On March 11, 2012, 17-year-old open water junior worlds qualified Barbara Benke from Brazil was tested positive to the substance Isometheptene (Class S.6 Stimulants), and therefore imposed a sanction of 4 month’s ineligibility starting on that day. And on March 25, 2012, 19-year-old 2009 Youth Asian Games champion Litvina Yuliya from Kazakhstan was tested positive to the substance Methylhexaneamine (Class S.6 Stimulants), and imposed a sanction of 6 month’s ineligibility. See FINA here and here