Monitoring Of Environmental Samples Research Articles

The Identification of Acetic Acid-Ethanol Mixture Using Gas Sensor Array and Ensemble Regression

Identification of acetic acid-ethanol mixtures using a commercial gas sensor array equipped with ensemble regression has been carried out. The gas sensor analysis was simple, rapid, and fast since it did not require any sample preparation. A quantitative analysis of the acetic acid-ethanol mixture was carried out to determine the sensitivity and selectivity of the sensor in distinguishing the concentration of the acetic acid and ethanol mixture. This study focuses on the coefficient of determination of 80% of the calibration data set and recovery of 20% of the testing data set. The models showed excellent performance,specifically, the Bagging and Random Forest r2 for the ethanol calibration data reached 0.91 and 0.94, respectively. The corresponding ethanol test recoveries were 99.95% and 97.84%, indicating the robustness of the model in accurately predicting ethanol concentration. Acetic acid test recoveries were 100.56% and 101.38% with r2 of 0.89 and 0.93 for Bagging and Random Forest regression, respectively. Hence, the commercial gas sensor array equipped with ensemble regression can be applied to the quantification of the acetic acid – ethanol mixture and demonstrate opportunities for the practical use of this gas sensor array in analyzing real samples, i.e. human breath or environmental monitoring samples.

Association of exposure to indoor molds and dampness with allergic diseases at water-damaged dwellings in Korea

This study aims to characterize levels of molds, bacteria, and environmental pollutants, identify the associations between indoor mold and dampness exposures and childhood allergic diseases, including asthma, allergic rhinitis, atopic dermatitis, using three different exposure assessment tools. A total of 50 children with their parents who registered in Seoul and Gyeonggi-do in Korea participated in this study. We collated the information on demographic and housing characteristics, environmental conditions, and lifestyle factors using the Korean version of the International Study of Asthma and Allergies in Childhood questionnaire. We also collected environmental monitoring samples of airborne molds and bacteria, total volatile organic compounds, formaldehyde, and particulate matter less than 10 µm. We evaluated and determined water damage, hidden dampness, and mold growth in dwellings using an infrared (IR) thermal camera and field inspection. Univariate and multivariate regression analyses were performed to evaluate the associations between prevalent allergic diseases and exposure to indoor mold and dampness. Indoor mold and bacterial levels were related to the presence of water damage in dwellings, and the mean levels of indoor molds (93.4 ± 73.5 CFU/m3) and bacteria (221.5 ± 124.2 CFU/m3) in water-damaged homes were significantly higher than those for molds (82.0 ± 58.7 CFU/m3) and for bacteria (152.7 ± 82.1 CFU/m3) in non-damaged dwellings (p < 0.05). The crude odds ratios (ORs) of atopic dermatitis were associated with < 6th floor (OR = 3.80), and higher indoor mold (OR = 6.42) and bacterial levels (OR = 6.00). The crude ORs of allergic diseases, defined as a group of cases who ever suffered from two out of three allergic diseases, e.g., asthma and allergic rhinitis, and allergic rhinitis were also increased by 3.8 and 9.3 times as large, respectively, with water damage (+) determined by IR camera (p < 0.05). The adjusted OR of allergic rhinitis was significantly elevated by 10.4 times in the water-damaged dwellings after adjusting age, sex, and secondhand smoke. Therefore, a longitudinal study is needed to characterize dominant mold species using DNA/RNA-based sequencing techniques and identify a causal relationship between mold exposure and allergic diseases in the future.

Candidate biomarkers of antibiotic resistance for the monitoring of wastewater and the downstream environment

Urban wastewater treatment plants (UWTPs) are essential for reducing the pollutants load and protecting water bodies. However, wastewater catchment areas and UWTPs emit continuously antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs), with recognized impacts on the downstream environments. Recently, the European Commission recommended to monitor antibiotic resistance in UWTPs serving more than 100 000 population equivalents. Antibiotic resistance monitoring in environmental samples can be challenging. The expected complexity of these systems can jeopardize the interpretation capacity regarding, for instance, wastewater treatment efficiency, impacts of environmental contamination, or risks due to human exposure. Simplified monitoring frameworks will be essential for the successful implementation of analytical procedures, data analysis, and data sharing. This study aimed to test a set of biomarkers representative of ARG contamination, selected based on their frequent human association and, simultaneously, rare presence in pristine environments. In addition to the 16S rRNA gene, ten potential biomarkers (intI1, sul1, ermB, ermF, aph(3′’)-Ib, qacEΔ1, uidA, mefC, tetX, and crAssphage) were monitored in DNA extracts (n = 116) from raw wastewater, activated sludge, treated wastewater, and surface water (upstream and downstream of UWTPs) samples collected in the Czech Republic, Denmark, Israel, the Netherlands, and Portugal. Each biomarker was sensitive enough to measure decreases (on average by up to 2.5 log-units gene copy/mL) from raw wastewater to surface water, with variations in the same order of magnitude as for the 16S rRNA gene. The use of the 10 biomarkers allowed the typing of water samples whose origin or quality could be predicted in a blind test. The results show that, based on appropriate biomarkers, qPCR can be used for a cost-effective and technically accessible approach to monitoring wastewater and the downstream environment.

Establishment of a Single Temperature Incubation Approach for Environmental Monitoring Samples with Focus on Mold Recoveries.

A robust environmental monitoring program is essential to properly estimate and identify microorganisms in cleanrooms, ensuring that microbial contamination remains acceptably low, and a good state of control is maintained in the manufacturing areas. The incubation conditions are important to support optimal microbial recoveries, considering that there is no single culture medium, temperature and incubation time that can recover all microorganisms. Particularly molds are quite sensitive microorganisms, and some species may have very specific nutritional and environmental needs. In this study, a two-phase approach was used to identify a single incubation-temperature approach that could recover most of the cleanroom microbial flora with focus on molds. Phase 1 included a growth promotion study performed in the laboratory using pharmacopeial and in-house strains, comparing different media (SDA and TSA) at single or dual incubation-temperature approaches for 5 or 6 days. Phase 2 was based on an in situ study where sampling was performed in different areas of a pharmaceutical facility, comparing the recoveries at different incubation conditions. In addition, extension studies of phase 1 and phase 2 were performed to get a better understanding of growth requirements for in-house molds. The results show that an incubation on Tryptone Soy Agar (TSA) at 25-30° for 3-4 days was able to recover most tested microorganisms in phase 1 and a large variety of microorganisms in phase 2, indicating that the single incubation-temperature is an optimal approach for the recovery of microorganisms in cleanrooms. Exceptions were noted for one strain of the species Cutibacterium acnes, a microaerophilic bacterium for which anaerobiosis and higher temperatures were needed, and two mold strains (Sistotrema brinkmannii and Stereum hirsutum), indicating that those molds required a specific media (Sabouraud Dextrose Agar, SDA) for their proliferation. The results showed that TSA incubated at single or dual incubation-temperature approach cannot compensate for the absence of SDA for some environmental molds that may be atypical in cleanrooms. Therefore, in addition to TSA, certain monitoring with SDA at e.g., cleanroom entrance points may be beneficial to recover molds with very specific nutritional requirements.

Metabarcoding airborne pollen from subtropical and temperate eastern Australia over multiple years reveals pollen aerobiome diversity and complexity

eDNA metabarcoding is an emergent tool to inform aerobiome complexity, but few studies have applied this technology with real-world environmental pollen monitoring samples. Here we apply eDNA metabarcoding to assess seasonal and regional differences in the composition of airborne pollen from routine samples collected across successive years. Airborne pollen concentrations over two sampling periods were determined using a continuous flow volumetric impaction air sampler in sub-tropical (Mutdapilly and Rocklea) and temperate (Macquarie Park and Richmond), sites of Australia. eDNA metabarcoding was applied to daily pollen samples collected once per week using the rbcL amplicon. Composition and redundancy analysis of the sequence read counts were examined. The dominant pollen families were mostly consistent between consecutive years but there was some heterogeneity between sites and years for month of peak pollen release. Many more families were detected by eDNA than counted by light microscopy with 211 to 399 operational taxonomic units assigned to family per site from October to May. There were 216 unique and 119 taxa shared between subtropics (27°S) and temperate (33°S) latitudes, with, for example, Poaceae, Myrtaceae and Causurinaceae being shared, and Manihot, Vigna and Aristida being in subtropical, and Ceratodon and Cerastium being in temperate sites. Certain genera were observed within the same location and season over the two years; Chloris at Rocklea in autumn of 2017–18 (0.625, p ≤ 0.004) and 2018–19 (0.55, p ≤ 0.001), and Pinus and Plantago at Macquarie Park in summer of 2017–18 (0.58, p ≤ 0.001 and 0.53, p ≤ 0.003, respectively), and 2018–19 (0.8, p ≤ 0.003 and 0.8, p ≤ 0.003, respectively). eDNA metabarcoding is a powerful tool to survey the complexity of pollen aerobiology and distinguish spatial and temporal profiles of local pollen to a far deeper level than traditional counting methods. However, further research is required to optimise the metabarcode target to enable reliable detection of pollen to genus and species level.

Electrochemical sensor design based on CuO nanosheets/ Cellulose derivative nanocomposite for hydrazine monitoring in environmental samples

Synthesis of electrode materials with stable and advanced functionality is highly required to design susceptible and selective electrochemical sensors to fast screen various targets such as hazardous environmental analytes. A nanocomposite-based electrode material was synthesized for hydrazine (HZ) detection in environmental samples. The CuO nanosheets (CuO NSs) decorated the surface of Cellulose acetate butyrate (CAB) were synthesized by a simple and one-step approach. The materials of CuO NSs/CAB and CAB were characterized using field emission scanning electron microscopy (FE-SEM), Fourier transform-infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Raman spectroscopy, and ultraviolet (UV). The designed material of CuO shows a nanosheet structure with irregular sheet size and distribution and a sheet size of ∼17 nm. The CAB rough surface, high surface, and functionalization (i.e., OH, acetate and butyrate) increase the loading of CuO nanosheet that enhance the catalytic active sites. Moreover, the structural morphology and composition of CuO NSs/CAB play a key role in the design of a highly active surface for electrocatalytic oxidation of HZ molecules. The CAB was decorated by CuO NSs and acted as the mediated surface for catalytic oxidation and signalling transduction of HZ molecules. The CuO acted as the active electrocatalyst, and the CAB acted as a hydrophilic surface to induce the binding and loading of HZ molecules. The CuO NSs/CAB shows a highly sensitive sensor with a low limit of detection (0.15 µM) and a wide linear range of 0.5–100 mM. The designed electrode of CuO NSs/CAB provides a selective sensor assay for the detection of HZ in environmental samples with a high recovery range of 96.34–99.64 %, high stability, and good reproducibility.

Current RT-qPCR to detect SARS-CoV-2 may give positive results for related coronaviruses

Some weeks after the first CoVID-19 outbreak, the World Health Organization published some real-time PCR (qPCR) protocols developed by different health reference centers. These qPCR designs are being used worldwide to detect SARS-CoV-2 in the population, to monitor the prevalence of the virus during the pandemic. Moreover, some of these protocols to detect SARS-CoV-2 have widely been applied to environmental samples for epidemiological surveillance purposes. In the present work, the specificity of these currently used RT-qPCR designs was validated in vitro using SARS-CoV-2 and highly related coronaviral genomic sequences and compared to performance of the commercially available GPS™ CoVID-19 dtec-RT-qPCR Test. Assays performed with SARS-CoV-2-related genomes showed positive amplification when using some of these qPCR methods, indicating they may give SARS-CoV-2 false positives. This finding may be particularly relevant for SARS-CoV-2 monitoring of environmental samples, where an unknown pool of phylogenetically close-related viruses may exist.

Advances in Detection of Antibiotic Pollutants in Aqueous Media Using Molecular Imprinting Technique-A Review.

Antibiotics constitute one of the emerging categories of persistent organic pollutants, characterised by their expansion of resistant pathogens. Antibiotic pollutants create a major public health challenge, with already identifiable detrimental effects on human and animal health. A fundamental aspect of controlling and preventing the spread of pollutants is the continuous screening and monitoring of environmental samples. Molecular imprinting is a state-of-the-art technique for designing robust biomimetic receptors called molecularly imprinted polymers (MIPs), which mimic natural biomolecules in target-selective recognition. When integrated with an appropriate sensor transducer, MIP demonstrates a potential for the needed environmental monitoring, thus justifying the observed rise in interest in this field of research. This review examines scientific interventions within the last decade on the determination of antibiotic water pollutants using MIP receptors interfaced with label-free sensing platforms, with an expanded focus on optical, piezoelectric, and electrochemical systems. Following these, the review evaluates the analytical performance of outstanding MIP-based sensors for environmentally significant antibiotics, while highlighting the importance of computational chemistry in functional monomer selection and the strategies for signal amplification and performance improvement. Lastly, the review points out the future trends in antibiotic MIP research, as it transits from a proof of concept to the much demanded commercially available entity.

Determination of multiclass pesticides in river sediments via matrix solid-phase dispersion extraction and gas chromatography-tandem mass spectrometry.

A fast and environment-friendly analytical method was implemented to determine multiclass pesticides in river sediments. Twenty-three pesticides-organochlorine pesticides, organophosphorus pesticides, and triazines-were extracted via matrix solid-phase dispersion (MSPD) and analyzed by gas chromatography-tandem mass spectrometry (GC-MS/MS). Florisil demonstrated excellent analytes uptake capability as the extractant phase, with suitable selectivity for treating complex sediment samples. Under defined extraction conditions, the MSPD-GC-MS/MS method demonstrated robustness in the n inter-day analysis of sediments from different sources, providing limit of quantifications (LOQs) between 5 and 15ng/g, linear responses in the range between LOQs and 150ng/g, extraction recoveries of 71%-106%, and precision, assessed as relative standard deviation below 20%. The MSPD significantly reduced samples and solvents' consumption, providing critical environmental gains compared to traditional extraction methods like Soxhlet. Finally, the method was applied to analyze sediment samples from three different collection areas of the Subachoque River (Cundinamarca, Colombia), demonstrating a fast, efficient, confident, and profitable analytical tool for pollution control and monitoring in environmental samples. The method allowed us to determine the current use in Colombia of banned pesticides under the 2001 Stockholm Convention.

Analyzing aggregate environmental monitoring data for Listeria spp. in frozen food manufacturing environments

Food processors face serious challenges due to the ubiquity and prevalence of Listeria monocytogenes in production and processing facilities. Environmental monitoring for Listeria within the industry is important and detection of Listeria spp. is often used as an indicator for the potential presence of L. monocytogenes in the food processing environment. Environmental monitoring data from the frozen food manufacturing industry was compiled and analyzed to evaluate the adequacy of current practices in mitigating risks of L. monocytogenes in the processing environment and to determine if there are trends that could be used to further refine industry practices. A method to collect anonymous data for analysis to build a strong aggregate data set from multiple facilities was used. Information included general descriptions of each facility and specific information about individual environmental monitoring test results from environmental zones 2–4, or nonfood contact surfaces. Information collected from facilities included the size of the facilities and how environmental monitoring samples were collected and analyzed. For each individual sample, information collected included the area or equipment sampled and the result of each sample. Descriptors were provided to allow for grouping of similar results. The data represents environmental monitoring samples that were collected between six months to a year prior to the beginning of this research. Twenty-seven facilities provided 42,799 environmental monitoring observations. Environmental zones 3 and 4 had a higher estimated marginal probability of Listeria positive results compared to zone two for routine environmental monitoring samples (p < 0.05). Pre-lethality and post-lethality production areas had a higher probability of Listeria positive results compared to lethality areas for all environmental samples (p < 0.05). Cold storage locations, i.e., coolers and freezers had a significantly higher probability for a Listeria positive result than noncold storage areas (p < 0.01). Applying statistical modeling and comparing estimated marginal probabilities of aggregate Listeria prevalence data from processing operations across the industry can provide information for guidance on focusing sanitation within processing operations to reduce risk related to L. monocytogenes. These data help to identify common themes in the industry and determine potential areas on which to focus when testing for prevalence of Listeria spp. within the food processing environment. This study serves as a useful baseline for continued improvement in environmental monitoring across all frozen food manufacturing facilities. • Environmental monitoring samples from frozen food facilities were collected. • Twenty-seven facilities provided 42,799 environmental monitoring observations. • Zones 3/4 had a higher probability of Listeria positive results compared to zone 2.

A 5-Point Listeria Control Plan: A European Perspective

With an aging population and no reduction in Listeria cases, listeriosis is likely to become even more important in Europe, and all potential food industry control measures should be explored. A Listeria 5-point control plan to manage the occurrence of Listeria in high hygiene food manufacturing areas has been developed and trialed in the United Kingdom and Ireland since 2016; it comprises these points: • Prevent entry of Listeria into high hygiene food manufacturing areas using effective barriers. • Ensure that the high hygiene manufacturing infrastructure (building structure, equipment, and utensils) cannot harbor and/or allow the growth of Listeria (Listeria sources). • Ensure that high hygiene good manufacturing practices limit the cross-contamination vectors that can carry Listeria from sources to product or product- contact surfaces. • Design an effective cleaning and disinfection program that will kill or remove any Listeria that has entered the high hygiene area since the previous cleaning program. • Provide an environmental monitoring and microbiological verification sampling program that monitors and verifies Listeria control procedures. This review suggests that the plan develops a team ethos among factory technical, production, engineering, and hygiene functions and that success has been achieved in reducing the prevalence of Listeria in product and the environment.

MiniPANDA device for alpha–gamma coincidence measurements

MiniPANDA is a detector system for alpha–gamma coincidence measurements for environmental monitoring samples under atmospheric pressure. It is designed to enhance traditional gamma spectrometry with coincidence techniques and list mode data workflow. The performance of the detector is evaluated using a microscopic 238Pu particle sample and an air radioactivity surveillance sample with traces of artificial nuclides. Significant improvement of sensitivity, a factor of 2.6–3.0, for alpha-particle emitting nuclides was achieved under normal measurement times, while maintaining the ability to perform traditional gamma spectrometry. The capability for alpha spectrometry is demonstrated by determining the activities of alpha-particle emitting nuclides from a sample containing 226Ra progeny.

Paenibacillus tianjinensis sp. nov., isolated from corridor air.

A Gram-stain-positive, facultatively anaerobic, non-motile, endospore-forming and rod-shaped bacterium, occurring singly or in pairs, designated TB2019T, was isolated from environmental monitoring samples of corridor air collected at the Tianjin Institute for Drug Control, Tianjin Province (PR China). The isolate was able to grow at 15-40 °C (optimum growth at 37 °C), pH 6.0-8.0 (pH 7.0) and in the presence of 0-2% (w/v) NaCl (0% NaCl). Comparison of 16S rRNA gene sequences indicated that TB2019T was most closely related to Paenibacillus typhae CGMCC 1.11012T (98.63%), Paenibacillus albidus Q4-3T (98.19%), Paenibacillus borealis DSM 13188T (97.55%), Paenibacillus helianthi P26ET (97.33%) and Paenibacillus odorifer DSM 15391T (97.19%). The digital DNA-DNA hybridization and the average nucleotide identity values between TB2019T and the five type strains mentioned above ranged from 20.7 to 25.0% and 75.2 to 81.3%, respectively, and the genomic DNA G+C content was 49.52 mol%. The diagnostic cell-wall sugar was ribose, and the diagnostic amino acid was meso-diaminopimelic acid. The polar lipids of TB2019T included diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, three unidentified aminophospholipids and one unidentified phospholipid. MK-7 was the predominant menaquinone, and anteiso-C15:0 (30.6%) was the major fatty acid. Based on the polyphasic taxonomic data, strain TB2019T represents a novel species of the genus Paenibacillus, for which the name Paenibacillus tianjinensis sp. nov. is proposed. The type strain is TB2019T (=CICC 25065T=JCM 34610T).

The Effectiveness of “River Chief System” Policy: An Empirical Study Based on Environmental Monitoring Samples of China

There has been controversy in theory and practice among studies about the governance of the “River Chief System” (RCS) policy and the watershed management issues behind it. This paper uses the regression discontinuity (RD) method and the water pollution monitoring data of 150 state-controlled monitoring points in China from 2007 to 2018 at the China National Environmental Monitoring Station to empirically study the effect of the “River Chief System” on water pollution treatment and the influencing factors behind the effect of the “River Chief System”. The results show that the “River Chief System” policy has a positive impact on river pollution treatment in the observation term. The implementation effectiveness of the “River Chief System” is limited by factors such as the boundaries of the river chief’s jurisdictions, the administrative conflict among river chiefs, local government environmental expenditure capacity, and environmental pressure. It is believed that the key to basin governance is to further improve the synergistic model of basin governance among regions.

Assessing Approaches of Human Inhalation Exposure to Polycyclic Aromatic Hydrocarbons: A Review.

Polycyclic aromatic hydrocarbons (PAHs) are a class of important organic pollutants widely emitted from anthropogenic activities, with a general distribution in the gas and particulate phases. Some PAHs are carcinogenic, teratogenic, and mutagenic. Inhalation exposure to PAHs is correlated with adverse health outcomes in the respiratory and cardiovascular systems. Thus, it is significant to determine the exposure level of the general population. This study summarizes the evaluation methods for PAH exposure, focusing on different exposure parameters. External exposure can be determined via the collection of the environmental pollution concentration through active samplers or passive samplers during environmental monitoring or personal sampling. Time-activity patterns give critical exposure information that captures the exposure period, origin, and behaviors. Modeling is a labor-less approach for human exposure estimation, and microenvironmental exposure requires specific research. It is important to select appropriate methods to quantify the exposure level to provide accurate data to establish the exposure–risk relationship and make scientific suggestions for the protection of public health.

Functionalized 2D Germanene and Silicene Enzymatic System

AbstractIn recent years, 2D Group 14 graphane analogs, such as germanane, methyl germanane, and siloxene, have taken materials scientists by storm due to their facile synthesis procedures and the numerous attractive properties proffered. Due to their fascinating properties, these emerging Group 14 graphane analogs are studied for varied applications including supercapacitors, photocatalysts, and sensors. Although several groups have reported the viability of using Group 14 graphane analogs for the construction of biosensors, they are mainly based upon computational studies, and few experimental studies are conducted. This paper aims to experimentally investigate the feasibility of using germanane and siloxene‐based materials as 2D functional support for enzymatic systems. The heterogeneous electron transfer kinetics and the glucose sensing response of the as‐synthesized germanane, methyl germanane, and siloxene are examined, and the most outstanding material, germanane, is employed for further construction of electrochemical glucose biosensor. The fabricated biosensing platform delivers excellent analytical performances, displaying good linearity over various magnitudes of glucose concentrations, and possesses a low detection limit. The findings reported herein showcase the potential of applying these 2D Group 14 graphane analogs for future developments of highly selective and sensitive biosensors for biomedical, environmental monitoring, and food sampling applications.

Optimization of a pre-metabolization procedure using rat liver S9 and cell-extracted S9 in the Ames fluctuation test

Many environmental pollutants pose a toxicological hazard only after metabolic activation. In vitro bioassays using cell lines or bacteria have often no or reduced metabolic activity, which impedes their use in the risk assessment. To improve the predictive capability of in vitro assays, external metabolization systems like the liver S9 fraction are frequently combined with in vitro toxicity assays. While it is typical for S9 fractions that samples and testing systems are combined in the same exposure system, we propose to separate the metabolism step and toxicity measurement. This allows for a modular combination of metabolic activation by enzymes isolated from rat liver (S9) or a biotechnological alternative (ewoS9R) with in vitro bioassays that lack metabolic capacity. Benzo(a)pyrene and 2-aminoanthracene were used as model compounds to optimize the conditions for the S9 metabolic degradation/activation step. The Ames assay with Salmonella typhimurium strains TA98 and TA100 was applied to validate the set-up of decoupling the S9 activation/metabolism from the bioassay system. S9 protein concentration of 0.25 mgprotein/mL, a supplement of 0.13 mM NADPH and a pre-incubation time of 100 min are recommended for activation of samples prior to dosing them to in vitro bioassays using the regular dosing protocols of the respective bioassay. EwoS9R performed equally well as Moltox S9, which is a step forward in developing true animal-free in vitro bioassays. After pre-incubation with S9 fraction, chemicals induced bacteria revertants in both the TA98 and the TA100 assay as efficiently as the standard Ames assay. The pre-incubation of chemicals with S9 fraction could serve for a wide range of cellular in vitro assays to efficiently combine activation and toxicity measurement, which may greatly facilitate the application of these assays for chemical hazard assessment and monitoring of environmental samples.

Ultra trace simultaneous determination of 50 polycyclic aromatic hydrocarbons in biota using pMRM GC-MS/MS

A saponification extraction method with gas chromatography pseudo-MRM (pMRM) mass spectrometry detection was developed for the determination of 50 total polycyclic aromatic hydrocarbons (TPAH50, a combination of parent and alkylated homologues) in biota. The method was aimed at monitoring and identification of potential TPAH contaminants in bitumen impacted environments. Alkylated PAHs were determined by multi-level, quantitative calibration using parent PAHs. The developed and thoroughly validated method required only one injection for TPAH50 analysis which represents significant saving of time and expensive authentic alkylated standards. The current method was tested with certified reference mussel tissue NIST 1974c and performed well. In a comparison study, the method reached a limit of quantitation (LOQ) for the TPAH50 between 0.1 and 0.2 ng g−1, while the QuEChERs enhanced matrix removal – lipid (EMR) kit produced by Agilent showed an LOQ of 5–10 ng g−1. The current method relied on response factors (RF) for the quantitation of alkylated PAHs determined against parent PAHs. These RFs were shown to be stable and consistent over the course of 1 year, during which over 200 routine environmental biota monitoring samples were analyzed. The environmental biota monitoring samples analyzed include muscle, carcass and liver, with an average total PAH50 concentration of 13, 90 and 135 ng g−1, respectively. Results show significant differences in the distributions of 1 ringed, 2 ringed, 3 ringed, 4 ringed, and 5+ ringed TPAHs between the types of biota samples.

Event-specific multiplex PCR method for four genetically modified cotton varieties, and its application

Multiplex polymerase chain reaction (PCR) methods have been developed and validated for screening, tracing, and regulating genetically modified (GM) crops in quarantine and environmental monitoring. In this study, we aimed to develop a method to simultaneously detect four GM cotton varieties in order to establish a screening system for cotton volunteers. Based on the sequence of DNA in the junction between introduced gene and flanking genomic DNA of four GM cotton events, herbicide-tolerant MON88701 and DAS-81910-7 and insect-resistant COT102 and T304-40, event-specific primers were designed and a multiplex detection method was developed. The simplex PCR results supported the multiplex PCR results; the amplification efficiency of the novel multiplex PCR method was increased compared with that of the Joint Research Centre (JRC) method. Based on the accuracy and efficiency, the method can be applied to detect and identify randomly mixed reference materials and suspected cotton volunteers. To apply this multiplex PCR method to living modified (LM) environmental monitoring samples, we performed additional PCR analysis to identify whether the volunteers were the four LM cotton varieties. As a result, 66 cotton volunteers were identified with stack event, comprising one or two of the four LM cotton events, and all stacks have been approved in South Korea for food, feed, and processing. These results indicated that our novel multiplex method is suitable for LMO identification.

Propidium monoazide-quantitative polymerase chain reaction (PMA-qPCR) assay for rapid detection of viable and viable but non-culturable (VBNC) Pseudomonas aeruginosa in swimming pools.

Lack of culturability in the viable but non-culturable (VBNC) bacteria and the ability to regain infectivity in favourable conditions is one of the new challenges of public health providers for Pseudomonas aeruginosa monitoring in environmental samples. Propidium monoazide quantitative polymerase chain reaction (PMA-qPCR) is one of the promising methods for timely detection of VBNC pathogens in environmental samples. We developed and used a method for the first time to detection of VBNC P. aeruginosa in swimming pool water samples using a membrane filter (MF). Moreover, the dominant model of the distribution of colonies on the MF and the effect of the culture medium and MF type on colony recovery by MF were evaluated. Swimming pool samples were subjected to conventional culture-based, qPCR and PMA-qPCR methods and the results were compared for the presence of VBNC P. aeruginosa in the samples. The positivity rate was 21% and 75% for P. aeruginosa in water samples as confirmed by standard culture-based and qPCR methods, respectively. Furthermore, of 24 samples, 9 (37.5%) were positive for VBNC P. aeruginosa. The developed qPCR/PMA-qPCR assay can detect the VBNC bacteria directly from aquatic samples and may result in better monitoring of recreational waters.