That's the power steering cooling line / pipe. Follow the pipes back into the engine bay and you'll see that the connect to hoses ( with clamps ). Make sure the clamps are tight and in good working order. Then check the hoses them selves for any signs of leakage.
To test the area for leaks, make sure your power steering fluid is at the correct level, then ( with the engine running ) get someone to operate the power steering from lock to lock while you hold a decent size piece of cardboard near the suspect area and look for any pressure spray / leakage ( don't use your hands because pressurised hydrualic fluid "could" wind up going through your skin & into your blood stream ).
See how you go with that