Prenatal Exposure to Tetrachloroethylene-Contaminated Drinking Water and the Risk of Congenital Anomalies: A Retrospective Cohort Study

BACKGROUND: Prior animal and human studies of prenatal exposure to solvents including tetrachloroethylene (PCE) have shown increases in the risk of certain congenital anomalies among exposed offspring. OBJECTIVES: This retrospective cohort study examined whether PCE contamination of public drinking water supplies in Massachusetts influenced the occurrence of congenital anomalies among children whose mothers were exposed around the time of conception. METHODS: The study included 1,658 children whose mothers were exposed to PCE-contaminated drinking water and a comparable group of 2,999 children of unexposed mothers. Mothers completed a self-administered questionnaire to gather information on all of their prior births, including the presence of anomalies, residential histories and confounding variables. PCE exposure was estimated using EPANET water distribution system modeling software that incorporated a fate and transport model. RESULTS: Children whose mothers had high exposure levels around the time of conception had an increased risk of congenital anomalies. The adjusted odds ratio of all anomalies combined among children with prenatal exposure in the uppermost quartile was 1.5 (95% CI: 0.9, 2.5). No meaningful increases in the risk were seen for lower exposure levels. Increases were also observed in the risk of neural tube defects (OR: 3.5, 95% CI: 0.8, 14.0) and oral clefts (OR 3.2, 95% CI: 0.7, 15.0) among offspring with any prenatal exposure. CONCLUSION: The results of this study suggest that the risk of certain congenital anomalies is increased among the offspring of women who were exposed to PCE-contaminated drinking water around the time of conception. Because these results are limited by the small number of children with congenital anomalies that were based on maternal reports, a follow-up investigation should be conducted with a larger number of affected children who are identified by independent records.National Institute of Environmental Health (5 P42 ES007381); National Institutes of Healt

Pilot-Scale Modeling of Colloidal Silica Delivery to Liquefiable Sands

Passive site stabilization is a developing technology for in situ mitigation of liquefaction risk without surface disruption and involves slow injection of stabilizing materials into the liquefiable sand. In this study, colloidal silica injection was performed in a pilot-scale facility having dimensions of 243 cm by 366 cm in plan and 122 cm in depth. The pilot-scale facility is the largest of its kind in the United States. It is equipped with electrical conductivity cells which provide real-time monitoring of grout advancement in the soil. Injection rates ranging between 135 and 9000 ml/min/well were used to investigate the optimal rate for grout delivery. In low injection rates, colloidal silica sank instead of traveling horizontally. With higher injection rates, sinking was less noticeable. After treatment, the model was excavated and soil samples were extracted to investigate the grout penetration. Soil recovered from block samples was tested for unconfined strength in the laboratory. The 3D flood simulator UTCHEM was used to simulate the experimental results. The results of actual experiments showed that even 1% percentage colloidal silica provides significant strength after a month of curing

Differential Gene Expression in Liver, Gill, and Olfactory Rosettes of Coho Salmon (Oncorhynchus kisutch) After Acclimation to Salinity.

Most Pacific salmonids undergo smoltification and transition from freshwater to saltwater, making various adjustments in metabolism, catabolism, osmotic, and ion regulation. The molecular mechanisms underlying this transition are largely unknown. In the present study, we acclimated coho salmon (Oncorhynchus kisutch) to four different salinities and assessed gene expression through microarray analysis of gills, liver, and olfactory rosettes. Gills are involved in osmotic regulation, liver plays a role in energetics, and olfactory rosettes are involved in behavior. Between all salinity treatments, liver had the highest number of differentially expressed genes at 1616, gills had 1074, and olfactory rosettes had 924, using a 1.5-fold cutoff and a false discovery rate of 0.5. Higher responsiveness of liver to metabolic changes after salinity acclimation to provide energy for other osmoregulatory tissues such as the gills may explain the differences in number of differentially expressed genes. Differentially expressed genes were tissue- and salinity-dependent. There were no known genes differentially expressed that were common to all salinity treatments and all tissues. Gene ontology term analysis revealed biological processes, molecular functions, and cellular components that were significantly affected by salinity, a majority of which were tissue-dependent. For liver, oxygen binding and transport terms were highlighted. For gills, muscle, and cytoskeleton-related terms predominated and for olfactory rosettes, immune response-related genes were accentuated. Interaction networks were examined in combination with GO terms and determined similarities between tissues for potential osmosensors, signal transduction cascades, and transcription factors

HII Region Oxygen Abundances in Starbursting Transition Dwarf Galaxies

We present empirical HII region oxygen abundances for a sample of low-luminosity starburst galaxies which are in a short lived evolutionary state. All five galaxies are characterized by centrally concentrated star formation, which is embedded in smooth stellar envelopes resembling dE-like systems. The galaxies also have small gas contents with typical M_{HI}/L_{B} ~ 0.1 resulting in gas exhaustion timescales less than 1 Gyr, even when molecular gas is considered. We find, compared to other morphologically similar systems, the galaxies of this sample have surprisingly high oxygen abundances with 12 + log(O/H) ~ 9.0. We propose that these objects are a subclass of evolved blue compact dwarfs, which have exhausted most of their gas supply while retaining their metals. We further propose that we are seeing these objects during a short phase in which they are nearing the end of their starburst activity, and could become early-type dwarfs.Comment: 13 pages, 3 figures, accepted by ApJ Letter

A conservation genomics workflow to guide practical management actions

Owing to decreasing costs and increased efficiency, it is now conceivable that conservation genomic information can be used to improve the effectiveness of recovery programs for many, if not most, threatened plants. We suggest that a simple genomic study be viewed as an initial step in conservation decision-making, as it informs long-term recovery efforts in various ways. We present biodiversity managers and conservation biologists with a simple, standardized workflow for genomic research that can guide efficient collection, analysis and application of genomic information across disparate threatened plants. Using two case studies, ‘Banksia vincentia’ and Daphnandra johnsonii, we demonstrate how a single round of genotyping by sequencing e a one-time cost e produces multiple directly applicable benefits, and how generating genomic information as early as possible can enhance conservation outcomes. We argue for a shift away from asking whether genomic information is needed or justified, and a shift towards consideration of the questions that need to be addressed. Such questions should aimed at cost-effectively guiding multiple practical aspects of a threatened plant’s management plan. The workflow presented here should help relevant stakeholders design a sampling strategy that directly suits their questions and needs