Quantifying the anthropogenic fraction of fatty alcohols in a terrestrial environment

Abstract

Fatty alcohols are naturally produced hydrocarbons present in all living organisms. They are also used in detergent and cosmetic formulations, may be sourced from either petroleum or biological materials, and are typically disposed of down the drain. This study was conducted on the Luray catchment, Virginia, USA, where sales data indicate that approximately 2 kg of fatty alcohols from detergent enter the wastewater every day. Reconstructing fatty alcohols in the influent on the basis of sales data indicated a mix of odd and even chain compounds, with C(12) being dominant. This profile was influenced strongly by liquid laundry detergents (69%). Sediment and soil samples from the catchment were analyzed by gas chromatography-mass spectrometry and by stable isotope ratio mass spectrometry to determine the δ(13)C and δ(2)H signatures. The long-chain components in agricultural soils and river sediments were distinguishable clearly from the algal fatty alcohols produced within the river system. The wastewater was a mixture of fecal and detergent sources of fatty alcohols in a ratio of 75:25%. The fatty alcohols in the effluent had different stable isotopic signatures and chain-length profiles from the influent, indicating that these compounds are not the same as those that entered the treatment plant. The total quantity of fatty alcohols leaving the treatment plant through the effluent pipe was low compared with the input. Analysis of the contributions based on the stable isotopes and profiles suggests that of the fatty alcohols present in the river system downstream of the treatment plant, 84% were derived from terrestrial plant production, 15% came from in situ algal synthesis, and 1% were derived from the effluent.

iSTREEM®: An approach for broad-scale in-stream exposure assessment of “down-the-drain” chemicals

“…Modeled results from iSTREEM can identify the spatial distribution of worst‐case scenarios (highest exposure) on which monitoring efforts can be optimally focused. For example, a national site selection was conducted for monitoring surfactants in sediment using the iSTREEM model and related data sources to identify locations of highest potential exposure that were also within practical proximity to a sediment collection contractor (Sanderson et al ; Mudge et al ). Although the iSTREEM model currently does not directly incorporate a probabilistic component, the model can be used as a tool within a probabilistic assessment.…”

Environmental Safety of the Use of Major Surfactant Classes in North America

“…Recent studies by Mudge (2012) and Mudge et al (2008), Mudge et al (2010), and Mudge et al (2012) have shown that LCOHs from both fecal and detergent sources rapidly biodegrade in wastewater treatment facilities, as discussed below. In effluent, the remaining alcohols have a signature that is unlike influent, as a result of mixed-liquor in situ (bacterial) synthesis of alcohols.…”

“…The alkyl chain length of LCOH (Table 1) was identified by the OECD HPV program to range from C 6 to C 22 (The Organisation for Economic Co-operation and Development [OECD], 2006); however, the typical range in detergents of interest is between C 9 to C 18 as verified in several monitoring programs for alcohol and alcohol-based surfactants (Mudge et al, 2008, 2010, 2012; Mudge, 2012). The alcohol group is usually located in the terminal position of the aliphatic chain, but not necessarily so, and are normally saturated (no double bonds).…”

Determining the Bio‐Based Carbon Content of Surfactants

“…The δ 13 C for many crude oils is in the range of −23 to −28‰. This may be compared to −26 to −36‰ for terrestrial plant matter and −20 to −26‰ for unicellular algae (Mudge et al, 2012). Since these ranges overlap, this may not be definitive in separating out the two sources.…”