Toxicity of 3‐Amino‐1: 2: 4‐Triazole to Activated Sludge Biomass

3‐amino‐1: 2: 4‐triazole (AT), a potent weed killer, added to activated sludge, caused immediate and drastic reduction in oxygen uptake by biomass. AT, a known specific inhibitor of catalases of animal and plant sources, did not appreciably alter catalase of activated sludge biomass.     

Characterizing the urban heat island in current and future climates in New Jersey

Climate change caused by increased anthropogenic emissions of carbon dioxide (CO₂) and other greenhouse gases is a long-term climate hazard with the potential to alter the intensity, temporal pattern, and spatial extent of the urban heat island (UHI) in metropolitan regions. Particular meteorological conditions—including high temperature, low cloud cover, and low average wind speed—tend to intensify the heat island effect. Analyses of existing archived climate data for the vicinities of Newark and Camden, New Jersey indicate urban to suburban/rural temperature differences over the previous half-century. Surface temperatures derived from a Landsat thermal image for each site were also analyzed for spatial patterns of heat islands. Potential interactions between the UHI effect and projected changes in temperature, wind speed, and cloud cover are then examined under a range of climate change scenarios, encompassing different greenhouse gas emissions trajectories. The scenarios include those utilized in the Metropolitan East Coast Regional Assessment of Climate Variability and Change and the A2 and B2 scenarios of the Intergovernmental Panel on Climate Change (IPCC) Special Report on Emissions Scenarios (SRES).

The UHI effect was detected in Newark and Camden in both satellite surface-temperature and meteorological station airtemperature records. The average difference in urban—nonurban minimum temperatures was 3.0 °C for the Newark area and 1.5 °C for Camden. Extrapolation of current trends and the selected global climate models (GCMs) project that temperatures in the case study areas will continue to warm in the current century, as they have over the past half-century. An initial analysis of global climate scenarios shows that wind speed may decline, and that cloud cover may increase in the coming decades. These generally small countervailing tendencies suggest that urban—nonurban temperature differences may be maintained under climate change.

Overall warmer conditions throughout the year may extend the spatial and temporal dimensions of the urban-suburban heat complex. The incidence of heat-related morbidity and mortality are likely to increase with interactions between the increased frequency and duration of heat waves and the UHI effect. Camden and Newark will likely be subjected to higher temperatures, and areas experiencing UHI-like conditions and temperature extremes will expand. Thus, urban heat island-related hazard potential is likely to increase in a warmer climate.     

The use of polymerase chain reaction for the identification of sciaenid eggs

Traditionally, sciaenid eggs have been identified based on morphological characteristics such as size, number of oil globules and/or pigmentation patterns. Identification of sciaenid eggs by these procedures is time consuming and often inaccurate due to considerable egg size overlap among species. The utilization of molecular techniques for the identification of economically important species has become a fundamental component in ecological studies involving fish eggs and larvae. This study reports the development of a series of both multiplex and individual polymerase chain reactions to identify the eggs of 11 sciaenid species commonly found in the Gulf of Mexico and estuaries near Port Aransas and Corpus Christi, TX, USA. Following method development, the discriminatory power of the assay was first determined with samples from adult fish collected from Aransas and Corpus Christi Bays, Galveston Bay and the lower Laguna Madre in northern Mexico. Most (97%) of these fishes were correctly identified to the level of species. To demonstrate the applicability of the assay, wild fish eggs were collected and analyzed from the Aransas Pass tidal inlet from September through December 2005. During this period, the eggs of four target species were positively identified which was in keeping with current knowledge regarding the spawning areas and seasons of these sciaenids based on the presence of mature females, eggs and/or larvae. Future use of this method can provide valuable information to better discriminate spawning sites and seasons of these species.     

Effects of chemically spiked sediments on estuarine benthic communities: a controlled mesocosm study

Ambient sediments were collected from a reference site in the North Edisto River, SC and transferred to a laboratory facility to investigate effects of chemical contaminants on estuarine infaunal communities under controlled mesocosm conditions. Sediment contaminant slurries were prepared using dried sediments collected from the reference site and spiked with a metal (copper), a polycyclic aromatic hydrocarbon (pyrene), and a pesticide (4,4^′-dichlorodiphenyltrichloroethane) to yield nominal mean effects range–median (ERM) quotients of <0.01 (no addition), 0.1, and 1.0 and applied to control, low dose (TRT A), and high dose (TRT B) treatment groups, respectively. Sediment samples for contaminant and benthic analyses were collected at the start of the experiment, 1 month after dosing, and 3 months after dosing. Near-nominal mean ERM quotients of 0.001, 0.075, and 0.818 were measured initially after dosing and remained fairly constant throughout the experiment. Measures of benthic condition, diversity, and richness were significantly reduced in both treatment groups relative to the control 1 month after dosing and persisted in TRT B at 3 months. The results demonstrate that benthic community effects can be observed at mean ERM quotients that are about an order of magnitude lower than levels that have been shown to be associated with significant toxicity in acute laboratory bioassays with single species (e.g., amphipods) in other studies.     

The influence of temperature on the deactivation of commercial Pd/Rh automotive catalysts

Automotive catalyst deactivation can be promoted by thermal and poisoning mechanisms. Catalyst efficiency is reduced by thermal degradation resulting in the agglomeration of precious metals and the reduction of the washcoat surface area. In this paper, the temperature influence on the commercial Pd/Rh-based automotive catalyst performance was studied. Textural and physicochemical characterisation techniques were employed, such as X-ray fluorescence (XRF), atomic absorption spectrometry (AAS), N₂ physisorption, X-ray diffraction (XRD), temperature programmed reduction (TPR) and scanning electron microscopy coupled with energy-dispersive X-ray analysis (SEM–EDX). The catalysts were evaluated for CO and propane oxidation with a stoichiometric gas mixture similar to engine exhaust gas. The results indicated the transformation of alumina into high temperature phases and the formation of new mixed oxide phases. Evidence of sintered particles and several spots of palladium agglomerates was seen by SEM–EDX analysis. The activity results showed the effects of thermal deactivation on the conversion of the pollutants. In spite of exposure to extreme temperature conditions (72 h at 1200 °C), significant activity was still observed for carbon monoxide and propane oxidation reactions.     

Recently planted vegetation strips reduce Giardia runoff reaching waterways

Current methods for tracking pathogens across farmland and into surrounding waterways via runoff are limited and typically have been developed using artificially created landscapes. No studies have investigated how Giardia in farm runoff moves across the landscape, despite high prevalence rates in dairy cattle (Bos taurus) worldwide. Here, we report the development of a field-based tracking method specific for Giardia movement in runoff and use this technique to compare the pathogen reduction capability of recently planted vegetation strips with bare soil strips cleared of vegetation. Such scenarios represent typical events in schemes to plant vegetation barriers aimed at reducing waterway contamination. A significant treatment effect was identified, with 26% fewer Giardia detected in runoff collected from the planted strip (P = 0.006). These results highlight the immediate benefit of pathogen removal to be gained from vegetation planting. The successful discrimination of treatment effects by this new technique will enable the assessment of different vegetation types on runoff reduction and the effects of plant development over time.