Effect of microplastics on dry matter content in Lactuca sativa L.

Abstract

Plastics are commonly used in every field of life due to their ease of use and economics. If the plastic wastes are not disposed of properly, they form microplastics by breaking down into smaller particles with decomposition. Microplastics are chemical substances in polymer structure. They are difficult to dissolve in nature and require a long time. Microplastics, that spread to the environment in various ways, cause pollution and negatively affect organisms and ecosystems. 
 This study aimed to determine the effects of microplastics and the combined impact of microplastics and Cd on dry matter content (the ratio of dry mass to fresh mass of an organ), which is the one of the major plant traits for plant growth, in lettuce (Lactuca sativa L.). Five experiment sets were designed by using Simila variety lettuce seedlings, including (1) control, (2) 1.5 % microplastic (3) 2.5 % microplastic, (4) 1.5 % microplastic and 200 ppm Cd solution and (5) 2.5 % microplastic and 200 ppm Cd solution added. The polyethylene mulch pieces (2,5 mm x 4 mm) were used as microplastics. Results showed that the polyethylene microplastic addition to the soil significantly reduced aboveground and belowground DMCs of lettuce seedlings. Concentration of the microplastics in the soil was also effective on DMC. The Cd addition to the soils, which contain microplastics, a bit increased the DMC.