Last data update: May 13, 2024. (Total: 46773 publications since 2009)
Records 1-3 (of 3 Records) |
Query Trace: Humphrey JR[original query] |
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Onsite wastewater system nitrogen contributions to groundwater in coastal North Carolina
Humphrey Jr C , O'Driscoll M; , Deal N , Lindbo D , Thieme S , Zarate-Bermudez M . J Environ Health 2013 76 (5) 16-22 The objective of the study described in this article was | to evaluate the nitrogen contributions from two onsite wastewater systems (sites 1 and 2) to groundwater and adjacent surface waters in coastal Beaufort County, North Carolina. Groundwater levels and water quality parameters including total nitrogen, nitrogen species, temperature, and pH were monitored from October 2009 to May 2010. Nitrogen was also tested in groundwater from deeper irrigation or drinking water wells from the two sites and six additional neighboring residences. Mean total nitrogen concentrations | in groundwater beneath onsite wastewater systems 1 and 2 were | 34.3 ± 16.7 mg/L and 12.2 ± 2.9 mg/L, respectively, and significantly higher than background groundwater concentrations (<1 mg/L). Groundwater in the deeper wells appeared not to be influenced by the onsite systems. Groundwater nitrogen concentrations typically decreased with distance down-gradient from the systems, but were still elevated relative to background conditions more than 15 m from the systems and near the estuary. This was a pioneering effort to better understand the link of onsite systems, the fate of nitrogen in the environment, and public health. |
Safe lists for medications in pregnancy: inadequate evidence base and inconsistent guidance from Web-based information, 2011
Peters SL , Lind JN , Humphrey JR , Friedman JM , Honein MA , Tassinari MS , Moore CA , Mathis LL , Broussard CS . Pharmacoepidemiol Drug Saf 2013 22 (3) 324-8 PURPOSE: Medication use during pregnancy is common and increasing. Women are also increasingly getting healthcare information from sources other than their physicians. METHODS: This report summarizes an environmental scan that identified 25 active Internet sites that list medications reported to be safe for use in pregnancy and highlights the inadequate evidence base and inconsistent guidance provided by these sites. RESULTS: These lists included 245 different products, of which 103 unique components had been previously evaluated in terms of fetal risk by the Teratogen Information System (TERIS), a resource that assesses risk of birth defects after exposure under usual conditions by consensus of clinical teratology experts. For 43 (42%) of the 103 components that were listed as 'safe' on one or more of the Internet sites surveyed, the TERIS experts were unable to determine the fetal risk based on published scientific literature. For 40 (93%) of these 43, either no data were available to assess human fetal risk or the available data were limited. CONCLUSIONS: Women who see a medication on one of these 'safe' lists would be led to believe that there is no increased risk of birth defects resulting from exposure. Thus, women are being reassured that fetal exposure to these medications is safe even though a sufficient evidence base to determine the relative safety or risk does not exist. (Copyright (c) 2013 John Wiley & Sons, Ltd.) |
Evaluation of on-site wastewater system Escherichia coli contributions to shallow groundwater in coastal North Carolina
Humphrey Jr CP , O'Driscoll MA , Zarate MA . Water Sci Technol 2011 63 (4) 789-95 The study goal was to determine if on-site wastewater systems (OSWWS) installed in coastal areas were effective at reducing indicator bacteria densities before discharge to groundwater. Groundwater Escherichia coli (E. coli) densities and groundwater levels adjacent to 16 OSWWS in three different soil groups (sand, sandy loam, and sandy clay loam) were monitored and compared to background groundwater conditions on four occasions between March 2007 and February 2008 in coastal North Carolina. Groundwater beneath OSWWS had significantly (p≤0.05) lower densities of E. coli than septic tank effluent, but significantly higher densities of E. coli than background conditions for each soil type. Twenty three percent of all groundwater samples near OSWWS had E. coli densities that exceeded the EPA freshwater contact standards (single sample 235 cfu/100 mL) for surface waters. Groundwater E. coli densities near OSWWS were highest during shallow water table periods. The results indicate that increasing the required vertical separation distance from drainfield trenches to seasonal high water table could improve shallow groundwater quality. |
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