Quantitative analysis of trace metals in the Raritan River with inductively coupled plasma mass spectrometer

Raritan River is the largest river basin in New Jersey, providing the water supply for one million people in seven counties nearby. In this study, water samples collected from 11 Raritan River standard sampling stations along the Raritan Estuary to the Atlantic Ocean were analyzed for concentrations of trace metals and their isotopes. The concentration of each trace metal was measured with inductively coupled plasma mass spectrometer (ICP-MS), with normalization of internal standard and correction with acid blanks. The metal concentration levels were compared to the National Recommended Water Quality Criteria (NRWQC). Results showed that the metal concentrations generally increased with the sampling station number, indicating that more trace metals were distributed in seawater than freshwater along the river basin. None of the sampling stations had concentrations of Cr or Pb exceeding the NRWQC. For 64þ66Zn, only the water concentration (230 μg/L) at station 7 has exceeded the NRWQC. The concentrations of As at stations 9, 10, and 11 have exceeded the NRWQC, possessing potential risk for causing chronic disease. Furthermore, 63þ65Cu and 106þ111Cd concentrations at all sampling stations exceeded the limit set by NRWQC. Considering the potential health hazards of these trace metals, the sampling sites with excessive concentrations should be monitored.