Ramadass Kavitha, Megharaj Mallavarapu, Venkateswarlu Kadiyala, Naidu Ravi
Centre for Environmental Risk Assessment and Remediation, University of South Australia, Mawson Lakes, SA 5095, Australia.
Global Centre for Environmental Remediation (GCER) and Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRCCARE), Faculty of Science, University of Newcastle, ATC Building, Callaghan, NSW 2308, Australia.
Ecotoxicol Environ Saf. 2017 Aug;142:538-543. doi: 10.1016/j.ecoenv.2017.04.052. Epub 2017 May 4.
Diesel is a commonly used fuel and a key pollutant on water surface through leaks and accidental spills, thus creating risk directly to planktons as well as other aquatic organisms. We assessed the toxicty of diesel and its water accommodated fraction (WAF) towards two microalgal species, Pseudokirchneriella subcapitata and Chlorella sp. MM3. The toxicity criteria included were: chlorophyll a content as a growth parameter and induction of enzyme activities linked to oxidative stress. Increase in concentrations of diesel or its WAF significantly increased toxicity towards growth, measured in terms of chlorophyll a content in both the algae. Activities of antioxidant enzymes such as superoxide dismutase (SOD), peroxidase (POX) and catalase (CAT) in response to addition of diesel or diesel WAF to the microalgal cultures were dose-dependent. Diesel WAF was more toxic than diesel itself, suggesting that use of WAF may be more relevant for environmental risk assessment of diesel. The overall response of the antioxidant enzymes to toxicants' stress followed the order: POX≥SOD>CAT. The present study clearly demonstrated the use of SOD, POX and CAT as suitable biomarkers for assessing diesel pollution in aquatic ecosystem.
柴油是一种常用燃料，也是通过泄漏和意外溢出对水面造成污染的关键污染物，从而直接对浮游生物以及其他水生生物构成风险。我们评估了柴油及其水溶成分（WAF）对两种微藻——羊角月牙藻和小球藻MM3的毒性。评估的毒性标准包括：叶绿素a含量作为生长参数，以及与氧化应激相关的酶活性诱导。柴油或其WAF浓度的增加显著增加了对藻类生长的毒性，这是通过两种藻类中的叶绿素a含量来衡量的。向微藻培养物中添加柴油或柴油WAF后，抗氧化酶如超氧化物歧化酶（SOD）、过氧化物酶（POX）和过氧化氢酶（CAT）的活性呈剂量依赖性。柴油WAF比柴油本身毒性更大，这表明使用WAF可能更适用于柴油的环境风险评估。抗氧化酶对毒物胁迫的总体反应顺序为：POX≥SOD>CAT。本研究清楚地证明了使用SOD、POX和CAT作为评估水生生态系统中柴油污染的合适生物标志物。
