Microplastics research centres around their distribution within the water column and the effects they have once ingested by organisms. Therefore, little attention has been paid to the chemicals released from leaching plastic fragments and when studies have been conducted they have focused on single plastics of known origin, rather than plastic items more representative of those which end up in the environment consisting of a mixture of substances. The overall goal of this project is to investigate the molecular response and fitness outcomes of vertebrate and invertebrate model organisms as a result of combined environmental stress with the addition of stress experienced through exposure to plastic leachate derived from commercial products. It is expected that the combined stress of plastic leachate along with thermal and pH fluctuations will result in increased mortality and mutations within both vertebrate and invertebrate aquatic organisms. It is further expected that exposed individuals will experience an inhibited immune response and development along with negative behavioural and physiological changes.