The toxicity of a sample is indicated through the modification of fluorescence parameters based on chlorophyll fluorescence mission by photosynthetic enzyme complexes. The process is one of the most robust indicators for ecophysiologists. A plant bioassay can rapidly evaluate the toxicity of an effluent and can prove the efficacy of a treatment. Lab-Bell's LuminoTox is based on that widely accepted techniques. The LuminoTox test fit has two parts: a portable, powerful, and compact instrument and the PECs/consumables. The latter have been stabilized according to a proprietary technique to make sure that shelf life is commercially acceptable. The principle that supports the LuminoTox rapid toxicity screening device is described, along with a proposed, simple, effective method for selection of positive sample, in contrast to time-consuming and costly chemical and/or bioassay testing methods. Topics covered are the principle of operation, a representation of PEC with inhibition site, materials and method (reagents, preparation of PEC, and procedure), results and discussion, and the importance of ensuring that the blank, samples, and standards are treated in precisely the same way. Testing demonstrates that the LuminoTox device can provide a rapid screening and monitoring test for detection of toxicity in many molecules found in industrial or municipal effluents. The LuminoTox system is being automated to provide online monitoring of inadvertent or intended toxic discharges into the water supply or other environmental infrastructures.