Potassium permanganate (KMnO4) and potassium peroxymonosulfate (Oxone®) are chemical oxidants widely used in natural surface waters and wastewaters for the control and removal of pathogens and the prevention of disease caused by bacteria. However, KMnO4 and Oxone® have the ability to be toxic to aquatic life. Moreover, there is limited information within literature about the toxicity of these oxidizing agents to non-target organisms such as the microcrustacean Daphnia magna (D. magna). The purpose of this study was to evaluate the acute toxicity of KMnO4 and Oxone® to D. magna. The focus for this work is to determine the toxic effects on non-target organisms using the U.S. EPA approved Whole Effluent Toxicity (WET) Test performed with D. magna. Controlled Release Biodegradable Polymers (CRBP) were produced by encapsulating KMnO4 and Oxone® in polycaprolactone (PCL) per U.S. Patent #8,519,061. The CRBPs have previously been shown to be effective at reducing bacteria levels for Escherichia coli (E. coli), Enterococci, and total coliform in contaminated water. It was hypothesized that the CRBP could be a potential treatment technology to treat natural surface waters without toxicity to aquatic life. The CRBPs were tested at 0.1g KMnO4 encapsulated in 0.5g PCL and 0.3g Oxone® encapsulated in 0.5g PCL and released for 24h, 48h and 72h in 100-1000ml of natural surface test water to determine the toxic effects to D. magna. The results showed that the WET Test using D. magna demonstrated Oxone® CRBP can cause severe toxic effects to non-target organisms when released at any length of time, hence indicating potential damaging effects on higher level aquatic life that may receive effluents treated with this strong oxidant. Further results show that the KMnO4 CRBP caused minimal acute toxic effect in D. magna when released at longer lengths of time. These findings show KMnO4 CRBP exhibit promising minimal toxic effects on non-target organisms during environmental remediation