A study of the effects of chromium exposure on the growth of Pseudokirchneriella subcapitata (Korshikov) hindak evaluated by Central Composite Design and Response Surface Methodology

Abstract

The aim of this study was to evaluate the effects of chromium exposure on the growth of P. subcapitata using the Central Composite Design (CCD) and Response Surface Methodology (RSM). The highest values for algal density and biomass were obtained in the longest exposure times and for the lowest chromium concentrations. The CCD used for the analysis of treatment combinations showed that a second order polynomial regression model was in good agreement with experimental results, with R (2) = 81.50 and 89.90; for algal density and biomass (p < 0.05), respectively. Only the exposure time was significant for algal density. For chlorophyll, in contrast, the exposure time, chromium concentration and their interaction significantly affected the growth of P. subcapitata. The findings confirmed the sensitivity of P. subcapitata to chromium (VI), which makes it a suitable bioindicator of environmental contamination for this metal.

Using response surface methodology to assess the effects of iron and spent mushroom substrate on arsenic phytotoxicity in lettuce (Lactuca sativa L.)

“…This indicated that the developed model could provide useful information for predicting the influences of the Fe and SMS contents on As toxicity towards plant growth within a range of tested factors. As expected, the response surface methodology; particularly CCD, was a valuable tool for evaluating the mathematical relationships between selected variables and the responses using minimal experimental sets, without the loss of any statistical reliability [19,22,44].…”

“…The response surface model consists of a group of empirical methodologies for analyzing the relationships between a cluster of controlled experimental parameters (Fe and SMS in the present study) and the observed responses (the root elongation of lettuce in study using non-As treated soil and EC 50 of As in the phytotoxicity study) according to one or more selected criteria [22]. In the present study, the second-order central composite design (CCD) was adopted to evaluate the effects of the Fe and SMS contents on the root growth of lettuce, and phytotoxicity on exposure to As.…”

“…To take the declared objectives of our experiment and render them into a quantitative measurement [22], the EC 50 values were estimated and applied in comparison studies on the As toxicity in the test soils. The estimated EC 50 (ranging from 29 to 147 mg As kg −1 dry soil) varied depending on the treated levels of Fe and SMS (Fig.…”

A new method for analysis of the toxicity of organophosphorus pesticide, dimethoate on rotifer based on response surface methodology

“…In contrast, response surface methodologies (RSMs) are a collection of mathematical and statistical techniques for experimental design, model development and analysis of problems, with the advantage that it could generate a maximum amount of information on the direct effect of test factors and their interactions [16]. In addition, the experimental design in RSM could help the researchers to verify if changes in the independent factors produced a statistically significant variation of the observed response [17]. Therefore, concentration-time-response analyses by RSM might predict how an organism displays a concentration and exposure time interactive sequence of different regulatory or compensatory response during exposure to pollutants.…”

Ecological risk assessment in pesticide contamination scenarios: from individuals to ecosystems responses

“…This microalgae constitute an important group of photosynthetic organisms that present high sensitivity and are widely used for the assessment the impacts on aquatic ecosystems (e.g. Giloni-Lima et al 2010;Rodgher et al 2012;. Environmental effects caused by pesticides can potentially the impact of microalgae community and modulate the primary productivity system and photosynthesis (Ferraz et al 2009).…”