Pollution control and environmental protection have become a worldwide issue of concern. The aliphatic hydrocarbons (AHs), aromatic hydrocarbons (ArHs) such as benzene and toluene, and polycyclic aromatic hydrocarbons (PAHs), including benzo[
2. Sources of hydrocarbons
The major hydrocarbon sources are petroleum and petroleum combustion; however, their emission sources can be classified as phytogenic (natural), petrogenic, and pyrogenic. To recognize pollutant type and migration, circumstances play a key role for their origin . Hydrocarbons can enter to the environment via dispersion, evaporation, dissolution, adsorption, and other processes including petroleum and petroleum combustion [13, 14]. Petrogenic sources generally pollute groundwater and threaten the environment because petrogenic source products including lubricants and fuels leak from the tanks and release into the environment . The USEPA specified 16 priority PAHs in a petroleum source, namely, alkylated naphthalene, dibenzothiophene, fluorene, phenanthrene, and chrysene series . The pyrogenic PAHs are produced during the fuel combustion because there are suitable conditions that are high temperature and absence of oxygen. Also, pyrolysis of fat and incomplete combustion besides power plants are the most prominent hydrocarbon sources . Hydrocarbons and their derivatives are a significant environmental concern due to their extensive use and toxic mechanism action, and these products are highly available in aquatic medium [18, 19]. Industrial activities and chemical plants produce PAHs, and they are considered as petrogenic and natural PAH sources . During fat pyrolysis and incomplete combustion processes, anthropogenic emissions of PAHs are released into the environment [7, 8]. On the other hand, PAH sources were classified as natural, industrial, domestic, agricultural, and mobile by Ravindra et al. . Hydrocarbons are usually generated by various sources including wildfires, oil seepages, volcanic activities, and other sources. Moreover, these natural hydrocarbons are mainly produced during organic material chemical conversions in microorganisms, fungi, plants, sediments, etc. [16, 22, 23, 24].
3. Health threat and environmental impact assessment
Recent studies have recognized the effects of toxicity, mutagenicity, and carcinogenicity of hydrocarbons. Increasing contamination level of these pollutants in environment especially in aquatic media is a significant environmental concern because they are used frequently and show environmental toxic effects [25, 26, 27, 28]. The USEPA and World Health Organization (WHO) classified PAHs and total petroleum hydrocarbons (TPHs) as POP groups in marine and coastal environment [29, 30]. The most of PAHs have been banned by health authorities due to their long half-life, wide distribution, and high bioaccumulation in the food chain, as well as their potential for toxicity to humans, because these compounds are highly lipid soluble and these toxic chemicals can bioaccumulate from environment to the gastrointestinal tract of mammals [25, 31]. When animals and humans are exposed to hydrocarbons, it is probable that they have various health problems because they are vulnerable and endangered against these components. Research on some hydrocarbons including benzo[
4. Conclusion and future perspectives
The main aim of this study is to provide contemporary information on a variety of hydrocarbons present in the environment, exposure routes, and their adverse effects on ecosystem. Hydrocarbon sources, human health impact, and effect on the environment have been thoroughly investigated and presented. In light of this information, generated by natural or anthropogenic sources, hydrocarbons’ mutagenic, teratogenic, and carcinogenic characteristics have caused serious concerns in today’s environment; thus, various remediation techniques are needed to remove these hazardous chemicals from the environment. Therefore, some suggestions were presented as:
All health authorities should develop standard methods for analysis of hydrocarbons and share it for all researchers.
Researchers should develop more various remediation techniques available for hydrocarbons, and they should be applicable on every aspect of the environment such as soil, water, and air.
After the treatment process, developed remediation techniques should not leave behind any second pollutant.
Ecological risk assessment should be evaluated using the risk quotient.
Techniques for removing hydrocarbons from the environment should be developed, but it is important that preventive measures can be taken to prevent these pollutants from entering the food chain and environment.