Bioaccumulation Of Polycyclic Aromatic Hydrocarbons Research Articles

Bioaccumulation of Polycyclic Aromatic Hydrocarbons in Tissues (Gills and Muscles) of (Catfish) Chrysichthys nigrodidatatus from Crude Oil Polluted Water of Ogoniland, River State, Nigeria

Bioaccumulation of Polycyclic Aromatic Hydrocarbons in Tissues (Gills and Muscles) of (Catfish) Chrysichthys nigrodidatatus from Crude Oil Polluted Water of Ogoniland, River State, Nigeria

ОЦЕНКА ПОКАЗАТЕЛЕЙ ЗАГРЯЗНЕНИЯ ТУНДРОВЫХ ФИТОЦЕНОЗОВ ПОЛИЦИКЛИЧЕСКИМИ АРОМАТИЧЕСКИМИ УГЛЕВОДОРОДАМИ

14 structures of polycyclic aromatic hydrocarbons (PAHs) were identified in the organogenic soil horizon and plants of the south shrub tundra belt, at a background plot and at a coal mine. The polyarenes in soils and plants were mainly represented by light structures. On the background and polluted areas, mosses of Pleurozium schreberi, Polytrichum commune and grasses of Deschampsia caespitosa, Festuca ovina contained the highest PAH amounts. PAH bioaccumulation in plants is mainly dependent on their physiological features. 4 plant groups with different PAH bioaccumulation capabilities were identified on the basis of the calculated biological absorption coefficient. The toxicological activity of polyarenes for both soils and plants at the background and polluted areas was determined by heavy PAHs. The highest values of toxicological activity were observed for mosses and grassy plants whilst the lowest values were for shrubs. PAHs at the plots under study are mainly of petrogenic origin.

Source characterisation and mid-term spatial and temporal distribution of polycyclic aromatic hydrocarbons in molluscs along the Basque coast (northern Spain)

The variability of polycyclic aromatic hydrocarbons (PAH) measured in the soft tissues of Mediterranean mussels (Mytilus galloprovincialis) and Pacific oysters (Crassostrea gigas) are investigated. Samples were collected from estuarine waters within the Basque Country (Bay of Biscay), between 2003 and 2011. PAH bioaccumulation showed some seasonality and significant differences were observed between cold (autumn–winter) and warm (spring–summer) seasons. Sites located within the ports of Bilbao and Pasaia showed the highest PAH concentrations in molluscs, and the highest percentages of samples above the established Environmental Quality Standards and Environmental Assessment Criteria. Probably due to human activities carried out in the area, no clear trends were observed, between 2003 and 2011, for the autumn data. Since the Basque coast is an area with high population density and industrial activity, the congener profiles (which reveal the predominance of tetra-aromatics) and the diagnostic ratios identified urban/industrial combustion processes as the main PAH sources. However, natural and petrogenic sources cannot be disregarded.

The influence of various biochars on the bioaccessibility and bioaccumulation of PAHs and potentially toxic elements to turnips (Brassica rapa L.)

The influence of amending a contaminated soil with different dry-pyrolyzed biochars on the bioaccessibility and biouptake of polycyclic aromatic hydrocarbons (PAH) and potentially toxic elements (PTE) in turnip (Brassica rapa L.,) was investigated. This is the first study to examine the influence of biochar amendments on turnips grown in a contaminated soil. The biochars came from different local feedstocks, including sewage sludge biochar (SSBC), soybean straw biochar (SBBC), rice straw biochar (RSBC) and peanut shell biochar (PNBC). The biochars were applied to soil at 2% and 5% amendments, and the resulting influence on various soil and porewater properties were quantified. The bioaccessible concentrations of PAHs in soil and their bioaccumulation in B. rapa L. significantly (P<0.05) decreased in the biochar amended soils. Biochar additions significantly (P≤0.05) reduced the bioaccumulation of PTEs (As, Cd, Cu, Pb and Zn) in B. rapa L, though not as much as for PAHs. The most effective biochar at reducing both PAHs and PTEs was PNBC (P≤0.05). Amendments of 5% biochar were more effective at reducing contaminant bioaccessibility than amendments at 2% (P<0.05). Crop yield, however, increased the most for the 2% biochar amendments, in particular for SSBC (with a 49% increase in crop yield compared to the non-amended soil). Therefore, which biochar would be the most advantageous in this system would require a cost-benefit analysis between increasing crop yield (best achieved with 2% SSBC amendments) and decreasing the PAH and PTE uptake (best achieved with 5% PNBC amendments).

PAH assessment in the main Brazilian offshore oil and gas production area using semi-permeable membrane devices (SPMD) and transplanted bivalves

The Campos Basin is Brazil's main oil and gas production area. In 2013, more than 50 million cubic meters of produced water (PW) was discharged into these offshore waters. Despite the large volumes of PW that are discharged in the Campos Basin each day, the ecological concern of the chemicals in the PW are not completely understood. Polycyclic aromatic hydrocarbons (PAH) are the most important contributors to the ecological hazards that are posed by discharged PW. This study aimed to evaluate the potential bioaccumulation of PAH using transplanted bivalves (Nodipecten nodosus) and semi-permeable membrane devices (SPMD). The study was conducted in two platforms that discharge PW (P19 and P40). Another platform that does not discharge PW (P25) was investigated for comparison with the obtained results. Time-integrated hydrocarbon concentrations using SPMD and transplanted bivalves were estimated from the seawater near the three platforms. The bioaccumulation of the PAH in the transplanted bivalves at platforms P19 and P40 were up to fivefold greater than the bioaccumulation of the PAH at platform P25. The lowest PAH concentrations were estimated for platform P25 (4.3–6.2ngL−1), and the highest PAH concentrations were estimated for platform P19 (9.2–37.3ngL−1). Both techniques were effective for determining the bioavailability of the PAH and for providing time-integrated hydrocarbon concentrations regarding oil and gas production activities.

How does predation affect the bioaccumulation of hydrophobic organic compounds in aquatic organisms?

It is well-known that the body burden of hydrophobic organic compounds (HOCs) increases with the trophic level of aquatic organisms. However, the mechanism of HOC biomagnification is not fully understood. To fill this gap, this study investigated the effect of predation on the bioaccumulation of polycyclic aromatic hydrocarbons (PAHs), one type of HOC, in low-to-high aquatic trophic levels under constant freely dissolved PAH concentrations (1, 5, or 10 μg L(-1)) maintained by passive dosing systems. The tested PAHs included phenanthrene, anthracene, fluoranthene, and pyrene. The test organisms included zebrafish, which prey on Daphnia magna, and cichlids, which prey on zebrafish. The results revealed that for both zebrafish and cichlids, predation elevated the uptake and elimination rates of PAHs. The increase of uptake rate constant ranged from 20.8% to 39.4% in zebrafish with the amount of predation of 5 daphnids per fish per day, and the PAH uptake rate constant increased with the amount of predation. However, predation did not change the final bioaccumulation equilibrium; the equilibrium concentrations of PAHs in fish only depended on the freely dissolved concentration in water. Furthermore, the lipid-normalized water-based bioaccumulation factor of each PAH was constant for fish at different trophic levels. These findings infer that the final bioaccumulation equilibrium of PAHs is related to a partition between water and lipids in aquatic organisms, and predation between trophic levels does not change bioaccumulation equilibrium but bioaccumulation kinetics at stable freely dissolved PAH concentrations. This study suggests that if HOCs have not reached bioaccumulation equilibrium, biomagnification occurs due to enhanced uptake rates caused by predation in addition to higher lipid contents in higher trophic organisms. Otherwise, it is only due to the higher lipid contents in higher trophic organisms.

Distribution and accumulation of polycyclic aromatic hydrocarbons (PAHs) in the food web of Nansi Lake, China.

The concentrations of polycyclic aromatic hydrocarbons (PAHs) were analyzed in water, sediment, and biota (aquatic plant, shrimp, and fish) of Nansi Lake by gas chromatography-mass spectrometry (GC-MS). The concentrations of total PAHs were 27.54-55.04 ng L(-1) in water, 80.31-639.23 ng g(-1) dry weight (dw) in sediments, 20.92-192.78 ng g(-1) dw in aquatic plants, and 67.3-533.9 ng g(-1) dw in fish and shrimp muscles. The ratios of phenanthrene to anthracene (Ph/An), fluoranthene to pyrene (Flu/Pyr), and low molecular weight to high molecular weight (LMW/HMW) in sediment indicated that the sources of the PAHs were a mixture of pyrolytic and petrogenic contamination at most sampling sites in Nansi Lake. The composition profile of PAHs in plants was similar to that in water and animals with 2-3 ring PAHs being dominant. The 4-6 ring PAHs were the dominant PAH compounds in sediment. There is a positive correlation between sediment and aquatic plants, but their PAH composition profiles were different, implying that aquatic plant absorption of PAHs from sediment is selective and the accumulation of PAHs in aquatic plants is different. The concentration of PAHs in fish showed a positive correlation with plants, reflecting that the PAHs in fish are mainly absorbed from aquatic plants rather than directly from the water. Bioaccumulation of LMW PAHs in aquatic biota was higher than HMW PAHs. The biota-sediment accumulation factor (BSAF) values of total PAHs in the plants Potamogeton lucens Linn and Ceratophyllum demersum Linn were higher than that in most animals. The BSAF values of total PAHs in animals were in the following order: Cyprinus carpio>Macrobrachium nipponense>Carassius auratus>Channa argus. There was no significant relationship between PAH bioaccumulation and trophic levels in Nansi Lake. Risk assessment of PAHs in water, sediment, and animals indicated that the water environment of Nansi Lake is safe at present. It is worthwhile to note that benzo [a] anthracene (BaA), benzo [a] pyrene (BaP), indeno [1,2,3-cd] pyrene (InP), dibenz [a, h] anthracene (DBA), and benzo [ghi] perylene (BghiP) were detected in sediment, plants, and animals at all sampling sites, and they have potential carcinogenicity to the organisms of Nansi Lake.

Bioaccumulation of polycyclic aromatic hydrocarbons in Manila clam (Ruditapes philippinarum) exposed to crude oil-contaminated sediments

The bioaccumulation of 16 United States Environmental Protection Agency (USEPA) priority polycyclic aromatic hydrocarbons (PAHs) and alkylated PAHs in the Manila clam, Ruditapes philippinarum exposed to sediments artificially contaminated by Iranian Heavy Crude Oil was measured and the biota-sediment accumulation factor (BSAF) was estimated through laboratory experiments. The proportion of 16 PAHs accumulated in the tissue of R. philippinarum was only from 3 to 7% of total PAHs. Among 16 PAHs, the concentration of naphthalene was highest in the tissue. Alkylated PAHs were highly accumulated more than 93% of total PAHs. The C3 dibenzothiophene was most highly accumulated. The relative composition of alkylated naphthalenes in the tissue of R. philippinarum was lower than in the sediments. In contrast, those of alkylated compounds of fluorenes, phenanthrenes, dibenzothiophenes were higher in the tissue than the sediments. The BSAF for sum of 16 PAHs was 0.11 to 0.13 g carbon/g lipid and that for alkylated PAHs was 0.05 to 0.06 g carbon/g lipid. Naphthalene showed the highest BSAF value. Alkylated PAHs with the same parent compound, BSAF tended to increase with the number of alkylated branch increased, except for alkylated chrysenes. BSAF of total PAHs lies between that of field-based values, and are also similar to those of other persistent organic pollutants (PCBs, DDTs, HCHs). This study provides the BSAF values of individual alkylated PAHs accumulated in R. philippinarum for the first time and will be used as a basis for further understanding the bioaccumulation of organic contaminants in the marine benthic organisms.

Evaluating the contribution of ingested oil droplets to the bioaccumulation of oil components — A modeling approach

The dietary uptake of oil droplets by aquatic organisms has been suggested as a possible exposure pathway for oil-related chemicals. We confronted two bioaccumulation models, one including and one neglecting oil droplet uptake, with measured polycyclic aromatic hydrocarbon (PAH) body burdens of five marine species. The model without oil droplet uptake was able to predict 75% of the observations within one order of magnitude. Total PAH body burdens were predicted within a factor of five. For most species, inclusion of oil droplet uptake did not improve model accuracy, suggesting a negligible contribution of oil droplet uptake to PAH bioaccumulation. Only for Mytilus edulis, model accuracy improved (up to five times) after the inclusion of oil droplet uptake. Our findings suggest filter feeding as a determinant for the PAH uptake via oil droplets, but more research is needed to test this hypothesis.

Polar polycyclic aromatic compounds from different coal types show varying mutagenic potential, EROD induction and bioavailability depending on coal rank

Investigations of the bioavailability and toxicity of polycyclic aromatic compounds (PAC) have rarely considered the heterogeneity of coals and the impact of more polar PAC besides polycyclic aromatic hydrocarbons (PAH).Earlier, we investigated the toxicity of eight heterogeneous coals and their extracts. In the present study, the hazard potential with respect to mechanism-specific toxicity of polar fractions of dichloromethane extracts from coals was studied. Polar extract fractions of all coal types except for anthracite induced EROD activity (determined in RTL-W1 cells), independent of coal type (Bio-TEQs between 23±16 and 52±22ng/g). The polar fractions of all bituminous coal extracts revealed mutagenic activity (determined using the Ames Fluctuation test). No significant mutation induction was detected for the polar extract fractions from the lignite, sub-bituminous coal and anthracite samples, which indicates a higher dependency on coal type for polar PAC here.Additionally, information on bioavailability was derived from a bioaccumulation test using the deposit-feeding oligochaete Lumbriculus variegatus which was exposed for 28days to ground coal samples. Despite the high toxic potential of most coal extracts and a reduced biomass of Lumbriculus in bituminous coal samples, bioaccumulation of PAH and mortality after 28days were found to be low. Limited bioaccumulation of PAH (up to 3.6±3.8mg/kg EPA-PAH) and polar PAC were observed for all coal samples. A significant reduction of Lumbriculus biomass was observed in the treatments containing bituminous coals (from 0.019±0.004g to 0.046±0.011g compared to 0.080±0.025g per replicate in control treatments).We conclude that bioavailability of native PAC from coals including polar PAC is low for all investigated coal types. In comparison to lignite, sub-bituminous coals and anthracite, the bioavailability of PAC from bituminous coals is slightly increased.

In-situ partitioning and bioconcentration of polycyclic aromatic hydrocarbons among water, suspended particulate matter, and fish in the Dongjiang and Pearl Rivers and the Pearl River Estuary, China

The partitioning and bioaccumulation of polycyclic aromatic hydrocarbons (PAHs) in water, suspended particulate matter (SPM), and fish samples from the Dongjiang River (DR), Pearl River (PR), and the Pearl River Estuary (PRE) were examined. Although PAHs are much lower in PRE than in DR or PR, PAHs in some fish species are significantly higher in PRE than in DR or PR. Aqueous or particulate PAHs respectively show significant correlations with dissolved organic carbon, particulate organic matter, and chlorophyll a, suggesting that biological pumping effect regulates their distribution. The in situ partitioning coefficients (logKoc) for PAHs are one order magnitude higher than the empirical logKoc–logKow correlation. The bioconcentration factor (BCF) is slightly higher for the marine fish than for the freshwater fish. The above phenomena indicate that BCF may vary due to the diversity of fish species, feeding habits, and metabolism of PAHs in fish.

Quantitative Assessment of Polycyclic Aromatic Hydrocarbons and Heavy Metals in Fish Roasted with Firewood, Waste Tyres and Polyethylene Materials

The bioaccumulation and biomagnification of PAHs along successive trophic levels is an important means of exposure to human and animal life. This study evaluated Polycyclic Aromatic Hydrocarbons (PAHs) and heavy metals in fresh fish and fish samples processed/ roasted with smoke/heat/flame generated from firewood, waste tyre and polyethylene materials. PAHs and heavy metals were determined with Gas chromatography with flame ionization detector (GC-FID) and Atomic Absorption Spectrophotometer (AAS) respectively. Significant differences (P<0.05) were observed in the concentrations of PAHs and heavy metals in the heat-processed fish when compared to fresh fish. Appreciable amount of carcinogenic PAHs; benzo(a)pyrene, benz(a)anthracene and dibenz(a,h)anthracene benz(a)anthracene and dibenz(a,h)anthracene and heavy metals such as cadmium (Cd), zinc (Zn) and lead (Pb) were detected in processed/roasted fish samples.

The effects of sewage sludge and sewage sludge biochar on PAHs and potentially toxic element bioaccumulation in Cucumis sativa L.

The presence of contaminants such as polycyclic aromatic hydrocarbons (PAHs) and potentially toxic elements (PTEs), including As, Cd, Cu, Pb and Zn, restricts the application of sewage sludge (SS) to agricultural land. This research established that the conversion of SS to SS biochar (SSBC) significantly (p⩽0.01) decreased PAH and available PTE concentrations. Once added to soil both SS and SSBC significantly (p⩽0.05) decrease PAH availability. Bioaccumulation of PAHs into Cucumis sativa L. was reduced by both SSBC (44–57%) and (to a lesser extent 20–36%) by SS. Following addition to soil SSBC significantly (p⩽0.05) reduced available PTEs (except Cd), while SS significantly (p⩽0.05) increased PTE availability. As a consequence SSBC significantly (p⩽0.05) reduced PTE bioaccumulation (except Cd and Zn), while SS increased PTE bioaccumulation. These results suggest SSBC to be a candidate for soil amendment that offers advantages over SS in terms of PAH/PTE bioaccumulation mitigation.

Influence of carbon nanotubes with preloaded and coexisting dissolved organic matter on the bioaccumulation of polycyclic aromatic hydrocarbons to Chironomus plumosus larvae in sediment

The ubiquity of dissolved organic matter (DOM) in an aqueous environment may have influence on the carbonaceous material's impact on the bioaccumulation of polycyclic aromatic hydrocarbons (PAHs) to benthonic organisms in contaminated sediment. In the present study, 1 multiwalled carbon nanotube (MWNT); 2 types of DOM (fulvic acid and tannic acid), and 2 PAHs (pyrene and chrysene) were selected to study the influence of MWNT with preloaded and coexisting DOM on the bioaccumulation of PAHs to Chironomus plumosus larvae in sediment. Moreover, the freely dissolved concentrations of PAHs were measured to explore the influence mechanisms. The results showed that despite the presence or absence of preloaded or coexisting DOM, the presence of 1% MWNT in sediments suppressed the biota-sediment accumulation factor (BSAF) and elevated the water-based bioaccumulation factor (BAF) of PAHs. However, the BSAF and BAF values generally decreased with the increase of 2 forms of both DOM; this was caused by the combined impact of DOM and MWNT on the freely dissolved concentrations of PAHs and the ingestion behavior of benthic organisms.

Comparative study of polycyclic aromatic hydrocarbons in coral tissues and the ambient sediments from Kenting National Park, Taiwan

Surface sediments and corals (Acropora sp. and Montipora sp.) from the coastline of Kenting were analyzed in 2009 and 2010 for content levels of polycyclic aromatic hydrocarbons (PAHs) using gas chromatography-mass spectrometry. The total PAH concentrations (t-PAH) in corasls (143–1715 ng g−1 dw) were significantly higher than in the ambient sediments (2–59 ng g−1 dw) indicating the bioaccumulation of PAHs in corals. The spatial and seasonal variation in PAH levels suggested that land-loaded contaminants may be the main source of PAHs in the Kenting coral reefs. Based on molecular indices, PAHs were substantially of petroleum origin. The major PAH components were phenanthrene, pyrene and fluorine, but PAH congeners in corals and sediments still have characteristic composition patterns which would be altered by the bio/accumulation mechanisms. Further study is essential to assess and understand the impacts of these chemicals on coral reefs.

Effects of crude oil exposure on bioaccumulation of polycyclic aromatic hydrocarbons and survival of adult and larval stages of gelatinous zooplankton.

Gelatinous zooplankton play an important role in marine food webs both as major consumers of metazooplankton and as prey of apex predators (e.g., tuna, sunfish, sea turtles). However, little is known about the effects of crude oil spills on these important components of planktonic communities. We determined the effects of Louisiana light sweet crude oil exposure on survival and bioaccumulation of polycyclic aromatic hydrocarbons (PAHs) in adult stages of the scyphozoans Pelagia noctiluca and Aurelia aurita and the ctenophore Mnemiopsis leidyi, and on survival of ephyra larvae of A. aurita and cydippid larvae of M. leidyi, in the laboratory. Adult P. noctiluca showed 100% mortality at oil concentration ≥20 µL L−1 after 16 h. In contrast, low or non-lethal effects were observed on adult stages of A. aurita and M. leidyi exposed at oil concentration ≤25 µL L−1 after 6 days. Survival of ephyra and cydippid larva decreased with increasing crude oil concentration and exposition time. The median lethal concentration (LC50) for ephyra larvae ranged from 14.41 to 0.15 µL L−1 after 1 and 3 days, respectively. LC50 for cydippid larvae ranged from 14.52 to 8.94 µL L−1 after 3 and 6 days, respectively. We observed selective bioaccumulation of chrysene, phenanthrene and pyrene in A. aurita and chrysene, pyrene, benzo[a]pyrene, benzo[b]fluoranthene, benzo[k]fluoranthene, and benzo[a]anthracene in M. leidyi. Overall, our results indicate that (1) A. aurita and M. leidyi adults had a high tolerance to crude oil exposure compared to other zooplankton, whereas P. noctiluca was highly sensitive to crude oil, (2) larval stages of gelatinous zooplankton were more sensitive to crude oil than adult stages, and (3) some of the most toxic PAHs of crude oil can be bioaccumulated in gelatinous zooplankton and potentially be transferred up the food web and contaminate apex predators.

Accumulation of some potentially toxic metals and polycyclic aromatic hydrocarbons (PAHs) in marine clam Liochoncha ornata collected from the Omani Sea

Clam samples of Liochoncha ornata were collected for a period of one year from July 2009 to June 2010 at monthly interval. The soft tissue of clams was analyzed to detect some potentially toxic metals and polycyclic aromatic hydrocarbons (PAHs). Accumulation of Hg, Cd and Pb in the clam tissues showed variability with a mean concentration of 0.011±0.009, 1.769±0.942 and 0.015±0.039 µg/g wet weight for Hg, Cd and Pb, respectively. Cadmium had recorded a particularly high potential of accumulation in L. ornata. The bioaccumulation of PAHs in the clams appeared to be selective and ranged from 4.80 to 12.0 ng/g; wet weight. The most carcinogenic PAHs, such as benzo (a) pyrene and dibenz (a,h) anthracene, were in all cases below the limits of detection. No distinctive relationship was found between different size class and contaminant uptake by the clam. The concentrations of both of Pb and Hg in L. ornata, were found to be below the safe limits suggested by various authorities and thus gave no indication of pollution by such elements. However, continuous monitoring of these and other pollutants in the coastal marine ecosystem is advised. Key words: Clam, Mercury, Cadmium, Pb, polycyclic aromatic hydrocarbons (PAHs), Oman.

Interspecific comparison of polycyclic aromatic hydrocarbons and persistent organochlorines bioaccumulation in bivalves from a Mediterranean coastal lagoon

The bioaccumulation of polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) was characterized in cockle, oyster and noble pen shell from nine areas in the Mar Menor lagoon with different hydrodynamic and pollutant sources. Biota, sediment and water samples were simultaneously collected in the spring and autumn of 2010. Considering all bivalve samples, PAH concentrations ranged from 8.98 to 370μg·kg−1 d.w., those of PCBs from 0.15 to 42.36μg·kg−1 d.w. and those of DDXs from below detection limit to 240.6μg·kg−1 d.w., where p,p′-DDE was the main fraction. The bioaccumulation of PAHs was similar for cockle, oyster and noble pen shell, being higher close to ports and wastewater effluents. However, DDX and PCB bioaccumulations in oyster and noble pen shell were significantly higher than in cockle in spring (p=0.02). The first organic pollutant bioaccumulation data for noble pen shell were obtained in this study, showing a preferential accumulation of pyrene. The increase of PAH bioaccumulation in autumn, as compared to spring, was low, due to high water temperatures during the summer, which favoured PAH dissipation processes. No significant seasonal variations were detected for OCPs and PCBs, except in some specific areas. The PAH, PCB and OCP levels detected in these bivalves were lower than OSPAR/MED POL environmental assessment criteria, except for p,p′-DDE in bivalves sited close to El Albujón watercourse mouth.

Interactions between zooplankton and crude oil: toxic effects and bioaccumulation of polycyclic aromatic hydrocarbons.

We conducted ship-, shore- and laboratory-based crude oil exposure experiments to investigate (1) the effects of crude oil (Louisiana light sweet oil) on survival and bioaccumulation of polycyclic aromatic hydrocarbons (PAHs) in mesozooplankton communities, (2) the lethal effects of dispersant (Corexit 9500A) and dispersant-treated oil on mesozooplankton, (3) the influence of UVB radiation/sunlight exposure on the toxicity of dispersed crude oil to mesozooplankton, and (4) the role of marine protozoans on the sublethal effects of crude oil and in the bioaccumulation of PAHs in the copepod Acartia tonsa. Mortality of mesozooplankton increased with increasing oil concentration following a sigmoid model with a median lethal concentration of 32.4 µl L−1 in 16 h. At the ratio of dispersant to oil commonly used in the treatment of oil spills (i.e. 1∶20), dispersant (0.25 µl L−1) and dispersant- treated oil were 2.3 and 3.4 times more toxic, respectively, than crude oil alone (5 µl L−1) to mesozooplankton. UVB radiation increased the lethal effects of dispersed crude oil in mesozooplankton communities by 35%. We observed selective bioaccumulation of five PAHs, fluoranthene, phenanthrene, pyrene, chrysene and benzo[b]fluoranthene in both mesozooplankton communities and in the copepod A. tonsa. The presence of the protozoan Oxyrrhis marina reduced sublethal effects of oil on A. tonsa and was related to lower accumulations of PAHs in tissues and fecal pellets, suggesting that protozoa may be important in mitigating the harmful effects of crude oil exposure in copepods and the transfer of PAHs to higher trophic levels. Overall, our results indicate that the negative impact of oil spills on mesozooplankton may be increased by the use of chemical dispersant and UV radiation, but attenuated by crude oil-microbial food webs interactions, and that both mesozooplankton and protozoans may play an important role in fate of PAHs in marine environments.

Use of Fe3O4@nSiO2@mSiO2Magnetic Mesoporous Microspheres for Fast Determination of the Sorption Coefficients of Polycyclic Aromatic Hydrocarbons to Bovine Serum Albumin in Aqueous Phase

Polycyclic aromatic hydrocarbons (PAHs) are concerned due to their carcinogenic and teratogenetic effects to human beings. As an important carrier in blood, serum albumin is able to bind to many chemicals and transports them to all parts of the organism. Therefore, it is crucial to determine the partitioning of PAHs to biological phases to evaluate the bio-accumulation of PAHs in organisms. Due to the aqueous solubility of serum albumin, it is difficult to separate the freely dissolved PAHs from the serum albumin associated PAHs with traditional extraction techniques. Although negligible depletion solid-phase microextraction (nd-SPME) is efficient in sensing the freely dissolved PAHs, it suffers from long equilibration time. In this work, we developed a quick approach for the determination of sorption coefficients of PAHs to bovine serum albumin (BSA) by using Fe3O4@nSiO(2)@mSiO(2) magnetic mesoporous microspheres. In the synthesis of Fe3O4@nSiO(2)@mSiO(2) materials, trace amount of hexadecyl trimethyl ammonium (CTAM(+)) template was kept in the mesopores of these materials to function as sorbent for the extraction of PAHs. The mesoporous structure hinders the extraction of BSA associated PAHs due to the volume exclusion effect, and only the freely dissolved PAHs can access into mesoporous and are extracted by CTAM(+). The large surface area (186 m(2)/g) and high pore volume (0.16 cm(3)/g) of the Fe3O4@nSiO(2)@mSiO(2) microspheres provide enlarged contact area for extraction. Furthermore, the thin mesoporous layer (approximate to 50 nm) shortened the diffusion distance of PAHs from aqueous phase to CTAM(+) sorbent. These above characteristics enhanced the extraction efficiency and reduced the equilibration time (t(90%)) to 66 min, which is less than 1/200 of that by nd-SPME. In addition, the magnetic microspheres can be conveniently collected from the solution after extraction by applying an appropriate magnetic field. Combining the proposed extraction procedure with GC-MS determination, the partition coefficients of PAHs to BSA were measured with values in the range of 10(3.94) to 10(5.00), which were basically consistent with that by nd-SPME (10(3.53)similar to 10(4.99)).