LC-MS/MS analysis of pharmaceuticals in the Irish aquatic environment and the potential for human exposure

Reports concerning the quantitative analysis of pharmaceuticals in marine ecosystems are somewhat limited. It is necessary to determine pharmaceutical fate and assess any potential risk of exposure to aquatic species and ultimately, seafood consumers. However, in Ireland very little research has been carried out to determine the presence of pharmaceutical residues in the aquatic environment. The research carried out investigates the occurrence of pharmaceuticals in the Irish aquatic environment and their potential to bioaccumulate in aquatic organisms and pose a risk to human health via dietary intake. Pharmaceutical residues were determined in liquid matrices, such as wastewater effluent, marine surface water (MSW) and artificial seawater (ASW), using solid phase extraction (SPE) in combination with liquid chromatography-tandem mass spectrometry (LC-MS/MS). Pharmaceutical extraction from marine mussels and fish tissues required an additional pressurised liquid extraction (PLE) step prior to SPE and LC-MS/MS. The results of an in situ study, in which caged Mytilus spp. were deployed at three sites on the Irish coastline over a 1-year period are presented. All of the selected pharmaceuticals were quantified in wastewater effluent and marine surface waters and three out of the five monitored pharmaceuticals were detected in environmentally exposed mussel tissue. The potential for pharmaceutical bioaccumulation in fish via trophic level transfer was investigated. A 28-day in vivo experiment was carried out in a flow-through system in which rainbow trout were fed wild marine mussels sampled from one of the most contaminated sites in Ireland. Although low-level residues of trimethoprim were detected in the mussel tissues, no bioaccumulation was reported for this drug or any of the other selected compounds in the liver of the exposed fish. The effect of steaming on the concentrations of five pharmaceutical residues in exposed mussel tissue was investigated in an attempt to assess the potential risk of exposure to humans via ingestion of contaminated seafood. An in vivo experiment was carried out exposing marine mussels to pharmaceutical concentrations via direct injection and water uptake. A selection of water-exposed mussels were cooked (via steaming) resulting in a significant increase of parent pharmaceutical concentrations in the bivalves

Assessing the reliability of uptake and elimination kinetics modelling approaches for estimating bioconcentration factors in the freshwater invertebrate, Gammarus pulex

This study considers whether the current standard toxicokinetic methods are an accurate and applicable assessment of xenobiotic exposure in an aquatic freshwater invertebrate. An in vivo exposure examined the uptake and elimination kinetics for eight pharmaceutical compounds in the amphipod crustacean, Gammarus pulex by measuring their concentrations in both biological material and in the exposure medium over a 96 h period. Selected pharmaceuticals included two anti-inflammatories (diclofenac and ibuprofen), two beta-blockers (propranolol and metoprolol), an anti-depressant (imipramine), an anti-histamine (ranitidine) and two beta-agonists (formoterol and terbutaline). Kinetic bioconcentration factors (BCFs) for the selected pharmaceuticals were derived from a first-order one-compartment model using either the simultaneous or sequential modelling methods. Using the simultaneous method for parameter estimation, BCF values ranged from 12 to 212. In contrast, the sequential method for parameter estimation resulted in bioconcentration factors ranging from 19 to 4533. Observed toxicokinetic plots showed statistically significant lack-of-fits and further interrogation of the models revealed a decreasing trend in the uptake rate constant over time for rantidine, diclofenac, imipramine, metoprolol, formoterol and terbutaline. Previous published toxicokinetic data for 14 organic micro-pollutants were also assessed and similar trends were identified to those observed in this study. The decreasing trend of the uptake rate constant over time highlights the need to interpret modelled data more comprehensively to ensure uncertainties associated with uptake and elimination parameters for determining bioconcentration factors are minimised

Bioaccumulation of metals in juvenile rainbow trout 1 (oncorhynchus mykiss) via dietary exposure to blue mussels

The potential for metals to bioaccumulate in aquatic species, such as fish, via trophic level transfer was investigated. An in vivo experiment was set up in a flow-through system in which juvenile rainbow trout were fed blue mussels collected from a Class A pristine site and an effluent-impacted river estuary, over a period of 28 days. Selected elements (As, Cd, Cr, Co, Cu, Fe, Pb, Mn, Mo, Ni, Se, Sn, V, Zn) were determined in the mussels and fish tissues (muscle and skin) collected at 0, 14 and 28 days. This study reveals the occurrence of metals in mussels sampled in the Irish marine environment and highlights the bioaccumulation potential of metals in fish tissues via trophic transfer. All 14 monitored metals were determined in the mussels collected from both sites and mussels collected from the effluent-impacted site contained three times more Co, Mo, Sn and V than the mussels collected from the Class A site. Following a 28-day dietary exposure, concentrations of As and Se (fish muscle), and Pb, Se and Zn (fish skin), were significantly greater in fish feeding on contaminated mussels compared to those with a regular fish feed diet. The significance of metal detection and bioaccumulation in the mussel and fish tissues, highlights the potential for metal exposure to humans through the food chain. As fish are recommended as a healthy and nutritious food source, it is important to fully understand metal bioaccumulation in commercially important aquatic species and ensure the safety of human consumers

Bioremediation of waste under ocean acidification: Reviewing the role of Mytilus edulis

Waste bioremediation is a key regulating ecosystem service, removing wastes from ecosystems through storage, burial and recycling. The bivalve Mytilus edulis is an important contributor to this service, and is used in managing eutrophic waters. Studies show that they are affected by changes in pH due to ocean acidification, reducing their growth. This is forecasted to lead to reductions in M. edulis biomass of up to 50% by 2100. Growth reduction will negatively affect the filtering capacity of each individual, potentially leading to a decrease in bioremediation of waste. This paper critically reviews the current state of knowledge of bioremediation of waste carried out by M. edulis, and the current knowledge of the resultant effect of ocean acidification on this key service. We show that the effects of ocean acidification on waste bioremediation could be a major issue and pave the way for empirical studies of the topic

The changing relationship between business ethics and buyer behaviour in the past decade

Over the past ten years the term ‘business ethics’ has become a popular topic considering the level of corruption within organisations which has created a high level of media coverage. There is much misconception as to what exactly business ethics is by both consumers and organisations. It can broadly be described as an organisation conducting their practices and procedures in a manner that ensures ‘rightness in behaviour’ (Bartels, 1967, p.22). The exposure of this topic has led consumers to question where products and services are sourced from and consumers’ now not only require a product to be priced adequately but also expect for an organisation to be ethical, however organisations are struggling to strike a balance between these needs (Hiller, 2010). The researcher has used both questionnaire’s and a number of in-depth interviews in the aim not only to profile who an ethical consumer is but also to explore what organisations’ consumers currently consider to be un/ethical. Although it was difficult to categorise an ethical consumer by their gender, social class and age, the researcher did discover what traits an ethical consumer is likely to posses and why business ethics has become increasingly important

Gradient liquid chromatographic retention time prediction for suspect screening applications: a critical assessment of a generalised artificial neural network-based approach across 10 multi-residue reversed-phase analytical methods

For the first time, the performance of a generalised artificial neural network (ANN) approach for the prediction of 2492 chromatographic retention times (tR) is presented for a total of 1117 chemically diverse compounds present in a range of complex matrices and across 10 gradient reversed-phase liquid chromatography-(high resolution) mass spectrometry methods. Probabilistic, generalised regression, radial basis function as well as 2- and 3-layer multilayer perceptron-type neural networks were investigated to determine the most robust and accurate model for this purpose. Multi-layer perceptrons most frequently yielded the best correlations in 8 out of 10 methods. Averaged correlations of predicted versus measured tR across all methods were R2=0.918, 0.924 and 0.898 for the training, verification and test sets respectively. Predictions of blind test compounds (n=8–84 cases) resulted in an average absolute accuracy of 1.02±0.54 min for all methods. Within this variation, absolute accuracy was observed to marginally improve for shorter runtimes, but was found to be relatively consistent with respect to analyte retention ranges (~5%). Finally, optimised and replicated network dependency on molecular descriptor data is presented and critically discussed across all methods. Overall, ANNs were considered especially suitable for suspects screening applications and could potentially be utilised in bracketed-type analyses in combination with high resolution mass spectrometry

Suspect screening and quantification of trace organic explosives in wastewater using solid phase extraction and liquid chromatography-high resolution accurate mass spectrometry

The first comprehensive assessment of 34 solid phase extraction sorbents is presented for organic explosive residues in wastewater prior to analysis with liquid chromatography-high resolution accurate mass spectrometry (LC-HRMS). A total of 18 explosives were selected including nitramines, nitrate esters, nitroaromatics and organic peroxides. Three polymeric divinylbenzene-based sorbents were found to be most suitable and one co-polymerised with n-vinyl pyrrolidone offered satisfactory recoveries for 14 compounds in fortified wastewater (77–124%). Limits of detection in matrix ranged from 0.026–23 μg L−1 with R2 ≥ 0.98 for most compounds. The method was applied to eight 24-h composite wastewater samples from a London wastewater works and one compound, 2,4-dinitrotoluene, was determined over five days between 332 and 468 g day−1 (225–303 ng L−1). To further exploit the suspect screening capability, 17 additional explosives, precursors and transformation products were screened in spiked wastewater samples. Of these, 14 were detected with recoveries from 62 to 92%, highlighting the broad applicability of the method. To our knowledge, this represents the first screen of explosives-related compounds in wastewater from a major European city. This method also allows post-analysis detection of new or emerging compounds using full-scan HRMS datasets to potentially identify and locate illegal manufacture of explosives via wastewater analysis

The determination of pharmaceutical residues in cooked and uncooked marine bivalves using pressurised liquid extraction, solid-phase extraction and liquid chromatography-tandem mass spectrometry

An optimised and validated method for the determination of pharmaceutical residues in blue mussels (Mytilus spp.) is presented herein, as well as an investigation of the effect of cooking (by steaming) on any potential difference in human exposure risk. Selected pharmaceuticals included two non-steroidal anti-inflammatory drugs (diclofenac and mefenamic acid), an anti-biotic (trimethoprim), an anti-epileptic (carbamazepine) and a lipid regulator (gemfibrozil). An in vivo exposure experiment was set up in the laboratory in which mussels were exposed either directly by injection (10 ng) or daily through spiked artificial seawater (ASW) over 96 h. In liquid matrices, pharmaceutical residues were either determined using liquid chromatography-tandem mass spectrometry (LC-MS/MS) directly, or in combination with solid phase extraction (SPE) for analyte concentration purposes. The extraction of pharmaceuticals from mussel tissues used an additional pressurised liquid extraction (PLE) step prior to SPE and LC-MS/MS. Limits of quantification of between 2 and 46 ng.L-1 were achieved for extracted cooking water and ASW, between 2 and 64 µg.L-1 for ASW in exposure tanks, and between 4 and 29 ng.g-1 for mussel tissue. Method linearities were achieved for pharmaceuticals in each matrix with correlation coefficients of R2>0.975. A selection of exposed mussels was also cooked (via steaming) and analysed using the optimised method to observe any effect on detectable concentrations of parent pharmaceuticals present. An overall increase in pharmaceutical residues in the contaminated mussel tissue and cooking water was observed after cooking