Microplastics can float on the surface or remain suspended at various depths in the water column. During summer stratification, our depth profile found the lowest concentrations at the surface, the highest in the middle, and lower concentrations again near the bottom of the lake. This one-time test was conducted in August at the deepest point of the lake (west of Oak Island). Water samples were collected every 5 m from the surface down to 20 m, just above the lake floor.
Why? All other water samples were obtained from the top 10 cm of the water column, while sediment samples were taken from the bottom. This depth profile helped us understand what is happening in the middle of the water column. These results show that microplastics are present below the surface, especially in the middle layers of the stratified lake. Since the openings in a typical foot valve are larger than many microplastic particles, they can be sucked into your plumbing system.
