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A paler shade of green? The toxicology of biodiesel emissions: recent findings from studies with this alternative fuel
Citation:
Madden, M. A paler shade of green? The toxicology of biodiesel emissions: recent findings from studies with this alternative fuel. Biochimica et Biophysica Acta. Elsevier Science Ltd, New York, NY, 1860(12):2856-62, (2016).
Impact/Purpose:
In order to better understand the balance of advantages and disadvantages of the use of biodiesel in the nation’s energy structure, a comprehensive, up to date, life cycle analyses is needed to be in order to determine the overall utility of using a liquid fatty acid based fuel. One component of the life cycle analyses lacking in adequate data and findings is the endstage use where potential human toxicity could occur.The purpose of this review is to examine more recent findings of the toxicity of specifically biodiesel combustion emissions related to human health. The reader is referred to a 2007 review of then reported effects of biodiesel toxicology with additional literature reported in a book chapter related to biodiesel emission toxicology. A search with the term “biodiesel” in PubMed revealed 66 and 129 hits for the years 2006 and 2007, respectively, but an increase to 1812 and 1620 hits in 2014 and 2015, respectively. Included in this update are reports utilizing a variety of approaches that assist in determining potential health related outcomes from exposures to biodiesel or components of biodiesel. Typically surrogates of health effects are measured and reported as an early biomarker in a pathway believed to be involved in the development of an adverse response or disease. Effects of biodiesel combustion emissions on health endpoints could be incorporated into life cycle analyses of this fuel use.
Description:
Background: Biodiesel produced primarily from plants and algal feedstocks is believed to have advantages for production and use compared to petroleum and to some other fuel sources. There is some speculation that exposure to biodiesel combustion emissions may not induce biological responses or health effects or at a minimum reduce the effects relative to other fuels. In evaluating the overall environmental and health effects of biodiesel production to end use scenario, empirical data or modeling data based on such data are needed.Scope of Review: This manuscript examines the available toxicology reports examining combustion derived biodiesel emissions since approximately 2007, when our last review of the topic occurred. Toxicity derived from other end uses of biodiesel- eg, spills, dermal absorption, etc- are not examined. Findings from biodiesel emissions are roughly divided into three areas: whole non-human animal model exposures; in vitro exposures of mammalian and bacterial cells (used for mutation studies primarily); and human exposures in controlled or other exposure fashions. Major Conclusions: Overall, these more current studies clearly demonstrate that biodiesel combustion emission exposure- to either 100% biodiesel or a blend in petroleum diesel- can induce biological effects. There are reports that show biodiesel exposure generally induces more effects or a greater magnitude of effect than petroleum diesel, however there are also a similar number of reports showing the opposite trend. It is unclear whether effects induced by exposure to a blend are greater than exposure to 100% biodiesel. Taken together, the evidence suggest biodiesel emissions can have some similar effects as diesel emissions on inflammatory, vascular, mutagenic, and other responses. General Significance: While acute biodiesel exposures can show toxicity with a variety of endpoints, the potential effects on human health need further validation. Additionally there are few or no findings to date on whether biodiesel emissions can induce effects or even a weaker response that petroleum diesel with repeated exposure scenarios such as in an occupational setting.
