Entity

Time filter

Source Type

Rancho Cordova, CA, United States

Phillips B.M.,University of California at Davis | Anderson B.S.,University of California at Davis | Voorhees J.P.,University of California at Davis | Hunt J.W.,University of California at Davis | And 4 more authors.
Journal of Pesticide Science | Year: 2010

As part of a statewide assessment of pyrethroid pesticides and sediment toxicity in urban creeks, sites throughout California were screened, and thirty were chosen to evaluate the potential of pyrethroids to contribute to biological impacts. Sediment samples from four sites containing varied concentrations of pyrethroids were investigated using toxicity identification evaluations (TIEs) to determine causes of toxicity. Treatments were conducted on both whole sediment and interstitial water to determine the role of pyrethroids in the observed toxicity to the amphipod Hyalella azteca, and to evaluate TIE method performance. Whole sediment treatments included the addition of binding resins for organics and metals, and specific treatments designed to alter pyrethroid toxicity, including the addition of carboxylesterase enzyme, the addition of piperonyl butoxide (a pyrethroid synergist), and the testing of sediments at two temperatures. Interstitial water TIEs included solid-phase extraction (SPE) columns to reduce and return toxicity caused by organics and metals, as well as the treatments specific to pyrethroids. Resin and SPE column treatments characterized the causes of toxicity as organic compounds. Results of pyrethroid-specific treatments in whole sediment were variable, but similar treatments in interstitial water demonstrated pyrethroids were contributing to toxicity. Measured pyrethroid concentrations in whole sediment and interstitial water SPE extracts were high enough to have contributed to toxicity. Using both whole sediment and interstitial water TIEs and chemical analysis provided multiple lines of evidence that pyrethroids contributed to toxicity. © Pesticide Science Society of Japan. Source


Miller M.A.,Marine Wildlife Veterinary Care and Research Center | Miller M.A.,University of California at Santa Cruz | Kudela R.M.,University of California at Santa Cruz | Mekebri A.,Water Pollution Control Laboratory | And 11 more authors.
PLoS ONE | Year: 2010

"Super-blooms" of cyanobacteria that produce potent and environmentally persistent biotoxins (microcystins) are an emerging global health issue in freshwater habitats. Monitoring of the marine environment for secondary impacts has been minimal, although microcystin-contaminated freshwater is known to be entering marine ecosystems. Here we confirm deaths of marine mammals from microcystin intoxication and provide evidence implicating land-sea flow with trophic transfer through marine invertebrates as the most likely route of exposure. This hypothesis was evaluated through environmental detection of potential freshwater and marine microcystin sources, sea otter necropsy with biochemical analysis of tissues and evaluation of bioaccumulation of freshwater microcystins by marine invertebrates. Ocean discharge of freshwater microcystins was confirmed for three nutrient-impaired rivers flowing into the Monterey Bay National Marine Sanctuary, and microcystin concentrations up to 2,900 ppm (2.9 million ppb) were detected in a freshwater lake and downstream tributaries to within 1 km of the ocean. Deaths of 21 southern sea otters, a federally listed threatened species, were linked to microcystin intoxication. Finally, farmed and free-living marine clams, mussls and oysters of species that are often consumed by sea otters and humans exhibited significant biomagnification (to 107 times ambient water levels) and slow depuration of freshwater cyanotoxins, suggesting a potentially serious environmental and public health threat that extends from the lowest trophic levels of nutrient-impaired freshwater habitat to apex marine predators. Microcystin-poisoned sea otters were commonly recovered near river mouths and harbors and contaminated marine bivalves were implicated as the most likely source of this potent hepatotoxin for wild otters. This is the first report of deaths of marine mammals due to cyanotoxins and confirms the existence of a novel class of marine "harmful algal bloom" in the Pacific coastal environment; that of hepatotoxic shellfish poisoning (HSP), suggesting that animals and humans are at risk from microcystin poisoning when consuming shellfish harvested at the land-sea interface. © 2010 Miller et al. Source


Werner I.,University of California at Davis | Deanovic L.A.,University of California at Davis | Miller J.,AQUA Science | Denton D.L.,U.S. Environmental Protection Agency | And 4 more authors.
Environmental Toxicology and Chemistry | Year: 2010

The current study investigated the potential of vegetated drainage ditches for mitigating the impact of agricultural irrigation runoff on downstream aquatic ecosystems. Water column toxicity to larval fathead minnow (Pimephales promelas),and the amphipod Hyalella azteca was measured for 12 h or less at the ditch inflow and outflow, using custom-built in situ exposure systems. In addition, water and sediment samples were subject to standard toxicity tests with Ceriodaphnia dubia and H. azteca, respectively. No acute toxicity to larval fathead minnow was observed; however, runoff was highly toxic to invertebrates. Passage through a 389- to 402-m section of vegetated ditch had a mitigating effect and reduced toxicity to some degree. However, runoff from an alfalfa field treated with chlorpyrifos remained highly toxic to both invertebrate species, and runoff from a tomato field treated with permethrin remained highly toxic to H. azteca after passage through the ditch. Predicted toxic units calculated from insecticide concentrations in runoff and 96-h median lethal concentration (LC50) values generally agreed with C. dubia toxicity measured in the laboratory but significantly underestimated in situ toxicity to H. azteca. Sediments collected near the ditch outflow were toxic to H. azteca. Results from the current study demonstrate that experimental vegetated ditches were unable to eliminate the risk of irrigation runoff to aquatic ecosystems. In addition, protective measures based on chemical concentrations or laboratory toxicity tests with C. dubia do not ensure adequate protection of aquatic ecosystems from pyrethroid-associated toxicity. © 2010 SETAC. Source


Melwani A.R.,San Francisco Estuary Institute | Gregorio D.,State Water Resources Control Board | Jin Y.,State Water Resources Control Board | Stephenson M.,Moss Landing Marine Laboratories | And 5 more authors.
Marine Pollution Bulletin | Year: 2014

This study examined trends in contaminants measured during three decades of "Mussel Watch" monitoring on the California coast. Chlorinated organic contaminants and butyltins declined the most rapidly, with tissue concentrations in 2010 that were up to 75% lower than during the 1980s. Silver and lead declined at about half of the stations statewide, but generally exhibited slower rates of decline relative to the organic compounds. In contrast, copper increased at many stations, and PAHs showed little evidence for declines. Mussels from San Francisco Bay and the Southern California Bight were historically the most contaminated and have had the steepest declines. Overall, these data show that the "Mussel Watch" approach to monitoring contaminants in California has provided some of the best evidence of the effectiveness of actions to improve water quality over the past 30. years. These datasets also highlight challenges that remain in managing PAHs and copper. © 2013 Elsevier Ltd. Source


Vasquez M.E.,University of California at Davis | Rinderneck J.,Office of Spill Prevention and Response | Newman J.,Resource Conservation Services Plumas Sierra and Nevada Counties | Mcmillin S.,Pesticide Investigations Unit | And 4 more authors.
Environmental Toxicology and Chemistry | Year: 2012

In September 2007, Lake Davis (near Portola, California) was treated by the California Department of Fish and Game with CFT Legumine, a rotenone formulation, to eradicate the invasive northern pike (Esox lucius). The objective of this report is to describe the fate of the five major formulation constituents-rotenone, rotenolone, methyl pyrrolidone (MP), diethylene glycol monethyl ether (DEGEE), and Fennedefo 99-in water, sediment, and brown bullhead catfish (Ameiurus nebulosus; a rotenone-resistant species) by determination of their half-lives (t 1/2) and pseudo first-order dissipation rate constants (k). The respective t 1/2 values in water for rotenone, rotenolone, MP, DEGEE, and Fennedefo 99 were 5.6, 11.1, 4.6, 7.7, and 13.5 d; in sediments they were 31.1, 31.8, 10.0, not able to calculate, and 48.5 d; and in tissues were 6.1, 12.7, 3.7, 3.2, and 10.4 d, respectively. Components possessing low water solubility values (rotenone and rotenolone) persisted longer in sediments (not detectable after 157 d) and tissues (<212 d) compared with water, whereas the water-miscible components (MP and DEGEE) dissipated more quickly from all matrices, except for Fennedefo 99, which was the most persistent in water (83 d). None of the constituents was found to bioaccumulate in tissues as a result of treatment. In essence, the physicochemical properties of the chemical constituents effectively dictated their fate in the lake following treatment. © 2012 SETAC. Source

Discover hidden collaborations