Method development for aquatic ecotoxicological characterization factor calculation for hydrocarbon mixtures in life cycle assessment

Abstract

Most pollutants are released into the environment in the presence of other contaminants, creating complex mixtures. In life-cycle impact assessment (LCIA) methods, characterization factors (CFs) are used to obtain the potential impacts associated with each contaminant emission. Current LCIA methods do not include CFs to evaluate the potential impacts of complex organic mixtures on ecosystems. This study explores the possibility of developing new CFs for petroleum mixtures. Petroleum products are an example of mixtures whose constituents have a common toxic mode of action: the narcosis effect. Characterization factors were calculated for a series of representative constituents of a specific petroleum mixture and also for different fractions of the same mixture developed using the hydrocarbon block (HBM) and Total Petroleum Hydrocarbon Criteria Working Group (TPHWG) methods. Finally, CFs were developed for the mixture itself as a whole by using experimental property measurements and estimations. The soil-water partitioning coefficient, water solubility, degradation kinetic constant in soil, octanol-water partitioning coefficient, and vapor pressure were measured while the molar weight and the degradation kinetic constants in air, water, and sediments were estimated. The highest aquatic ecotoxicological CFs, no matter the approach chosen, were obtained for an emission to freshwater up to 2.2 × 10(+07) PAF·m(3) ·d/kg for the highest CF. CF distributions obtained using the different blocking method and experimental CFs obtained for oil as a whole are, on average, not significantly different, given the known uncertainty of ecotoxicological models in LCIA. Consequently, all the CFs obtained using the different blocking methods from the literature are considered relevant for characterizing the potential impact for aquatic ecotoxicity of petroleum substances.

Ex-situ biodegradation of petroleum hydrocarbons using Alcanivorax borkumensis enzymes

“…Enzymatic degradation can be affected by many parameters, such as the hydrocarbons present in the contaminated site, the concentration of the pollutant, the environmental compartment in which the process is being carried out and the enzymes adaptation [27,28].. In the current study the influence of substrate concentration on the degradation rate of A. borkumensis, was very representative.…”

The potential ecotoxicological impact of pharmaceutical and personal care products on humans and freshwater, based on USEtox™ characterization factors. A Spanish case study of toxicity impact scores

“…Toxicologists consider that compounds which affect the same organ can cause an additive effect; LCA do not work with target organisms, their impact categories are much broader, so it is more difficult for this methodology to manage the possible synergistic or antagonistic effects of mixtures (UNEP, 2003). In this sense, some researches were conducted in order to obtain CFs for evaluating the potential impacts of complex mixtures on ecosystems, such as the studies carried out by Bamard et al (2011) who developed a method to calculated CFs for hydrocarbon mixtures, and Li et al (2015), who improved health impact estimates of 16 polyclyclic aromatic hydrocarbons (PAH) with the USEtox TM method. They explored the importance of emission profiles for the PAH mixture and illustrated how these improvements affect the LCIA case study; but for the majority of existing compounds which can reach the environment, be mixed and interact with it, much still remains to be studied.…”

A re‐evaluation of PETROTOX for predicting acute and chronic toxicity of petroleum substances

“…[1,2]. It has been broadly applied to assess aquatic, soil, and sediment toxicity, multimedia exposures, product and site risk, and life cycle, in a variety of other research and regulatory contexts [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19].…”