New Zealand Journal of Marine and Freshwater Research abstracts
Impact of pulp and paper mill effluent on water quality
and fauna in a New Zealand hydro-electric lake
ANGELA D. SHARPLES
CLIVE W. EVANS
Developmental Biology and Cancer
Research Group
School of Biological Sciences
University of Auckland
Private Bag 92 019
Auckland, New Zealand
Abstract The Kinleith pulp and paper mill discharges effluent
into the Kopakorahi arm of Lake Maraetai (New Zealand) resulting in an effluent
gradient defined by the effluent visibility (Secchi disc), transmittance (465
nm), temperature, and oxygen level that is discernible at least as far down
stream as the adjoining Lake Waipapa. This effluent gradient is reflected in
the composition of the fauna caught in fyke nets which at the most
effluent-exposed sites is dominated by goldfish (Carassius auratus) and
is depauperate in pollution-sensitive species such as freshwater crayfish
(Paranephrops planifrons) and trout (Salmo trutta and
Oncoryhynchus mykiss). In 1991 the Kinleith mill undertook substantial
process modifications which have resulted in improvements in the water quality
of the discharge. Secchi disc visibilities have increased markedly at the most
effluent-exposed sites since modernisation of the mill and similar improvements
have been observed in light transmittance. A seasonal trend in water
temperature not previously observed was recorded at the most effluent-exposed
sites following modernisation, and dissolved oxygen levels at these sites rose
markedly. Improvements in the water quality of the recipient since the mill
modernisation are reflected in changes in the sampled fauna in particular the
occurrence of trout at sites from which they were previously absent.
Keywords pulp and paper mill; effluent; pollution; water
quality
New Zealand Journal of Marine and Freshwater Research, 1998, Vol. 32:
31-53
0028-8330/98/3201-0031 $7.00/0 (c) The Royal Society of New Zealand
1998
PDF file of entire paper: medium quality (2306K); (scanned from paper original: notes about this process)
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