Evaluating Aquatic Toxicity by Visual Inspection of Thallus Color in the Green Macroalga Ulva: Testing a Novel Bioassay

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• 作者：Young-Seok Han ; Murray T. Brown ; Gyoung Soo Park ; Taejun Han
• 刊名：Environmental Science & Technology
• 出版年：2007
• 出版时间：May 15, 2007
• 年：2007
• 卷：41
• 期：10
• 页码：3667 - 3671
• 全文大小：285K
• 年卷期：v.41,no.10(May 15, 2007)
• ISSN：1520-5851

文摘

A novel bioassay that uses visual inspection of reproductionof the aquatic green macroalga Ulva has been developedfor testing toxic chemicals. The method employs atechnique to quantify percentage reproduction based onthallus color change during the progression of reproduction.The validity of visual inspection as a reliable methodwas supported by a high test score (80.4) from a test ofthe ability of 97 first year university students with no biologybackground to evaluate reproduction by visual observationafter 30 min training. The sensitivity of the method wasassessed using a reference toxicant (sodium dodecyl sulfate;SDS; EC₅₀ = 7.1 mg·L^-1), heavy metals Cu (0.063 mg·L^-1),Cd (0.217 mg·L^-1), Pb (0.840 mg·L^-1), Zn (0.966 mg·L^-1),formalin (1.458 mg·L^-1), diesel fuel (3.7 mL·L^-1), and is shownto be similar or better than more established aquatictoxicity bioassays. Toxicity data obtained by the Ulvabioassay for elutriates of sludge collected from nine differentlocations were directly compared with the commerciallyavailable Microtox test. Ulva reproduction was significantlyinhibited in all elutriates with the greatest and leasttoxic effects, estimated by toxicity units (TU) observed inelutriates from industrial waste (13.1 TU) and a filtration bed(4.8 TU), whereas values ranging from 1 to 4.5 TU wereobtained from the Microtox test, confirming that the Ulvabioassay is more sensitive. Correlation analyses for EC₅₀ dataversus the concentrations of toxicants in the sludgeindicated a significant relationship between toxicity andfour heavy meals (Cd, Cu, Pb, Zn) for the Ulva bioassay butno such correlation was detected by the Microtox test.The new bioassay method is simple to use, easy to interpret,economical, and eco-relevant so would be a valuableaddition to aquatic toxicity testing protocols for a widerange of toxicants. Moreover, since Ulva has a widegeographical distribution and species have similarreproductive processes, the test method has worldwideapplication.