Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: DrugBank:EXPT01348 (EPA)
 7,185 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Nannochloropsis sp. was grown with different levels of nitrate, phosphate, salinity and temperature with CO(2) at 2,800 microl l(-1). Increased levels of NaNO(3) and KH(2)PO(4) raised protein and polyunsaturated fatty acids (PUFAs) contents but decreased carbohydrate, total lipid and total fatty acids (TFA) contents. Nannochloropsis sp. grew well at salinities from 22 to 49 g l(-1), and lowering salinity enhanced TFA and PUFAs contents. TFA contents increased with the increasing temperature but PUFAs contents decreased. The highest eicosapentaenoic acid (EPA, 20:5 omega3) content based on the dry mass was above 3% under low N (150 microM NaNO(3)) or high N (3000 microM NaNO(3)) condition. Excessive nitrate, low salinity and temperature are thus favorable factors for improving EPA yields in Nannochloropsis sp.
 ...
PMID:Response of growth and fatty acid compositions of Nannochloropsis sp. to environmental factors under elevated CO2 concentration. 1679 19

This study evaluated the effectiveness of soils with different textures and thickness to treat BOD, N and P eluted from household septic effluent. The assessments were accomplished by leaching undisturbed soil monoliths of 30, 45 and 60 cm thickness and 25 cm in diameter, representing the four different textural groups and hydraulic loadings recommended by the Kentucky Health Department, with domestic wastewater effluent collected regularly from a household septic system. Effluent concentrations were monitored daily over a 15d period for biochemical oxygen demand (BOD), total-N, NH4-N, NO3-N and total-P concentrations. The results of the study indicate an alarming frequency of failure to comply with EPA criteria for BOD, total-N and NH4-N concentrations when using a 30 cm vertical separation distance between the bottom of the drain field and a limiting soil interface. The treatment performance was particularly poor in coarse-textured soils, apparently due to insufficient reactive surface area. Although biomat development over time is expected to improve the treatment for some of these parameters, the high influent levels of BOD pose great concerns for surface and groundwater contamination during the early stages of operation. Fine-textured soils generally provided better treatment efficiency and more consistent compliance with EPA standards for BOD, total-N, NH4-N and total-P, as well as greater nitrification/denitrification potential. Treatment efficiency and compliance usually improved with increasing soil depth, with the 60 cm thickness providing the most consistent performance and compliance with MDL requirements. Considering that increasing soil thickness requirements may be impractical in many marginal soils, complementary or alternative treatment technologies should be adopted to improve treatment efficiency and prevent further deterioration of the quality of water resources.
 ...
PMID:Nutrient removal from septic effluents as affected by soil thickness and texture. 1681 11

We have developed chronic toxicity reproductive 5-day tests to study the effects of Pb, as Pb(NO(3))(2), and Hg, as HgCl(2), exposure in the freshwater rotifer Lecane quadridentata. We used "r" (the instantaneous growth rate) as the endpoint. The test was performed using EPA medium at two food levels (10(5) and 10(6) cells/mL of Nannochloris oculata) at a controlled temperature of 25 degrees C and an L/D cycle of 16:8 h. We monitored the levels of both metals, using atomic absorption, at days 0, 2, and 5 of each experiment. Our results showed that rotifers fed at higher food concentrations were capable of withstanding higher levels of metal toxicity than those fed at lower food concentrations (EC50 = 0.704 versus 0.664 mg/L(-1) for lead, P < 0.05; EC50 = 0.057 versus 0.054 for mercury, P < 0.05). Our atomic absorption analysis showed that although 66% of lead nitrate can be taken up by algal cells efficiently and removed from the medium, rotifers also play an important role removing additional lead from the medium (up to 44% in some treatments). In the case of mercuric chloride, most of the mercury is bound by the salts contained in EPA medium or discarded by the organisms, and the remainder is removed by N. oculata in <48 h.
 ...
PMID:Study of the effects of Pb and Hg toxicity using a chronic toxicity reproductive 5-day test with the freshwater rotifer Lecane quadridentata. 1694 17

Arsenic compounds have been applied at the land surface as pesticides in agricultural areas globally. The purpose of this study was to evaluate the fate of anthropogenic arsenic applications related to agriculture, using arsenic applications on cotton in the southern High Plains (SHP), Texas, as a case study and examining possible linkages with contamination of the underlying Ogallala aquifer in this region, where 36% of wells exceed the new EPA 10 microg/L standard. Unsaturated zone soil samples were collected from boreholes beneath natural ecosystems (grassland/ shrubland) to provide a control (no arsenic application) (5 profiles) and cotton cropland (20 profiles) for analyses of water-extractable arsenic, vanadium, phosphate, chloride, and nitrate. Natural ecosystem profiles have high arsenic concentrations at depth (maximum of 7.2-69.6 microg As/ kg dry soil at 5.9-21.4 m depth) that are attributed to a geologic source. Most profiles beneath cotton cropland have high arsenic concentrations within the upper meter (profile means 1.7 to 31.6 microg/kg) that correlate with phosphate (r = 0.70, p < 0.01) and are attributed to anthropogenic arsenic application associated with phosphate fertilizer application. High arsenic concentrations at >1 m depth (profile means < or =36.3 microg/kg) found in cropland profiles are attributed to a geologic source because of similarity with profiles beneath natural ecosystems, lack of correlation with phosphate, and pore-water ages that predate anthropogenic arsenic application in many profiles. GIS analyses showed poor correlations between groundwater arsenic and percent cultivated land (r = -0.15, p < 0.01), groundwater nitrate (r = 0.30, p < 0.01), and water table depth (r= -0.31, p < 0.01), further supporting the idea that anthropogenic-derived arsenic in the shallow subsurface is not linked to groundwater arsenic contamination in this region.
 ...
PMID:Unsaturated zone arsenic distribution and implications for groundwater contamination. 1799 28

We investigated the influence of riparian and whole watershed land use as a function of stream size on surface water chemistry and assessed regional variation in these relationships. Sixty-eight watersheds in four level III U.S. EPA ecoregions in eastern Kansas were selected as study sites. Riparian land cover and watershed land use were quantified for the entire watershed, and by Strahler order. Multiple regression analyses using riparian land cover classifications as independent variables explained among-site variation in water chemistry parameters, particularly total nitrogen (41%), nitrate (61%), and total phosphorus (63%) concentrations. Whole watershed land use explained slightly less variance, but riparian and whole watershed land use were so tightly correlated that it was difficult to separate their effects. Water chemistry parameters sampled in downstream reaches were most closely correlated with riparian land cover adjacent to the smallest (first-order) streams of watersheds or land use in the entire watershed, with riparian zones immediately upstream of sampling sites offering less explanatory power as stream size increased. Interestingly, headwater effects were evident even at times when these small streams were unlikely to be flowing. Relationships were similar among ecoregions, indicating that land use characteristics were most responsible for water quality variation among watersheds. These findings suggest that nonpoint pollution control strategies should consider the influence of small upland streams and protection of downstream riparian zones alone is not sufficient to protect water quality.
 ...
PMID:Headwater influences on downstream water quality. 1799 8

One objective of the U.S. Environmental Protection Agency's (EPA's) Supersite Program was to provide data that could be used to more thoroughly evaluate and improve air quality models, and then have those models used to address both scientific and policy-related issues dealing with air quality management. In this direction, modeling studies have used Supersites-related data and are reviewed here. Fine temporal resolution data have been used both to test model components (e.g., the inorganic thermodynamic routines) and air quality modeling systems (in particular, Community Multiscale Air Quality [CMAQ] and Comprehensive Air Quality Model with extensions [CAMx] applications). Such evaluations suggest that the inorganic thermodynamic approaches being used are accurate, as well as the description of sulfate production, although there are significant uncertainties in production of nitric acid, biogenic and ammonia emissions, secondary organic aerosol formation, and the ability to follow the formation and evolution of ultrafine particles. Model applications have investigated how PM levels will respond to various emissions controls, suggesting that nitrate will replace some of the reductions in sulfate particulate matter (PM), although the replacement is small in the summer. Although not part of the Supersite program, modeling being conducted by EPA, regional planning organizations, and states for policy purposes has benefited from the detailed data collected, and the PM models have advanced by their more widespread use.
 ...
PMID:EPA Supersites Program-related emissions-based particulate matter modeling: initial applications and advances. 1831 42

The presence of polycyclic aromatic hydrocarbons (PAHs) may change the mechanisms of metal uptake, thus influencing kinetics and extent of metal phytoextraction. Studies on the subject are scarce, particularly for salt marsh plants. The aim of this work was to investigate the effect of PAHs on the uptake of Cu by Halimione portulacoides, a plant commonly found in salt marshes. Experiments were carried out in the laboratory, either in hydroponics (sediment elutriate) or in sediment soaked in elutriate, which were prepared with sediment and water from a salt marsh of the Cavado river estuary (NW Portugal). Groups of H. portulacoides (grown in a greenhouse) were exposed to those media during six days. Cu2+ (as Cu(NO3)2), 10(2) and 10(4) microg l(-1), was added to the media as well as 1.6 microg l(-1) of the sixteen EPA priority PAHs (0.1 microg l(-1) of each PAHs). Cu was assayed in solutions, sediments and different plant tissues before and after experiments. After exposure, photosynthetic efficiency and levels of chlorophylls were also measured, indicating that plant stress indicators were identical in all plants independently of the media to which the plants were exposed. PAHs influenced both the soluble Cu fraction and Cu uptake by plants. The amounts of metal accumulated in both roots and stems were significantly higher when the 10(4) microg l(-1) of Cu enriched elutriate was amended with PAHs. Thus, results suggest that PAHs may modify Cu solubility, the Cu sorption by plants and/or the passive penetration of Cu into the root cells. Therefore, the combined effects of different types of pollutants should be taken in consideration when studying the remediation potential of plants, namely in terms of phytoextraction.
 ...
PMID:Can PAHs influence Cu accumulation by salt marsh plants? 1853 25

A combined bioelectrochemical and sulfur autotrophic denitrification system (CBSAD) was evaluated to treat a groundwater with nitrate contamination (20.9-22.0mgNO(3)(-)-N/L). The reactor was operated continuously for several months with groundwater to maximize treatment efficiency under different hydraulic retention times (HRT) and electric currents. The denitrification rate of sulfur autotrophic part followed a half-order kinetics model. Moreover, the removal efficiency of bioelectrochemical part depended on the electric current. The reactor could be operated efficiently at the HRT ranged from 4.2 to 2.1h (corresponding nitrogen volume-loading rates varied from 0.12 to 0.24 kg N/m(3)d; and optimum current ranged from 30 to 1000 mA), and the NO(3)(-)-N removal rate ranged from 95% to 100% without NO(3)(-)-N accumulation. The pH of effluent was satisfactorily adjusted by bioelectrochemical part, and the sulfate concentration of effluent was lower than 250 mg/L, meeting the drinking water standard of China EPA.
 ...
PMID:Using the combined bioelectrochemical and sulfur autotrophic denitrification system for groundwater denitrification. 1861 37

One of the most urgent needs for future progress in reducing the substantial impacts of ambient air particulate matter (PM) on human health is to determine which of its components are having the greatest effects. The EPA's Speciation Trends Network (STN) has been operating since 2000. It generates 24-h average fine PM component concentrations for sulfate and nitrate ions, elemental and organic carbon (EC/OC), and many elements on an every third or sixth day basis for one or a few sites in most large US cities. To date, a small number of research studies, summarized in this paper, have used available STN and other supplemental data to identify and quantify the influences of specific components or source-related mixtures on measures of health-related impacts. These pioneering studies have demonstrated the potential utility of using such data in analyses that can provide a sound basis for guiding future research and control activities on those PM sources that have the greatest public health relevance. Unfortunately, the STN data collection methods used are expensive, and data have therefore been too sparse for studies of short-term health effects, where semi-continuous data, or at least daily 24-h concentration data are needed, as well as for regional concentration distributions that are needed for definitive analyses. Furthermore, because of cost considerations, there is virtually no prospect of collecting the data needed by the health researchers for more definitive analyses as long as there is continued reliance on current FRM sampling and analysis methodologies. At the second EPA-HEI Workshop on "Air Quality and Health Researchers Working Together" in RTP, NC on 16 and 17 April 2008, many participants concluded that it was both desirable, and possibly technically and economically feasible, to re-equip the STN sites with an automated system of semi-continuous monitors for sulfate, nitrate, EC, OC, and semi-continuous multistage PM samplers for non-volatile elements, providing continuous records of PM components with an averaging time of approximately 6 h for both thoracic coarse mode PM, fine PM, and perhaps ultrafine PM as well. The availability of such data would greatly accelerate the accumulation of knowledge on PM component exposure-response relationships that would provide a sound basis more targeted air quality standards and pollution control measures.
 ...
PMID:Semi-continuous speciation analyses for ambient air particulate matter: an urgent need for health effects studies. 1895 93

The determination of orthophosphate in aqueous media by differential pulse polarography is described. It is based on determination of the molybdenum in 12-phosphomolybdic acid. High sensitivity is achieved by measuring the polarographic wave due to the catalytic reduction of perchlorate or nitrate in the presence of molybdenum(VI). The method is suitable for samples as small as 3.5 ml which contain as little as 9 ng of phosphorus per ml. The average relative deviation is 3.0% at the 0.045 mg/l. phosphorus level and 1.6% at the 1.2 mg/l. level. Results for the analysis of EPA quality-control water and real surface-water samples are reported.
 ...
PMID:Differential pulse polarographic determination of orthophosphate in aqueous media. 1896 23


<< Previous 1 2 3 4 5 6 7 8 9 Next >>