Assessment of sediment toxicity during anaerobic biodegradation of vegetable oil using Microtox® and Hyalella azteca bioassays

Abstract

ABSTRACT:The potential ecological impacts of anaerobic degradation of vegetable oil on freshwater sediments were investigated. Sediment toxicity was evaluated using two regulatory biotests: the Microtox 1 Solid Phase Test and an amphipod (Hyalella azteca) bioassay. The results of the Microtox test showed that the toxicity of the vegetable-oil-contaminated sediments (about 17-33 g oil/kg dry sediments) increased after 2 weeks incubation and then decreased to near background levels after incubation for 8 weeks under anaerobic conditions. The amphipod toxicity bioassay showed that the toxicity of fresh contaminated sediments decreased over time and returned to background levels within 8 weeks. These results suggest that the impact of vegetable oils on organisms within sediments may be limited. To account for the significance of environmental conditions, additional studies over a wide range of incubation conditions (e.g., temperature, nutrient concentration) and other test organisms at various trophic levels are recommended for both acute and chronic toxicity assessment. #

Effect of vegetable oil addition on bioaccessibility and biodegradation of polycyclic aromatic hydrocarbons in historically contaminated soils

“…Anaerobic degradation of vegetable oil may result in a higher transient increase of toxicity 48, 50. The inhibitory effect caused by canola oil concentrations of the same order as those presently applied on bacteria and sediment‐dwelling organisms was observed to be below related toxicity threshold values 50. Thus the use of canola oil in the same concentration range as applied in the present study is not expected to be of considerable environmental concern.…”

“…Rapid mineralisation of plant oil in soils, however, requires an adequate supply of oxygen and nutrients, which significantly impedes, if not satisfied, microbial activity 25, 35. Anaerobic degradation of vegetable oil may result in a higher transient increase of toxicity 48, 50. The inhibitory effect caused by canola oil concentrations of the same order as those presently applied on bacteria and sediment‐dwelling organisms was observed to be below related toxicity threshold values 50.…”

Effects of Vegetable Oil Pollution on Aquatic Macroinvertebrate Assemblage in a Freshwater Wetland and Its Use as a Remediation Tool

“…Although clay can effectively transfer vegetable oil from the water to sediments where anaerobic degradation of vegetable oil can occur, the metabolic intermediates of degradation may be toxic to microorganisms (Cherrington et al 1991), mussels (Mudge 1995) and amphipods (Li et al 2007). Transient sediment toxicity was also observed during the anaerobic biodegradation of vegetable oil in freshwater sediments (Li and Wrenn 2004).…”

Application of vegetable oils in the treatment of polycyclic aromatic hydrocarbons-contaminated soils

“…The toxicity of the oil residues in soil can be expected to decrease over time as the oil degrades [109], although it is not related to its persistency in the soil [112]. This means that it is important to monitor both biodegradation and toxicity of the oil in its application in soil remediation.…”

“…Rapid mineralisation requires an adequate supply of oxygen and nutrients. In systems lacking in oxygen, anaerobic degradation of vegetable oil may result in a higher transient increase of toxicity [109].…”