Stream Sediment Geochemistry of Four Small Drainages on the North Shore of Kauai West of Hanalei

Open-File Report 2019-1007
By:  and 

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Abstract

Geochemical compositions of fine-grained stream sediment from four drainages on the north shore of the island of Kauai, Hawaii, west of Hanalei and two back-beach sites were explored to increase understanding about land-based runoff and ecological risk from runoff to nearshore coral communities. Stream and beach sediment were collected between July 30 and August 2, 2016, and major, minor, and trace elements in the less than 63 micrometer-diameter fraction were analyzed by inductively coupled plasma optical emission spectroscopy and mass spectroscopy. The potentially toxic metals Cr, Cu, Ni, and Zn exceeded levels at which adverse biological effects could be observed; however, these metals seemed to be largely mineral-bound and thus were unlikely to harm organisms. Cd and Pb were below levels of ecological concern. Only a small amount of fine-grained sediment was retained on beaches west of Hanalei sampled in summer 2016 (mean=8.8 percent, median=0.4 percent, range=0–92.8 percent, n=41). Although the scarcity of fine-grained sediment precluded land-based runoff sourcing to the nearshore region, it did indicate that fine-grained sediment and associated contaminants did not accumulate over the long term in the sampled intertidal, subtidal, and reef-flat environments, which would reduce sediment-related pressures on coral communities there.

Suggested Citation

Takesue, R.K., and Storlazzi, C.D., 2018, Stream sediment geochemistry of four small drainages on the north shore of Kauai west of Hanalei: U.S. Geological Survey Open-File Report 2019–1007, 11 p., https://doi.org/10.3133/ofr20191007.

ISSN: 2331-1258 (online)

Study Area

Table of Contents

  • Abstract
  • Introduction and Study Description
  • Geologic Setting
  • Methods
  • Results
  • Summary
  • Acknowledgments
  • References
  • Appendixes

Additional publication details

Publication type Report
Publication Subtype USGS Numbered Series
Title Stream sediment geochemistry of four small drainages on the north shore of Kauai west of Hanalei
Series title Open-File Report
Series number 2019-1007
DOI 10.3133/ofr20191007
Year Published 2019
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) Pacific Coastal and Marine Science Center
Description iv, 11 p.
Country United States
State Hawaii
City Hanalei
Other Geospatial Kauai
Online Only (Y/N) Y