Some additives used in the plastic materials are surfactants but frequently they are not used for their surface or interfacial activity. Surfactant-like stuffs may increase the leaching concentration of persistent organic pollutants (POPs) to a certain extent.
To my knowledge, there is none but there is a project at ACES, Stockholme uni currently working on it.
There was that research published in Science (in 2017 i believe) with larval fish that was so flawed and later claimed to be fraudulent that has now been withdrawn. I would expect most of the POP's to diffuse in and out of most plastics but whether that is of any significance to aquatic animals is another and far more important question. However, solid state diffusion rates are usually fairly low and obtaining significant mass transfer or permeability (solubility times diffusion rate). It will "leach" but how much and how fast is something else.
If the POP's are in thermodynamic equilibrium between the water and the small plastic, when ingested by the fish it could come to equilibrium via diffusion with the lipids in the fish. However, we need to note that for every kg of dry wt feed a fish eats, it has to pass almost a million kg of water through its gills to obtain O2 and dump CO2. The potential POP mass transfer across the gills directly to and from the water can be the controlling factor in both bio-magnification/uptake and elimination of POP's .
If you look at the partitioning coefficients between oil/water, particulate/water, fats/water, plastics/water for the POP's they are all very high (depending upon the specific chemical species) implying that the concentrations should increase up the food chain much faster than they do. In aquatic system with organisms that obtain O2 from the water, this is the big mass transfer mechanism driving the system towards equal chemical activities of the POP's in all components, including the fats of the fish. Even if fish eat POP's, they can come back out the gills. This is not true of air breathers for non-volatile POP's so we see marine mammals and birds get into problems with POP's, but not fish.
That is why so called research on POP's in farmed salmon depends more on the water it was reared in and the fat content of the species (farmed Atlantic are much higher than Alaska canning salmon) and by reporting whole fish numbers using farmed samples from populous area like the N. Atlantic or BC Canada or Washington and using low fat Alaska samples as controls they can make claims of a difference between farmed and wild, while ignoring wild salmon from the same areas with the same levels per gm of fat. Hite, et. al. Science a few years back.
There is a long history of "advocacy science" by activists in this area mixed with with some good science while ignoring the 800 lb gorilla of bottom trawling fisheries. Most of these chemicals also are adsorbed and absorbed by sediments making a sink for POP's, but bottom trawlers put those sediments back into the water column allowing the POP's to return to the food chain as the come to chemical equilibrium with algae in the water column.
We have no way of eliminating most POP's from our bodies except in our sweat which is why the "cure" for chloral-acne from PCB or DDT's in industrial setting (long before OSHA and overreaching tight standards) was steam baths.
This can become a ripe area for more junk science as plastics in the ocean increase in numbers as they decrease in size.
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