Pyrene sediment concentration

Hegeman, W.J.M., van der Weijden, C.H., Loch, J.P.G. (1995) Sorption of benzo[a]pyrene and phenanthrene on suspended harbor sediment as a function of suspended sediment concentration and salinity A laboratory study using the cosolvent partition coefficient. Environ. Sci. Technol. 29, 363-371. 

Coal tar creosote-derived phenanthrene, 1,2-benzanthracene, and benzo[a]pyrene have been detected in river sediments at concentrations of up to 231, 62, and 16 mg/kg (wet basis), respectively, directly downstream from the site of a former wood treatment facility. At 4,000 meters from the source, these levels decreased to 0.35, 1.02, and 0.40 mg/kg (wet basis), respectively (Black 1982). Creosote-derived PAHs were also detected in the sediments of Pensacola Bay and a drainage stream in the vicinity of a former wood treatment facility near Pensacola, Florida. PAH concentrations ranged from 200 pg/g for naphthalene to 140 mg/kg for anthracene in stream sediments concentrations in Pensacola Bay ranged from 75 (ig/kg for benzanthracene to 190 pg/kg for fluoranthene (Elder and Dresler 1988). 

Environmental Fate of Hydrocarbons, A few studies have shed light on the fate of hydrocarbons in the marine environment. In coastal marine sediments, PAHs accumulate from urban sources and are converted to intermediate products and CO2 by metabolism, photooxidation, and other processes. In their Controlled Ecosystem Pollution Experiment (CEPEX), Lee et al. (1978) concluded that hydrocarbons were deposited in the sediment by falling particles, although they did not specifically study the direct uptake of waterborne PAH by sediment. Their results show that in the first few days of a one-time addition of oil that the sediment concentration of naphthalenes was high and then steadily decreased to below detection by day 17, whereas anthracene, fluoranthene, benz[a]anthracene, and benzo-[a]pyrene concentrations in the sediment steadily increased over the 17 d of the experiment. It was also proposed by Lee et al. (1978) that hydrocarbons from an oil slick that are smaller than 15 carbons volatilize quickly and only to a limited degree for those with 15-25 carbons. They concluded that most LPAHs were removed primarily by microbial degradation and that HPAHs were removed by photooxidation and sedimentation. Another study has shown that when oil is added to the water column, total hydrocarbons rapidly decrease in the water but aromatic hydrocarbons increase in the sediment (Gordon et al. 1976). 

A few studies have examined tissue-sediment correlations of PAHs in fish, usually with indicators of exposure other than concentrations of parent compounds in tissue. Studies with English sole Parophrys vetulus) have shown a dose-response relationship between exposure to benzo [a] pyrene or PAH-rich sediment extract and benzo [a] pyrene-like bile fluorescence levels (Collier and Varanasi 1991). Moreover, a wide range of fish species from sites with increased sediment concentrations of PAHs have demonstrated... 

Turner, A., Rawling, M.C. (2002) Sorption of benzo[a]pyrene to sediment contaminated by acid mine drainage contrasting particle concentration-dependencies in river water and seawater. Water Res. 36, 2011-2019. 

To evaluate the potential risk of Ebro river sediments, the concentrations detected were compared to actual legislation. The WFD does not specifically address sediment management [95]. In contrast to this, the Canadian sediment quality guidelines for the protection of aquatic life [96] provide data for different types of sediments and include 33 compounds, PAHs and DDTs among them. All the PAHs included in the Canadian guidelines are present above the limit, ranging from 3% of the samples for naphthalene to 90% for dibenzo(a,h)anthracene. Special attention has to be paid to benzo(a)pyrene and dibenzo(a,h)anthracene, considered... 

Sediments and biota collected from the Hersey River, Michigan, in 1978, were heavily contaminated with phenanthrene, benz[a]anthracene, and benzo[a]pyrene when compared to a control site. Elevated PAH concentrations were recorded in sediments, whole insect larvae, crayfish muscle, and flesh of lampreys (family Petromyzontidae), brown trout (Salmo trutta), and white suckers (Catostomus commersoni), in that general order (Black et al. 1981). The polluted collection locale was the former site of a creosote wood preservation facility between 1902 and 1949, and, at the time of the study, received Reed City wastewater treatment plant effluent, described as an oily material with a naphthalene-like odor (Black et al. 1981). In San Francisco Bay, elevated PAH concentrations in fish livers reflected elevated sediment PAH concentrations (Stehr et al. 1997). In Chesapeake Bay, spot (Leiostomus xanthurus) collected from a PAH-contaminated tributary (up to 96 mg PAHs/kg DW sediment) had elevated cytochrome P-450 and EROD activity in liver and intestine microsomes (Van Veld et al. 1990). Intestinal P-450 activity was 80 to 100 times higher in fish from highly contaminated sites than in conspecifics from reference sites intestinal EROD activity had a similar trend. Liver P-450 and EROD activity was about 8 times higher in spot from the contaminated sites when compared to the reference sites. Liver P-450 activity correlated positively with sediment PAH, but intestinal P-450 activity seemed to reflect dietary exposure (Van Veld et al. 1990). The poor correlation between hepatic concentrations of PAHs and P-4501A is attributed to the rapid metabolism of these compounds (van der Weiden et al. 1994). 

An example of first-order plots is shown in Fig. 1 for benzo[a]pyrene (i.e., B[a]P) sorption on three different soils (in terms of organic matter content) and two sediment samples (marine and fresh water) at two different concentrations [1]. It can be noted that the plots are linear at both concentrations, which would indicate that the sorption process is first order. The findings that the rate constants are not significantly changed with concentration is a good indication that the reaction is first order under the experimental conditions that were imposed. 

Figure 3. Critical concentration behavior of actin self-assembly. For the top diagram depicting the macroscopic critical concentration curve, one determines the total amount of polymerized actin by methods that measure the sum of addition and release processes occurring at both ends. Examples of such methods are sedimentation, light scattering, fluorescence assays with pyrene-labeled actin, and viscosity measurements. Forthe bottom curves, the polymerization behavior is typically determined by fluorescence assays conducted under conditions where one of the ends is blocked by the presence of molecules such as gelsolin (a barbed-end capping protein) or spectrin-band 4.1 -actin (a complex prepared from erythrocyte membranes, such that only barbed-end growth occurs). Note further that the barbed end (or (+)-end) has a lower critical concentration than the pointed end (or (-)-end). This differential stabilization requires the occurrence of ATP hydrolysis to supply the free energy that drives subunit addition to the (+)-end at the expense of the subunit loss from the (-)-end.

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