successful seed germ encompasses a lot of factors, temperature, humidity, light or lack of light, age of seed, storage and treatment of seed, even the imperceptible factors like slight drying on the edges of the tray, slight light leaks if darkness is required, temperature variations, etc. Then there are the possible pathogens in the soil/germ mix. each species of seed will require a slightly different treatment for optimum germination. As far as tests for pesticides, I don't know of any, and typically the residual effect of present day pesticides is pretty short. I think the advice given about recycling/composting within your garden, knowing the source is always the best - on all levels.
Lisa in Mpls.