During industrial activity of Public Joint Stock Company "AVTOVAZ" there is emission of waste water to Kuibyshevsky water reservoir. Principles of control of degree of toxicity of waste waters and other toxins are discussed. Results of investigation of toxicity of waste water of "AVTOVAZ" company as a factor of negative impact to environment on the example of Kuibyshevsky water reservoir are described. Results allow drawing the following general conclusions: the surface waters of Kuibyshevsky water reservoir in the place of emission of waste water of Public Joint Stock Company "AVTOVAZ are toxic, but do not have acute toxicity.