeared inversely related to plasma lactate levels. Such physiological responses to multiple stressors, when paired with internal tissue concentrations, identify the utility of employing biological read across approaches to identify adverse outcomes of heart medications and potentially other cardiotoxicants impacting fish cardiovascular function across DO gradients.

Gas chromatography-mass spectrometry screening methods for select UV filters, synthetic musks, alkylphenols, an antimicrobial agent, and an insect repellent in fish.

Two screening methods have been developed for simultaneous determination of ten extensively used personal care products (PCPs) and two alkylphenol surfactants in fish. The methods consisted of extraction, clean-up, derivatization and analysis by gas chromatography-mass spectrometry with selected ion monitoring (GC-SIM-MS) or gas chromatography-tandem mass spectrometry (GC-MS/MS) techniques. Among solvents tested to assess recovery of target compounds from 1-g tissue homogenates, acetone was selected as optimal for extracting compounds with dissimilar physicochemical properties from fish tissue. Initial experiments confirmed that GC-SIM-MS could be applied for analysis of lean fillet tissue (<1% lipid) without gel-permeation chromatography (GPC), and this approach was applied to assess the presence of target analytes in fish fillets collected from a regional effluent-dominated stream in Texas, USA. Benzophenone, galaxolide, tonalide, and triclosan were detected in 11 of 11 environmental samples at concentrations ranging from; 37 to 90, 234 to 970, 26 to 97, and 17 to 31 ng/g, respectively. However, performance of this analytical approach declined appreciably with increasing lipid content of analyzed tissues. Successful analysis of samples with increased lipid content was enabled by adding GPC to the sample preparation protocol and monitoring analytes with tandem mass spectrometry. Both analytical approaches were validated using fortified fillet tissue collected from locations expected to be minimally impacted by anthropogenic influences. Average analyte recoveries ranged from 87% to 114% with RSDs <11% and from 54% to 107% with RSDs <20% for fish tissue containing <1% and 4.9% lipid, respectively. Statistically derived method detection limits (MDLs) for GC-SIM-MS and GC-MS/MS methodologies ranged from 2.4 to 16 ng/g, and 5.1 to 397 ng/g, respectively.

Aquatic toxicity of sertraline to Pimephales promelas at environmentally relevant surface water pH.

Researchers recognize that ionization state may influence the biological activity of weak acids and bases. Dissociation in aqueous solutions is controlled by the pKa of a compound and the pH of the matrix. Because many pharmaceuticals are implicitly designed as ionizable compounds, site-specific variability in pH of receiving waters may introduce uncertainty to ecological risk assessments. The present study employed 48-h and 7-d toxicity tests with Pimephales promelas exposed to the model weak base pharmaceutical sertraline over a gradient of environmentally relevant surface water pHs. The 48-h experiments were completed in triplicate, and the average lethal concentration values were 647, 205, and 72 microL sertraline at pH 6.5, 7.5, and 8.5, respectively. Survivorship, growth, and feeding rate (a nontraditional endpoint linked by other researchers to sertraline's specific mode of action) were monitored during the 7-d experiment. Adverse effects were more pronounced when individuals were exposed to sertraline at pH 8.5 compared to pH 7.5 and 6.5. The pH-dependent toxicological relationships from these studies were related to in-stream pH data for two streams in the Brazos River basin of central Texas, USA. This predictive approach was taken because of the scarcity of environmental analytical data for sertraline. The results of this study emphasized temporal variability associated with in-stream pH linked to seasonal differences within and between these spatially related systems. Relating site-specific pH variability of surface waters to ionization state may allow researchers to reduce uncertainty during ecological risk assessment of pharmaceuticals by improving estimates of biological effects associated with exposure.

Occurrence of pharmaceuticals and personal care products in fish: results of a national pilot study in the United States.

Pharmaceuticals and personal care products are being increasingly reported in a variety of biological matrices, including fish tissue; however, screening studies have presently not encompassed broad geographical areas. A national pilot study was initiated in the United States to assess the accumulation of pharmaceuticals and personal care products in fish sampled from five effluent-dominated rivers that receive direct discharge from wastewater treatment facilities in Chicago, Illinois; Dallas, Texas; Orlando, Florida; Phoenix, Arizona; and West Chester, Pennsylvania, USA. Fish were also collected from the Gila River, New Mexico, USA, as a reference condition expected to be minimally impacted by anthropogenic influence. High performance liquid chromatography-tandem mass spectrometry analysis of pharmaceuticals revealed the presence of norfluoxetine, sertraline, diphenhydramine, diltiazem, and carbamazepine at nanogram-per-gram concentrations in fillet composites from effluent-dominated sampling locations; the additional presence of fluoxetine and gemfibrozil was confirmed in liver tissue. Sertraline was detected at concentrations as high as 19 and 545 ng/g in fillet and liver tissue, respectively. Gas chromatography-tandem mass spectrometry analysis of personal care products in fillet composites revealed the presence of galaxolide and tonalide at maximum concentrations of 2,100 and 290 ng/g, respectively, and trace levels of triclosan. In general, more pharmaceuticals were detected at higher concentrations and with greater frequency in liver than in fillet tissues. Higher lipid content in liver tissue could not account for this discrepancy as no significant positive correlations were found between accumulated pharmaceutical concentrations and lipid content for either tissue type from any sampling site. In contrast, accumulation of the personal care products galaxolide and tonalide was significantly related to lipid content. Results suggest that the detection of pharmaceuticals and personal care products was dependent on the degree of wastewater treatment employed.