Accumulation Of Benzo Research Articles

The health risk for seafood consumers under future ocean acidification (OA) scenarios: OA alters bioaccumulation of three pollutants in an edible bivalve species through affecting the in vivo metabolism

The current knowledge about the effect of pCO2-driven ocean acidification on the bioaccumulation of pollutants in marine species is still scarce, as only limited types of pollutants have been investigated. Therefore, to obtain a better understanding of the effect of ocean acidification on the process of bioaccumulation and subsequent food safety, the accumulation of benzo[a]pyrene (B[a]P), chloramphenicol (CAP), and nitrofurazone (NFZ) in an edible bivalve species, Tegillarca granosa, under present and near-future ocean acidification scenarios was investigated in the present study. The health risks associated with consuming contaminated blood clams were also assessed using target hazard quotient (THQ), lifetime cancer risk (CR), or margin of exposure (MoE). To explain the alterations in bioaccumulation of these pollutants, the expressions of genes encoding corresponding key metabolic proteins were analyzed as well. The results obtained showed that ocean acidification exerted a significant effect on the accumulation of B[a]P, NFZ, and CAP in the clams. After four-week exposure to B[a]P, NFZ, or CAP contaminated seawater acidified with CO2 at pH 7.8 and 7.4, significantly greater amounts of B[a]P and lower amounts of NFZ and CAP were accumulated in the clams compared to that in the control. Although no non-carcinogenic risk of consuming B[a]P-contaminated blood clams was detected using the THQ values obtained, the CR values obtained indicated a high life-time risk in all groups. In addition, according to the MoE values obtained, the health risks in terms of consuming NFZ- and CAP-contaminated clams were significantly reduced under ocean acidification scenarios but still cannot be ignored, especially for children. The gene expression results showed that the ability of clams to eliminate B[a]P may be significantly constrained, whereas the ability to eliminate NFZ and CAP may be enhanced under ocean acidification scenarios, indicating that the changes in the accumulation of these pollutants may be due to the altered in vivo metabolism.

Trends in the Accumulation of Benzo(A)Pyrene by Natural Grassy Vegetation in the Novocherkassk Power Station Impact Zone

Trends in the Accumulation of Benzo(A)Pyrene by Natural Grassy Vegetation in the Novocherkassk Power Station Impact Zone

Carbon nanopowder acts as a Trojan-horse for benzo(α)pyrene in Danio rerio embryos

Carbon-based nanoparticles (CBNs) are largely distributed worldwide due to fossil fuel combustion and their presence in many consumer products. In addition to their proven toxicological effects in several biological models, attention in recent years has focussed on the role played by CBNs as Trojan-horse carriers for adsorbed environmental pollutants. This role has not been conclusively determined to date because CBNs can decrease the bioavailability of contaminants or represent an additional source of intake. Herein, we evaluated the intake, transport and distribution of one of the carbon-based powders, the so-called carbon nanopowder (CNPW), and benzo(α)pyrene, when administered alone and in co-exposure to Danio rerio embryos. Data obtained by means of advanced microscopic techniques illustrated that the “particle-specific” effect induced a modification in the accumulation of benzo(α)pyrene, which is forced to follow the distribution of the physical pollutant instead of its natural bioaccumulation. The combined results from functional proteomics and gene transcription analysis highlighted the different biochemical pathways involved in the action of the two different contaminants administered alone and when bound together. In particular, we observed a clear change in several proteins involved in the homeostatic response to hypoxia only after exposure to the CNPW or co-exposure to the mixture, whereas exposure to benzo(α)pyrene alone mainly modified structural proteins. The entire dataset suggested a Trojan-horse mechanism involved in the biological impacts on Danio rerio embryos especially due to different bioaccumulation pathways and cellular targets.

Paternal exposure to cigarette smoke condensate leads to reproductive sequelae and developmental abnormalities in the offspring of mice

Paternal smoking is associated with infertility, birth defects and childhood cancers. Our earlier studies using cigarette smoke condensate (CSC) demonstrated several deleterious changes in male germ cells. Here, we hypothesize that chronic paternal exposure to CSC causes molecular and phenotypic changes in the sire and the offspring, respectively. In this mouse study, CSC caused DNA damage and cytotoxicity in testes via accumulation of benzo(a)pyrene (B[a]P) and cotinine. Decreased expression of growth arrest and DNA damage inducible alpha (Gadd45a), aryl hydrocarbon receptor (Ahr), and cyclin-dependent kinase inhibitor 1A (P21) was seen in CSC exposed testes. Apoptotic germ cell death was detected by induction of Fas, FasL, and activated caspase-3. The CSC-exposed males displayed reduction in sperm motility and fertilizing ability and sired pups with reduced body weight and crown-rump length, and smaller litter size with higher numbers of resorption. This model of CSC exposure demonstrates testicular toxicity and developmental defects in the offspring.

Polycyclic aromatic hydrocarbons in insular and coastal soils of the Russian Arctic

The content and individual component compositions of polycyclic aromatic hydrocarbons in polar soils of the Russian Arctic sector have been studied. The contamination of soils near research stations is identified from the expansion of the range of individual polycyclic aromatic hydrocarbons, the abrupt increase in the content of heavy fractions, and the accumulation of benzo[a]pyrene. Along with heavy hydrocarbons, light hydrocarbons (which are not only natural compounds, but also components of organic pollutants) are also accumulated in the contaminated soils. Heavy polycyclic aromatic hydrocarbons are usually of technogenic origin and can serve as markers of anthropogenic impact in such areas as Cape Sterligov, Cape Chelyuskin, and the Izvestii TsIK Islands. The content of benzo[a]pyrene, the most hazardous organic toxicant, appreciably increases in soils around the stations, especially compared to the control; however, the level of MPC is exceeded only for the soils of Cape Chelyuskin.

New alternative method of benzo[a]pyrene extractionfrom soils and its approbation in soil under technogenic pressure

The optimization of benzo[a]pyrene extraction conditions by subcritical water extraction method from soils is the purpose of the research. The optimal conditions for benzo[a]pyrene recovery are 30-min extraction by water in a special steel cartridge at 250 °C and 100 atm. Studies were conducted on the soils of monitoring plots subjected to Novocherkassk Power Station emissions. Monitoring plots were established at different distances from the Novocherkassk Power Station (NPS; 1.0–20.0 km). It was shown that the use of water in subcritical state as a solvent for benzo[a]pyrene extraction from soil allows to avoid large volumes of organic solvents and to decrease the time of sample preparation. It is shown that the maximum benzo[a]pyrene maintenance was observed in soils of the monitoring plots located most close (to 5 km) to a pollution source in the area of the prevailing direction of a wind rose. Dynamics of pollutant accumulation in soils depend on number of Novocherkassk state district power station emissions. The method of benzo[a]pyrene subcritical water extraction from soil was developed and approbated during long-term monitoring researches of technogenic polluted territories. The optimum conditions for benzo[a]pyrene extraction from soil have been determined: the soil is treating by subcritical water at 250 °C and 100 atm of pressure for 30 min. Trends in the accumulation of benzo[a]pyrene in soil zones of the thermal power plant influence have been researched over a 5-year period of monitoring observations by subcritical water extraction method. Benzo[a]pyrene accumulation in soils depends on the technogenic emissions to the atmosphere from Novocherkassk power station and on the soil physical and chemical properties.

Approbation of express-method for benzo[a]pyrene extraction from soils in the technogenic emission zone territories

The benzo[a]pyrene accumulation and migration regularities in chernozemic soils under the aerotechnogenic emission zone were revealed on the basis of long-term monitoring researches. A new method of subcritical water extraction has been developed for determination of benzo[a]pyrene from soils of the emissions zone of Novocherkassk Power Station one of the largest thermal power enterprises in Russian Federation. It is shown that the soils adjacent to a source of emission are polluted by benzo[a]pyrene at distance to 5 km. Trends in the accumulation of benzo[a]pyrene in soil zones of the thermal power plant influence have been researched over a 5-year period of monitoring observations. The assessment of soils pollution extent by benzo[a]pyrene is given.

Geoecology of benzo[a]pyrene as a coal pyrolysis product

The accumulation of benzo[a]pyrene as a coal pyrolysis product in the soil cover of Chelyabinsk and its surroundings, which are characterized by a high concentration of industrial enterprises and power plants within the confines of the city, was evaluated. The concentrations of this carcinogenic substance in various soils were found higher than the maximum permissible concentration (20 μg/kg).

Time-resolved fluorescence studies of the effects of metabolism on the In Vitro reversible binding and accumulation of benzo[a]pyrene in DNA

Time-resolved fluorescence techniques have been employed to compare the DNA association constant of the parent hydrocarbon benzo[a]pyrene versus that of trans-7, 8-dihydroxy-7, 8-dihydrobenzo[a]pyrene. The latter molecule is a highly carcinogenic metabolite derived from benzo[a]pyrene. Solubilization experiments were also carried out to compare the maximum total uptake of benzo[a]pyrene and of the metabolite by DNA. In the solvent system used in the association constant measurements (20% methanol) the association constant for benzo[a]pyrene is 3.0+0.3 × 104 M-1 while that of the more polar proximate carcinogen is 7.5 times lower. The results of the solubilization studies carried out in buffered aqueous medium demonstrate that at a DNA concentration of 5 × 10-4 M in PO-4 the maximum uptake of benzo[a]pyrene into DNA is one molecule per 2.2+0.5 × 103 nucleotide bases. The maximum uptake of the more soluble proximate carcinogen is 4 to 25 times greater than that of the parent hydrocarbon. The present results indicate that metabolism of benzo[a]pyrene leads to the formation of a nonreactive proximate carcinogen which has a lower binding constant than the parent hydrocarbon, but which is better able to diffuse through a polar medium and to accumulate at ultimate biological target sites.

Gadd45a, the gene induced by the mood stabilizer valproic acid, regulates neurite outgrowth through JNK and the substrate Paxillin

Paternal smoking is associated with infertility, birth defects and childhood cancers. Our earlier studies using cigarette smoke condensate (CSC) demonstrated several deleterious changes in male germ cells. Here, we hypothesize that chronic paternal exposure to CSC causes molecular and phenotypic changes in the sire and the offspring, respectively. In this mouse study, CSC caused DNA damage and cytotoxicity in testes via accumulation of benzo(a)pyrene (B[a]P) and cotinine. Decreased expression of growth arrest and DNA damage inducible alpha (Gadd45a), aryl hydrocarbon receptor (Ahr), and cyclin-dependent kinase inhibitor 1A (P21) was seen in CSC exposed testes. Apoptotic germ cell death was detected by induction of Fas, FasL, and activated caspase-3. The CSC-exposed males displayed reduction in sperm motility and fertilizing ability and sired pups with reduced body weight and crown-rump length, and smaller litter size with higher numbers of resorption. This model of CSC exposure demonstrates testicular toxicity and developmental defects in the offspring.

Structure-activity relationships of synthetic analogs of jasmonic acid and coronatine on induction of benzo[c]phenanthridine alkaloid accumulation in Eschscholzia californica cell cultures.

A facile test system based on the accumulation of benzo[c]phenanthridine alkaloids in Eschscholzia californica cell suspension culture (an indicator of defense gene activation) has been used to analyze a series of synthetic compounds for elicitor-like activity. Of the 200 jasmonic acid and coronatine analogs tested with this system, representative results obtained with 49 of them are presented here. The following can be summarized concerning structure-activity relationships: there is a large degree of plasticity allowed at the C-3 of jasmonic acid in the activation of defense genes. The carbonyl moiety is not strictly required, but exocyclic double bond character appears necessary. The pentenyl side chain at C-2 cannot tolerate bulky groups at the terminal carbon and still be biologically active. Substitutions to the C-1' position are tolerated if they can potentially undergo beta-oxidation. Either an alkanoic acid or methyl ester is required at C-1, or a side chain that can be shortened by beta-oxidation or by peptidase hydrolysis. Coronatine and various derivatives thereof are not as effective as jasmonic acid, and derivatives in inducing benzo[c]phenanthridine alkaloid accumulation. Jasmonic acid rather than the octadecanoic precursors is therefore considered to be a likely signal transducer of defense gene activation in planta.

Uptake and Depuration of Two Polycyclic Aromatic Hydrocarbons, Fluorene and Benzo(a)pyrene, in the Mussel Mytilus Edulis and the Diatom Phaeodactylum Tricornuteum

Abstract In laboratory exposures, uptake rates from water for both benzo(a)pyrene and fluorene were 1-2 orders of magnitude higher in missels than in diatoms, while depuration rates were similar. Bioconcentration factors in mussels were 21428 and 394 for benzo(a)pyrene and fluorene, respectively, and 636 and 11 in diatoms. Accumulation of benzo(a)pyrene in mussels through trophic transfer from algae amounted to 1.3% of total residue in molluscs.

Role of particulate organic matter in decreasing accumulation of polynuclear aromatic hydrocarbons by Daphnia magna.

Accumulation of benzo[a]pyrene (BaP) and anthracene (A) byDaphnia magna in the presence of suspended yeast cells was analyzed using multicompartment models. The rate coefficient for uptake of polynuclear aromatic hydrocarbon (PAH) due to ingestion of yeast cells laden with sorbed chemical was only 3 to 15% of the rate coefficient for uptake of dissolved PAH. Uptake and accumulation of BaP was reduced 97% due to sorption of PAH to naturally occurring organic matter (humic acids). Accumulation of hydrophobic chemicals in aqueous systems appears to depend on the amount of chemical in solution and on the amount of chemical sorbed to particles entering the food chain. Chemicals sorbed to suspended organic matter, including dissolved or colloidal organic matter, have greatly reduced availability.

Oxidation and Accumulation of Benzo(a)pyrene in the Presence of the Baltic Algae

AbstractIn batch experiments with 0.5 nM benzo(a)pyrene in artificial sea water there are investigated the distribution and degradation of benzopyrene in the presence of various plants: Cladophora glomerata, Enteromorpha intestinalis, Fucus vesiculosus and Chara aspera (in each case 10 … 20 g/l dry weight). The conversion of benzopyrene in the presence of the plants is considerably promoted compared with the pure autoxidation, except in the presence of Fucus. Obviously, there prevails initially the accumulation of benzopyrene in the biomass. Whereas for Fucus even after 10 d still 89% of benzopyrene can be detected in the biomass, in the other species a degradation of benzopyrene in the biomass takes place, the respective oxidation products as diols, quinones and phenols being detected in the biomass in proportionately higher concentrations. With the exception of Fucus, the degradation of benzopyrene comes up to 40 … 60% within a period of 5 … 6d with the other species tested.

Uptake of benzo[a]pyrene by gonadal tissue of flatfish (family Pleuronectidae) and its effects on subsequent egg development.

Accumulation of benzo[a]pyrene (BaP) by sexually mature flatfish gonad, its transfer to developing gametes, and its subsequent effects on developing embryos were studied. Thin-layer chromatography revealed both unmetabolized BaP and polar metabolites in the ovary, wolffian ducts, oocytes, and semen of English sole 24 h after ip injection with 200 microCi [3H]BaP. Concentrations of BaP and its metabolites were 3-11 times higher in oocytes and semen than in gonadal tissue. Fertilized eggs from flathead sole that had been fed 4.0 mg BaP 5 h before spawning demonstrated a significantly lower (p less than 0.001) hatching success (11.9%) than eggs from control fish (56.6%). Morphological abnormalities were found in only 1.6% of control embryos but in 5.6% of embryos from treated females.

Accumulation of Benzo[a]pyrene in a Larval Bivalve via Trophic Transfer

The diatom Thalassiosira pseudonana was cultured in 10 μg/L 14C-benzo[a]pyrene (B[a]P) and subsequently fed to larvae of the hard clam Mercenaria mercenaria. The rate of direct uptake of B[a]P from seawater by the diatoms was much greater than the rate of trophic transfer of B[a]P from the diatoms to the clam larvae. This was attributed to greater efficiency of direct uptake and to the larger quantity of B[a]P available in the water. A comparison of direct uptake by bivalves (as reported in the literature) with trophic transfer measured in the present investigation indicated that the processes may be equally important in accumulation of B[a]P in natural populations of bivalves.Key words: benzo[a]pyrene, trophic transfer, bivalve larvae

A study of the mechanism of intestinal absorption of benzo(a)pyrene

1. 1. Benzo(a)pyrene and other polynuclear aromatic hydrocarbons are readily absorbed from the gut when fed to rats, but little is known about the mechanism of the absorption. To study the mechanism, everted sacs of small intestine were incubated in a medium containing a lipid emulsion of benzo(a)pyrene (50–1500 μM). After incubation, the concentration of benzo(a)pyrene in the sac tissue and in the medium inside the sac was determined by spectrofluorimetric analysis of chloroform extracts. 2. 2. For incubation medium concentrations above 200 μM, accumulation of benzo(a)pyrene in the sac tissue increased exponentially with increase in incubation medium concentration. The transfer of benzo(a)pyrene from sac tissue to the inside medium was proportional to the concentration in the sac tissue. The regression lines were not greatly influenced by fasting, rat age, or sex. Comparison of incubation at 0, 23 and 42° with that at 37° showed a lowered sac accumulation at 0° and an increase in accumulation with temperature. Anaerobiosis and/or 0.1 M iodoacetate did not appreciably influence sac tissue accumulation. Benzo(a)pyrene also accumulated in strips of small and large intestine and slices of liver and kidney and epididymal fat. The feature of exponential accumulation was not limited to tissue, for adsorption isotherms and time curves for string incubated in the same media has the same forms as those obtained for the sacs. Intragastric doses of benzo(a)pyrene appeared quickly in thoracic duct lymph and reached a peak in 3–4 h, but no more than 20% of the dose was recovered in the lymph. An exponential relationship between size of intragastric dose and concentration in adipose and mammary tissue, 18 h later, was noted. 3. 3. The data are in accord with a mechanism of physical adsorption of benzo(a)pyrene to the intestinal mucosal surfaces and them passive diffusion into and through the intestinal wall. Two phases of adsorption are postulated: first, unilayer (Langmuir) adsorption, then multilayer (Polanyi) adsorption which would account for the exponential nature of the accumulation.