Bromide is commonly used as a tracer in studies of water and chemical transport in soil and rock because it is relatively nonreactive with soil and rock constituents and because of its low environmental background concentrations. Based on a largely ignored modification of an American Public Health Association standard colorimetric method for determining Br– using phenol red and chloramine-T(CT), we have corrected an internal error and recast the technique for use with 96-well microplates. Furthermore, the addition of thiosulfate to quench the undesirable chlorination reaction as previously published is shown to be unnecessary and even detrimental following the use of NH4+ to produce chloramine from excess Cl species. The method detection limit is 0.11 mg L–1 Br–; negative interference with dissolved organic C can be addressed by either standard additions or solid-phase extraction with C18 sorbent. By reducing the sample size from 300 to 20 µL, the concentration range can be expanded from 12 mg L–1 Br– to as much as 300 mg L–1 Br–.
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Testing laboratory, UK
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Parallel Evaporation
Customer: Testing laboratory, UKThis leading international testing, inspection and certifi cation organisation which assesses customers’ products and commodities against a wide...
Silver nanoparticles (Ag‐NPs) are widely applied nowadays for their antibacterial activity. Their increasing use in consumer products implies that they will find their way into the environment via waste water treatment plants. It was the aim of the present study to compare the ecotoxicological impact of two differently designed Ag‐NPs using the solid contact test for the bacterial strain Arthrobacter globiformis. In addition, a miniaturized version of this test system was established which requires only small‐sized...
Critical body residues (CBRs) are the measured tissue toxicant concentrations yielding a median dose–response on a dry‐weight or lipid‐normalized basis. They facilitate management decisions for species protection using tissue analysis. Population CBR is the mean dose yielding 50% population suppression and was predicted here in Amphiascus tenuiremis for fipronil sulfide (FS) using lifetables and the Leslie matrix. Microplate bioassays (ASTM E‐2317‐14) produced biomass sufficient for dry mass and lipid‐normalized...
The present study was conducted (1) to develop a rapid quantification method of polyhydroxyalkanoates (PHA) concentration in activated sludge by Nile blue A staining and fluorescence measurement and (2) to perform on-line monitoring of PHA concentrations in activated sludge. Activated sludge samples collected from laboratory scale sequencing batch reactors and full-scale wastewater treatment plants were stained with Nile blue A and their fluorescence intensities were determined. There was a high correlation (R2 >...
Among the GDSL family of serine esterases/lipases is a group of bacterial enzymes that posses C-terminal extensions involved in outer membrane anchoring or translocation. ApeE from Salmonella enterica serovar Typhimurium, a member of this group, has been expressed in Escherichia coli and was resistant to protease digestion when the protease was added to whole cells, indicating a periplasmic localization. The five consensus blocks conserved within all GDSL esterases were identified in ApeE by multiple sequence...
Methods for measuring toxicity or
respiratory activity of microbial cultures can be used as tools for assessing
the presence of chemicals and their impact on the streams. The proposed toxicity
test is based on the respirometric characteristics of the bacteria according to
the principals of Biolog’s microplate system. As the microorganism are
utilizing the carbon source (peptone), the reduction of the tetrazolium dye as
the redox indicator is taking place, leading to a developing change in the well’s
color...
Processing waste discharges, manufacturing effluents
and sewage would not normally have been a problem
50 years ago, but the advent of almost unchecked
industrial growth the latter half of the last century has
created the POTENTIAL for a wide variety of
characterized pollutants to enter the environment of
any municipality. The toxic METALS are tested by
approved State & Federal methods defined in SW-846,
RCRA, NPDES and TCLP protocols to check various
industries, such as Plating shops, Foundries, Metal
Re...
Natural phytoplankton assemblages from a freshwater lake in Trelew (Province of Chubut, Patagonia, Argentina) were exposed to natural solar radiation at different depths in a water basin filled with fresh water rich in humic substances. Samples were taken at regular intervals for DNA extraction and subsequent analysis of DNA damage by determining the formation of thymine dimers using an immuno-dot-blot procedure. The use of a colorimetric detection system based on the reaction of alkaline phosphatase with BCIP...
Whole effluent toxicity (WET) testing has evolved into a critical element of many National Pollutant Discharge Elimination System (NPDES) permits issued to both industrial and municipal dischargers. Over 6,500 dischargers to both fresh and salt waters are required to conduct toxicity tests to determine if their effluent might be potentially toxic to organisms in the receiving system. While commonplace for many permits, WET tests (and subsequent activities if toxicity is detected) are often poorly understood by...
OVERVIEW
When chlorine is added to a water supply containing certain organics, the formation of halogenated organics occurs. Called `trihalogenated methanes` (THM`s) these reaction products are suspected carcinogens and maximum allowable limits in municipal supplies are imposed by the U.S. Environmental Protection Agency (EPA). To reduce the potential for the formation of THM`s, many U.S. municipal supplies are converting their chlorine (Cl2) disinfection method to chloramine addition. Chloramines have a low...
Imagine being in charge of a chemical company. One day a fire breaks out, and an employee, designated as a first responder, is killed fighting the blaze. Then OSHA investigators discover that the man died primarily because both his training and his equipment were inadequate. This scenario is why CPL 2-2.59A should put anyone who runs a HAZMAT facility into a state of introspection. These employers need to ask themselves: `When was the last time that our Emergency Response Plan was brought up to date? Do our...
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