Method for biologically monitoring the environment (variants) and a system for carrying out said method

The invention relates to ecological environment monitoring based on native animals functional state control. The method includes exposure a test animal to IR radiation using an optical radiation source and a transmitting optical fiber; receiving the reflected IR radiation using a receiving optical fiber; converting the reflected IR radiation to an electrical signal; determining a sample of values of the signal periods and the sample dispersion; and forming a danger signal when the threshold value exceeds the sample dispersion. The system contains a cardiac activity sensor which includes a transmitting and receiving optical fibers, an optical radiation source and optical radiation receiver; an amplifier, an analog-to-digital converter and a computer. The output end of transmitting fiber and the input end of receiving fiber have the same direction and are positioned at a distance R satisfying the inequality (pid2P)0.07-2.2(1/(pid2P))0.02@R@(pid2P)0.07+2.2(1/(pid2P))0.02.