In the last trading session, Wall Street rebounded from the sell-off witnessed at the end of last week. Among the top ETFs, (SPY Quick QuoteSPY - Free Report)  inched up 0.2%, (DIA Quick QuoteDIA - Free Report)  slipped 0.2%, and (QQQ Quick QuoteQQQ - Free Report)  moved 1.6% higher on the day.

Two specialized ETFs are worth noting as both saw trading volume that was far outside the normal. In fact, both these funds experienced volume levels that were more than double their average for the most-recent trading session. These ETFs may be worth watching in the coming days to see if the increased investor interest continues.

(PHO Quick QuotePHO - Free Report) : Volume 7.39 Times Average

This water resources ETF was under the microscope as about 0.80 million shares moved hands. This compares with an average trading volume of roughly 0.11 million shares and came as PHO slipped about 0.1% in the last trading session. PHO has been down 1.4% over the past month.

(GSC Quick QuoteGSC - Free Report) : Volume 5.23 Times Average

This small-cap ETF was in the spotlight as around 0.15 million shares moved hands compared with an average of 23,000 shares a day. We also saw some price movement as GSC rose 1.1% in the last session. GSC has gained 1.6% over the past month.