*TSX down 42.81 points at 13,229.49
*Eight of 10 sectors weaker (Updates with details, comments)
By Claire Sibonney
TORONTO, Jan 10 (Reuters) - Toronto's main stock index fell on Monday morning, after dropping for all four trading days last week, as a flare-up of concern over the euro zone debt crisis dampened appetite for risk.
Base-metals miners slid 2 percent after the price of copper declined, with Teck Resources plunging 3.4 percent to C$59.82. [MET/L]. The euro zone worries pushed up the U.S. dollar, making metals costlier for non-U.S. investors.
"I think we're partly paying back for the very strong December ... it's unrealistic to expect continual strength in the market," said Ian Nakamoto, director of research at MacDougall, MacDougall & MacTier.
"There's always going to be some sort of pullbacks here as the worries that played out last year continue this year ... in particular what's going on with sovereign debt in Europe. It's a bit of deja vu but we just haven't solved the problems."
The latest concern came after senior euro zone source said in a Reuters interview on Sunday that pressure was growing on Portugal from Germany and France to seek financial help from the European Union and International Monetary Fund to prevent the debt crisis spreading. [ID:nLDE7080FG]
Also weighing a bit on sentiment, China's trade surplus fell 6 percent to $183 billion last year. [ID:nTOE709033]
At 10:20 a.m. (1520 GMT), the Toronto Stock Exchange's S&P/TSX composite index .GSPTSE was down 42.81 points, or 0.3 percent, at 13,229.49. Eight of the index's 10 main groups were weaker.
Limiting the index's losses, its gold-mining subsector firmed 0.4 percent as the price of the precious metal steadied, following a recent losing streak. [GOL/]
Barrick Gold Corp (ABX.TO) rose 0.3 percent to C$48.82, while Goldcorp Inc (G.TO) climbed 0.7 percent to C$42.82.
In individual company news, HudBay Minerals (HBM.TO) slumped 2.6 percent to C$16.32 after it said it would buy Norsemont Mining NOM.TOfor C$362.8 million. [ID:nSGE70908D] Norsemont shares were up 5.4 percent at C$4.50,
Baffinland Iron Mines BIM.TO gained 0.7 percent to C$C$1.43 after Nunavut Iron Ore said it would boost its takeover offer to C$1.45 in cash per share, plus one exchange right per common share. [ID:nN10262785]
Canadian Natural Resources CNQ.TO jumped 1.5 percent to C$41.20 after the company said it expects to have a repair schedule readied next week after a fire broke out at its main oil sands project in northern Alberta. [ID:nN07198897]
($1=$1.00 Canadian) (Reporting by Claire Sibonney; editing by Peter Galloway)