Effects of Salinity and Temperature on the Bioavailability of Dispersed Petroleum Hydrocarbons to the Golden-Brown Algae, Isochrysis galbana

Comparative studies were done to determine the influence of a dispersant on the bioavailability of naphthalene from crude oil to the unicellular golden-brown algae, Isochrysis galbana, under changing temperature and salinity conditions. Conditions were selected to represent a range (two temperatures, 12 and 20°C, and two salinities, 22 and 34‰) encountered in Pacific waters, where extensive crude oil transport and refining occurs. Cells were exposed to laboratory preparations of either the water-accommodated fraction (WAF) of Prudhoe Bay crude oil (PBCO) or a dispersed oil (DO) mixture of PBCO and Corexit 9527? spiked with [U-¹⁴C]naphthalene. Uptake increased by as much as 50% in DO, 20°C exposures run at 22‰ (0.24 μmol naphthalene/g algae in WAF, 0.37 μmol naphthalene/g algae in DO) compared with comparable exposures at 34‰ (0.23 μmol naphthalene/g algae in WAF, 0.37 μmol naphthalene/g algae in DO). A 24-h bioaccumulation factor (BAF) calculated in the absence of steady state indicated increasing bioaccumulation with decreasing temperature. No significant variation in relative metabolite composition occurred under the different experimental conditions. Results of these experiments showed that the use of dispersants enhanced the uptake of naphthalene by microalgae under a variety of temperature and salinity conditions, independent of aqueous concentration. Received: 18 September 1997/Accepted: 5 February 1998     

Influence of a dispersant on the bioaccumulation of phenanthrene by topsmelt (Atherinops affinis)

Chemical dispersants enhance oil spill dispersion by forming water-accommodated micelles with oil droplets. However, how dispersants alter bioavailability and subsequent bioaccumulation of hydrocarbons is not well understood. Thus, the goal was to investigate the influence of a chemical dispersant on the disposition (uptake, biotransformation, and depuration) of a model hydrocarbon, [14C]-phenanthrene ([14C]PHN), by larval topsmelt (Atherinops affinis). Exposure was via aqueous-only or combined dietary and aqueous routes from a water-accommodated fraction (WAF) of Prudhoe Bay Crude Oil (PBCO) or a WAF of Corexit 9527-dispersed PBCO (DO). Trophic transfer was measured by incorporating into exposure media both a rotifer (Brachionus plicatilis) as food for the fish and a phytoplankton (Isochrysis galbana) as food for the rotifers. Short-term (4 h) bioconcentration of PHN was significantly decreased in topsmelt when oil was treated with dispersant (P < 0.05), but differences diminished after 12 h. When trophic transfer was incorporated, PHN accumulation was initially delayed but after 12 h attained similar levels. Dispersant use also significantly decreased the proportion of biotransformed PHN (as 9-phenanthrylsulfate) produced by topsmelt (P < 0.05). However, overall PHN depuration was not affected by dispersant use. Thus, chemical dispersant use in oil spill response may reduce short-term uptake but not long-term accumulation of hydrocarbons such as PHN in pelagic fish.     

Toxicity testing of crude oil and related compounds using early life stages of the crimson-spotted rainbowfish (Melanotaenia fluviatilis)

The toxicity of petroleum hydrocarbons to marine aquatic organisms has been widely investigated; however, the effects on freshwater environments have largely been ignored. In the Australian freshwater environment, the potential impacts of petroleum hydrocarbons are virtually unknown. The toxicity of crude oil and related compounds were measured in the sensitive early life stages of the crimson-spotted rainbowfish (Melanotaenia fluviatilis). Waterborne petroleum hydrocarbons crossed the chorion of embryonic rainbowfish, reducing survival and hatchability. Acute exposures resulted in developmental abnormalities at and above 0.5 mg/L total petroleum hydrocarbons (TPH). Deformities included pericardial edema, disturbed axis formation, and abnormal jaw development. When assessing the acute toxicities of the water-accommodated fraction (WAF) of crude oil, dispersants, dispersant-oil mixtures, and naphthalene to larval rainbowfish, the lowest to highest 96-h median lethal concentrations for day of hatch larvae were naphthalene (0.51 mg/L), dispersed crude oil WAF (DCWAF)-9527 (0.74 mg/L TPH), WAF (1.28 mg/L TPH), DCWAF-9500 (1.37 mg/L TPH), Corexit 9500 (14.5 mg/L TPH), and Corexit 9527 (20.1 mg/L). Using naphthalene as a reference toxicant, no differences were found between the sensitivities of larval rainbowfish collected from adults exposed to petroleum hydrocarbons during embryonic development and those collected from unexposed adults.     

Hsp60-Induced Tolerance in the Rotifer Brachionus plicatilis Exposed to Multiple Environmental Contaminants

Hsp60 induction was selected as a sublethal endpoint of toxicity for Brachionus plicatilis exposed to a water accommodated fraction (WAF) of Prudhoe Bay crude oil (PBCO), a PBCO/dispersant (Corexit 9527(R)) fraction and Corexit 9527(R) alone. To examine the effect of multiple stressors, exposures modeled San Francisco Bay, where copper levels are approximately 5 microgram/L, salinity is 22 per thousand, significant oil transport and refining occurs, and petroleum releases have occurred historically. Rotifers were exposed to copper at 5 microgram/L for 24 h, followed by one of the oil/dispersant preparations for 24 h. Batch-cultured rotifers were used in this study to model wild populations instead of cysts. SDS-PAGE with Western Blotting using hsp60-specific antibodies and chemiluminescent detection were used to isolate, identify, and measure induced hsp60 as a percentage of control values. Both PBCO/dispersant and dispersant alone preparations induced significant levels of hsp60. However, hsp60 expression was reduced to that of controls at high WAF concentrations, suggesting interference with protein synthesis. Rotifers that had been preexposed to copper maintained elevated levels of hsp60 upon treatment with WAF at all concentrations. Results suggest that induction of hsp60 by chronic low-level exposure may serve as a protective mechanism against subsequent or multiple stressors and that hsp60 levels are not additive for the toxicants tested in this study, giving no dose-response relationship. The methods employed in this study could be useful for quantifying hsp60 levels in wild rotifer populations.     

EROD Induction and Biliary Metabolite Excretion Following Exposure to the Water Accommodated Fraction of Crude Oil and to Chemically Dispersed Crude Oil

Immature Atlantic salmon (Salmo salar) were exposed to water accommodated fraction (WAF) of Bass Strait crude oil or to Corexit 9527–dispersed crude oil for 6 days, followed by a depuration period of 29 days. Serum sorbitol dehydrogenase (SDH) levels, indicator of liver damages, remained low during the experiment. Hepatic EROD activity was induced within 2 days following the onset of the exposure in both treatments, and persisted for 2–4 and 4–6 days after transfer to clean sea water in the WAF and dispersed oil treatment, respectively. Naphthalene-type metabolites, determined by fixed-wavelength fluorescence detection, appeared in the bile of the fish with 2 days' delay compared to EROD induction. In both treatments, EROD activity induction and levels of naphthalene-type metabolites in the bile were significantly related. The biliary levels of naphthalene-type metabolites were over 15 times higher in fish exposed to dispersed crude oil relative to fish exposed to the WAF of Bass Strait crude oil. BaP-type metabolites appeared only in the bile of the fish exposed to the WAF, possibly due to BaP-type compounds remaining associated with the dispersant in the water column or to an inhibition of Phase II detoxification enzymes by the dispersant. Bile metabolites as determined by fixed-wavelength fluorescence and EROD induction appear to be sensitive and complementary biomarkers of exposure to PAH. Received: 17 March 1999/Accepted: 7 June 1999     

Responses of embryonic and larval inland silversides,Menidia beryllina,to No. 2 Fuel oil and oil dispersants in seawater

Embryonic inland silversides, Menidia beryllina, in the early blastula stage were exposed to the water-soluble fraction (WSF) of No. 2 Fuel oil and the oil dispersants Corexit 7664^® and 9527^®, singly and in combination. An ordinal ranking system was used to score observed daily craniofacial, cardiovascular, and skeletal responses in control embryos and those exposed to 1%, 10%, and 100% concentrations of the WSF of No. 2 Fuel oil, the dispersants Corexit 7664^® and 9527^® applied at the recommended field application concentrations, and the combination of No. 2 Fuel oil and respective dispersants in seawater. The non-parametric Kruskal-Wallis analysis of variance (ANOVA) and post hoc analyses were used to identify statistically significant differences for control embryos and those exposed to No. 2 Fuel oil and dispersants.Embryos exposed to No. 2 Fuel oil in 20 salinity seawater showed significant (0.01) responses only at the 100% WSF concentration. Corexit 7664^® tested singly elicited significant responses at 10% and 100% concentrations. When No. 2 Fuel oil and Corexit 7664^® were combined at recommended field application concentrations of the dispersant, the oil and dispersant mixture resulted in significant (0.01) responses at 1%, 10%, and 100% exposure concentrations. In contrast, Corexit 9527^® did not cause significant responses at the three test concentrations of 1%, 10%, and 100% of the recommended field application rate. However, when No. 2 Fuel oil and Corexit 9527^® were combined in seawater, the 10% and 100% exposure concentrations resulted in statistically significant (0.01) embryonic responses, relative to controls. Chemical analyses indicated that both dispersants increased the total WSF of No. 2 Fuel oil in seawater.Contribution No. 897 of the Gulf Breeze Environmental Research Laboratory     

Oil and related toxicant effects on mallard immune defenses

A crude oil, a petroleum distillate, and chemically dispersed oil were tested for their effects on resistance to bacterial infection and the immune response in waterfowl. Sublethal oral doses for mallards were determined for South Louisiana crude oil, Bunker C fuel oil, a dispersant—Corexit 9527, and oil/Corexit combinations by gizzard intubation. Resistance to bacterial challenge (Pasteurella multocida) was significantly owered in mallards receiving 2.5 or 4.0 ml/kg of Bunker C fuel oil, 4.0 ml/kg of South Louisiana crude oil, and 4.0 ml/kg of a 50:1 Bunker C fuel oil/Corexit mixture daily for 28 days. Ingestion of oil or oil/Corexit mixtures had no effect on mallard antibody-producing capability as measured by the direct spleen plaque-forming assay.     

The influence of water temperature on induced liver EROD activity in Atlantic cod (Gadus morhua) exposed to crude oil and oil dispersants

Juvenile Atlantic cod were exposed to either the water-accommodated fraction (WAF) or the chemically enhanced water-accommodated fraction (CEWAF) of Mediterranean South American (MESA), a medium grade crude oil at three different temperatures. Two concentrations of each mixture were tested, 0.2% and 1.0% (v/v) at 2, 7 and 10 °C. Corexit 9500 was the chemical dispersant tested. The liver enzyme ethoxyresorufin-O-deethylase (EROD) was measured during a 72-h exposure. The WAF of oil had significant (P<0.05) effect on enzyme activity compared to controls at only one sampling time: 48 h at 10 °C. Exposure of CEWAF of oil resulted in significantly (P<0.05) elevated EROD activity compared to controls. The level of EROD induction was temperature related with higher induction being observed in cod exposed to CEWAF at higher temperatures. Total polycyclic aromatic hydrocarbon (PAH) concentrations in exposure water were significantly higher in chemically dispersed mixtures. While PAH concentrations were lower in the 2 °C water compared to 7 or 10 °C (8.7 vs 11.9 μg mL⁻¹), the level of EROD induction was approximately 9 and 12 times lower at 2 °C compared to 7 or 10 °C, respectively, suggesting the metabolic rate of the cod plays a role in the enzyme response. These data suggest the risk of negative impacts associated with exposure to chemically dispersed oil may be affected by water temperature and that risk assessment of potential effects of WAF or CEWAF should consider the effects of water temperature on the physiology of the fish as well as the effectiveness of dispersants.     

Comparative toxicity of two oil dispersants, superdispersant-25 and corexit 9527, to a range of coastal species

The acute toxicity of the oil dispersant Corexit 9527 reported in the literature is highly variable. No peer-reviewed data exist for Superdispersant-25 (SD-25). This study compares the toxicity of the two dispersants to a range of marine species representing different phyla occupying a wide range of niches: The marine sediment-dwelling amphipod Corophium volutator (Pallas), the common mussel Mytilus edulis (L.), the symbiotic snakelocks anemone Anemonia viridis (Forsk?l), and the seagrass Zostera marina (L.). Organisms were exposed to static dispersant concentrations for 48-h and median lethal concentration (LC50), median effect concentration (EC50), and lowest-observable-effect concentration (LOEC) values obtained. The sublethal effects of 48-h exposures and the ability of species to recover for up to 72 h after exposure were quantified relative to the 48-h endpoints. Results indicated that the anemone lethality test was the most sensitive with LOECs of 20 ppm followed by mussel feeding rate, seagrass photosynthetic index and amphipod lethality, with mussel lethality being the least sensitive with LOECs of 250 ppm for both dispersants. The results were consistent with current theory that dispersants act physically and irreversibly on the respiratory organs and reversibly, depending on exposure time, on the nervous system. Superdispersant-25 was found overall to be less toxic than Corexit 9527 and its sublethal effects more likely to be reversible following short-term exposure.     

Investigating the Potential Impacts of Chlorophenols on the Lake Baikal (Siberia, Russia) Food Web by Employing Daphnia Grazing Bioassays and a Chlorella Growth Bioassay

A grazing bioassay was employed to assess the impacts of chlorophenols on Daphnia magna and Daphnia pulex. The effects of two chlorophenols, pentachlorophenol (PCP) and 4-chlorophenol, were investigated at concentrations of 0.001, 0.01, and 0.1 mg · L⁻¹ over a 96-h period. All tests were conducted in water from the southern basin of Lake Baikal (Siberia). For D. magna, grazing rates were significantly depressed after exposure to 0.001 mg · L⁻¹ of PCP for 48 h or to 0.01 mg · L⁻¹ of 4-chlorophenol for 96 h. However, neither chemical continued to depress filtering rates as either dose or time increased, thus effective concentrations (EC₅₀s) could not be determined. This prevents the use of this bioassay as a tool for assessing exposure to chlorophenols, but it is still useful in that it provides insight into potential ecological effects. In the case of D. pulex, depressed rates were also found at 0.001 mg · L⁻¹ of PCP after 48 h; due to problems with the control, no conclusions were drawn for the effect of 4-chlorophenol on this species. The growth rates of Daphnia's prey, Chlorella vulgaris, were also investigated in the presence of these chemicals; no observable effects were found at any concentration during the 96-h period, implying that ecosystem effects may be limited to higher trophic levels. Received: 28 November 1996/Accepted: 28 October 1997     

Toxicity and Pathogenicity Testing of the Insect Pest Control Fungus Metarhizium anisopliae

Renewed interest in the use of Metarhizium anisopliae and its toxins for insect control prompted the following safety assessment. A neutral extract (methylene chloride, pH 7.2), derived from M. anisopliae cultures, was evaluated for toxicity and mutagenicity using aquatic animal bioassays and the Ames test. The average LC₅₀ of the neutral extract obtained in static, acute 96-h tests conducted with ≤24-h-old Mysidopsis bahia was 2.41 mg L⁻¹. By partially purifying destruxins from the neutral extract, it was shown that destruxins alone were not responsible for the observed toxicity in mysids. The neutral extract was fetotoxic to developing grass shrimp, Palaemonetes pugio, and frog, Xenopus laevis, embryos; the LC₅₀ values were 52 and 32 mg L⁻¹, respectively. Eye spot abnormalities were observed in shrimp and frog embryos exposed to the neutral extract. In extract-exposed frog embryos, moderate to severe cranial, facial, and gut malformations were also observed. The neutral extract was toxic to juvenile mosquito fish, Gambusia affinis, at an LC₅₀ value of 141 mg L⁻¹. Adult female G. affinis surviving a 24-h exposure to 200 μg ml⁻¹ of the neutral extract produced healthy broods. After 3 months, no mortalities or adverse effects were observed in adult G. affinis fed a diet partially composed of a freeze-dried M. anisopliae culture. The neutral extract did not show mutagenicity in the Ames test using strains TA98 and TA100 with and without metabolic activation by rat liver S9. Significant (p  ≤ 0.05) mortalities were obtained when embryos of grass shrimp and inland silverside fish, Menidia beryllina, were exposed to the same lot of M. anisopliae conidiospores. Exposure of frog embryos to M. anisopliae conidiospores did not cause significant (p > 0.05) mortalities or malformations. Received: 31 October 1997/Accepted: 5 February 1998     

A review of the toxicity of chemical dispersants

Chemical dispersants are a mixture of various surfactants and solvents. Most dispersants are proprietary, and the complete composition is not often public knowledge. Chemical dispersants used for the cleanup and containment of crude oil toxicity became a major concern after the 2010 Deepwater Horizon oil crisis in the Gulf of Mexico. During the crisis, millions of liters of chemical dispersants (Corexit 9527 and 9500) were used--the largest known application of dispersants in the field. As of February 2011, 38 peer-reviewed articles were available on the toxicity of 35 different chemical dispersants. Nalco, BP, Shell, and Total Special Fluids manufacture a variety of chemical dispersants. Most notably, Nalco manufactures Corexit 9527 and 9500, and 19 miscellaneous dispersants are manufactured by others. Most studies examined the lethality of the dispersants. Several nonlethal end points were considered, including the effect on predator/prey recognition, enzyme activity changes, effects on hatchability, and the threshold for bradycardia. The animals studied included Daphnia (small planktonic crustaceans), anemones, corals, crustaceans, starfish, mollusks, fish, birds, and rats. Studies in birds and mammals are distinctly lacking. The variety of chemical dispersants, the variability in test methods, and the lack of distinct species overlap between studies make it difficult to compare and deduce which dispersant is most toxic and which is least. Here, we offer some attempt at comparing Corexit 9527 and 9500 (because these have had the largest field application), but significantly more research is needed before clear conclusions can be drawn.     

Correspondence between occupational exposure limit and biological action level values for alkoxyethanols and their acetates

Objectives: The Finnish occupational exposure limit (OEL) values for alkoxyethanols and their acetates were lowered in 1996. A reevaluation of the correspondence between the new OEL value and the biological action level (BAL) was thus needed. This study was conducted in silkscreen printing enterprises, where 2-alkoxyethanols and their acetates are mainly used as solvents. The air/urine correlations between 2-methoxyethylacetate, 2-ethoxyethylacetate, 2-butoxyethanol, 2-butoxyethylacetate, and 2-methoxyacetic (MAA), 2-ethoxyacetic (EAA), and 2-butoxyacetic acid (BAA) were evaluated on an individual and time-related basis at four different enterprises. Methods: Inhalation exposure to alkoxyalcohols and their acetates was monitored with diffusion badges (n = 38) for an entire work week. Urinary excretion of alkoxyacetic acids immediately after the shift and at 14–16 h after exposure (n = 112) was analyzed by a gas chromatograph equipped with a flame-ionization detector. Results: Inhalation exposure to 2-methoxyethylacetate at 0.5 cm³/m³ corresponded to MAA excretion of 3 mmol/mol creatinine in urine at 14 to 16 hours after exposure. The next-morning urinary EAA excretion of 37 mmol/mol creatinine corresponded to an 8-h 2-ethoxyethylacetate exposure of 2 cm³/m³ when all collected data were included. This average EAA excretion was 69% of the German BAT value and only 34% of the American biological exposure index (BEI) value. Urinary EAA excretion was 30–40% lower at the beginning of the work week than at the end of the work week. On the other hand, EAA excretion was 10–20% higher than that measured at 14–16 h after exposure. Urinary BAA excretion of 75 mmol/mol creatinine in postshift urine corresponded to an 8-h 2-butoxyethanol and 2-butoxyethylacetate exposure of 5 cm³/m³. This BAA excretion was 87% of the German BAT value. Conclusion: According to these results, it seems that the BAL for MAA and EAA should be 3 and 50 mmol/mol creatinine as measured at 14–16 h after exposure, respectively. The BAL value for BAA seems to be 70 mmol/mol creatinine in postshift samples. These recommendations are valid only if samples are collected at the end of the work week. Received: 29 January 1997 / Accepted: 2 July 1997     

Effects of Dispersant and Oil on Survival and Swimming Activity in a Marine Copepod

Knowledge of lethal and sublethal effects of crude oil and dispersants on mesozooplankton are important to understanding ecosystem impacts of oil spills in marine environments. Here we (1) establish median lethal concentrations for water accommodated fractions of Corexit EC9500A dispersant, MC-252 crude oil (WAF), and dispersed crude oil (CEWAF) for the coastal copepod Labidocera aestiva, and (2) assess acute effects on L. aestiva swimming activity. Mortality assays with L. aestiva support that copepods are more sensitive than other zooplankton taxa to dispersant toxicity, while WAF and CEWAF are generally similar in their toxicity to this copepod species and other zooplankton. Acute effects on L. aestiva activity included impaired swimming upon WAF and CEWAF exposure. These results highlight that copepods are particularly sensitive to dispersant exposure, with acute effects on survival most evident with dispersant alone, and on swimming behavior when dispersant is mixed with crude oil.     

Indoor exposure to polycyclic aromatic hydrocarbons and carbon monoxide in traditional houses in Burundi

Objectives: Wood combustion is used as a major energy source in African countries and could result in indoor, pollution-related health problems. This exploratory study was undertaken to estimate polycyclic aromatic hydrocarbon (PAH) and carbon monoxide exposure in individuals living in traditional rural houses in Burundi. Methods: Standard methods were used to determine indoor air concentrations of 12 PAHs, and carbon monoxide. The urinary excretion of 1-hydroxypyrene (1-OHP) was measured in occupants of traditional houses, and compared with that of individuals living in the town of Bujumbura, the capital of Burundi. Results: Mean airborne concentration of four volatile PAHs, naphthalene, fluorene, phenanthrene and acenaphthene, exceeded 1 μg/m³, and that of benzo(a)pyrene was 0.07 μg/m³. Naphthalene was by far the main PAH contaminant, with a mean concentration (±standard deviation) of 28.7 ± 23.4 μg/m³, representing on average 60–70% of total PAH concentration. Carbon monoxide mean concentration (±standard deviation) was 42 ± 31 mg/m³, and correlated with total PAH concentration. Geometric mean urinary 1-OHP excretion (range) in people living in traditional houses was 1.50 (0.26–15.62) μmol/mol creatinine, a value which is on average 30 times higher than that of people living in the capital (0.05 (0.009–0.17) μmol/mol creatinine). Conclusions: It appears that the substantially high concentrations of the studied contaminants constitute a potential health hazard to the rural population of Burundi. Received: 15 July 1999 / Accepted: 20 November 1999     

Skin absorption of the industrial catalyst dimethylethylamine in vitro in guinea pig and human skin, and of gaseous dimethylethylamine in human volunteers

Objectives: The aims of the study were threefold: to assess the skin uptake of the industrial catalyst dimethylethylamine (DMEA) (a) in vitro from water solutions by fresh guinea-pig and human skin specimens, (b) in gaseous form in vivo in human volunteers, and (c)␣to estimate the relevance of the uptake as an occupational hazard. Methods: Specimens from the in vitro and in vivo experiments were analysed by gas chromatography using a nitrogen-sensitive detector. Design: DMEA, diluted with water or isotonic saline solution was applied to fresh human or guinea-pig skin, mounted in Teflon flow-through cells with a perfusion fluid flow rate of 1.5 ml/h, samples being collected at 2-h intervals for 48 h. Three healthy male volunteers each had their right forearm exposed (in a Plexiglass chamber) for 4 h to DMEA at each of three different levels (250, 500 and 1000 mg/m³ air). Urine was collected up to 24 h after the start of each experiment. Results: DMEA penetrated both guinea-pig and human skin. The median steady-state flux and permeability coefficient (K _p) values, were 0.009 mg/cm² × h and 0.001 cm/h, respectively, for guinea-pig skin, and 0.017 mg/cm² × h and 0.003 cm/h, respectively, for human skin. The median uptake in the three volunteers at the different DMEA exposure levels (250, 500 or 1000 mg/m³) was 44, 64 and 88 μg, respectively. The median K _p for all experiments was 0.037 cm/h. Conclusion: Uptake of DMEA through the skin is of far less importance than simultaneous uptake via the airways. Thus, the amount of DMEA excreted in urine is a variable of limited use for the purposes of biological monitoring. Although a wide range of K _p values was obtained in the in vitro experiments, both for guinea-pig and human skin, there was no marked difference in median K _p values between the two types of skin. The K _p values were lower than those obtained for human forearm skin in vivo. However, future studies of other tertiary aliphatic amines may show the in vitro␣method to yield values predictive of those obtained in in vivo studies. Received: 20 May 1996 / Accepted: 10 March 1997     

Biological monitoring of triethylamine among cold-box core makers in foundries

Objectives: The objectives of the study were to assess triethylamine (TEA) exposure in cold-box core making and to study the applicability of urinary TEA measurement in exposure evaluation. Methods: Air samples were collected by pumping of air through activated-charcoal-filled glass tubes, and pre- and postshift urine samples were collected. The TEA concentrations were determined by gas chromatography. Design: Tea was measured in air and urine samples from the same shift. Breathing-zone measurements of 19 workers in 3 foundries were included in the study, and stationary and continuous air measurements were also made in the same foundries. Pre- and postshift urine samples were analyzed for their TEA and triethylamine-N-oxide (TEAO) concentrations. Results: The TEA concentration range was 0.3–23 mg/m³ in the breathing zone of the core makers. The mean 8-h time-weighted average exposure levels were 1.3, 4.0, and 13 mg/m³ for the three foundries. Most of the preshift urinary TEA concentrations were under the detection limit, whereas the postshift urinary TEA concentrations ranged between 5.6 and 171 mmol/mol creatinine. The TEAO concentrations were 4–34% (mean 19%) of the summed TEA+TEAO concentrations. The correlation between air and urine measurements was high (r = 0.96, P < 0.001). A TEA air concentration of 4.1 mg/m³ (the current ACGIH 8-h time-weighted average threshold limit value) corresponded to a urinary concentration of 36 mmol/mol creatinine. Conclusions: The TEA exposure levels of foundries and their core makers vary greatly. Stationary air measurements in factories are not sufficient to assess TEA exposure; instead, personal sampling is needed. The biological monitoring of TEA in postshift urine samples provides a practical and accurate method for assessing exposure. Received: 9 May 1997 / Accepted: 27 August 1997     

Toxicity of petroleum crude oils and their effect on xenobiotic metabolizing enzyme activities in the chicken embryo in ovo

Microliter quantities of a Prudhoe Bay crude oil (PBCO) applied to the shell of fertile chick eggs during various stages of development induced cytochrome P-450 levels and mixed-function oxidase activities within the liver of the embryo. PBCO (5 microliter) applied on Day 11 of incubation was found to maximally induce within 24 hr embryo hepatic cytochrome P-450 levels (fourfold), naphthalene hydroxylase (sixfold), benzo[a]pyrene 3-hydroxylase (14-fold), and 7-ethoxyresorufin O-deethylase (24-fold). Glutathione S-transferase was not induced. Crude oils are known to be highly toxic to avian embryos, especially during the early stages of development. The LD50 of PBCO and Hibernia crude oil applied to the egg shell on Day 8 of incubation was found to be 1.3 and 2.2 microliter, respectively. Mixed-function oxidase-dependent metabolism of crude oil components may be required for toxicity since administration of 20 micrograms of disulfiram in dioxane 1 hr prior to application of 1.3 microliter of PBCO reduced embryo mortality from 60 to 20%.     

Cytochrome P4501A Induction and Porphyrin Accumulation in PLHC-1 Fish Cells Exposed to Sediment and Oil Shale Extracts

The present study describes the use of a fish hepatoma cell line (PLHC-1) in monitoring the biological effects of sediments collected from recipient waters of the oil shale industry. Sampling sites were located in River Purtse and River Kohtla in northeast Estonia. The effects of pure oil shale on the PLHC-1 cells were also studied. The cells were exposed to n-hexane–extracted samples in 48-well plates for 24 h, and 7-ethoxyresorufin O-deethylase (EROD) activity, total protein, and porphyrin content were measured in the exposed cells. Polycyclic aromatic hydrocarbon (PAH) contents in the samples were measured by high-performance liquid chromatography (HPLC). All the sediment and oil shale samples induced CYP1A activity and led to porphyrin accumulation in the cells. The most potent inducers were the sediments collected near the oil shale processing plants (site Lüganuse in River Purtse and Kohtla in River Kohtla), as well as those at the most downstream site in River Purtse (Purtse). These samples possessed high total PAH contents, ranging from 4,270 to nearly 150,000 μg/kg dry sediment. The presence of other lipophilic organic contaminants in the samples was not determined in this study. Both EROD activity and porphyrin content exhibited biphasic induction curves, and the ED₅₀ ¹ values for EROD activity were lower than the ED₅₀s for porphyrin content. 2,3,7,8-Tetrachlorodibenzo-p-dioxin induction equivalents (TCDD-EQs) calculated from EROD induction potencies correlated well with total PAHs (r ² = 0.827 and p = 0.003 for log-transformed data) and also with individual PAHs. TCDD-EQs for porphyrin content did not correlate significantly with total PAHs (log-log r² = 0.785, p = 0.116). The biological potency and PAH contamination of the samples showed the same rank order, except at Lüganuse, where sediment extracts induced CYP1A and porphyrins more than could have been expected based on PAH contents. Bioassay-derived induction EQs (normalized to dibenz(a,h)anthracene) were 20- to 3,200-fold greater than EQs calculated from the concentrations of five PAHs, suggesting important contributions from other compounds or nonadditive effects. The PLHC-1 cells proved to be a sensitive bioanalytical tool for sediments contaminated with PAH-type pollutants in the oil shale processing area. We suggest further use of this bioassay in screening and monitoring waters with similar background of pollution as in northeast Estonia. Received: 24 August 1998/Accepted: 22 July 1999     

Biomonitoring of exposure to ethylene oxide and propylene oxide by determination of hemoglobin adducts: correlations between airborne exposure and adduct levels

Objectives: Ethylene oxide (EO) and propylene oxide (PO) are important industrial chemicals. Exposure to these directly acting mutagens may be monitored by determination of their adducts to hemoglobin (Hb). This study establishes correlations between airborne concentrations of EO and PO and their Hb adducts in petrochemical workers. Methods: In three different studies conducted during maintenance shutdown of petrochemical plants the external occupational exposure to EO and PO was assessed by personal air monitoring (PAM). The internal exposure to EO and PO was concomitantly assessed by determination of N-(2-hydroxyethyl)valine (HOEtVal) and N-(3-hydroxypropyl)valine (HOPrVal) in blood samples of the operators using the N-alkyl-Edman degradation method. Results: In the first study, PAM was applied once a month at random over a period of 4 months. Blood samples for Hb-adduct determination were collected at the end of this period. No significant correlation was found between PAM and Hb-adduct data. In the next two studies, PAM was applied to the operators during the entire shift on every working day during the shutdown. Blood samples were collected before and immediately after the shutdown period. Highly significant correlations were found between the increment in the concentration of HOEtVal and HOPrVal over this period and the total exposure to EO and PO, respectively. Conclusions: Time-integrated exposure to EO or PO can be readily and reliably assessed by measurement of the concentration of HOEtVal or HOPrVal in a small blood sample. In workers occupationally exposed to low concentrations of EO or PO, good correlations were found between these Hb adducts and the airborne concentrations of EO and PO. These correlations allow the calculation of tentative biological exposure limits (BELs) for EO and PO. At the current Dutch occupational exposure limit (OEL) for EO (0.84 mg m⁻³, 8-h TWA) the BEL is 3.2 nmol HOEtVal/g globin. At the value of 10 mg m⁻³ (8-h TWA), which is currently being investigated as the new Dutch OEL for PO, the corresponding BEL is 5.3 nmol HOPrVal/g globin. Received: 28 July 1998 / Accepted: 28 November 1998