『Abstract
　Accumulation and distribution of heavy metals and phosphorus in sediments impact water quality. There has been an increasing concern regarding fish health in the St. Lucie Estuary, which is related to increased inputs of nutrients and metals in recent decades. To investigate vertical changes of contaminants (P, Cd, Cr, Co, Cu, Ni, Pb, Zn, and Mn) in sediments of the St. Lucie Estuary in South Florida, 117 layer samples from six of the 210 to 420 cm depth cores were analyzed for their total and water-soluble P and heavy metals, clay, total Fe, Al, K, Ca, Mg, Na, and pH. Principal component analysis (PCA) was used in two sets of analytical data (total and water-soluble contaminant concentrations) to document changes of contaminants in each core of sediments. The PCA of total contaminants and minerals resulted in two factors (principal components). The first and second factors accounted for 61.7 and 17.2％ of the total variation in all variables, and contrast indicators associated with contaminants of P, Cd, Co, Cr, Ni, Pb, Zn, and Mn and accumulation of Fe and Al oxides, respectively. The first factor could be used for overall assessment of P and heavy metal contamination, and was higher in the upper 45-90 cm than lower depths of each core. The concentrations of P and heavy metals in the surface layers of sediments significantly increased, as compared with those in the sediments deeper than 45-9- cm. The PCA of water-soluble contaminants developed two factors. The second factor (Cu-P) was higher in the upper than the lower depths of the sediment, whereas the highest score of the first factor (Cd-Co-Cr-Ni-Pb-Zn-Mn) occurred below 100 cm. The water-soluble Cu and P concentrations were mainly dependent on their total concentrations in the sediments, whereas the water-soluble Cd, Co, Cr, Ni, Pb, Zn, and Mn concentrations were mainly controlled by pH.

Keywords: Heavy metals; Muck sediment; Phosphorus; Vertical distribution; Water solubility; South Florida』

Introduction
　Site description
Materials and methods
　Sampling and processing
　Analysis methods
　Statistical analyze
Results and discussion
　pH and clay content
　Vertical distribution of phosphorus and heavy metals
　Water-solubility of phosphorus and heavy metals
General Discussion
Conclusions
Acknowledgments
References

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