The Use of Freshwater and Saltwater Animals to Distinguish Between the Toxic Effects of Salinity and Contaminants in Irrigation Drain Water

Abstract

Irrigation drain waters entering Stillwater Wildlife Management Area (SWMA) in south‐western Nevada contain elevated levels of salinity and several inorganic contaminants (As, B, Cu, Li, Mo, and Sr). Mortalities of fish and waterfowl at the management area are believed to be associated with the poor water quality of the drains. The objective of the present study was to use fresh‐water and saltwater animals to distinguish between the toxic effects of salinity and contaminants in effluent samples collected from irrigation drain waters. Static acute effluent tests were conducted with water collected from four sites at SWMA. Animals acclimated or cultured in fresh water (fathead minnows, Pimephales promelas; amphipods, Hyalella azteca; cladocerans, Daphnia magna) and salt water (striped bass, Morone saxatilis; amphipods, Hyalella azteca; and cladocerans, Daphnia magna) were used to separate toxic effects of salinity from the effects of inorganic contaminants in the drain water. One drain water (TJ drain, salinity 19 parts per thousand (grams per liter), osmolality 503 mmol/kg, hardness 3,780 mg/L as CaCO3) was toxic only to freshwater animals and saltwater cultured daphnids; water from a receiving pond (Pintail Bay, salinity 23 g/L, osmolality 542 mmol/kg, hardness 830 mg/L as CaCO3) was toxic to both freshwater and saltwater animals. Acute tests conducted with reconstituted waters representative of the Pintail Bay sample indicated that atypical ion ratios were toxic to striped bass and amphipods, even without the addition of inorganic contaminants. However, the addition of inorganic contaminants representative of the Pintail Bay sample increased the toxicity of this reconstituted water. These findings indicate that the toxicity of the TJ drain sample was related mainly to elevated salinity and that the toxicity of the Pintail Bay sample was a function of inorganic contamination and atypical ion ratios in combination with elevated salinity.

Subsurface Agricultural Irrigation Drainage: The Need for Regulation

“…The drainage was highly toxic, causing mortality within 96 hr (59). Reconstituted water formulated to resemble surface water from Stillwater NWR, but without the complement of trace element contaminants (e.g., As, B, Cu, Li, MO, Sr), was toxic to salt-tolerant organisms (60). However, the level of toxicity increased in samples that also included trace elements at concentrations normally found in the drainage.…”

“…The results indicated that salinity, contaminants, and atypical ratios of major ions (e.g., sulfate, magnesium, chloride, sodium, etc.) all acted together to cause the observed toxicity; no single contaminant or water-quality variable was responsible (59,60).…”

“…pacts-i.e., additive, synergistic, or antagonistic effects-that would not be effectively controlled through single-substance regulations (e.g., individual water quality standards for heavy metals, organic compounds, etc.). Subsurface irrigation drainage produces multiple contaminant impacts on aquatic species (37,38,59,60), and should be regulated with this fact in mind. Current state and national water quality criteria applicable to single contaminants do not protect against the combined effects of trace elements and unusual ionic ratios which are important in determining the toxicity of irrigation drainage to aquatic life (38,59).…”

Dissolved Solids as HD Bioeffluent Toxicants.

“…Salt toxicity for daphnia magna ranges from 0.6-1 %. 5,6 Since the ceriodaphnia are typically more sensitive than daphnia magna, their tolerance to salt would be less. Open literature has shown that the sensitivity to sodium chloride between daphnia magna and ceriodaphnia dubia differ by approximately 50% (ceriodaphnia being more sensitive).…”

Avaliação e identificação da toxicidade (Toxicity Identification Evaluation - TIE) do efluente líquido do pólo industrial de Belford Roxo, RJ e sua contribuição na qualidade das águas do corso inferior do Rio Sarapuí, sub-bacia do Rio Iguaçú, Bacia da Baía da Guanabara, RJ, Brasil

“…O monitoramento ecotoxicolôgico, entre outras aplicações, contribui no estabelecimento de critérios de qualidade de águas e sedimentos de modo a proteger a biota aquática, no monitoramento de efluentes industriais e áreas de influência, como também na avaliação da eficiência de sistemas de tratamento (USEPA, 1989;USEPA, 1991b Baseado em trabalhos como BOELTER et al (1992), DWYER et al (1992) e INGERSOLL et al (1992, DICKERSON et al (1996) apresenta um modelo para previsão dos efeitos para C. dúbia a partir da concentração dos oito principais íons. Tal modelo, baseado em uma regressão logística multivariada foi aplicado em 22 sítios de 4 estados norte-americanos.…”