An evaluation of the influence of stock origin and out-migration history on the disease susceptibility and survival of juvenile Chinook salmon.

Various methods have been developed to mitigate the adverse effects of the Federal Columbia River Power System on juvenile Pacific salmon out-migrating through the Columbia River basin. In this study, we found that hatchery-reared spring Chinook salmon Oncorhynchus tshawytscha in the river are in varying degrees of health, which may affect delayed mortality and the assessment of the effectiveness of management actions to recover listed stocks (e.g., barging fish downstream versus leaving fish in the river). A laboratory disease challenge with Listonella anguillarum was completed on fish from Rapid River Hatchery and Dworshak National Fish Hatchery (NFH) with different out-migration histories: (1) transported by barge, (2) removed from the river before barging, or (3) left to travel in-river. Barged fish from Rapid River Hatchery experienced less mortality than fish from Dworshak NFH. No statistical differences were found between the hatcheries with fish that had in-river out-migration histories. We suggest that the stressors and low survival associated with out-migration through the hydropower system eliminated any differences that could have been present. However, 18-25% of the fish that were barged or collected before barging died in the laboratory before the disease challenge, compared with less than 2% of those that traveled in-river. Owing to disproportionate prechallenge mortality, the disease-challenged populations may have been biased; thus, they were also considered together with the prechallenge mortalities. The synthesis of prechallenge and disease-challenged mortalities and health characteristics evaluated during out-migration indicated that the benefit of barging was not consistent between the hatcheries. This finding agrees with adult survival and delayed mortality estimates for the individual hatcheries determined from adult returns. The results suggest that the health status of fish and their history before entering the hydropower system (hatchery of origin and out-migration path) are critical variables affecting the conclusions drawn from studies that evaluate mitigation strategies.

Factorial experimental designs for enhancement of concurrent poly(hydroxyalkanoate) production and brewery wastewater treatment.

The influence of four main process parameters--solids retention time (SRT), hydraulic retention time (HRT), anoxic-oxic cycling, and carbon-to-nitrogen ratio (C/N ratio)--on poly(hydroxyalkanoate) (PHA) production, while treating brewery wastewater, was studied. Two sets of two-level, three-factor experimental designs were implemented to (1) determine the effects and interactions among process parameters, (2) assess their significance to PHA production, and (3) approximate optimal operational conditions. The HRT and SRT were found to be the crucial operational parameters affecting PHA production. The highest PHA content of 55% (on a cell-weight basis) was produced at a 4-day HRT and 4-day SRT, whereas a maximum PHA concentration of 907 mg/L was obtained at a 2-day HRT and 12-day SRT. The effect of anoxic conditions on PHA production was insignificant. The C/N ratio played a more important role in the PHA concentration in the system than in the PHA content in the biomass.

Creating a community coalition to address violence.

Building a community-wide coalition to address violence evolved out of a five-year federally funded project on abuse during pregnancy. The setting for this coalition building is Haverhill, Massachusetts, a city of about 60,000, located northeast of Boston in the Merrimack River Valley. For nearly eight years, representatives of more than 30 agencies and institutions have been meeting monthly and creating programs and strategies to address violence in homes, schools, and neighborhoods, and designing interventions for children witnessing this violence. The purpose of this article is to describe the process of coalition building and provide an analysis of this work.

Production of polyhydroxyalkanoate during treatment of tomato cannery wastewater.

Polyhydroxyalkanoate (PHA) production was achieved using tomato cannery waste coupled with a mixed microbial culture during wastewater treatment. The two-stage PHA production process comprised a sequencing batch reactor (SBR), operating under a periodic feast-famine regime, to accomplish simultaneously wastewater treatment and selection of PHA-accumulating microbes, followed by a batch reactor for the production of PHA-rich biomass. The SBRs were efficient at removing soluble carbon (84%), ammonia (100%), and phosphorus (76%). Meanwhile, PHA-accumulating microbes were enriched under the SBR operating conditions, and PHA content on a cell-weight basis was within the range 7 to 11% in nonfiltered wastewater and 2 to 8% in filtered wastewater. Subsequently, batch studies were implemented with varying loading rates, ranging from 0.4 to 3.2 food-to-microorganism ratios. A maximum 20% PHA content on a cell-weight basis was obtained. Based on the experimental results, a PHA biosynthesis-degradation kinetic model was developed to (1) aid in the design of a pilot- or full-scale PHA production process coupled with wastewater treatment and (2) determine optimal conditions for harvest of PHA-rich biomass.

Validation of hollow fiber ultrafiltration and real-time PCR using bacteriophage PP7 as surrogate for the quantification of viruses from water samples.

A quantitative real-time TaqMan PCR system for Pseudomonas aeruginosa bacteriophage PP7 was designed to detect PP7 as surrogate in performance tests of 2 hollow fiber ultrafiltration systems in series. Fifty-six storm water samples from 21 sites representing agricultural, urban and highway locations in California were collected. The optimized procedure gave recoveries of spiked PP7 of 64+/-4.8% (mean+/-SEM). The PP7 assay was validated over 5 orders of magnitude with an assay limit of detection of 5 gene copies per reaction volume. Sample-dependent variables like enzymatic inhibition during PCR analysis, filtration recovery and extraction efficiency were quantified and incorporated to calculate a specific sample limit of detection (S(LOD)) for the spiked surrogate PP7. S(LOD) values were highly variable among samples; they were independent of physicochemical parameters including conductivity, turbidity, total suspended solids and pH but strongly correlated with the dilution factor required to relieve enzymatic inhibition during PCR analysis. To determine actual gene copies of PP7, a dilution approach was developed that involves assaying several dilutions within a range where inhibitors do not affect the efficiency of amplification and linear regression to determine the theoretical C(t) value when there is no inhibition. For the detection of viral pathogens, an internal standard like PP7 can be used to calculate filtration recoveries when quantifying pathogens and to determine whether filtration or inhibitor concentration affect nucleic acid extraction efficiency. Additionally, by defining S(LOD) values per sample and pathogenic organism analyzed, it should be possible to critically investigate the absence of detects for a particular pathogen and determine probabilities of risk associated with a specific sample limit of detection.

PCR detection of specific pathogens in water: a risk-based analysis.

The relative concentration of pathogens in water samples collected from storm drains and adjacent surfaces was evaluated using established PCR-based protocols. Out of the 58 samples collected from 21 different storm drains, 22% were PCR positive for Escherichia coli ETEC, Salmonella, or adenovirus. The risk of swimming related illnesses associated with detection of E. coli ETEC and Salmonella ranged from 0.39 to 30:100 000 and 0.3-25:1000, respectively. The detection limit corresponding to a negative-PCR result was evaluated in reference to water quality standards developed using a risk-based approach that integrates human dose-response data with acceptable levels of risk promulgated by the U.S. EPA for recreational contact. The percent of samples with an acceptable detection limit ranged from 0% for Giardia lamblia and Shigella to 100% for E. coli ETEC. The principal factor influencing the detection limit of G. lamblia and Shigella was sample volume. The principal factor influencing the detection limit of the remaining bacteria and protozoa, including E. coli O157:H7, Salmonella, and Cryptosporidium parvum, was the presence of inhibitory compounds in the purified nucleic acid extracts. Both recovery and inhibition adversely impacted the detection limit of viruses. Ambient water quality standards based on the occurrence of specific pathogens enumerated with PCR-based assays could serve as a method of evaluating the biological quality of water but only after significant improvements in filtration and purification protocols. The risk-based methodology developed in this study can be used to evaluate future improvements in filtration and purification protocols.