IMPACT OF INDUSTRIAL DYES ON ALGAL GROWTH

The deterioration of water quality because of industrial dye discharges is becoming an emerging environmental problem throughout the world. Dyes are directly discharged into nearby water bodies which in turn affect the aquatic ecosystem and human health. Dyes were degraded by means of biological methods. This study involves the application of two algae (Chlorella vulgaris and Spirulina) and oxidation pond in the decolourisation of dyes. The UV spectromax M3 spectrophotometer was used in reading absorbance values. Methylene blue (MB) (20 mg/l, 50 mg/l and 100mg/l), Eriochrome Black T (EBT) (20mg/l, 50mg/l and 100mg/l) and Melanoidin (100mg/l, 250mg/l and 500mg/l) at different concentrations were used for this study. Decolourisation was recorded in a 10-day experiment. In Spirulina, maximum dye removal was 92.37 percent (20mg/l) in methylene blue dye, 54.24 percent (20 mg/l) in EBT and 45.89percent (100mg/l) in melanoidin while in oxidation pond, the maximum dye removal was 91.84 percent (20mg/l) in methylene blue dye, 93.22percent (20mg/l) in EBT and 46.1 percent (100mg/l) in melanoidin and in Chlorella vulgaris, the maximum dye removal was 91.3 percent (20mg/l) in methylene blue dye, 79.25 percent (20mg/l) in EBT and 57 percent (100mg/l) in melanoidin. The dye removal was dependent on algal concentration and dye concentration. Gel puncture method was used to determine the toxicity of individual dyes on algae (Mixed sample, Scenedesmus and Lake Sample) at varying concentration of dyes.

Spectroscopic Determination of Fluoride Using Eriochrome Black T (EBT) as a Spectrophotometric Reagent from Groundwater

Fluoride health problem is a great concern worldwide, most often as a result of groundwater intake. Thus, determination of fluoride is vital to take appropriate measures upon fluoride contamination of water. Potentiometric method of analysis is reliable for the determination of fluoride in various samples. In addition, spectroscopic methods are found important to quantify fluoride levels from water; however, several factors hinder its easier determination. Among the bottlenecks, the use of toxic chemicals and tedious steps in preparing chemicals (e.g., SPADNS method) are to mention a few. In this study, a spectrophotometric method was developed for the determination of fluoride from groundwater using Eriochrome Black T (EBT) as a spectroscopic reagent. Experimental parameters that influence the determination of fluoride including ligand type, kinetics, pH, and ligand-to-metal ratio were assayed. Evaluation of fluoride levels showed that Beer–Lambert’s law is obeyed in the range of 0.3–5.0 mg/L at 544 nm. The calibration curve, resulting in good linearity (R2 = 0.9997), was considered during quantitative analysis of the samples and in the spiking analysis. The limits of detection (LOD) and quantification (LOQ) of the method were found to be 0.19 and 0.64 mg/L, respectively. The precision studied in terms of intraday and interday at three concentration levels showed less than 5.4% RSD. Applicability of the method was investigated by analyzing groundwater samples spiked with fluoride standards, and satisfactory recoveries in the range of 98.18–111.4 were demonstrated. The developed spectrophotometric method has been successfully applied for fluoride determinations in groundwater samples. Thus, it could be used as an attractive alternative for the determination of fluoride from groundwater.