Science Inventory

The relative importance of waterborne and dietborne As exposure on survival and growth of juvenile fathead minnows

Citation:

Erickson, R., Dave Mount, T. Highland, R. Hockett, C. Jenson, AND T. Lahren. The relative importance of waterborne and dietborne As exposure on survival and growth of juvenile fathead minnows. AQUATIC TOXICOLOGY. Elsevier Science Ltd, New York, NY, 211:18-28, (2019). https://doi.org/10.1016/j.aquatox.2019.03.008

Impact/Purpose:

Previous work demonstrated that dietborne exposures could be important for assessing the risk of inorganic arsenic to rainbow trout. The present work extended this work to fathead minnows and demonstrated that both the absolute sensitivity to dietborne exposure and the relative importance of dietborne exposure to waterborne exposures are less for fathead minnow than for rainbow trout. Thus, the incorporation of the dietborne route of exposure into risk assessments will be less important for fathead minnows and similar fish than for rainbow trout. Given that different species can differ markedly in this regard, application of this work to regulatory benchmarks for arsenic will require information other species and endpoints.

Description:

The survival and growth of juvenile fathead minnow were investigated at various combinations of waterborne exposure to arsenate and dietborne exposures using a diet of oligochaete worms that had been exposed to inorganic arsenic. Previous work with rainbow trout established that dietborne arsenic can reduce fish growth at environmentally relevant concentrations and could be more important than waterborne exposures. This was found to be less true for fathead minnows, with dietborne effects requiring several-fold higher concentrations in the diet than rainbow trout and uptake via diet versus water being substantially less important than for rainbow trout. These interspecies differences reflect complex relationships regarding accumulation, chemical speciation, and effects from dietborne and waterborne As exposures that differ substantially between the species, and underscore a need for care in relating such effects information to real-world exposures. The present study also underscored the need for more care in testing and expressing growth effects in long-term exposures to fish, because apparent toxic effects can be confounded by the relationship of control fish growth to size, the food ration relative to fish size, and issues regarding wet weight versus dry weight.