Mining and fisheries protection : sediment impact models

• Main Author: Newcombe, Charles P.
• Language: English
• Published: 2009
• Online Access: http://hdl.handle.net/2429/10533

Review of the available water quality literature yields two promising water quality "models" for assessing sediment impact in aquatic ecosystems. One is relatively new (1996, 1997), and the other several decades old (1965). Both are of potential use in remediation or in the design and implementation of a mine reclamation program. The new model is based on a compendium of data which links dose (concentration of suspended sediment [mg/L] and duration of exposure [hours]) and response (ill effect) in fishes and aquatic invertebrates. "Dose" is expressed as mg˙h˙Lˉ¹ (milligram-hours per liter), and ill effect is expressed on a 15-step semi-quantitative scale. This "dose-response" model (the first of its kind in this branch of fisheries science) offers predictive capability much needed in environmental reclamation and remediation. It has potential utility in the design of mitigation measures when environmental impacts are unavoidable; and (potentially) in the field of pollution credit trading when there is a need to establish functional equivalence among disparate sediment pollution events, thereby to balance credits and debits. The older model is a classic. It offers two parts of interest here: the first describes half a dozen modes of action of suspended sediment on fishes; the second draws general conclusions about the effect of ambient suspended sediment and the size of fish populations. This "model" is an excellent primer because it offers a concise summary of knowledge available up to 1965. Its "modes of action" and "general conclusions" are still current today. This reflects the thoroughness of the review on which the model is based, and the relatively slow pace at which new sediment impact knowledge is created.