A novel antibody-based biosensor method for the rapid measurement of PAH contamination in oysters.

Conventional PAH analytical methods are time-consuming and expensive, limiting their utility in time sensitive events (i.e. oil spills and floods) or for widespread environmental monitoring. Unreliable and inefficient screening methods intended to prioritize samples for more extensive analyses exacerbate the issue. Antibody-based biosensor technology was implemented as a quantitative screening method to measure total PAH concentration in adult oysters (Crassostrea virginica) - a well-known bioindicator species with ecological and commercial significance. Individual oysters were analyzed throughout the historically polluted Elizabeth River watershed (Virginia, USA). Significant positive association was observed between biosensor and GC-MS measurements that persisted when the method was calibrated for different regulatory subsets of PAHs. Mapping of PAH concentrations in oysters throughout the watershed demonstrates the utility of this technology for environmental monitoring. Through a novel extension of equilibrium partitioning, biosensor technology shows promise as a cost-effective analysis to rapidly predict whole animal exposure to better assess human health risk as well as improve monitoring efforts.

Evaluating porewater polycyclic aromatic hydrocarbon-related toxicity at a contaminated sediment site using a spiked field-sediment approach.

Although the complexity of contaminant mixtures in sediments can confound the identification of causative agents of adverse biological response, understanding the contaminant(s) of primary concern at impacted sites is critical to sound environmental management and remediation. In the present study, a stock mixture of 18 polycyclic aromatic hydrocarbon (PAH) compounds was prepared to reflect the variety and relative proportions of PAHs measured in surface sediment samples collected from discrete areas of a historically contaminated industrial estuary. This site-specific PAH stock mixture was spiked into nontoxic in-system and out-of-system field-collected reference sediments in dilution series spanning the range of previously measured total PAH concentrations from the region. Spiked sediments were evaluated in 10-d Leptocheirus plumulosus tests to determine whether toxicity in laboratory-created PAH concentrations was similar to the toxicity found in field-collected samples with equivalent PAH concentrations. The results show that toxicity of contaminated sediments was not explained by PAH exposure, while indicating that toxicity in spiked in-system (fine grain, high total organic carbon [TOC]) and out-of-system (course grain, low TOC) sediments was better explained by porewater PAH concentrations, measured using an antibody-based biosensor that quantified 3- to 5-ring PAHs, than total sediment PAH concentrations. The study demonstrates the application of site-specific spiking experiments to evaluate sediment toxicity at sites with complex mixtures of multiple contaminant classes and the utility of the PAH biosensor for rapid sediment-independent porewater PAH analysis. Environ Toxicol Chem 2018;37:893-902. © 2017 SETAC.

A highly sensitive monoclonal antibody based biosensor for quantifying 3-5 ring polycyclic aromatic hydrocarbons (PAHs) in aqueous environmental samples.

Immunoassays based on monoclonal antibodies (mAbs) are highly sensitive for the detection of polycyclic aromatic hydrocarbons (PAHs) and can be employed to determine concentrations in near real-time. A sensitive generic mAb against PAHs, named as 2G8, was developed by a three-step screening procedure. It exhibited nearly uniformly high sensitivity against 3-ring to 5-ring unsubstituted PAHs and their common environmental methylated PAHs, with IC50 values between 1.68-31 µg/L (ppb). 2G8 has been successfully applied on the KinExA Inline Biosensor system for quantifying 3-5 ring PAHs in aqueous environmental samples. PAHs were detected at a concentration as low as 0.2 µg/L. Furthermore, the analyses only required 10 min for each sample. To evaluate the accuracy of the 2G8-based biosensor, the total PAH concentrations in a series of environmental samples analyzed by biosensor and GC-MS were compared. In most cases, the results yielded a good correlation between methods. This indicates that generic antibody 2G8 based biosensor possesses significant promise for a low cost, rapid method for PAH determination in aqueous samples.

Near real-time, on-site, quantitative analysis of PAHs in the aqueous environment using an antibody-based biosensor.

Rapid, on-site, quantitative assessments of dissolved polycyclic aromatic hydrocarbons (PAHs) were demonstrated for two field applications. The platform, a KinExA Inline Sensor (Sapidyne Instruments), employed the monoclonal anti-PAH antibody, 7B2.3, which has specificity for 3- to 5-ring PAHs. A spatial study was conducted near a dredging site where contaminated sediments were being removed, and a temporal study was performed during a rainfall event. Most importantly, the generation of near real-time data guided management decisions in the field and determined proper sampling protocols for conventional analyses. The method was able to determine PAH concentrations as low as 0.3 µg/L, within 10 min of sample acquisition, and to assess 80+ samples (not including standards and blanks) in less than 3 d. These results were compared with a laboratory-based gas chromatography-mass spectrometry method in which a wide array of PAHs, including alkylated homologs, were examined. This system shows great promise as a field instrument for the rapid monitoring of PAH pollution.

Predicting survival of grass shrimp (Palaemonetes pugio) exposed to naphthalene, fluorene, and dibenzothiophene.

The composition and persistence of dissolved polycyclic aromatic hydrocarbons (PAHs) released to the water column during oil spills are altered by weathering, tidal transport, and addition of dispersants. Conventional toxicity effect metrics, such as the median lethal concentration (LC50), are inaccurate predictors of mortality from all toxicant exposure duration/concentration combinations likely to occur during spills. In contrast, survival models can predict the proportions of animals dying as a consequence of exposures differing in duration and intensity. Extending previous work with ethylnaphthalene, dimethylnaphthalene, and phenanthrene, survival time models were developed that include exposure duration and concentration to predict time to death for grass shrimp (Palaemonetes pugio). Two additional PAHs (naphthalene and fluorene) and a heterocyclic aromatic hydrocarbon (dibenzothiophene) were evaluated for the present study. Preliminary explorations of these models confirmed that quantitative structure- activity regression models were possible for predicting survival model parameters from compound characteristics. Conventional 48-h LC50s also were calculated for the compounds and combined with published LC50s to predict relative PAH toxicity to P. pugio based on octanol-water partitioning.

Validation of an antibody-based biosensor for rapid quantification of 2,4,6-trinitrotoluene (TNT) contamination in ground water and river water.

Nitroaromatics are common pollutants of soil and groundwater at military installations because of their manufacture, storage, and use at these sites. Long-term monitoring of these pollutants comprise a significant percentage of restoration costs. Further, remediation activities often have to be delayed, while the samples are processed via traditional chemical assessment protocols. Here we describe a rapid (<5 min), cost-effective, accurate method using a KinExA Inline Biosensor for monitoring of 2,4,6-trinitrotoluene (TNT) in field water samples. The biosensor, which is based on KinExA technology, accurately estimated the concentration of TNT in double-blind comparisons with similar accuracy to traditional high-performance liquid chromatography(HPLC). In the assessment of field samples, the biosensor accurately predicted the concentration of TNT over the range of 1-30,000 microg/L when compared to either HPLC or quantitative gas chromatography-mass spectrometry (GC-MS). Various pre-assessment techniques were explored to examine whether field samples could be assessed untreated, without the removal of particulates or the use of solvents. In most cases, the KinExA Inline Biosensor gave a uniform assessment of TNT concentration independent of pretreatment method. This indicates that this sensor possesses significant promise for rapid, on-site assessment of TNT pollution in environmental water samples.

Predicting survival of grass shrimp (Palaemonetes pugio) during ethylnaphthalene, dimethylnaphthalene, and phenanthrene exposures differing in concentration and duration.

Both exposure duration and concentration determine the lethal consequences of polycyclic aromatic hydrocarbons (PAHs) released during oil spills. Many factors, such as weathering, tidal transport, and addition of surfactants, can change the composition of individual dissolved compounds and the duration over which an individual is exposed. Conventional toxicity testing methods produce effect metrics, such as the median lethal concentration (LC50), that are not applicable to predicting mortality at all toxicant exposure durations that are likely to occur during a spill. In the present study, survival time models were developed that explicitly include toxicant exposure duration and concentration to predict time-to-death for grass shrimp (Palaemonetes pugio) exposed to three PAHs (1-ethylnaphthalene, 2,6-dimethylnaphthalene, and phenanthrene) commonly found in the water-soluble fraction derived from oil. Conventional 48-h LC50s also were calculated for the compounds (ethylnaphthalene, 295 microg/L; dimethylnaphthalene, 500 microg/L; and phenanthrene, 360 microg/L). In contrast to LC50s, survival models and associated response surfaces can be used to predict the proportions of shrimp that will die at various times throughout the exposure period.

Kepone in James River fish: 1976-2002.

In late 1975, it was discovered that a manufacturing facility had not only exposed workers to the chlorinated pesticide, Kepone, but had also severely contaminated the James River estuary. To assess the potential for the public to be exposed to Kepone through the consumption of contaminated seafood, the Commonwealth of Virginia initiated a finfish-monitoring program in late 1975. Over 13,000 samples have been collected and analyzed as part of this effort. Kepone levels in most species began falling when the production of Kepone ended, but the average concentrations remained over the action limit of 0.3 microg g(-1) wet weight until the early 1980s. By 1988 few fish contained Kepone concentrations greater than the action limit. Kepone is still detected in the majority of white perch and striped bass samples taken from the James River and a fish consumption advisory is still in effect thirty years after the source of contamination was removed.