Dependence between LD50 for Rodents and LC50 for Adult Fish and Fish Embryos.

We revealed empirical dependences between common logarithm of a ratio of rat oral LD50 to LCa50 for adult fish and lgP for 50 different chemicals; and common logarithm of a ratio of the oral LD50 in rodents to LCe50 for fish embryos and lgP for 30 different chemicals. The dependences were obtained by constructing a trend line between experimental points and calculation of Pearson's R correlation coefficient as a measure of regression significance. These dependences can show the influence of substance lipophilicity on its toxicity for aquatic organisms comparing to mammals.

[TOXICOMETABOLOMICS: DETERMINATION OF MARKERS OF CHRONIC EXPOSURE TO LOW DOSES OF ALIPHATIC HYDROCARBONS].

The metabolic profile of plasma of white non-linear rats was investigated under normal conditions and after chronic inhalational exposure to low doses of aliphatic hydrocarbons with the number of carbon atoms from 6 to 10. Metabolic profile was determined with combination of gas chromatography-mass spectrometry and high performance, high resolution liquid chromatography-mass spectrometry with subsequent use of chemometrical methods for data treatment and presentation. It was shown that continuous 90-day exposure to a mixture of C6-C10 saturated hydrocarbons at concentration of 160 ± 20.5 mg/m³ results in various impairments of metabolic processes in liver and kidneys. Exposure to hydrocarbons at doses of 31.4 ± 5.6 mg/m³ and 5.2 ± 1.8 mg/m³ evoked significantly smaller changes. Novel metabolic markers of the toxic effect of low concentrations of C6-C10 aliphatic hydrocarbons were revealed. The ratio of concentrations of pyrophosphoric and oxalic acids in rat blood plasma was found to be the most sensitive marker called <>. A hypothesis is put forward about the redox balance violation as the leading pathogenetic mechanism of neuropathies and concomitant pathologies associated with hydrocarbon chronic intoxication.

Aliphatic and polycyclic aromatic hydrocarbons in the surface sediments from the Eastern Aegean: assessment and source recognition of petroleum hydrocarbons.

MATERIALS AND METHODS: Aliphatic and polycyclic aromatic hydrocarbons (PAHs) were determined in surficial sediments from the Aegean Sea in the Eastern Mediterranean in 2008. RESULTS: Total aliphatic hydrocarbons (n-C12 to n-C35) ranged from 330 to 2,660 ng g(-1) dry weight (dwt), while aromatics (19 PAHs) varied between 73.5 and 2,170 ng g(-1) dwt. Total concentrations of both aliphatic hydrocarbons and PAHs ranged from a relatively low to a moderate PAHs pollution compared to other urbanized coastal areas worldwide. PAH consisted mainly of pyrolytic four- to five-ring compounds. Both pyrolytic and petrogenic PAHs are present in most samples, although petroleum-derived PAH are dominant at Izmir Inner Bay (IIB) and Dardanelles Strait, and pyrolytic sources are prevalent in other sampling sites. A high contribution of perylene, a diagenetic originated PAH, to the total penta PAHs was found greater than 70% in Meric River Estuary, Dikili Bay, Candarli Bay, and Gokova Bay sites. CONCLUSION: The spatial distributions of aliphatic hydrocarbons and PAHs indicated that urban runoff and transport from the continental shelf is the major input pathway of anthropogenic and biogenic hydrocarbons from terrestrial sources in the near-shore area. PAH levels at all sites were below the effects range-low (ERL) and effects range-median (ERM) values except fluorene. The average and maximum fluorene concentrations exceeded ERL, but below ERM, in the IIB. Meanwhile, the concentration levels of naphthalene, fluorene, phenanthrene, fluoranthene, pyrene, benzo[a]anthracene, and chrysene were higher than threshold effect level values at the same site, but all these compounds were significantly lower than the probable effect level values. The results indicated that the sediments should have potential biological impact.

Screening of Australian native grasses for rhizoremediation of aliphatic hydrocarbon-contaminated soil.

Rhizoremediation involves the breakdown of contaminants in soil resulting from microbial activity that is enhanced in the plant root zone. The objective of this study was to identify Australian native grass species as suitable candidates for rhizoremediation application. Seeds of nine perennial Australian native grasses were sown in soil from a mine site and artificially contaminated with a 60:40 diesel/oil mixture at concentrations of 1% (w/w), 0.5% (w/w), and 0% (control). Seedling emergence was not adversely affected by the presence of hydrocarbon contamination for all but one grass species. Three promising species (Brachiaria decumbens, Cymbopogon ambiguus, and Microlaena stipoides var. Griffin) were assessed for growth characterization in contaminated and uncontaminated soils. The evaluated species survived for 120 days in the contaminated soil and, in some instances, produced considerably more root biomass in the presence of contamination. C. ambiguus showed growth stimulation in the presence of contamination (1% and 0.5% w/w) with significantly increased root biomass production compared with the control (p = 0.0001). B. decumbens and M. stipoides showed tolerance, without adverse growth effects in the presence of diesel/oil at the exposed concentrations. Stimulation of the rhizosphere microbial population that is capable of degrading diesel/oil was found for all of the species tested, using a most probable number method for enumeration. This investigation has identified suitable candidates for further investigation of their rhizoremediation potential.