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Transport and Fate
Phenanthrene, along with many other PAH compounds, are considered ubiquitous in the environment, as they have been found in the air, water, soils, and in plants and crops. A majority of phenanthrene ends up in the soil. Wet and dry deposition of PAHs present in urban emissions and wildfire smoke can transport phenanthrene from the atmosphere to soil and surface waters of lakes, rivers, and streams. Phenanthrene in wildfire ash can also be incorporated into the soil or be washed into aquatic ecosystems through water erosion and runoff. In the soil, phenanthrene primarily undergoes either mineralization or is converted to bound residues in the soil matrix. Microbes play a dominant role in converting phenanthrene to non-extractable residues, which can become bioavailable for soil organisms, posing a toxic threat to this ecosystem. From the soil, plants can take up phenanthrene through the roots. A study done on wheat plants showed that phenanthrene is taken up by the plant in two phases: the fast phase, in which phenanthrene diffuses into the roots from the surrounding soil through passive and active uptake, and the slow phase, in which phenanthrene is distributed throughout the plant and accumulates in the tissues.

A majority of the phenanthrene entering aquatic organisms comes from storm water runoff and effluent wastewater discharge from industrial facilities using fossil fuels. Once in freshwater or marine aquatic ecosystems, the phenanthrene partitions between the aqueous and particulate phases. Because PAHs like phenanthrene are extremely insoluble in water, they can remain in the water column as well as sorb onto organic carbon in soil particles and accumulate in benthic sediments. The phenanthrene in these sediments can accumulate in the tissues of benthic organisms, and phenanthrene present in the water column and in crude oil from oil spills on the surface can accumulate in fish and other pelagic organisms. Along with sorption and accumulation, phenanthrene can be lost through biodegradation and photodegradation. Marine bacteria, algae, and other microbes can metabolize PAHs, removing them from aquatic ecosystems. Phenanthrene, along with other PAH compounds, are photosensitive, which also means they can degrade in the presence of UV radiation; however, photodimerisation and photooxidation can create metabolites that are more toxic than the original compounds.

Health Effects
The most common way in which phenanthrene and other PAHs enter the human body is through inhalation. It can also enter the body if the skin comes into contact with contaminated soils or other products containing phenanthrene, or if contaminated food or water is ingested. Phenanthrene is a known irritant, and can cause the skin to become sensitive in the presence of sunlight. Phenanthrene is extremely lipid-soluble and can accumulate readily in the lungs, gut, and fat of humans. Although there are virtually no tests done on human subjects, the toxicity of phenanthrene has been studied in rats and rabbits. According to multiple animal toxicology studies, phenanthrene is a non-carcinogenic compound and was found to not induce the growth of mammary tumors in rats. A study of in utero exposure to PAHs done on rats showed that phenanthrene induced abnormal lipid metabolism through epigenic modification. This is the modification of DNA, resulting in changes of how genes are expressed and regulated. The study also showed that the transcription of genes related to lipogenisis, the metabolic process for fat storage, were upregulated. Blood chemistry has also been performed on rats injected with phenanthrene and ozonized forms of phenanthrene. Phenanthrene injections in the blood led to significant elevations in the rats' serum aspartate aminotransferase (serum AST) and and y-glutamyl transpeptidase levels. Serum AST and y-glutamyl transpetidase are enzymes that are released in the body as a response to liver damage. The subchronic and chronic effects of phenanthrene have not yet been documented in the literature; however, because people are exposed to phenanthrene in higher amounts relative to other PAHs and its metabolites are easily detected in urine, phenanthrene has been proposed as a good biomarker for general PAH exposure. Although it is not considered to be a carcinogen, phenanthrene is still one of the 16 PAH compounds included on the EPA's Priority Pollutants list.