title: Toxicity and oxidative stress induced by used and unused motor oil on freshwater microalga, Pseudokirchneriella subcapitata.
abstract: Although used motor oil from automobiles is one of the major pollutants through storm water in urban environments leading to contamination of water bodies, very little information is available on its toxicity towards growth of microalgae. Also, to our knowledge, there are no data on the used motor oil-induced oxidative stress in microalgae. We therefore investigated the toxicity of used and fresh motor oil on growth and antioxidant enzymes of a microalga, Pseudokirchneriella subcapitata. In general, used oil was more toxic to the alga than fresh oil. Used oil at 0.20 % inhibited algal growth, measured in terms of chlorophyll a, by 44 % while fresh oil was nontoxic up to 2.8 %. Water-accommodated fraction (WAF) of the used oil at >50 % concentration exhibited significant toxicity while WAF from fresh oil was nontoxic even up to 100 %. Used oil and its WAF, even at lower concentrations, increased the levels of antioxidant enzymes indicating algal response to the toxicity stress. When the alga was exposed to WAF from fresh motor oil, no alterations in the antioxidant enzyme levels were evident. The present investigation suggests that contamination of aquatic systems with used oil could potentially affect the ecosystem health via disruption of primary producers that are located at the base of the food chain.
authors.affiliation: Centre for Environmental Risk Assessment and Remediation (CERAR), University of South Australia, Mawson Lakes, SA, 5095, Australia.
authors.forename: Kavitha
authors.initials: K
authors.lastname: Ramadass
authors.forename: Mallavarapu
authors.initials: M
authors.lastname: Megharaj
authors.forename: Kadiyala
authors.initials: K
authors.lastname: Venkateswarlu
authors.forename: Ravi
authors.initials: R
authors.lastname: Naidu
mesh_terms: D002734:Chlorophyll / Q000378:metabolism*; D000077194:Chlorophyll A; D000460:Chlorophyta / Q000187:drug effects*; D005618:Fresh Water; D058086:Microalgae / Q000187:drug effects*; D018384:Oxidative Stress / Q000187:drug effects*; D010578:Petroleum / Q000633:toxicity*; D014874:Water Pollutants, Chemical / Q000633:toxicity
chemical_list: D010578:Petroleum; D014874:Water Pollutants, Chemical; D002734:Chlorophyll; D000077194:Chlorophyll A