Monitoring acute and chronic water column toxicity in the Northern Sacramento–San Joaquin Estuary, California, USA, using the euryhaline amphipod, Hyalella azteca: 2006 to 2007

Abstract

After the significant population decline of several pelagic fish species in the Northern Sacramento-San Joaquin (SSJ) Estuary (CA, USA) in 2002, a study was performed to monitor water column toxicity using the amphipod Hyalella azteca. From January 1, 2006 to December 31, 2007, water samples were collected biweekly from 15 to 16 sites located in large delta channels and main-stem rivers, selected based on prevalent distribution patterns of fish species of concern. Ten-day laboratory tests with H. azteca survival and relative growth as toxicity endpoints were conducted. The enzyme inhibitor piperonyl butoxide ([PBO], 25 µg/L) was added to synergize or antagonize pyrethroid or organophosphate (OP) insecticide toxicity, respectively. Significant amphipod mortality was observed in 5.6% of ambient samples. Addition of PBO significantly changed survival or growth in 1.1% and 10.1% of ambient samples, respectively. Sites in the Lower Sacramento River had the largest number of acutely toxic samples, high occurrence of PBO effects on amphipod growth (along with sites in the South Delta), and the highest total ammonia/ammonium concentrations (0.28 ± 0.15 mg/L). Ammonia/ammonium, or contaminants occurring in mixture with these, likely contributed to the observed toxicity. Pyrethroid insecticides were detected at potentially toxic concentrations. Overall, results of this study identified specific areas and contaminants of concern and showed that water in the Northern SSJ Estuary was at times acutely toxic to sensitive invertebrates.

A comparison of the sublethal and lethal toxicity of four pesticides in Hyalella azteca and Chironomus dilutus

“…For H. azteca, both sublethal endpoints were effective to detect low-level pesticide concentrations. The concentrations causing significant effects on all three endpoints in both species are within the range of environmentally relevant concentrations as reported in previous monitoring studies in different states of the USA (Anderson et al 2006;Phillips et al 2012;Smith and Lizotte 2007;Werner et al 2010). For example, studies in Californian creeks by Budd et al (2009) and Weston and Lydy (2012) NOEC no observed effective concentration, LC50 lethal concentration resulting in 50 % mortality of the population, EC50 effect concentration resulting in 50 % reduction in growth, SE standard error, C.I.…”

Tracking pyrethroid toxicity in surface water samples: Exposure dynamics and toxicity identification tools for laboratory tests with Hyalella azteca (Amphipoda)

“…For example, Deanovic et al compared the sensitivity and effectiveness of a chronic 10‐d H. azteca water‐column test with the standard 7‐d C. dubia test endpoints, and concluded that the H. azteca test detected pyrethroid presence far more effectively than the C. dubia test. As an additional advantage, H. azteca can be employed in tests for water quality monitoring in both fresh and brackish water bodies . Whereas it is being used as a model species in standard sediment and acute water‐column toxicity testing , few monitoring programs use chronic H. azteca water‐column tests for monitoring .…”

Contaminant Effects on California Bay–Delta Species and Human Health

“…The copper threshold established for enclosed bays and estuaries is 4.8 μg L -1 . Dissolved copper concentrations up to 4.64 and 4.93 μg L -1 were detected in freshwater water samples from Cache-Lindsey Slough and Rough and Ready Island, respectively, and elevated dissolved copper concentrations of 37.2 and 58.9 μg L -1 have also been detected at Suisun Bay and Carquinez Strait, respectively (Werner et al 2010a). A recent study indicated that although the effect of copper on salmon olfaction is reduced in brackish and saline waters, copper can still cause avoidance behavior at environmentally relevant concentrations.…”