AQUATIC ECOTOXICOLOGICAL IMPACT ASSESSMENT
Aquatic Toxicity and Ecotoxicological Impact Assessment
EnviroGulf Consulting assesses contaminant risk to ecological resources using an ecotoxicological and extrapolation approach based on: reviews and evaluations of contaminant data to identify the nature of the hazard; reviews of toxicity data in the literature; identification of the conditions of exposure (e.g., intensity, frequency, and duration of exposure) based on either monitoring data or predicted by modelling; and a combination of the information on toxicity and exposure data to estimate the probability that receiving water organisms may be adversely affected by the contaminant(s) or wastewater discharge being examined.
The Principal of EnviroGulf Consulting has an in-depth understanding of the principles involved in assessing the fate, behaviour and effects of contaminants in aquatic ecosystems. This expertise allows the ability to anticipate, document and predict biological and toxicity effects.
The main services available are as follows:
- Advice service on effluent toxicity testing and assessment.
- Design, planning and supervision of bioassays and toxicity tests performed in situ using wastewater discharges.
- Toxicological assessment of industrial wastewater discharges, component effluent streams, and receiving water environments using modelling procedures.
- Ecotoxicological evaluation of monitoring data on waters receiving waste and wastewater discharges.
- Determination of contaminant pathways.
- Assessment of client's compliance with toxicity criteria and requirements set by regulatory authorities.
Toxicity Bioassays and Tests
EnviroGulf Consulting subcontracts analytical and toxicological laboratories to conduct the following tests under supervision, as well as taking concurrent test media samples for chemical analysis.
EnviroGulf Consulting subcontractors can provide a broad range of toxicity tests with freshwater, marine and estuarine organisms. These tests conform with requirements of the ANZECC/ARMCANZ Water and Sediment Quality Guidelines and the National Ocean Disposal Guidelines for dredged Material issued by Environment Australia (2002). Some of the tests offered below follow the Organisation for Economic Co-operation and Development (OECD) guidelines for toxicity effects on aquatic organisms.
The following are example toxicity tests using freshwater orgainsms.
- Microtox acute toxicity test
- OECD TG 201 - 72-hr Selenastrum capricornutum growth inhibition
- OECD TG 221 - 7-day Lemna minor growth test
- OECD TG 202 - 48-hr acute Ceriodaphnia dubia survival
- OECD TG 202 - 48-hr acute Daphnia magna survival
- OECD TG 211 - 7-day Ceriodaphnia dubia partial life-cycle
- OECD TG 211 - 21-day Daphnia magna partial life-cycle
- 96-hr freshwater shrimp acute toxicity test
- OECD TG 203 - Short-term toxicity testing (96hrs)
- 7-day imbalance and growth
- OECD TG 204 - Long-term toxicity testing (14 days)
- OECD TG 210 - Early Life Stage Toxicity
- OECD TG 212 - Short-term Toxicity Test on embryos and sac-fry
- OECD TG 215 - Juvenile Growth (28 days)
- OECD TG 305 - Bioconcentration: Flow-through Fish Test
- 10-day Rainbowfish Embryo Development and Survival
Estuarine and Marine Water Tests:
The following are example toxicity tests using freshwater orgainsms.
- 72-hr growth inhibition using Nitzschia closterium
- 72-hr growth using Isochrysis aff. galbana
- 72-hr germination success using Hormosira banksii
- 72-hr germination success using Ecklonia radiata
- 14-day growth using Hormosira banksii
- 14-day growth using Ecklonia radiata
- Bivalve molluscs:
- 48-hr larval development using Sydney rock oyster or Pacific Oyster
- 48-hr larval development using Doughboy scallop
- 72-hr larval development using mussel
- Sea urchins:
- 1-hr sea urchin fertilisation success
- 72-hr sea urchin larval development
- Tiger prawn acute toxicity
- 96-hr acute amphipod survival using Melita plumulosa
- 96-hr acute amphipod survival using Allorchestes compressa
- 96-hr fish imbalance (species depending on availability)
- 7-day fish imbalance and growth (species depending on availability)
Field In situ Tests:
- Fish held in aquaria or cages:
- Fish exposed in aquaria supplied by pumped effluent.
- Fish exposed in floating cages moored in effluent streams or receiving waters.
The above toxicity tests are conducted according to standardised procedures developed overseas and approved by local regulatory authorities. Where effluents have degradable toxicants, continuous flow-through or semi-static (solution renewal) tests may be substituted.
Chronic Toxicity Testing
Dilution and dispersion of effluent toxicants in receiving waters results in low concentrations of toxicants and chronic exposure conditions. EnviroGulf Consulting does not recommend clients to conduct chronic toxicity testing, unless specifically required by regulatory authorities. Retrospective biological monitoring of receiving waters is recommended for investigating sublethal effects and ecosystem response in receiving waters. In this manner toxicant acclimatisation and behavioural avoidance are taken into account, and corrective actions may be taken if unforeseen subtle sublethal effects are manifested in the receiving environment.
The normal approach to predicting the effects of toxic wastewater discharges is an examination of the concentrations and mass-flows of toxicants in the receiving waters in relation to the known quality characteristics of an effluent discharge. EnviroGulf Consulting uses a complementary approach using a predictive toxicity index based on a toxic units model which uses the LC50 values of commonly occurring pollutants in receiving waters.
EnviroGulf Consulting also operates a computerised version of the toxic units model for predicting the toxicity of complex effluents containing dissolved metal contaminants, cyanides and, or, phenols and offers this service to clients as part of an overall ecotoxicological assessment.
Research Fellow, Applied Hydrobiology Research Station, Uttoxeter, England:
- Responsible for contract research investigations of the long-term effects of oxidised sewage effluent containing heavy metals on experimental stream ecosystems (mesocosms). Contaminants at issue were cadmium, lead, chromium, nickel, copper and zinc.
- Studies included assessments of the long term effects on algae, macroinvertebrates and fish (eggs, eleutheroembryos, larvae, juveniles and adults).
- Protracted in situ toxicity testing was carried out and related to water quality based on continuous and 15-minute snap water sampling.
Ecotoxicological studies and impact assessment:
- West Qurna-2 Oilfield Development Project (2010 - 2011) - Baseline assessments of soil, surface water and groundwater contamination from radionuclides (depleted uranium), hydrocarbons, metals, chemical warfare agents (sulphur mustard and tabun), exploded and unexploded ordnance, drill cuttings and drilling fluids, and salinisation in south-eastern Iraq (to Coffey Environments for LukOil).
- Bell Bay Pulp Mill Project (2007) - Review of the behaviour, toxicity and fate of effluent-derived chlorate (ClO3-) in the marine environment, including an assessment of chlorate persistence and natural degradation processes (to Gunns Limited).
- Basslink Draft Integrated Impact Assessment Statement (2000-2002) - Assessment of the marine biological effects of chlorine produced oxidants and halogenated organic compounds produced at the positive electrode (anode) of the proposed Basslink Interconnector across Bass Strait - on the basis of computer-predicted chlorine residual concentrations and transport and dispersion modelling (to NSR for Basslink Proprietory Limited).
- Ramu Nickel Project Environmental Plan (1999) - Riverine, coastal and deep-sea environmental impact of lateritic nickel mining wastes and wastewaters (to NSR for Highlands Pacific Limited).
- East Perth Gasworks Site Rehabilitation (1990) - Planning and implementation of surveys for estuarine waters, bed sediments and associated fauna for environmental impact and risk assessment of polynuclear aromatic hydrocarbons in groundwater and surface runoff from a former gasworks site contaminating the Swan River, Western Australia (with NSR for Camp. Scott & Furphy Pty. Ltd.).
- ANM Boyer Pulp and Paper Mill (1989) - Analysis and interpretation of process effluent and metal residues in the River Derwent and environmental consequences of river dredging operations (with NSR for Benders Civil Developments Pty. Ltd.).
- Ramu Nickel Project (1998-99) - Riverine, coastal and deep-sea environmental impact of lateritic nickel mining wastes and wastewaters (to NSR for Highlands Pacific Limited).
- Northshore Noosa Project (1986) - Review of sewage effluent management options and assessment of potential water quality impacts on the Noosa River, Queensland (with NSR/Maunsell & Partners for Leisuremark Australia Pty,. Ltd).
- Beaconsfield Gold Mine (1989) - Environmental assessment of the toxicity of cyanidation tailing and tailing pond cyanogenic supernatant and prediction of potential environmental effects on the Tamar Estuary, Tasmania (with NSR for John Miedecke & Partners Pty. Ltd.).
- Bukit Young Goldmine (1989) - Assessment of water and wastewater management, disposal and detoxification of cyanided gold mill and heap leach effluents from the Bukit Young Gold Mine, Sarawak, Malaysia (with NSR for Middle East Timber Company, Singapore).
- Port Moresby industrial Port Study (1986) - Assessment of the marine biological effects of constructing and operating a proposed copper concentrate transhipment terminal within Port Moresby's Halifax Harbour (with NSR for PNG Harbours Board).
- Butler Transport Chemical Fire (1986) - Assessment of the impact and potential toxicity of leachate from contaminated soil remaining on site after clean-up operations on aquatic life in a tidal channel and Dynon Road Wildlife Reserve (with NSR Environmental Consultants Pty. Ltd.).
- Misima Gold Project Environmental Plan (1985-86) - Assessment of the marine biological effects of at-depth marine tailing disposal and near-surface dumping of soft oxidised waste, on the basis of aeration-dilution and bioassay tests, field dump trials and predictions of waste transport and dispersion (with NSR for Placer (PNG) Pty. Limited).
- Porgera Gold Project Environmental Plan (1985-86) - Assessment of river biological effects of mill tailing and mine waste disposal, based on laboratory aeration-dilution and bioassay tests and river transport modelling (with NSR for Placer (PNG) Pty. Limited).
Technical Reports / Publications:
- EnviroGulf Consulting (2007). Review of the behaviour, toxicity and fate of effluent-derived chlorate (ClO3-) in the marine environment, including an assessment of chlorate persistence and natural degradation processes. Technical Report No. CR 001/3. Bell Bay Pulp Mill Project. July 2007.
- Balloch, D. (1985). Procedures for the toxicity testing and monitoring of mining wastewaters. Ok Tedi Mining Limited, Papua New Guinea. Technical Report No. PA/03/85-6.
- Balloch, D. (1984). The effects of particulate and dissolved copper on aquatic organisms. Ok Tedi Mining Limited, Papua New Guinea. Technical Report No. PA/03/84-29.
- Balloch, D. (1984). Toxicity of cadmium and a review of water quality criteria. Ok Tedi Mining Limited, Papua New Guinea. Technical Report No. PA/03/84-13.
- Hortle, G.H., Balloch, D. and Maie, A.Y. (1990). Marine benthic fauna, sediment and trace metals near Daru Island, Western Province, Papua New Guinea. Science in New Guinea, 16(1): 1-12.