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Simple apparatus for conducting acute toxicity bioassays under field conditions
Water Research Pergamon Press 1973. Vol. 7, pp. 821-822. Printed in Great Britain
SIMPLE APPARATUS FOR CONDUCTING ACUTE TOXICITY BIOASSAYS UNDER FIELD CONDITIONS M. R. FALK Canada Department of the Environment, Fisheries Service, 114 Garry Street, Winnipeg, Manitoba R3C 1G1, Canada (Received 5 October 1972)
Abstract--The description and operation of apparatus for conducting acute toxicity bioassays in the field are given. The apparatus proved to be very satisfactory under field conditions being inexpensive, light and portable, as well as giving satisfactory results.
INCREASEDefforts at water pollution control often require bioassays with fish in field locations. There is a real need for equipment which can be used for such on-the-spot tests, which is simple and easily portable, yet still provides good quality results which are sufficiently valid. The apparatus outlined here was designed to meet these requirements for work in the Northwest Territories carried out by the Canada Department of the Environment, Fisheries Service. DESCRIPTION Six bioassay cages were c o n s t r u c t e d o u t o f 3.81 c m a l u m i n u m angle frames. Ind i v i d u a l cages m e a s u r e d 61 x 30.5 × 30.5 cm. C o n n e c t i o n s were m a d e with t r i a n g u l a r
81cm
FIG. 1. Schematic diagram of six bioassay cages lashed together in a 2 × 3 configuration. 821
822
\ ! R. F~LK
anchor plates and stainless steel nuts and bolts. Within each cage a 0.64 cm braided nylon mesh bag with an opening of 100 cm 2 was suspended and attached along the top edge (Fro. 1). OPERATION The six bioassay cages were lashed together in a 2 x 3 configuration and anchored to the bottom of a lake shore in about 20 cm of water. Locations were chosen to afford as much protection from wave action as possible. A 46 x 96 cm, 4 ml plastic bag was placed in each mesh bag. Five concentrations and one control, each with 20 1., were used during an experiment. Before an experiment small minnows were seined from adjacent water bodies and kept in a holding cage close to the bioassay cages. Concentrations were made up in each container and the temperatures were allowed to stabilize to that of the lake for 1 h. Light aeration was supplied through a small air pump driven by a portable generator. Aeration kept the dissolved oxygen near saturation and circulated the water, keeping the temperature the same as that in the lake. Ten fish were added to each cage and were checked at geometrically increasing intervals for 96 h. The openings of the plastic bags were folded over to prevent dilution by precipitation. COMMENTS The apparatus proved to be very satisfactory under field conditions. Fish in the control tests survived with no mortality. Through mixing by aeriation, temperature did not vary more than 2.0°C over a 96-h period. Results obtained from experiments were comparable with those obtained from bioassays conducted under controlled laboratory conditions. The portable apparatus was much cheaper to set up than the controlled laboratory tests, and also had a great saving in shipping costs for effluent.
SIMPLE APPARATUS FOR CONDUCTING ACUTE TOXICITY BIOASSAYS UNDER FIELD CONDITIONS M. R. FALK Canada Department of the Environment, Fisheries Service, 114 Garry Street, Winnipeg, Manitoba R3C 1G1, Canada (Received 5 October 1972)
Abstract--The description and operation of apparatus for conducting acute toxicity bioassays in the field are given. The apparatus proved to be very satisfactory under field conditions being inexpensive, light and portable, as well as giving satisfactory results.
INCREASEDefforts at water pollution control often require bioassays with fish in field locations. There is a real need for equipment which can be used for such on-the-spot tests, which is simple and easily portable, yet still provides good quality results which are sufficiently valid. The apparatus outlined here was designed to meet these requirements for work in the Northwest Territories carried out by the Canada Department of the Environment, Fisheries Service. DESCRIPTION Six bioassay cages were c o n s t r u c t e d o u t o f 3.81 c m a l u m i n u m angle frames. Ind i v i d u a l cages m e a s u r e d 61 x 30.5 × 30.5 cm. C o n n e c t i o n s were m a d e with t r i a n g u l a r
81cm
FIG. 1. Schematic diagram of six bioassay cages lashed together in a 2 × 3 configuration. 821
822
\ ! R. F~LK
anchor plates and stainless steel nuts and bolts. Within each cage a 0.64 cm braided nylon mesh bag with an opening of 100 cm 2 was suspended and attached along the top edge (Fro. 1). OPERATION The six bioassay cages were lashed together in a 2 x 3 configuration and anchored to the bottom of a lake shore in about 20 cm of water. Locations were chosen to afford as much protection from wave action as possible. A 46 x 96 cm, 4 ml plastic bag was placed in each mesh bag. Five concentrations and one control, each with 20 1., were used during an experiment. Before an experiment small minnows were seined from adjacent water bodies and kept in a holding cage close to the bioassay cages. Concentrations were made up in each container and the temperatures were allowed to stabilize to that of the lake for 1 h. Light aeration was supplied through a small air pump driven by a portable generator. Aeration kept the dissolved oxygen near saturation and circulated the water, keeping the temperature the same as that in the lake. Ten fish were added to each cage and were checked at geometrically increasing intervals for 96 h. The openings of the plastic bags were folded over to prevent dilution by precipitation. COMMENTS The apparatus proved to be very satisfactory under field conditions. Fish in the control tests survived with no mortality. Through mixing by aeriation, temperature did not vary more than 2.0°C over a 96-h period. Results obtained from experiments were comparable with those obtained from bioassays conducted under controlled laboratory conditions. The portable apparatus was much cheaper to set up than the controlled laboratory tests, and also had a great saving in shipping costs for effluent.