European equity bourses are trading at session lows Friday, with oil and mining stocks the key laggards. Mining stocks are lower on profit-taking and reports that BHP Billiton's bid for Rio Tinto was facing increased scrutiny from the European regulators concerned about the impact on steel prices. CAC-40 is down 68pts (-1.35%), Xetra-DAX -91pts (-1.29%) and FTSE-100 is down 52pts (-0.84%).