Benzo[a]pyrene Equivalents Research Articles

Meteorological variations of PM 2.5/PM 10 concentrations and particle-associated polycyclic aromatic hydrocarbons in the atmospheric environment of Zonguldak, Turkey

Airborne particulate matter (PM 2.5 and PM 10) concentrations were measured in Zonguldak, Turkey from January to December 2007, using dichotomous Partisol 2025 sampler. Collected particulate matter was analyzed for 14 selected polycyclic aromatic hydrocarbons (PAHs) by high-performance liquid chromatography with fluorescence detection (HPLC-FL). The seasonal variations of PM 2.5 and PM 10 concentrations were investigated together with their relationships with meteorological parameters. The maximum daily concentrations of PM 2.5 and PM 10 reached 83.3 μg m −3 and 116.7 μg m −3 in winter, whereas in summer, they reached 32.4 μg m −3 and 66.7 μg m −3, respectively. Total concentration of PM 10-associated PAHs reached 492.4 ng m −3 in winter and 26.0 ng m −3 in summer times. The multiple regression analysis was performed to predict total PM 2.5- and PM 10-associated PAHs and benzo( a)pyrene-equivalent (BaPE) concentrations with respect to meteorological parameters and particulate mass concentrations with the determination coefficients ( R 2) of 0.811, 0.805 and 0.778, respectively. The measured mean values of concentrations of total PM 2.5- and PM 10-associated PAHs were found to be 88.4 ng m −3 and 93.7 ng m −3 while their predicted mean values were found to be 92.5 ng m −3 and 98.2 ng m −3, respectively. In addition, observed and predicted mean concentration values of PM 2.5-BaPE were found to be 14.1 ng m −3 and 14.6 ng m −3. The close annual mean concentrations of measured and predicted total particulate related PAHs imply that the models can be reliably used for future predictions of particulate related PAHs in urban atmospheres especially where fossil fuels are mainly used for heating.

Particle-associated polycyclic aromatic hydrocarbons in the atmospheric environment of Zonguldak, Turkey

Airborne fine (PM 2.5) and coarse (PM 2.5–10) particulate matter was collected from January to December in 2007 in Zonguldak, Turkey using dichotomous Partisol 2025 sampler. Fourteen selected polycyclic aromatic hydrocarbons (PAHs) in particulate matter were determined simultaneously by high-performance liquid chromatography with fluorescence detection (HPLC-FL) and seasonal distributions were examined. The source identification of PAHs in airborne particulates was performed by principal component analysis (PCA) in combination with diagnostic ratios. The predominant PAHs determined in PM 2.5 were pyrene, fluoranthene, benzo[ a]anthracene, chrysene, benzo[ b]fluoranthene and benzo[ a]pyrene. The total concentrations of PAHs were up to 464.0 ng m − 3 in fine and 28.0 ng m − 3 in coarse fraction in winter, whereas in summer times were up to 22.9 and 3.0 ng m − 3 respectively. Approximately 93.3% of total PAHs concentration was determined in PM 2.5 in winter and 84.0% in summer. The concentration levels of PAHs fluctuate significantly within a year with higher means and peak concentrations in the winter compared to that of summer times. Higher benzo( a)pyrene-equivalent (BaPE) concentrations of PAHs were obtained for PM 2.5 especially in winter. The results obtained from PCA in combination with diagnostic ratios revealed that coal combustion and vehicle emissions were the major pollutant sources for both PM 2.5 and PM 2.5–10 associated PAHs in studied area. Two principal components for PM 2.5 and three for PM 2.5–10 were identified and these accounted for 89.4 and 85.2% of the total variance respectively. The emissions from coal combustion were estimated to be the main source of PAHs in the ambient air particulates with contributions of 80.8% of total variance for PM 2.5 and 53.8% for PM 2.5–10.

Indoor Levels of Polycyclic Aromatic Hydrocarbons in Homes with or without Wood Burning for Heating

The aim of this study was to investigate the impact of domestic wood burning on indoor levels of polycyclic aromatic hydrocarbons (PAHs). Indoor and outdoor concentrations of 27 PAHs were measured during wintertime in homes with (n= 13) or without (n 0) wood-burning appliances and at an ambient site in a Swedish residential area where wood burning for space heating is common. Twenty-four hour indoor levels of anthracene, benzo(ghi)fluoranthene, cyclopenta(cd)pyrene, benz(a)anthracene, chrysene/triphenylene, benzo(a)pyrene (BaP), indeno(1,2,3-cd)pyrene, benzo(ghi)perylene, and coronene were significantly (about 3- to 5-fold) higher in homes with, compared with homes without, wood-burning appliances. The outdoor levels of PAHs were generally higher than the indoor levelsfor all PAHs exceptforthe methylated phenanthrenes. The total PAH cancer potency (sum of BaP equivalents) was significantly higher (about 4 times) in the wood-burning homes compared with the reference homes, with BaP being the largest contributor, while phenanthrene made the largest contribution to the total PAH concentration in indoor and outdoor air. The median indoor BaP level in the wood-burning homes (0.52 ng/m3) was 5 times higher than the Swedish health-based guideline of 0.1 ng/m3, which was also exceeded outdoors on all days (median 0.37 ng/m3).

RELATIVE IMPACT OF COEXPOSURE COMPARED TO SINGLE-SUBSTANCE EXPOSURE ON THE BIOTRANSFORMATION AND TOXICITY OF BENZO[a]PYRENE AND FLUORANTHENE IN THE MARINE POLYCHAETE CAPITELLA SP. I

Most biotransformation studies to date have concentrated on single-substance exposures. The biotransformation ability of organisms exposed to a single substance, however, may differ from that of organisms coexposed to binary or complex mixtures. The marine polychaete Capitella sp. I was exposed to either 31 microg/g dry weight sediment of benzo[a]pyrene (BaP) in a single-substance exposure or to a mixture of 31 and 28 microg/g dry weight sediment of BaP and fluoranthene (Flu), respectively (coexposure). Biotransformation capability and DNA damage were compared between treatments. Worms exposed to BaP alone accumulated total BaP equivalents to a significantly higher degree than coexposed worms (final body burden: 117.14 +/- 3.52 microg BaP equivalents/g dry wt tissue and 69.78 +/- 8.58 microg BaP equivalents/g dry wt tissue, respectively), probably because of a higher degree of BaP biotransformation in the latter. In addition, a larger percentage of the accumulated BaP equivalents was in the form of parent compound in worms exposed to BaP alone compared to coexposed worms on day 10 (87 and 56%, respectively). In coexposed worms, Flu was both accumulated and biotransformed to a considerably greater degree than BaP (final Flu body burden: 181.85 +/- 18.46 microg Flu equivalents/g dry wt tissue, 24% as parent compound). Neither treatment resulted in significant effects on growth or DNA damage. The present study shows that the extent to which bioaccumulation factors estimated from single-substance exposures have relevance for the field situation will depend on the degree to which accumulation is influenced by the presence of other contaminants. These results therefore are relevant for assessing risks from contaminated sediments.

Distribution, sources, and potential risk of polycyclic aromatic hydrocarbons (PAHs) in drinking water resources from Henan Province in middle of China

Distribution and risk assessment of polycyclic aromatic hydrocarbons (PAHs) in drinking water resources have been carried out for the first time in Henan Province, China. Water samples collected from four river systems and their tributaries, as well as groundwater resources, were analyzed according to EPA method 525.2. Total of 68 water samples were collected in 18 cities in Henan province in May, August and November, 2001. Concentrations of sum of 16 priority PAHs in water samples ranged from 15 to 844 ng/L with a mean value of 178 +/- 210 ng/L (n = 68). The spatial and temporal distribution of PAHs showed that the Huanghe and the Huaihe river systems had relatively higher concentrations of total PAHs. Higher concentrations of total PAHs were observed in August and November than in May, with respective mean values of 262, 232 and 33.6 ng/L. Ratios of Ant/(Ant + Phe) and Flur/(Flur + Pyr) were calculated to evaluate the possible sources of PAH contamination, which indicated that the coal combustion sources were the main contributors to PAHs in most drinking water resources. Some petrogenic (or pyrolytic) sources of PAHs were also found. The toxic equivalency factors (TEFs) were used to calculate benzo[a]pyrene equivalents (BaPE) for water samples. The average value of BaPE was 0.6 ng/L. The values in most stations were much lower than the guideline values in drinking water of Chinese Environmental Protection Agency (CEPA, 2.8 ng/L) and the US Environmental Protection Agency (US EPA, 200 ng/L). Overall, the drinking water resources in Henan province showed some carcinogenic potential.

Polycyclic aromatic hydrocarbons in marine organisms from the Adriatic Sea, Italy

Polycyclic aromatic hydrocarbons (PAHs) were analyzed in bivalves ( Mitylus galloprovincialis), cephalopods ( Todarodes sagittatus), crustaceans ( Nephrops norvegicus) and fish ( Mullus barbatus, Scomber scombrus, Micromesistius poutassou, Merluccius merluccius) in several pools coming from the Central Adriatic Sea. These marine organisms were selected because of their multitude, wide distribution and common use in the Italian diet, they were sampled and analyzed during the year 2004. Acenaphthene, benzo( a)pyrene, dibenz( a, h)anthracene, benzo( ghi)perylene and indeno(1,2,3- cd)pyrene showed levels below the instrumental detection limit in all samples. Fluorene, phenanthrene, anthracene, fluoranthene, benz( a)anthracene, benzo( b)fluoranthene and benzo( k)fluoranthene were detected at different concentrations in analyzed samples. Chrysene was detected only in mussels with very low values (average 0.74 ng g −1 wet weight). PAHs composition pattern was dominated by the presence of PAHs with 3-rings (62%) followed from those with 4-rings (37%) and 5-rings (1%). Atlantic mackerel, European hake and blue whiting showed the highest PAH concentrations, ranging from 44.1 to 63.3 ng g −1 wet weight, the group of invertebrate organisms showed a level of contamination about three times lower than those of the vertebrate groups. Mediterranean mussels that did not present very high levels of contamination expressed as sum of PAHs showed one of the highest values of benzo( a)pyrene equivalents (BaPEs). Conversely the latter value was very low in Atlantic mackerel even if this species reported the highest total PAH concentrations. No significant correlation was observed between weight, length and trophic levels and total PAHs.

Particulate polycyclic aromatic hydrocarbons and n-alkanes in recycled paper processing operations

The aliphatic and polycyclic aromatic fractions of dust collected in the vicinity of recycled paper processing operations were analyzed using gas chromatography/mass spectrometry. Total measured dust concentration (up to 8.73+/-2.02 mg/m3) fluctuated substantially in the different steps of paper manufacture. This was attributed to the type of the operation such as, the release of fibers and particles during paper cutting and the use of reactive chemicals and excessive water under high temperature and pressure during the bleaching and the water rinsing/drying step. Particulate polycyclic aromatic hydrocarbons (PAHs) (from fluorene to benzo[ghi]perylene with mean concentrations from 3.8+/-0.5 to 41.4+/-0.4 ng/m3) and the unresolved mixture of branched, cyclic and unsaturated hydrocarbons (UCM) were measured in all samples while, n-alkanes from n-C20 to n-C27, were only observed in cutting and packaging areas (from 180.6+/-18.9 to 4297.9+/-794.9 ng/m3). The profile of occupational PAHs in bleaching and treatment of contaminated recycled raw paper was comparable to that observed for anthropogenic activities. The values of molecular diagnostic ratios indicated the contribution of oil residues and emissions from worklifts and other equipment used for pulp and paper handling. Total benzo[a]pyrene-equivalent (BaP) concentrations of particulate PAHs (varied from 323 up to 1104 pg/m3), provided evidence that workers were exposed to high quantities of PAHs as compared with exposures to urban air and other indoor settings, posing long-term threat to their health.

Metabolites in bile of fish from São Sebastião Channel, São Paulo, Brazil as biomarkers of exposure to petrogenic polycyclic aromatic compounds

This study reports the analysis of polycyclic aromatic compound (PAC) metabolites, as biomarkers of exposure to PACs in marine environment. PAC metabolites were measured in bile samples from 14 species of demersal fish caught in the São Sebastião Channel (SSC), SE Brazilian coastline. Naphthalene (NPH) equivalents, phenanthrene (PHN) equivalents, and benzo[ a]pyrene (BaP) equivalents were quantified using a reverse-phase high-performance liquid chromatography coupled with fluorescence detection method. For all samples, the means (±standard deviation, n = 37) of concentrations obtained for NPH, PHN, and BaP equivalents were, respectively, 290,000 ± 200,000 ng/g, 18,000 ± 14,000 ng/g, and 970 ± 1900 ng/g. These results indicate recent exposure of these fish to PACs in their environment. In addition, two species ( Cyclichthys spinosus and Prionotus nudigula) of fish were analyzed in order to investigate local sources of PAC contamination in the SSC and the influence of the petroleum terminal in fish caught in remote areas. The results showed that these fish species potentially migrate along the channel, especially P. nudigula. Correlations among groups of PAC metabolites indicate the same petrogenic source for NPH and PHN equivalents and a combustion source (e.g., automobile, ships) for BaP equivalents. The ratio BaP/PHN equivalents (0.05 ± 0.07, n = 37) confirms the predominance of petrogenic PACs for contamination by these chemicals in this region.

Development of an Immunoassay for the Determination of Polyaromatic Hydrocarbons in Plasma Samples from Oiled Seabirds

External exposure assessment of oiled seabirds is undertaken by assessment of the percentage oil coverage of the plumage. Nondestructive monitoring of the toxic fraction of petroleum oils and diesels (polyaromatic hydrocarbons, PAHs) which enters the general circulation (internal exposure burden) of oiled seabirds is rarely undertaken. This is because the traditionally used chromatographic methods for plasma PAH analysis require larger sample volumes than those that can be safely collected from smaller species, such as guillemots (Uria aalge). Furthermore, these methods are not a cost-effective or practical approach for analysis of large numbers of birds in a short time period as part of an oil spill response in wildlife rehabilitation centers. This study describes the modification and validation of a commercially available PAH immunoassay (cRaPID PAH) to enable high-throughput, cost-effective, simple, and rapid determination of total PAH concentrations in 50 microL volumes of plasma. The limit of detection of the assay was 0.1 ng/mL as benzo-apyrene (BaP) equivalents with a working range of 0.120 ng/mL. As further validation of the immunoassay, PAHs were determined by GC-MS. GC-MS data were significantly positively correlated with corresponding immunoassay data for the same birds (r2 = 0.976, p < 0.001). The plasma PAH concentrations of 40 oiled guillemots stranded on U.K. shores were determined using the assay to demonstrate its usefulness for biomonitoring studies. The mean ,PAH concentration observed was 1.05 +/- 0.67 ppm (range 0.02-2.40 ppm as BaP equivalents). The modifications to the cRaPID PAH kit in this study enable nondestructive, high-throughput, semiquantitative determination of PAH concentrations in plasma samples suitable for exposure assessment of oiled seabirds during oil spill response and rehabilitation.

POLYCYCLIC AROMATIC HYDROCARBONS IN BALTIC SEA BIVALVES

Concentrations of parent polycyclic aromatic hydrocarbons (PAHs) in the bivalves Macoma balthica and Astarte borealis were studied as an indication of the state of the Baltic Sea. Samples were collected between 1999 and 2001 from the Gulf of Finland, the Eastern Gotland Basin, and the Southern Baltic Proper. PAHs were quantified by liquid chromatography with fluorescence detection. The sum of 12 PAHs varied between 44 and 298 ng/g (ww), with the most contaminated bivalves found in Hanö Bight (the Bornholm basin). High-molecular-weight PAHs predominated among the PAHs. The PAH profiles of M. balthica differed from those determined in sediment from the same area. Both pyrolytic and petrogenic origins were indicated. Toxic equivalency factors evaluated as benzo[a]pyrene equivalents (BaPEs) were used to assess the PAH contamination. BaPEs were higher than values for M. balthica found in the southern part of the Gulf of Finland in 1995 and much lower than values measured in 1987 after the most serious oil spill in the Gulf of Finland in the past 25 years.

Ecotoxicological Risks Associated with Land Treatment of Petrochemical Wastes. I. Residual Soil Contamination and Bioaccumulation by Cotton Rats (Sigmodon Hispidus)

Petrochemical waste contains both organic and inorganic contaminants that can pollute soil and may pose significant ecological risks to wildlife. Petrochemical waste typically is disposed of in land treatment units, which are widespread throughout Oklahoma and the United States. Few studies have been conducted evaluating possible toxicity risks to terrestrial organisms residing on these units. In this study, the extent of soil contamination with fluoride (F), metals, and organic hydrocarbons, the bioaccumulation of F and metals in cotton rats (Sigmodon hispidus), the relationship between contaminants in soil and in tissues of cotton rats, and the level of potentially toxic polycyclic aromatic hydrocarbons (PAHs) in soil were determined on land treatment units. Over a 2-yr period, cotton rats and soils were collected and analyzed from 5 land treatment and matched reference units. The number of land treatment units with soil metal contamination (in parentheses) included: Cr, Cu, Pb (5); Al, As, Ni, Sr, Zn (4); Ba (3); and Cd, V (2). The number of land treatment units with soil PAH contamination (in parentheses) were naphthalene, phenanthrene, benzo[g,h,i]perylene (3); acenaphthene, anthracene, pyrene, benz[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[a]pyrene, indeno[1,2,3-c,d]pyrene, dibenz[a,h]anthracene (2); and acenaphthylene, fluorene, fluoranthene, benzo[k]fluoranthene (1). Total PAH and total petroleum hydrocarbons (TPH) were elevated at all five land treatment units. Mean sums of benzo[a]pyrene (BaP) equivalents (BaP equiv ) were not affected on land treatment units as compared to reference units. Units 1 and 3 were significantly higher in levels of metals, total PAH, TPH, and BaP equiv than the other units. Pb and F bioaccumulated in bone and Pb bioaccumulated in kidney of cotton rats. F in bone of 496 to 2212 mg/kg was 3- to 15-fold greater than mean F in bone of cotton rats from reference units. Elevated levels of Pb in bone of 4.6 to 24.8 mg/kg were 460- to 2500-fold greater than mean Pb in bone of cotton rats from reference units. Elevated levels of Pb in kidney of 0.31 to 1.08 mg/kg were 10- to 36-fold greater than mean Pb in kidney of cotton rats from reference units. Bone F was an accurate predictor of the severity of dental fluorosis. Strong relationships were found between bone F and HCl-extractable F and bone F and total F in soils of land-treatment units. A strong relationship was discovered between Pb in bone and Pb in soil. Land treatment appears to have been effective as a remediation technology in reducing levels of individual PAHs and the sum of BaP equivalents to background levels on units 2, 4, and 5 but not on units 1 and 3. This study shows that certain contaminants such as Pb and F tend to bioaccumulate in cotton rats collected from land treatment units. Land treatment was ineffective in reducing levels of these contaminants to background levels that will not pose an increase in risk to terrestrial mammals. Therefore, to avoid accumulation of these contaminants in cotton rats and their possible deleterious effects, these contaminants should be measured, and land application rates of petrochemical waste should be managed to avoid excessive loading into soil systems.

Distribution of cytochrome P4501A1-inducing chemicals in sediments of the Delaware River-Bay system, USA

The Delaware River-Bay system, USA, was the subject of a study by the National Oceanic and Atmospheric Administration that involved chemical and biological analyses, including the use of the biomarker P450 human reporter gene system (HRGS) to document the occurrence and distribution of cytochrome P450 (CYP) 1A1-inducing compounds. Sediment extracts from 81 locations along the Delaware River, Delaware Bay and immediate coastline were tested by utilizing HRGS as an inexpensive screening test, and were also analyzed for polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls, with selected stations analyzed for dioxins and furans. Benthic community degradation has been observed when benzo[a]pyrene equivalents (BaPEq) exceeded 60 microg/g. The average levels of BaPEq for the largely industrialized upper, middle, and lower regions of the Delaware River were 107, 62, and 5 microg/g, respectively, excluding outliers. Tributaries leading into river averaged 21 microg/g BaPEq, whereas the central Bay and open coast had relatively low values (2.0 and 0.5 microg/g BaPEq, respectively). The HRGS values were highly correlated with total PAHs measured in the same sediment samples (r2 = 0.81). Overall, contamination levels consistently decreased from the upper and middle river sites as collection locations progressed down through the lower river and bay to the coast. Thus, despite the relatively high contaminant load in the river system, Delaware Bay and the immediate coastline seem to have relatively low levels of contaminants, and, therefore, impacts on the benthic organisms in the bay and coast would not be expected from these findings.

DERIVATION OF SHELLFISH HARVEST REOPENING CRITERIA FOLLOWING THE NEW CARISSA OIL SPILL IN COOS BAY, OREGON

Oil spills in Alaska, California, Maine, and other states have raised concerns regarding potential contamination of fish and shellfish, and have led to temporary closures of seafood harvests while health risks are assessed. Lacking standardized protocols, these assessments are generally ad hoc, site-specific efforts, with significant differences in risk evaluation criteria. This article describes the response of a state health agency to shellfish contamination following an oil spill on the Oregon coast, and discusses some of the factors that can complicate the evaluation of potential health risks from consumption of oil-contaminated shellfish. On 4 February 1999, the Japanese-owned cargo ship M/V New Carissa, carrying an estimated 400,000 gallons of light diesel and heavy fuel oil, ran aground 2 miles north of Coos Bay, Oregon. Damage to the ship?s hull from the grounding and pounding surf caused the release of an estimated 25,000 to 70,000 gallons of oil. Concern for potential contamination of local recreational shellfish and commercial oyster beds prompted the Oregon Department of Agriculture (ODA) to close shellfish harvesting in Coos and Douglas counties. ODA requested assistance from the Oregon Health Division in the derivation of risk-based criteria for reopening the shellfish harvest. Criteria were developed for the primary contaminants of concern, polycyclic aromatic hydrocarbons (PAHs) expressed as total benzo[a]pyrene (BaP) equivalents. "Safe (<10 µg/kg) and "unsafe" (>45 µg/kg) BaP equivalent levels were derived based on upper end (32.5 g/d) and average (7.5 g/d) estimates of shellfish consumption, respectively. Composite samples of oysters, clams, and mussels (15?20 per composite) were collected from target areas and analyzed for PAHs by gas chromatography/mass spectroscopy (GC/MS). Carcinogenic PAHs were converted to total BaP equivalents (wet weight) and compared with criteria. Two oyster samples, collected from a slough off of Coos Bay, contained 33.9 and 34.5 µg/kg BaP equivalents; all other samples had less than 10 µg/kg BaP equivalents. An evaluation of the PAH profiles in the two higher oyster samples indicated a primary source other than the New Carissa oil. Because shellfish sample BaP equivalents attributable to the New Carissa oil spill did not exceed 10 µg/kg, shellfish harvesting was reopened on 4 March 1999. This study revealed some of the inherent difficulties in attempting to quantify health risks from contaminated shellfish following an oil spill and demonstrated the clear need for standardized protocols for responding to such events.

Lifetime health risk assessment from exposure of recreational users to polycyclic aromatic hydrocarbons.

In order to assess the lifetime risk of skin cancer for recreational users from dermal exposure to polycyclic aromatic hydrocarbons (PAHs), sediment samples were collected from beach sites along the St. Marys River near Sault Ste. Marie, Ontario, and in Hamilton Harbor and Toronto Harbor, Ontario, and analyzed for PAHs. Dermal exposure and lifetime skin cancer risk were estimated as follows: Concentrations of 11 PAHs with sufficient or limited evidence of carcinogenicity or mutagenicity were converted to benzo(a)pyrene (BaP) equivalents using toxic equivalency factors (TEFs). Lifetime dermal exposure values were derived based on the BaP equivalents in the silt + clay fraction taken as representative of suspended sediment particulates to which recreational users would be exposed. The lifetime health risk of skin cancer associated with such exposures was above the negligible risk level of 1.0 x 10(-6) at offshore Rytac, Lake George Channel, and Bell Point beaches in the St. Marys River; at Pier 4 Park in Hamilton Harbor; and at Humber Bay, Sunnyside Beach, Cherry Beach, and Water Rats Sailing Club in Toronto Harbor. Risk was negligible inshore at the Rytac and Bell Point beaches and at Squirrel Island and Ojibway Trailer Park along St. Marys River, at Lax Beach in Hamilton Harbor; and at Centre Island in Toronto Harbor. Strategies to reduce risk were developed with these communities; a key recommendation was to take a bath or shower within 24 h after a swim because virtually all the PAHs on the skin would be removed.

The role of water ventilation and sediment ingestion in the uptake of benzo[A]pyrene in gizzard shad (dorosoma cepedianum)

AbstractThe objective of this study was to determine whether sediment ingestion or water ventilation was the primary route of uptake for benzo[a]pyrene (BaP) in the gizzard shad (Dorosoma cepedianum), a detritivorous fish. Two experiments were conducted in which fish were exposed to sediments spiked with 1 μg/g BaP. In the first experiment, fish were prevented from feeding by esophagus ligation. In the second experiment, 20 nonligated fish and 30 ligated fish were added to the aquarium. The nonligated fish roiled the water as they fed. Fish were collected 4, 8, 15, and 22 d after the experiments began. Gizzard shad metabolize BaP; therefore, the concentrations of BaP equivalents (parent BaP plus metabolite) were determined. Concentrations of BaP equivalents were significantly greater in the ligated fish in experiment 2 relative to those in experiment 1. In contrast, the concentration of BaP equivalents in the ligated fish in experiment 2 was not significantly different than that in the nonligated fish. Our results suggest that ventilation of turbid water may be a significant source of BaP for gizzard shad. Sediment ingestion, however, does not appear to significantly influence the total body concentration of BaP equivalents in gizzard shad.

Dose- and time-dependent formation of benzo[a]pyrene metabolite DNA adducts in the spiny lobster, Panulirus argus

Because of the apparent resistance of crustaceans to tumors following exposure to chemical carcinogens such as polycyclic aromatic hydrocarbons (PAHs), it was of interest to examine the ability of a model crustacean to form DNA adducts of a model PAH, benzo[a]pyrene (BaP). In-vitro studies showed that under optimal conditions, spiny lobster hepatopancreatic cytochrome P450 could metabolize a low concentration of BaP (3·5 μm) to products that bound covalently to exogenous DNA. For in-vivo studies, [ 3H]-BaP was administered at doses of 4 to 450 μg/kg to groups of spiny lobsters, and animals were sacrificed at 3 or 28 days after the dose. In spiny lobsters sacrificed at 3 days after the dose, the dose—response curve for binding of BaP metabolites to hepatopancreatic DNA was roughly linear in the range 4–200 μg/kg. Binding ranged from 0·04 to 4·2 pmol BaP equivalents bound/mg DNA. Spiny lobsters given 20 μg BaP/kg and sacrificed at 28 days after the dose had less than 10% of the DNA adducts found 3 days after the dose. These results suggest that the hepatopancreas can efficiently eliminate BaP metabolite DNA adducts. This may in part explain the resistance of crustaceans to chemical carcinogenesis.

Metabolism and macromolecular covalent binding of benzo[ a]pyrene in cultured fischer-344 rat lung type II epithelial cells

Pulmonary biotransformation of many xenobiotics may be important for the mutagenic, carcinogenic and/or toxic response of lung tissue to these compounds. Recently, a lung epithelial cell line (designated LEC), with morphological characteristics suggestive of type II cell origin, was developed in our laboratory. When LEC cells were co-cultivated with Chinese hamster ovary (CHO) cells in a cell-mediated mutagenesis assay, LEC metabolized promutagens to metabolites mutagenic to the CHO cells [A. P. Li, A. L. Brooks, J. M. Benson and F. F. Hahn, Environ. Mutagen. 4, 407 (1982)]. In the present investigation, rates of benzo[ a]pyrene (BaP) metabolism in type II lung cells were determined, and the effects of various pollutants on rates of BaP metabolism and covalent binding of BaP to LEC macromolecules were measured. Cultures of LEC cells were incubated for 24 hr with 5 μM [ 14C]BaP, and the culture medium was analyzed for organic- and water-soluble metabolites. LEC cells metabolized BaP to BaP-7,8-diol and BaP-9,10-diol with total rates of formation of these metabolites measured at 500–600 pmoles per 10 6. cells per 24 hr. BaP-9,10-diol was the major metabolite accounting for about 80% of the total BaP metabolized. Enzyme hydrolysis studies revealed the presence of small quantities (less than 20% of BaP metabolized) of the glucuronide conjugates of BaP-7,8-diol and 9-hydroxy-BaP. Pretreatment of LEC cells with benz[ a]anthracene, coal gas condensate, or diesel exhaust particle extract (DEP) prior to incubation with BaP resulted in a 2- to 5-fold increase in overall rates of BaP metabolism. The largest increase in covalent binding of [ 14C]BaP equivalents to LEC macromolecules was seen after LEC cells were pretreated with DEP (3-fold). The data suggest that lung epithelial cells may play an important role in the biological fate of inhaled xenobiotics.

Effects of polychlorinated biphenyls and environmental temperature on in vitro formation of benzo[ a]pyrene metabolites by liver of trout ( Salmo gairdneri)

Rainbow trout ( Salmo gairdneri) held at 7° and 16° were given Aroclor 1254 (PCB) (10mg/kg body wt) via intraperitoneal injections. The binding of [ 3H]benzo[ a]pyrene (BaP) to deproteinized salmon sperm DNA was assayed (pmoles BaP equivalents per mg DNA per mg protein) using the post-mitochondrial supernatant (S 10) fractions from livers of fish at 24–168 hr after the PCB exposure. Liver enzymes from the untreated fish acclimated at 7° yielded an average binding value (0.37 ± 0.17) which was significantly greater (P < 0.05) than the value (0.07 ± 0.03) for untreated fish at 16°. Liver supernatant fractions from PCB-induced fish acclimated at 16° and sampled at 24–120 hr showed a substantial increase (P < 0.05) in the binding (average value 2.4 ± 1.8) compared to the value obtained with untreated fish at 16°. At 24, 48 and 120 hr after the PCB treatment of fish held at 7°, there was no significant increase in the binding value or extent of metabolism of BaP compared to that obtained with the untreated fish at 7°. However, at 168 hr, three of four fish at 7° responded to the PCB treatment with significantly (P < 0.05) increased binding values (3.3 ± 1.6). Chromatographic analyses of the ethyl acetate-soluble metabolites revealed that 3-hydroxy BaP and 7,8- and 9,10-dihydrodiols were the major metabolites; K-region metabolites were formed in trace amounts in untreated and PCB-treated fish at both temperatures. No marked qualitative differences were observed in metabolite profiles after the PCB treatment; however, overall metabolism of BaP and production of reactive metabolites by liver enzymes were considerably (P < 0.05) enhanced in the PCB-induced fish at both 7° and 16°.