sql server service broker
Looks like you're using a tool not capable of identifying benign waits. See Wait statistics, or please tell me where it hurts. There is no impact, just bad monitoring.

I recommend you read Filtering out benign waits. The engine has certain background tasks and when these background tasks don't have any work they simply sit idle, waiting for work. while waiting for work, the wait times are aggregated by the wait stats but unfortunately there is no way to distinguish between 'wait for a resource to continue the work' or simply 'wait for something to do to start the work'. The later case is a 'benign wait'. The less work these tasks actually do, the more wait stats they aggregate. These tasks never shut down and there is no session to close. You have embarked on a snipe hunt.

For more details read Understanding how SQL Server executes a query and How to analyse SQL Server performance.