Freshwater organisms are exposed to a myriad of anthropogenic pollutants, and the physiological impacts of many of them remain understudied. Traditional endpoints such as mortality and reproduction are insufficient to determine the true risk level of pollutants, particularly where mixtures are concerned due to pollutant synergy and non-additive effects. Furthermore, these endpoints give little insight into the mechanisms of pollutants. This research evaluates the effects of a variety of chemicals on key enzymes and physiological markers in the cladoceran Daphnia magna, specifically alkaline phosphatase (ALP), acid phosphatase (ACP), β-galactosidase (βGal), lipase, lactate dehydrogenase (LDH), peptidase, glutathione-S-transferase (GST), lipid peroxides (LOOH), and reduced thiols, in order to assess the impact of a battery of pollutants. The tested pollutants were divided into 4 main categories: metals (aluminium, cadmium, cobalt, lithium, zinc, zirconium), non-steroidal anti-inflammatory drugs/NSAIDs (Acetylsalicylic acid, diclofenac, ibuprofen, indomethacin), pharmaceuticals (Diltiazem, metformin, chlorpromazine, mebendazole, propranolol), and general pollutants, a broader category (N-phosphonomethyl glycine, L-nicotine, 4-nitrophenol, phthalic acid). As aquatic pollution is rarely derived from a single chemical or pollutant, 2 mixture scenarios were also investigated. The first was a composite mixture of 8 chemicals taken from the previous 4 categories (lithium, aluminium, acetylsalicylic acid, propranolol, diltiazem, N-phosphonomethyl glycine, L-nicotine, metformin). Dose-response was investigated in this section using various concentrations of the composite mixture. The second scenario involved single, double, and triple mixtures of three selected chemicals (Lithium, propranolol, L-nicotine). EC50 concentrations for all listed chemicals and mixtures were derived from constructed toxicity curves. EC50 is defined here as the concentration of a substance required to have a 50% mortality rate in 4-day old Daphnia magna. Significant results were observed in all categories and mixtures, as well as non-additive toxicity effects in the mixture section. Novel biochemical data was produced for several understudied pollutants which can be found in the freshwater environment.