The use of computer image analysis in a Lemna minor L. bioassay

Our study presents a low-cost method (no expensive hardware platforms required) of quantified biomonitoring based on computer image analysis. The negative influence of toxins on surface waters was analysed. The method was verified on widespread freshwater macrophyte Lemna minor to test populations treated with non-ionic detergents. We showed that the proposed automated bioassay has a broad applicability in assessing the negative impacts of aquatic toxicants. This approach enabled fast and precise evaluation of the morphometric parameters of the duckweed test population. We observed that growth rate of L. minor reacts to non-ionic detergents, which is reflected by the change in the surface area. The decrease in the growth of L. minor was revealed at high doses of detergents. This test proved to be highly useful, because it is well repeatable and fast in its implementation. Unlike classical bioassays, the proposed test allows the elimination of measurement errors, resulting from observers’ subjectivity.