Improvement of the Bag-Mediated Filtration System for Sampling Wastewater and Wastewater-Impacted Waters

Environmental surveillance of poliovirus (PV) plays an important role in the global program for eradication of wild PV. The bag-mediated filtration system (BMFS) was first developed in 2014 and enhances PV surveillance when compared to the two-phase grab method currently recommended by the World Health Organization (WHO). In this study, the BMFS design was improved and tested for its usability in wastewater and wastewater-impacted surface waters in Nairobi, Kenya. Modifications made to the BMFS included the size, color, and shape of the collection bags, the filter housing used, and the device used to elute the samples from the filters. The modified BMFS concentrated 3–10 L down to 10 mL, which resulted in an effective volume assayed (900–3000 mL) that was 6–20 times greater than the effective volume assayed for samples processed by the WHO algorithm (150 mL). The system developed allows for sampling and in-field virus concentration, followed by transportation of the filter for further analysis with simpler logistics than the current methods. This may ultimately reduce the likelihood of false-negative samples by increasing the effective volume assayed compared to samples processed by the WHO algorithm, making the BMFS a valuable sampling system for wastewater and wastewater-impacted surface waters.     

The geomorphology and ecosystem service economic value baselines of tributary watersheds in Malaysia

Environment, Development and Sustainability - This study presents how a cluster of tributary watersheds was evaluated for geomorphology and ecosystem service economic value baselines. Tributary...     

Reproduction, larval growth, and reproductive development in African clawed frogs (Xenopus laevis) exposed to atrazine

Reproductive success and development of F2 offspring from F1 adult African clawed frogs (Xenopus laevis) exposed to atrazine throughout larval development and as sexually mature adults was examined. Larval X. laevis were exposed to one of four nominal concentrations of atrazine (0, 1, 10, 25 microg atrazine/l) beginning 96 hr after fertilization and continuing through two years post-metamorphosis. Clutch size and survival of offspring were used as measurement endpoints to gauge reproductive success of the F1 frogs. Larval survivorship and time to metamorphosis were used to gauge developmental success of the F2 offspring from atrazine-exposed frogs. Testes in F1 and F2 frogs were examined for incidence of anomalies, such as testicular ovarian follicles, and sex ratios in F2 offspring were investigated to determine if exposure to atrazine caused trans-generational effects (effects on F2 individuals due to exposure of F1 individuals). There were no effects of any of the studied concentrations of atrazine on clutch size of F1 frogs. There were also no effects on hatching success or time to metamorphosis. Sex ratios did not differ between F2 offspring among treatments. There was no evidence to suggest a transgenerational effect of atrazine on spawning success or reproductive development of X. laevis. This is consistent with the presence of robust populations of X. laevis in areas where they are exposed to atrazine that has been used for several decades for weed control in production of corn. Our observations also are consistent with the results of most other studies of frogs where no effects were found to be associated with exposure to atrazine. Our data do not support the hypothesis that atrazine significantly affects reproductive fitness and development of frogs.     

Individual identity is communicated through multiple pathways in male rock hyrax (<Emphasis Type="Italic">Procavia capensis</Emphasis>) songs

Communicating individual identity is essential for stable social systems. It is assumed that there are benefits for both senders and receivers to provide and discriminate identity cues. In this study, we investigate the possible routes senders use to acoustically broadcast their individual identity. Using discriminant function analysis of temporal and spectral acoustic measurements and analysis of song-element order, we explore the means male rock hyrax (Procavia capensis) singers utilize vocalization to express individual identity. Despite the fact that males use only three song elements, the pattern of acoustic characteristics, their temporal and frequency attributes vary according to the identity of singer. We show that in hyrax, individuality is expressed by highly variable, complex signals that are not condition dependent and are stable over years in singers that did not alter their spatial position. We also show that individuality signals are not linked to relatedness or to geographic location. The ability to discriminate individuals from vocal signatures needs to be further tested using controlled playback experiments.     

Air Pollution and Morbidity: SO2 Damages

The role of SO₂ and COH (coefficient of haze) as causative factors in hospital emergency room admissions for respiratory and cardiac disease is analyzed using data from Chicago's Cook County Hospital. Some of the findings are that, while COH appears not to affect morbidity, SO₂ does, with most important impacts being felt by those with cardiac disease, females, and the youngest and oldest age groups. It is concluded that marginal morbidity damages, about which little had been known, are not high relative to other damage categories. These damages are estimated to be on the order of 10 cents per microgram per cubic meter per person per year.     

PROCEDURE FOR THE ECONOMICAL EVALUATION OF WATER NETWORKS' PARAMETERS1

ABSTRACT: The Generalized Geometric Programming and Branch and Bound technique are used to reach optimally designed water systems with their variables in integer forms. The water systems and constraints are formulated by sets of nonlinear equations. A solution for a specific water system is presented.     

Adapting empirical equations to Lake Kinneret data by using three calibration methods

This paper examines whether the relationships between a number of characteristic limnological variables (suspended particulate matter, turbidity, Secchi depth, light attenuation, and chlorophyll a) determined for temperate lakes are consistent with the relationships found in Mediterranean lakes such as Lake Kinneret. We found that the use of published relationships between lake variables may lead to erroneous results when applied indiscriminately to other lake types.