Contaminants in Hamilton's urban stream sediments and ecotoxicity to amphipods

On this page: abstract, table of contents

Report: TR 2012/38

Author: SJ Clearwater (NIWA), T Valler (University of Waikato)

Abstract

NIWA was commissioned by the Waikato Regional Council to survey contaminants in urban stream sediments in Hamilton and determine if sediment-associated contaminants are likely to inhibit restoration of these waterways.

The focus of the present study was on sediment associated contaminants. Dissolved or waterborne contaminant concentrations were not evaluated, however dissolved contaminants can significantly impact urban streams.

In June 2011 sediments were sampled at 27 locations in streams in the city of Hamilton and in May 2012 a subset of these locations was sampled again. Concentrations of up to 23 elements in stream sediments were compared.

Contaminants in Hamilton's urban stream sediments and ecotoxicity to amphipods (1mb)

	Executive summary	7
1	Introduction	10
1.1	Background	10
1.2	Site selection, contaminant analysis and toxicity testing	11
1.3	Comparison with sediment quality guidelines	11
1.4	Establishing current "background" concentrations and contaminant sources	12
2	Methods	14
2.1	Site locations	14
2.2	Sediment collection	17
2.3	Sediment analysis	17
2.4	Amphipod toxicity testing	19
3	Results and discussion	20
3.1	Grain size and organic carbon content	20
3.2	Sediment organochlorines and polycyclic aromatic hydrocarbons	22
3.3	Amphipod toxicity test	23
3.4	Sediment metals 2011 and 2012	24
3.5	Summary of guideline exceedance and amphipod results for each site	32
3.6	Peacockes tributary of the Mangkotukutuku Stream	37
3.7	Rukuhia and Te Anau tributaries of the Mangakotukutuku Stream	37
3.8	Normandy A and Graham A	37
3.9	Kirikiriroa catchment	39
3.10	Waitawhiriwhiri catchment	40
3.11	Bankwood Park and Parana Park	41
3.12	Ranfurly	41
4	Conclusions	43
5	Acknowledgements	44
6	References	45
	Appendix A: Sediment contaminant concentrations	47
	Appendix B: Sediment metal concentrations	68

Contaminants in Hamilton's urban stream sediments and ecotoxicity to amphipods

Abstract

Table of contents