Low Level Polyaromatic Hydrocarbons (PAHs) and Alkylated PAHs
Due to their pervasive nature and widespread sources of release, Polycylic Aromatic Hydrocarbons (PAHs) are of concern for environmental and human health. The most toxic of these compounds have been classified as Priority and/or Toxic Substances under Canadian and US Regulations and standards are in place for allowable limits.
PAHs are a group of over 100 different chemicals that consist of two or more fused benzene rings. PAHs are divided into two categories: low molecular weight compounds which are composed of fewer than four rings and high molecular weight compounds, composed of at least four rings. Compunds containing a straight carbon side chain are referred to as alkylated PAHs. Number of rings relates to the solubility and volatility of compounds. The solubility and volatility of compounds relates to the number of rings.
AXYS has many years of experience providing quality trace analysis for PAHs by GC/MS in soil, solids, water and biota. AXYS analyzes PAHs based on a modified EPA 8270 / 1625 method which uses incremental C13 labeled surrogates prior to extraction and subsequent quantification through relative recovery factors (RRF) to enhance detection limits and accuracy. In response to client requests, we also test PAH biomarkers such as alkylated PAHs via a modification to the prescribed methods. We are accredited for PAHs by CALA and are NELAC accredited by New York and California.
PAHs may be released into the environment from hydrocarbon fuels, through the incomplete combustion of organic substances, or through natural decomposition processes. Lighter PAH compunds are generally more water soluble and therefore are more bioavailable to aquatic life and cause more acute effects However breakdown times are much shorter than for heavier compounds. PAHs with more than four rings, being less volatile and soluble, favor adherence to solid particles. They are are generally found in soil and sediment as complex mixtures. Alkylated PAHs are more persistent than their parent PAHs.
Since PAHs are environmentally ubiquitous, limiting exposure to them is difficult. Humans are generally exposed to PAHs through inhalation of PAHs attached to dust and other air particles, such as tobacco or wood smoke, and by eating and drinking substances that contain PAHs. Workplace exposure may be significant in certain industries. The heavier PAH compounds tend to be associated with more chronic health effects. US EPA has identified 16 priority PAHs that are thought to be carcinogenic through multiple routes of exposure, and can effect the immune, reproductive, nervous and endocrine systems. The most toxic PAH is benzo(a)pyrene.
AXYS specializes in measurement of PAHs to nanogram or lower concentrations from standard sample sizes. Our specialized sampling and analytical procedures may allow for much lower detection limits and reduced sample sizes in human and sediment matrices. We deliver legally defensible data under ISO 17025 certified systems applying methods accredited by NELAP and CALA. Electronic Data Deliverables (EDD), customized for download to our clients relational databases, are available in addition to standard format report and full data packages.
Please contact one of our Project Managers at 1 888 373 0881 or +1 (250) 655-5800 to discuss how AXYS can support your analytical advantage.
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