Agricultural chemical exposure in small farmers in Guyana

A study of self-reported injury from agricultural chemical exposure was conducted in farmers in rural Guyana. One hundred and ninety agricultural workers were studied, of which 167 (88%) were male. Morbidity from agricultural chemical exposure was common, with 87 farmers (46%) reporting having experienced at least one episode of illness after agricultural chemical exposure. Relatively few of the farmers sought medical assistance for their symptoms, with only 20 farmers (11%) visiting a local doctor and only two farmers (1%) reporting going to a hospital for treatment. Local farmer use of protective equipment was limited. Pyrethroids and herbicides paraquat and glyphosate were the most commonly used agricultural chemicals in the population studied. Data showed that exposure to agricultural chemicals remains frequent, with incidence of severe injury requiring less frequent medical attention.     

Glass Fibers and Their Use as Filter Media

Typical air quality effect levels of photochemical oxidants on specific plant substrates are illustrated. These include ambient oxidant exposure data measured as “total oxidant” as well as laboratory exposures to individual pure oxidants, ozone, or PAN compounds, since these oxidants are identified in photochemical smog. New terms, “PaNs” and “PAN-type” oxidant, have been proffered for purposes of clarification of the terminology. PAN-type oxidant more precisely defines the phytotoxicant complex causing silvering or bronzing of the lower leaf surfaces in lieu of the older term “oxidant.” Due to the recognition of several oxidizing phytotoxicants in recent years, it is recommended that the term oxidant be reserved for use as a generic term. A tabular classification of the oxidizing phytotoxicants found in community photochemical smog and the specific syndromes produced is provided.     

Metallsorption an Illit und Metallfreisetzung unter Einwirken der Aminosäuren Glycin und Histidin

The heavy metal ions Zn(II), Pb(II), Cr(III) and Hg(II) were examined in regard of their adsorption behaviour towards Kaolin W from Lohrheim (51% illite, 31% kaolinite and 18% quarz). By means of the Langmuir and Freundlich models the determined adsorption isothermes could be linearized. The ability of glycine and histidine solutions to release heavy metal ions, pre-adsorbed on Kaolin W (36,1–2300 mg kg^?1 Zn, Pb, Cr and Hg), was specified. It was found a low influence of glycine, but an evident influence of histidine to the metal release, expecially of Pb and Cr, depending on the metalcoating, metal-amino acid-ratio, experimental pH and testing period. The highest remobilisation fraction, up to 98%, could be found in the case of Zn. This elucidates an enhancement of the zinc release compared with the blank solution, without containing amino acids, to a factor of maximal 9,3. As far as Pb and Cr were concerned the histidine extraction exeeded the remobilisation in the blank solution by a maximum of 50,8 or 40. As Hg develops strong covalent bondings to illite by OH-bridges, the release of Hg was not affected by the amino acids.     

IMPACT OF MINING ACTIVITIES ON WATER QUALITY IN WESTERN NORTH CAROLINA1

ABSTRACT: An intensive water quality investigation was conducted in western North Carolina to determine whether water quality problems existed from point and nonpoint source inputs of sediment from surface mining activities. Depth integrated measurements of sediment transport and biological sampling of benthic communities indicated that very serious water quality problems were caused by erosion from a concentrated area of open pit mining for mica, kaolin, and feldspar. The erosion occurred on haul roads, active mines, inactive mines, and tailings disposal piles. The need for using specific “Best Management Practices” for erosion control on the mining operation is discussed. These practices need to be implemented to restore populations of trout to the degraded reaches of the river. Additional monitoring data are presented that indicate that the biological integrity of surface waters can be preserved in the vicinity of point source mining discharges when the operators utilize proper practices in settling and neutralizing their effluent. While much has been done to abate the point source discharges, attention now needs to be focused on the nonpoint sources of sediment from mining operations.     

Continuous-flow column study of reductive dehalogenation of PCE upon bioaugmentation with the Evanite enrichment culture

A continuous-flow anaerobic column experiment was conducted to evaluate the reductive dechlorination of tetrachloroethene (PCE) in Hanford aquifer material after bioaugmentation with the Evanite (EV) culture. An influent PCE concentration of 0.09 mM was transformed to vinyl chloride (VC) and ethene (ETH) within a hydraulic residence time of 1.3 days. The experimental breakthrough curves were described by the one-dimensional two-site-nonequilibrium transport model. PCE dechlorination was observed after bioaugmentation and after the lactate concentration was increased from 0.35 to 0.67 mM. At the onset of reductive dehalogenation, cis-dichloroethene (c-DCE) concentrations in the column effluent exceeded the influent PCE concentration indicating enhanced PCE desorption and transformation. When the lactate concentration was increased to 1.34 mM, c-DCE reduction to vinyl chloride (VC) and ethene (ETH) occurred. Spatial rates of PCE and VC transformation were determined in batch-incubated microcosms constructed with aquifer samples obtained from the column. PCE transformation rates were highest in the first 5 cm from the column inlet and decreased towards the column effluent. Dehalococcoides cell numbers dropped from approximately 73.5% of the total Bacterial population in the original inocula, to about 0.5% to 4% throughout the column. The results were consistent with estimates of electron donor utilization, with 4% going towards dehalogenation reactions.     

Optimization of Height of Release of Air Pollutants

A number of key projects in the Environmental Protection Agency (EPA) particulate R&;D program having applicability to industry are presented. For electrostatic precipitators (ESP) there is presented the result of work on large diameter discharge electrodes which provide a decrease in penetration of up to a factor of 4 when compared to conventional small diameter electrodes. Also discussed is the multistage ESP which provides a collection efficiency that would require a collecting plate area 4 or 5 times larger with conventional ESP technology. The E-SOX technology makes use of the multistage concept to free up space in the ESP for SO₂ removals of up to 90%. Electrostatically augmented fabric filtration provides a reduction in pressure drop of about 5 0% as compared to conventional fabric filtration. Wind tunnel modeling of windbreaks for material storage piles indicates a potential for providing engineering design data that would allow significant emission reduction caused by wind erosion     

Reinvestigating the pollution haven hypothesis: the nexus between foreign direct investments and environmental quality in G-20 countries

Environmental Science and Pollution Research - One of the most commonly debated concerns regarding foreign direct investment inflows is the associated environmental adversities that accompany the...     

Sonographic demonstration of fetal sacrococcygeal teratoma

Six cases of sonographically diagnosed fetal sacrococcygeal teratoma (SCT) are presented and illustrate the variable features of fetal SCT. The sonographic findings assisted the parents and perinatal team in making decisions, and in two of the cases the children survived after elective Cesarean section and prompt neonatal resection of the tumors. None of the patients showed signs of malignant degeneration of the teratoma or metastases. Fetal SCT no longer should be considered a uniformly fatal condition. The literature on sacrococcygeal teratoma detected after birth indicates that the mortality rate is correlated with the degree of extension of the tumor. Therefore, the classification of sonographically diagnosed fetal SCT according to its size and position is important for decisions regarding pregnancy management.