B. Kent Burnison

Detecting oil sands process-affected waters in the Alberta oil sands region using synchronous fluorescence spectroscopy.

Large volumes of oil sands process-affected waters (OSPW) are produced during the extraction of bitumen from oil sand. There are approximately 10(9) m(3) of OSPW currently being stored in settling basins on oil sands mining sites in Northern Alberta. Developers plan to create artificial lakes with OSPW and it is expected that this water may eventually enter the environment. This study was conducted in order to determine if synchronous fluorescence spectroscopy (SFS) could detect OSPW contamination in water systems. Water samples collected from ponds containing OSPW and selected sites in the Alberta oil sands region were evaluated using SFS with an offset value of 18 nm. OSPW ponds consistently displayed a minor peak at 282.5 nm and a broad major peak ranging between 320 and 340 nm. Water from reference sites within the oil sands region had little fluorescence at 282.5 nm but greater fluorescence beyond 345 nm. Naphthenic acids are the major toxic component of OSPW. Both a commercial naphthenic acid and a naphthenic acid extract prepared from OSPW had similar fluorescent spectra with peaks at 280 nm and 320 nm and minor shoulders at approximately 303 and 331 nm. The presence of aromatic acids closely associated with the naphthenic acids may be responsible for unique fluorescence at 320-340 nm. SFS is proposed to be a simple and fast method to monitor the release of OSPW into ground and surface waters in the oil sands region.

A toxicity identification evaluation approach to studying estrogenic substances in hog manure and agricultural runoff

Spreading liquid manure on agricultural fields is a routine way of disposing of animal manure and optimizing the use of nutrients for crops. Limited studies suggest that these wastes may contain a variety of endocrine-disrupting compounds (EDCs) that may be released into aquatic environments through runoff. The purpose of this study was to apply a toxicity identification and evaluation approach to isolate and identify estrogenic compounds in hog manure. A recombinant yeast estrogen screen bioassay was used to detect estrogenicity of high-performance liquid chromatography--separated hog manure fractions. Further analytical analyses of the fractions and comparison to authentic standards resulted in the identification of the endogenous estrogens 17 beta-estradiol (E2) and estrone, and the phytoestrogen metabolite, equol. High levels of equol (6.9-16.6 ppm) were found to be present in manure that was stored for several months. The endocrine-disrupting potential of equol was characterized further by using fish hormone estrogen receptor (ER), sex hormone binding protein (SSBP), and goldfish androgen receptor (AR) radioligand binding assays. Equol was found to be approximately 1,000- and 200-fold less potent that E2 in competing for binding sites of the SSBP and ER, respectively. Equols potency was 2,200-fold less than testosterone for the AR. Additional studies confirmed the presence of compounds with estrogenic activity in tile drain water after application of hog manure to an agriculture field. In this case, the contribution of equol to the total estrogenicity of the tile drain water was minimal relative to that of natural estrogens. Overall, this study indicates that further work is warranted to assess the impact that EDCs that originate from agricultural runoff may have on the ecology or physiology of exposed biota.

Interaction of cadmium toxicity in embryos and larvae of zebrafish (Danio rerio) with calcium and humic substances

The influence of humic substances (HS) and calcium (Ca) on cadmium (Cd) toxicity was determined using zebrafish (Danio rerio). Embryo and larvae of the zebrafish were exposed to various Cd concentrations (1.8; 2.8; 4.2; 6.2; 9.3 mg/l Cd) for 144 h. Combinations of low (0.2 mmol/l) and high (2 mmol/l) Ca, +HS (5 mg/l C) or -HS were used during Cd exposure. The toxicity of Cd was affected by (1) exposure concentration; (2) exposure time; (3) presence of HS; and (4) the Ca concentration. The results show that Ca and HS protect against Cd toxicity in zebrafish embryos. The best protection was in the high Ca-HS group, followed by high Ca+HS group and low Ca+HS group. The survival in the low Ca-HS group was the worse. Survival in the high Ca-HS group and the high Ca+HS group was similar with the exception of the highest Cd concentration (9.3 mg/l) where the survival of the high Ca+HS group was less than in the high Ca-HS group. The exposure system was modelled using a chemical equilibrium program (MINEQL+) to determine if the likely mechanism causing the anomalous result in the highest Cd concentration. The equilibrium model cannot explain these results, which suggests that this effect has a kinetic basis, such as time needed for Cd to displace Ca already bound by HS.

Fathead minnow (Pimephales promelas) reproduction is impaired when exposed to a naphthenic acid extract

Previous studies have demonstrated that oil sands process-affected water (OSPW) impairs the reproduction of fish and that naphthenic acids (NAs), a natural constituent of oil sands, are suspected of being responsible. This study evaluates the potential impact of NAs on the reproduction of adult fathead minnows (Pimephales promelas) under laboratory conditions. Fathead minnows exposed to a 10 mg/l naphthenic acid extract (NAE) for 21 days spawned fewer eggs and males had reduced expression of secondary sexual characteristics. Male fathead minnows exposed to a 5 mg/l NAE had lower plasma levels of 11-ketotestosterone whereas those exposed to a 10 mg/l NAE had lower concentrations of both testosterone and 11-ketotestosterone. Since OSPW also contains high concentrations of salts, this study also investigated whether they modify the toxicity of NAEs. Spawning was significantly reduced in fathead minnows exposed to a 10 mg/l NAE alone and in combination with NaHCO₃ (700 mg/l), typical of concentrations in OSPW(.) Interestingly, the addition of NaHCO₃ reduced the inhibitory effects of the NAE on the numbers of reproductive tubercles and plasma testosterone levels. Further studies showed that NaHCO₃ acted by reducing the uptake of the NAE to the fish. NaHCO₃ but not NaCl or Na₂SO₄ reduced the acute toxic effects of the NAE on fathead minnow embryo and larvae mortality. Collectively, these studies show that the NAs in OSPW have the potential to negatively affect reproduction in fathead minnows and that HCO₃⁻ reduces the acute and chronic toxicity of NAs.

Impact of natural organic matter (NOM) on freshwater amphipods

Natural organic matter (NOM) isolated from the eutrophic Sanctuary Pond (Point Pelee National Park, Canada) has an adverse impact on amphipod species (Gammarus tigrinus and Chaetogammarus ischnus from Lake Müggelsee, Germany, and Eulimnogammarus cyaneus, from Lake Baikal, Russia). Increases in amphipod mortality, changes in peroxidase activity and increases of heat shock protein (hsp70) expression were observed upon exposure to NOM. The highest resistance to the adverse impact of NOM was observed with the endemic Baikalian amphipod E. cyaneus. However, the mechanisms behind this finding remains obscure. If differences in the sensitivity of the hsp70 antibody may be excluded, different modes of action may be postulated: because the adverse impact of NOM may be caused by reactive oxygen species (ROS) and the NOM itself, the observed differences may be due to the action of ROS alone (with E. cyaneus) and a combination of both adverse modes of action (European species).

Transmission electron microscopy of the natural organic matter of surface waters.

Abstract Some components of aquatic natural organic matter (NOM) can be analysed effectively by methods of particle analysis employing transmission electron microscopy in conjunction with multi-method analytical approaches in the field, minimum perturbation techniques for sample handling and technology transfer from the biomedical sciences. The NOM components, include fulvic acids, colloidal fibrils and organic polymers of MW > 30 000. The use of a water-compatible embedding resin permits shape and size analyses of colloidal NOM (1–1000 nm) in ultrathin sections which minimize the misleading dehydration artifacts of the past. Experimentally induced perturbations allow one to follow aggregation/coagulation events at 1 nm resolution, while permitting the analyst to relate some components of coagulum structure to chemical entities. This review presents the current status of attempts to optimize a combination of analytical chemistry and transmission electron microscopy for describing NOM and its behaviour in surface waters.

Use of a (Quantitative) Structure–Activity Relationship [(Q)Sar] Model to Predict the Toxicity of Naphthenic Acids

Naphthenic acids (NA) are a complex mixture of carboxylic acids that are natural constituents of oil sand found in north-eastern Alberta, Canada. NA are released and concentrated in the alkaline water used in the extraction of bitumen from oil sand sediment. NA have been identified as the principal toxic components of oil sands process-affected water (OSPW), and microbial degradation of lower molecular weight (MW) NA decreases the toxicity of NA mixtures in OSPW. Analysis by proton nuclear magnetic resonance spectroscopy indicated that larger, more cyclic NA contain greater carboxylic acid content, thereby decreasing their hydrophobicity and acute toxicity in comparison to lower MW NA. The relationship between the acute toxicity of NA and hydrophobicity suggests that narcosis is the probable mode of acute toxic action. The applicability of a (quantitative) structure–activity relationship [(Q)SAR] model to accurately predict the toxicity of NA-like surrogates was investigated. The U.S. Environmental Protection Agency (EPA) ECOSAR model predicted the toxicity of NA-like surrogates with acceptable accuracy in comparison to observed toxicity values from Vibrio fischeri and Daphnia magna assays, indicating that the model has potential to serve as a prioritization tool for identifying NA structures likely to produce an increased toxicity. Investigating NA of equal MW, the ECOSAR model predicted increased toxic potency for NA containing fewer carbon rings. Furthermore, NA structures with a linear grouping of carbon rings had a greater predicted toxic potency than structures containing carbon rings in a clustered grouping.

Bioavailability, Trace Element Associations with Colloids and an Emerging Interest in Colloidal Organic Fibrils

There is an urgent need for environmental managers to understand better how to assess bioavailability as it relates to the physicochemical status of biologically-important trace elements in surface waters. As several of the chapters in this volume will show, it should be particularly revealing to improve our knowledge of the natural aquatic associations between trace elements and both true particles and colloids. More and more it is realized that such associations determine much of the specific nature of trace element speciation in surface waters.

The partitioning of fenvalerate to natural dissolved organic matter

Abstract The degree of association of the pyrethroid insecticide fenvalerate to dissolved organic matter (DOM) was measured with the reverse-phase partition coefficient ( K rp ) using Sep-Paks. Natural DOM of four size fractions ranging from 1 K molecular weight up to 1 μm was isolated from Jack Lake and Luther Marsh in Ontario, Canada, and compared to the commercial DOM substitute Aldrich humic acid (AHA). A generator column method to produce fenvalerate-saturated DOM solutions necessary for determining K rp was compared to the standard method of mixing the components in a bottle until equilibrium was reached. Using the bottle method, the association of fenvalerate to DOM was not significantly different (α = 0.05) for any of the DOM. With the generator column-produced solutions, the mean K rp of the smallest fraction (1 K 3 litres/kg, p 4 to 3.0 × 10 5 litres/kg). Jack Lake DOM had higher K rp values than Luther Marsh, which predominantly contained lower molecular weight DOM. The generator column method produced more precise K rp measurements between fenvalerate and DOM than the bottle method; however, the use of Sep-Paks to measure DOM association with hydrophobic chemicals which exhibit high breakthrough, such as fenvalerate, may produce questionable results.

Veränderung von Biokonzentration und Wirkung vom PSM in Anwesenheit von Huminstoffen

ZusammenfassungHuminstoffe, im Freiwasser im wesentlichen Fulvosäuren, können auf Organismen einen fördernden oder auch einen hemmenden Einflß ausüben. Dies wurde an bakterienhaltigen Algenkulturen, ebenso wie an Nematoden-Kulturen nachgewiesen. Die für derartige Effekte verantwortlichen Strukturelemente der Huminstoffe sind noch nicht bekannt.Fulvosäuren können ferner als Mediatoren für eine verstärkte Biokonzentration und—für aquatische Ökosysteme noch bedeutsamer —für die Zunahme von toxischen Wirkungen auftreten. Dies gilt nicht nur für den ökologisch unbedeutenden Fall von akut-toxischen Wirkungen, sondern insbesondere auch für subletale Langzeitwirkungen.AbstractHumic substances, in aqueous bodies primarily fulvic acids, may demonstrate an inhibitory as well as an activating influence on organisms. We present evidence with bacteria-containing algal cultures and with cultures of the nematodeCaenorhabditis elegans. Structural elements of the fulvic acids which may be responsible for such effects are not yet known.Furthermore, the presence of fulvic acids may lead to increases in bioconcentration of xenobiotics. Increase in the toxicity of xenobiotics in the presence of humic substances have also been described. We present studies applying lethal as well as sublethal toxicity endpoints.