The pullback in copper exchange traded funds amid a surge in volume shows investors are worried Europe’s debt upheaval might derail the economic recovery.

Many traders keep a close eye on copper exchange traded funds and notes because the red metal is seen as a leading indicator for the global economy.

The iPath Dow Jones-UBS Copper ETN (NYSEArca: JJC) was down more than 2% on Friday on concern that demand for industrial metals will subside. The First Trust ISE Global Copper Fund (NasdaqGM: CU) is down nearly 20% over the past month after slicing through its 200-day moving average.

Copper futures are down about 7% for the week, Bloomberg reports.

“There is a lot of disappointing macro data coming out of the U.S.,” Agnes Staines, an analyst at UBS AG in London, said, in a report. “As the market changes its sentiment toward an expectation for worse data, we’ll continue to see that being priced into commodities.” [Copper ETFs Crushed Along with Freeport, Miner Stocks.]

Despite Friday’s better-than-expected jobs report, U.S. economic data has been weak. Further adding to the skepticism are Europe’s sovereign debt problems, as Italy and Spain feel more pressure from financial markets. [Silver, Gold ETFs Eye Lower Start to Week.]