Our SenSafe® Boris Mercury Check for water quality testing is a quick and easy method to test for low levels of Mercury. The Maximum Contaminant Level (MCL) for Mercury set by the USEPA is 2 ppb. With Boris Mercury Check you can easily test to ensure that your water is well below this level. This test Detects ultra lows of Mercury from the ranges of 2-80 ppb. SenSafe® Boris Mercury Check is great for process testing and ideal for detecting unsafe levels of mercury in drinking water. This test will only detect Hg+2 ions in the sample. Other metals will interfere.