Synthetic musks are incorporated extensively in personal care products to improve their scent, increase their fragrance stability, and prolong their shelf-life. As a consequence, these persistent musks are being released at a considerable rate by wastewater treatment plants and are frequently detected in surface water, bottom sediment, air, and aquatic biota near urban areas. In addition to their hydrophobicity, two synthetic musks, Galaxolide (HHCB) and Tonalide (AHTN), were reported to cause endocrine disruption in fish species. Although most of the toxic effects in past studies were observed at high doses, HHCB and AHTN were shown to bioaccumulate very differently depending on the aquatic species tested. As bioaccumulation and fate of contaminants are important considerations when regulating persistent chemicals, an improved understanding of the bioaccumulation potential of these chemicals is needed. In this thesis, an assessment of the presence, bioconcentration and fate of HHCB and AHTH was provided in an area exposed to the effluent of the Gold Bar wastewater treatment plant in the North Saskatchewan River (Edmonton). HHCB and AHTN were quantified in fathead minnows (Pimephales promelas) exposed downstream of the effluent, with an adapted method for analysis of musks in fish, using PAHs as recovery standards. Method development and recoveries are summarized. Highest bioconcentration factors were 24,500 and 22,300 for HHCB and AHTN respectively, and were observed 1 km downstream of the outfall. Musks were found in most fathead minnows exposed at reference sites upstream as well as at the furthest site, 9.9 km from the outfall. Musk concentrations in water at these sites were used in the assessment of the fate of HHCB and AHTN by fugacity modeling with QWASI software. In order to assess fate, a contaminated portion of the North Saskatchewan River was divided in a series of compartments that were each treated as connected individual water bodies. HHCB and AHTN losses were mostly due to water advection and sedimentation fluxes. Model fit was assessed by comparing predicted to measured data.

Due to the wide spread occurrence of medroxyprogesterone acetate (MPA), a pharmaceutical compound, in wastewater effluent and surface waters, the objectives of this work were to determine the tissue specific uptake and bioconcentration factor (BCF) for MPA in common carp. BCFs were experimentally determined for MPA in fish using a 14-day laboratory test whereby carp where exposed to 100 μg/L of MPA for a 7-day period followed by a depuration phase in which fish were maintained in dechlorinated tap water for an additional 7 days. MPA concentrations in muscle, brain, liver and plasma were determined by liquid chromatography/mass spectrometry (LC/MS). The results from the experiment indicate that MPA can accumulate in fish, however, MPA is not considered to be bioaccumulative based on regulatory standards (BCF ≥ 1000). Although MPA has a low BCF value in common carp, this compound may cause reproductive effects in fish at environmentally relevant concentrations.

The goals of this dissertation work were to assess the bioaccumulation potential of carbamazepine and amiodarone, two widely used ionizable pharmaceutical compounds that possess mid-range and high LogD values, respectively, and to evaluate alternative methods to assess chemical accumulation in bluntnose minnows, catfish, and tilapia. Results indicated that carbamazepine does not appreciably bioaccumulate in fish tissue with BCFk and BAF carbamazepine values < 10. Amiodarone, however, with a log D of 5.87 at pH 7.4, accumulated in fish tissues with kinetic BCF values <2,400. Collectively, the data suggest that full and abbreviated laboratory-derived BCFs, BCFMs derived from S9 loss-of-parent assays, as well as field BAF values are similar for each of the two drugs. In summary, the results from this dissertation indicated: 1) The reduced design BCF test is a good estimate for the traditional OECD 305 test. 2) In vitro S9 metabolism assays provide comparable BCF estimates to the OECD 305 test. 3) Metabolism may play a large role in the accumulation of drugs in fish. 4) Reduced BCF tests and in vitro assays are cost effective and can reduce vertebrate testing.

Complex mixtures of biologically active pharmaceutical residues continuously enter aquatic environments via wastewater, where it can affect species through preserved human drug targets or cause unexpected effects in non-target species. Benzodiazepines and antihistamines are two highly consumed groups of pharmaceuticals that have been shown to bioconcentrate in aquatic organisms and induce behavioural alterations affecting individual fitness. Few studies have investigated bioaccumulation and possible ecological effects of co-occurring pharmaceuticals in food-webs. The aim of this study was to: 1) quantify and compare species-specific bioconcentration and bioaccumulation, by exposing a tri-trophic system consisting of algae, zooplankton and three-spined sticklebacks to oxazepam (benzodiazepine), fexofenadine (antihistamine) and a mixture of both, and 2) analyse if exposure to these pharmaceuticals induce behavioural alterations in sticklebacks, by using standardized behavioural experiments. Species-specific bioconcentration of both oxazepam and fexofenadine was confirmed (F3,98 = 3.061, p = 0.03) were algae and zooplankton bioconcentrated substantially more pharmaceuticals (~50-1800 μg kg-1) compared to sticklebacks (~0.1-6 μg kg-1). Uptake of oxazepam in both zooplankton and sticklebacks was significantly higher compared to fexofenadine (p &lt; 0.001).  Zooplankton and sticklebacks retained 16 and 0.3%, respectively, of fexofenadine from the consumed contaminated prey. Sticklebacks showed no direct behavioural alterations, but possible direct and indirect cascading effects might occur in co-occurrence with fish species exhibiting pharmaceutical-induced alterations. These findings highlight the importance of including consumption of contaminated prey as an important exposure route, when assessing effects of pharmaceuticals in the environment. Contamination magnitudes and subsequent effects are species-specific and vary depending on type of pharmaceuticals.

Abstract The objective of this study is to investigate the heavy metal pollution in our environment by sampling and analyzing the concentration of heavy metal in seawater, sediment, and aquatic organisms from the seaside along the Chang-hua Coastal Industrial Park. The Chang-hua Coastal Industrial Park, located by the west coast of Chung-hua county in middle Taiwan, is a large-scale and multi-functional industrial estate with industrial production, residence and leisure possibilities. Hsienhsi District is situated at the northern part of the Industrial Park. Lukang District is at the southern part. In the middle of it, it is Lunwei District. In the Chung-hua Coastal Industrial Park, there are the second most electroplate and metal coating factories in Taiwan. Metal waste from the process of electroplating and coasting could easily pollute the tidal flat in Chang-hua Coastal Industrial Park. In order to prevent potential pollution taking place, this study took seawater, segment, and the aquatic organisms from the coast of the Chung-hua Coastal Industrial Park to monitoring the concentration level of copper(Cu), zinc(Zn), nickel(Ni), lead(Pb), chromium(Cr) and cadmium(Cd) in each index. The bioconcentration factor (BCF) indicates distinctions of accumulation in various matrixes. Especially from BCFW and BCFS demonstrate that soldier crab is a better index to illustrate the accumulation of Pb and Cr. Muricidae is a better index for showing Cd accumulating concentration. Furthermore, saccostreamordax is the best index for illustrating accumulative level of Ni. Oyster is better in showing accumulating of Cu and Zn. Though each organism shows distinct accumulation of particular metal, they can still illustrate the concentration of other selected metals to image the pollution of the environment. The comparison of metal accumulating levels in seawater, segment, and aquatic organisms from each test site demonstrated: the heavy metal concentration at site2 was much higher than at the other sites. The second most heavy metal concentration was at site6 and site8. Matrixes at site4 contained the lowest heavy metal concentration. The result was thought to be caused by current capacities of factories in three districts of Chang-hua Coastal Industrial Park. Site2 was at Hsienhsi Districtin, in which contained about 58% of factories in residence. In Lukang District, it reached the highest-77%-where was site 6 and site 8. In terms of Site4, it situated at Lunwei District, where was Lunwei Harbor Reservation with least development following by least capacity of factories. Furthermore, without a sound environmental-protection biological sewage treatment device, residues and chemical waste produced from various highly contaminant industries would bring about this concentration comparison result as well.

Runoff and effluent discharge from mining activities has resulted in elevated concentrations of selenium in aquatic ecosystems. Bioavailability is dependent on chemical speciation. Although dissolved inorganic Se species are not directly toxic to organisms, uptake by primary producers and subsequent biotransformation to organo-selenium species substantially increase risk and bioaccumulation potential, potentially impairing reproduction in high-order organisms. The effects of dietary selenium exposure were assessed in two aquatic invertebrates: Ceriodaphnia dubia and Chironomus dilutus. Two generations of these organisms were exposed to seleniferous algae grown in 0-40 μg L-1 selenate. Dissolved selenate was readily absorbed and concentrated by algal species Pseudokirchneriella subcapitata and Chlorella kesslerii. Se had no effect on survival at treated concentrations. Dietary selenium exposures had little effect on reproductive endpoints in either invertebrate species, suggesting that invertebrates have the ability to regulate chronic Se exposures from dietary sources. These results provide valuable information concerning the effects of dietary selenium in aquatic invertebrates.

Through wastewater entering aquatic environments, aquatic insects are continuously exposed to pharmaceuticals including neurologically active antihistamines. The antihistamine hydroxyzine has previously been found to lower activity in damselflies and to reach 2000 times the concentration of surrounding water in damselfly tissue. The purpose of this short-term exposure study was to investigate if hydroxyzine also bioaccumulates in dragonflies and if dilute hydroxyzine (362 ± 50, mean ng/l ± SD) have effects on predator-prey interactions between dragonfly Aeshna grandis and damselfly Coenagrion hastulatum larvae, i.e. number of attacks and predation success. Predators and prey were captured and exposed during one, three or five days (with controls) before taking part in predation experiments; Dragonflies were put in separate containers with six damselflies, they were video recorded and attacks and predated damselflies noted during four hours. Tissue concentrations of hydroxyzine were analyzed from all dragonflies and a subsample of the damselflies showing a mean bioconcentration factor (BCF) of 27 and 7 respectively, surprisingly much lower than previous research. There was no difference in attack rate or predation efficiency between controls and exposed dragonflies. However, dragonflies exposed for five days were found to attack more and capture more prey than dragonflies exposed for one day, a change that was not seen in the controls. This confounding factor motivates further studies to clarify if hydroxyzine after a period of exposure can have a sublethal effect altering foraging and/or predator avoidance traits with the net result of increased predation success for dragonflies in the predator-prey interaction between dragonflies and damselflies.

Runoff and effluent discharge from mining activities has resulted in elevated concentrations of selenium in aquatic ecosystems. Bioavailability is dependent on chemical speciation. Although dissolved inorganic Se species are not directly toxic to organisms, uptake by primary producers and subsequent biotransformation to organo-selenium species substantially increase risk and bioaccumulation potential, potentially impairing reproduction in high-order organisms. The effects of dietary selenium exposure were assessed in two aquatic invertebrates: Ceriodaphnia dubia and Chironomus dilutus. Two generations of these organisms were exposed to seleniferous algae grown in 0-40 μg L-1 selenate. Dissolved selenate was readily absorbed and concentrated by algal species Pseudokirchneriella subcapitata and Chlorella kesslerii. Se had no effect on survival at treated concentrations. Dietary selenium exposures had little effect on reproductive endpoints in either invertebrate species, suggesting that invertebrates have the ability to regulate chronic Se exposures from dietary sources. These results provide valuable information concerning the effects of dietary selenium in aquatic invertebrates.

The presence of pharmaceuticals in the environment is becoming an increasing regulatory and scientific concern. Thus, the metabolic profile and bioconcentration potential of diazepam, a model benzodiazepine, were examined, as well as effects on the endocrine system in channel catfish. Through the use of specific and non-specific cytochrome P450 (CYP450) inhibitors, it was determined that CYP3A-like enzymes may play a role in the biotransformation of diazepam into temazepam; however, the isoform(s) required for the formation of other metabolites is still unknown. Overall, only around 7-8% of diazepam is biotransformed into two known metabolites. Due to the lack of inherent metabolism of diazepam in channel catfish, further analysis was conducted to determine the tissue-specific bioconcentration potential of diazepam in catfish. Various tissues were analyzed for the presence of diazepam as well as metabolites and bioconcentration factors (BCF) were calculated, which were all well below regulatory threshold values (> 2000). Additionally, modulation of the endocrine system by diazepam was examined by measuring steroid hormone concentrations and analyzing mRNA expression of selected steroidogenic enzymes and receptors. Two steroidogenic enzymes were modulated following diazepam exposure, indicating potential endocrine disrupting properties of diazepam. Together, these data suggest that diazepam exhibits low metabolic transformation rates in channel catfish, which may lead to accumulation of benzodiazepine compounds that may negatively affect the endocrine system. However, further studies should be aimed at identifying other steroidogenic enzymes and/or receptors that may be modulated following diazepam exposure.

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.