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Influence of watershed system management on herbicide concentrations in Mississippi Delta oxbow lakes.

The Mississippi Delta Management Systems Evaluation Area (MD-MSEA) project was established in 1994 in three small watersheds (202 to 1,497 ha) that drain into oxbow lakes (Beasley, Deep Hollow, and Thighman). The primary research objective was to assess the implications of management practices on water quality. Monthly monitoring of herbicide concentrations in lake water was conducted from 2000 to 2003. Water samples were analyzed for atrazine, cyanazine, fluometuron, metolachlor, and atrazine metabolites. Herbicide concentrations observed in the lake water reflected cropping systems of the watershed, e.g., atrazine and metolachlor concentrations were associated with the level of corn and sorghum production, whereas cyanazine and fluometuron was associated with the level of glyphosate-sensitive cotton production. The dynamics of herbicide appearance and dissipation in lake samples were strongly influenced by herbicide use, lake hydrology, rainfall pattern, and land management practices. The highest maximum concentrations of atrazine (7.1 to 23.4 microg L(-1)) and metolachlor (0.7 to 14.9 microg L(-1)) were observed in Thighman Lake where significant quantities of corn were grown. Introduction of s-metolachlor and use of glyphosate-resistant cotton coincided with reduced concentration of metolachlor in lake water. Cyanazine was observed in two lakes with the highest levels (1.6 to 5.5 microg L(-1)) in 2000 and lower concentrations in 2001 and 2002 (<0.4 microg L(-1)). Reduced concentrations of fluometuron in Beasley Lake were associated with greater use of glyphosate-resistant cotton and correspondingly less need for soil-applied fluometuron herbicide. In contrast, increased levels of fluometuron were observed in lake water after Deep Hollow was converted from conservation tillage to conventional tillage, presumably due to greater runoff associated with conventional tillage. These studies indicate that herbicide concentrations observed in these three watersheds were related to crop and soil management practices.

Acetamides↗

Seasonal bioavailability of sediment-associated heavy metals along the Mississippi river floodplain.

A value of simultaneously extracted metal to acid-volatile sulfide (SEM-AVS) can provide important information regarding metal availability in anaerobic sediment. SEM and AVS concentrations were obtained by the cold-acid purge-and-trap technique during spring and summer at six locations along the Mississippi River floodplain. SEM-AVS values and AVS concentrations did not vary significantly between locations during both seasons. AVS concentrations were significantly greater during summer than spring, resulting in significantly lower SEM-AVS values in summer. Total SEM concentrations did not significantly vary between seasons or specific locations. SEM-AVS values were greater than one at each location during both seasons. Sediment metal toxicity was predicted to be absent for benthic organisms along the river floodplain.

Animals↗

Fish tissue quality in the lower Mississippi River and health risks from fish consumption.

Between 1990 and 1994, samples of three shellfish species (i.e. blue crab, Callinectes sapidus;crayfish, Procambarus acutis; and river shrimp, Macrobrachium ohionii) and 16 fish species and were collected at six sites along the lower Mississippi River by the Louisiana Department of Environmental Quality, Office of Water Resources in coordination with the US Environmental Protection Agency. The fish species included: bigmouth buffalo (Ictiobus cyanellus); blue catfish (Ictalurus furcatus); carp (Cyprinus carpio); channel catfish (Ictalurus punctatus); cobia (Rachycentron canadum); flathead catfish (Pylodictis olivaris); freshwater drum (Aplodinotus grunniens); largemouth bass (Micropterus salmoides); long nose gar (Lepisosteus osseus); red drum (Sciaenops ocellatus); red snapper (Lutjanus campechanus); smallmouth buffalo (Ictiobus bubalus); spotted gar (Lepisosteus oculatus); striped bass (Morone saxatilis); white bass (Morone chrysops); and white crappie (Pomoxis annularis). Organic compound and heavy metal concentrations were measured in 161 composite fish tissue samples where each composite included three to 10 individual fish. Nineteen chemicals, found at measurable levels in sample tissues, were used in calculations of lifetime excess cancer and non-cancer risks due to fish consumption. We calculated: 574 chemical-specific cancer risks; 41 total cancer risks; and 697 margins of exposure based on a consumption rate of one 8-ounce meal per week (0.032 kg/day), a body weight of 70 kg and reported cancer potency factors and reference doses. We identified nine species of concern (blue catfish, carp, channel catfish, cobia, crayfish, flathead catfish, red drum, spotted gar and striped bass) based on total cancer risk greater than 10(-4) or margin of exposure greater than 1, and whether or not samples collected in subsequent years resulted in lower risks. The compounds primarily responsible for the elevated risks were aldrin, dieldrin, alpha-benzene hexachloride, gamma-benzene hexachloride, heptachlor epoxide, arsenic and mercury.

Animals↗

Quantities and associations of lead, zinc, cadmium, manganese, chromium, nickel, vanadium, and copper in fresh Mississippi delta alluvium and New Orleans alluvial soils.

The topic of this study is the effect of anthropogenic metals on the geochemical quality of urban soils. This is accomplished by comparing the metal contents and associations between two alluvial soils of the lower Mississippi River Delta, freshly deposited alluvial parent materials and alluvial soils collected from a nearby urban environment. Fresh alluvium samples (n = 97) were collected from the Bonnet Carré Spillway. The urban alluvial soil samples (n = 4026) were collected from New Orleans and stratified by census tracts (n = 286). The Spillway samples tend to have less Pb and Zn than generally noted for the baseline of natural soils. Except for Mn and V, Spillway alluvium contains significantly less metal than urban soils. For Spillway samples, the median metal content (in microg g(-1)) is 4.7 Pb, 11.1 Zn, 0.7 Cd, 164 Mn, 0.8 Cr, 3.9 Ni, 3.2 V, and 3.9 Cu. For urban soils, the median metal content (in microg g(-1)) is 120 Pb, 130 Zn, 3.2 Cd, 138 Mn, 2.1 Cr, 9.8 Ni, 3.8 V, and 12.7 Cu. Metal associations also differ between Spillway alluvium and urban alluvial soils. Fresh alluvium correlation coefficients between individual metals vary from 0.87 to 0.99 (P < 10(-13)) except for Cr which ranges from 0.57 to 0.68 (P < 10(-7)). The urban soil correlation coefficients for metals and the index value are 0.40-0.98. In urban soils, Pb, Zn, Cr, and Cu are dominant metals and highly associated, with a correlation coefficient ranging from 0.83 to 0.98 (P < 10(-25)). Their strong association justifies the use of GIS to map the integrated soil metal index (sum of the medians of metals by census tract) of New Orleans. Although also positively correlated (0.40-0.68, P < 10(-10)), Cd, Mn, Ni and V differ in their distribution in the city compared to Pb, Zn, Cr and Cu. Overall, significantly higher metal values occur in the inner city and lower values occur in outlying areas. The human health impact of the mixture of metals is not well understood. This study provides empirical data about the mixture and distribution of metals in New Orleans alluvial soils. Given common technical development, especially of traffic flows in cities, similar patterns of soil metals are expected for all US cities and probably international cities as well. Primary prevention of urban metal accumulations is necessary to enhance and sustain the development of urban culture.

Cadmium↗

Molecular-scale speciation of Zn and Ni in soil ferromanganese nodules from loess soils of the Mississippi Basin.

Determining how environmentally important trace metals are sequestered in soils at the molecular scale is critical to developing a solid scientific basis for maintaining soil quality and formulating effective remediation strategies. The speciation of Zn and Ni in ferromanganese nodules from loess soils of the Mississippi Basin was determined by a synergistic use of three noninvasive synchrotron-based techniques: X-ray microfluorescence (microXRF), X-ray microdiffraction (microXRD), and extended X-ray absorption fine structure spectroscopy (EXAFS). We show that Ni is distributed between goethite (alpha-FeOOH) and the manganese oxide lithiophorite, whereas Zn is bound to goethite, lithiophorite, phyllosilicates, and the manganese oxide birnessite. The selective association of Ni with only iron and manganese oxides is an explanation for its higher partitioning in nodules over the soil clay matrix reported from soils worldwide. This could also explain the observed enrichment of Ni in oceanic manganese nodules. The combination of these three techniques provides a new method for determining trace metal speciation in both natural and contaminated environmental materials.

Environmental Monitoring↗

Trace elements in lesser scaup (Aythya affinis) from the Mississippi flyway.

Previous research reported that concentrations of selenium in the livers of 88-95% of lesser scaup from locations in Lake Erie, Lake St. Clair, and Lake Michigan, USA were either elevated (10-33 microg/g dry weight [dw]) or in the potentially harmful range (> 33 microg/g dw). In order to determine the geographic extent of these high selenium concentrations, we collected lesser scaup in Louisiana, Arkansas, Illinois, Minnesota, Wisconsin, and Manitoba and analyzed the livers for 19 trace elements. We found that all trace element concentrations, except for selenium, generally were low. Arsenic, which usually is not detected in liver samples, was detected in Louisiana and may be related to past agricultural usages. Chromium, which also is not usually detected, was only present in lesser scaup from Arkansas and may be related to fertilizer applications. Cadmium and mercury concentrations did not differ among locations and concentrations were low. Selenium concentrations in Arkansas (geometric mean = 4.2 microg/g dw) were significantly lower than those in Louisiana (10.7 microg/g dw), Illinois (10.5 microg/g dw), and Minnesota (8.0 microg/g dw); concentrations in Wisconsin and Manitoba were intermediate (6.6 and 6.5 microg/g dw). About 25% of lesser scaup livers contained elevated selenium concentrations; however, none were in the harmful range. We concluded that selenium concentrations in lesser scaup in the Mississippi Flyway are elevated in some individuals, but not to the extent that has been documented in the industrial portions of the Great Lakes.

Animals↗

Brief assessment of severe language impairments: initial validation of the Mississippi aphasia screening test.

PRIMARY OBJECTIVE: To validate the Mississippi Aphasia Screening Test (MAST) which includes nine sub-scales measuring expressive and receptive language abilities. RESEARCH DESIGN: Evaluation of inpatients admitted to neurology, neurosurgery or rehabilitation units at two local hospitals and who were within 60 days of onset of a unilateral ischemic or haemorrhagic stroke (left hemisphere (LH; n=38); right hemisphere (RH; n=20)). Additional participants were recruited from the community to comprise a non-patient control sample (NP; n=36). METHODS: Data collection included administration of the MAST and chart review. RESULTS: The LH group showed more impairment than the RH and NP groups on summary scores. The LH group performed worse than the NP group on all sub-scales. The object recognition and verbal fluency sub-scales did not discriminate the stroke groups. CONCLUSION: Analyses suggest good criterion validity for the MAST in differentiating communication impairments among clinical and control samples.

Aphasia↗

Adherence to balance tolerance limits at the Upper Mississippi Science Center, La Crosse, Wisconsin.

Verification of balance accuracy entails applying a series of standard masses to a balance prior to use and recording the measured values. The recorded values for each standard should have lower and upper weight limits or tolerances that are accepted as verification of balance accuracy under normal operating conditions. Balance logbooks for seven analytical balances at the Upper Mississippi Science Center were checked over a 3.5-year period to determine if the recorded weights were within the established tolerance limits. A total of 9435 measurements were checked. There were 14 instances in which the balance malfunctioned and operators recorded a rationale in the balance logbook. Sixty-three recording errors were found. Twenty-eight operators were responsible for two types of recording errors: Measurements of weights were recorded outside of the tolerance limit but not acknowledged as an error by the operator (n = 40); and measurements were recorded with the wrong number of decimal places (n = 23). The adherence rate for following tolerance limits was 99.3%. To ensure the continued adherence to tolerance limits, the quality-assurance unit revised standard operating procedures to require more frequent review of balance logbooks.

Academies and Institutes↗

Pictorial key to the adults of hard ticks, family Ixodidae (Ixodida: Ixodoidea), east of the Mississippi River.

Six genera and 27 species of hard ticks (Ixodidae) currently are recognized in the United States east of the Mississippi River as follows: Amblyomma (4 species), Boophilus (1), Dermacentor (3), Haemaphysalis (2), Ixodes (16), and Rhipicephalus (1). We present a diagrammatic couplet key to the adults of the six genera and 27 species of Ixodidae found in the eastern portion of the United States.

Animals↗

Seasonal activity and relative abundance of Amblyomma americanum in Mississippi.

Ecological investigations of the lone star tick, Amblyomma americanum (L.), were conducted in 3 adjacent 60-m2 plots, located in Noxubee National Wildlife Refuge, Noxubee County, Mississippi. Ticks were collected weekly from July 1992 to July 1993 by flagging randomly selected lanes. During the year, larval ticks were collected first in early July, with peak numbers in September, and they were collected no later than late October. Nymphal ticks were collected from mid-March to late October, with peak numbers occurring in mid-May and early August. Adult ticks were found initially in early March, with peak numbers from mid-May to mid-June and were no longer collected by late August. Analyses of meteorological data indicated that the most influential parameter on tick activity was humidity.

Animals↗

Dust-mite-allergen concentrations in asthmatics' bedrooms in the Quad Cities (Illinois, USA) after the Mississippi River floods of 1993.

This study aimed to measure allergens from Dermatophagoides farinae and D. pteronyssinus and to examine possible relationships of these mite allergens with flooding and other housing factors. A total of 313 dust samples were collected from the bedrooms of 57 asthmatics in 45 homes in the Quad Cities (Illinois, USA) and analyzed by ELISA for the presence of the D. farinae and D. pteronyssinus allergens. Twenty of these homes had some flooding in the last 12 months due to the Mississippi River floods of 1993 and/or other factors. The log-transformed least-squares means of allergens collected were 28 ng/m2 for the D. farinae allergen and 26 ng/m2 for the D. pteronyssinus allergen. D. farinae allergen levels were significantly higher in homes located in the valley, in homes during the summer months, in homes with furred or feathered pets, in homes which had not been flooded in the last year, and in homes where rugs had been steam-cleaned in the last 12 months. D. pteronyssinus allergen levels were significantly higher in homes located in the valley, in homes during April and July-September, in homes with furred or feathered pets, and in homes with no dehumidifier.

Allergens↗

Indicators of substance use among pregnant adolescents in the Mississippi Delta.

Data were collected from 293 pregnant adolescents living in the southern Illinois section of the Mississippi Delta region concerning their substance use behaviors in 1989 and 1990. Subjects used a variety of drugs in the past and present. For example, 24.4% of the sample reported they presently smoked cigarettes. Alcohol was used by 20.4% in the previous five months, while 5.2% reported marijuana use during the same period. Regression models designed to predict substance use produced adjusted r2 values of .30 (SE = 1.06) for cigarette use, .38 (SE = .49) for marijuana use, and .43 (SE = .59) for alcohol use. Significant indicators included peer and personal substance use behavior, parental substance use, and having previously received mental health treatment.

Adolescent↗

An evaluation of a substance abuse education program for Mississippi delta pregnant adolescents.

A non-equivalent control group design was used to examine effectiveness of a drug and alcohol abuse prenatal care health education program for pregnant teens (N = 212) in the Mississippi delta region of southern Illinois. Experimental group posttest knowledge scores were significantly higher than control group scores; however, no significant differences occurred in attitudes between the two groups at posttest. Frequency of drug use decreased substantially for both experimental and control groups at posttest; however, significantly more experimentals than controls indicated they reduced or quit using drugs. The experimental group had a significantly lower rate of diabetes, anemia, and sexually transmitted diseases, and possibly a lower rate of spontaneous abortion depending on the statistical test used. Data suggest prenatal care health education programs may be effective methods for increasing patient awareness about the dangers of drug and alcohol abuse and may have an effect on infant and maternal outcomes.

Adolescent↗

Food safety program. Endrin monitoring in the Mississippi river.

Twelve successive monthly samplings and analyses of representative fish and shellfish and of mud and water from the lower Mississippi River showed neither a high concentration of endrin nor a time-ordered change in the concentration. The general absence of endrin from the samples indicated no significant contamination.

Animals↗

Catabolism of 5-chlorosalicylate by a Bacillus isolated from the Mississippi River.

A strain of Bacillus brevis isolated from a polluted section of the Mississippi River was shown to utilize 5-chloro-2-hydroxybenzoate (5-chlorosalicylate) as a sale source of carbon and energy. Enzymic analyses of cell-free extracts prepared from 5-chlorosalicylate-grown cells demonstrated that the initial step in the pathway involved cleavage of the aromatic ring between C1 and C2 by a specific 5-chlorosalicylate 1,2-dioxygenase. Loss of chloride from the growth substrate occurred after ring fission and was probably enzyme mediated. An intermediate chlorolactone apparently lost chloride by enzymatic hydrolysis with formation of maleylpyruvate. Maleylpyruvate was further degraded by both glutathione-dependent and glutathione-independent mechanisms, with these reactions being identical to the terminal reactions of the gentisate pathway. It was suggested that this novel 5-chlorosalicylate pathway may have evolved by recruitment of enzymes from an ancestral gentisate pathway.

Bacillus↗

Bacteriological water quality effects of hydraulically dredging contaminated upper Mississippi River bottom sediment.

Bacteriological effects of hydraulically dredging polluted bottom sediment in the navigation channel of the Upper Mississippi River (river mile 827.5 [about 1,332 km] to 828.1 [about 1,333 km]) were investigated. Bottom sediment in the dredging site contained high total coliform densities (about 6,800 most-probable-number total coliform index per g [dry weight] and 3,800 membrane filter total coliforms per g [dry weight]), and fecal coliforms comprised an average 32% of each total coliform count. Total coliform and fecal coliform densities in water samples taken immediately below the dredge discharge pipe were each approximately four times corresponding upstream values; fecal streptococcus densities were approximately 50 times corresponding upstream values. Correlation analysis indicated that mean turbidity values downstream to the dredging operation were directly and significantly (r greater than 0.94) related to corresponding total coliform, fecal coliform, and fecal streptococcus densities. Salmonellae and shigellae were not recovered from either upstream or downstream water samples. Turbidity and indicator bacteria levels had returned to predredge values within less than 2 km below the dredge spoil discharge area at the prevailing current velocity (about 0.15 m/s).

Enterobacteriaceae↗

Hemoglobin Mississippi (beta 44ser----cys). Studies of the thalassemic phenotype in a mixed heterozygote with beta +-thalassemia.

Hemoglobin Mississippi (HbMS: beta 44ser----cys) has anomalous properties that include disulfide linkages with normal beta-, delta-, gamma-, and alpha-chains, and the formation of high molecular weight multimers. While heterozygotes for HbMS are clinically and hematologically normal and carriers of the beta +-thalassemia gene in our family had mild microcytic anemia, the proband with HbMS-beta +-thalassemia had a hemoglobin level of 7 g/dl, mean corpuscular volume (MCV) of 68 fl, reticulocytes of 2-6%, HbF of 18%, marked anisocytosis and poikilocytosis, and splenomegaly, all features of thalassemia intermedia. With oxidant stress, her erythrocytes developed multiple dispersed Heinz bodies, but HbMS was only mildly unstable. HbMS was susceptible to proteolytic degradation in the presence of ATP. The unexpectedly severe clinical findings in HbMS-beta +-thalassemia may result from the proteolytic digestion of HbMS, as well as the excessive alpha-chains characteristic of beta +-thalassemia, which combined provide the increment of cellular damage that results in the phenotype of thalassemia intermedia.

Child↗

Teaching breast cancer screening to African American women in the Arkansas Mississippi river delta.

PURPOSE/OBJECTIVES: To determine the effectiveness of a multifaceted, culturally sensitive breast cancer education program for African American women in the Arkansas Mississippi River Delta. DESIGN: Experimental (i.e., posttest only, control group design). SETTING: African American churches and a county Extension Homemakers Club sponsored through the Arkansas Extension Homemakers council. SAMPLE: 53 African American women. The experimental group included 30 participants who had a mean age of 56 years, and the control group consisted of 23 participants with a mean age of 51 years. METHODS: After the presentation of a multifaceted, culturally sensitive breast cancer education program, a variety of instruments were administered to participants in the experimental group that measured dependent variables. Subjects in the control group completed the same instruments in the absence of a viable intervention. Data were analyzed using t tests. MAIN RESEARCH VARIABLES: Knowledge and beliefs about breast cancer. FINDINGS: The experimental group's mean scores were significantly higher than the control group's on the Breast Cancer Knowledge Test and the susceptibility scale of the Breast Cancer Screening Belief Scales. The experimental group also scored significantly higher than the control group on the confidence scale of the Breast Cancer Screening Belief Scales. CONCLUSIONS: The multifaceted, culturally sensitive breast cancer education program appeared to be responsible for the differences in scores between the experimental and control groups. IMPLICATIONS FOR NURSING: Culturally sensitive group educational programs aimed at helping African American women in the rural South become more knowledgeable about breast cancer and early detection clearly are needed. Such efforts also must focus on increasing women's confidence in effectively performing regular breast self-examination as well as their understanding of personal risk. Healthcare professionals play a major role in the development and implementation of these programs.

Black or African American↗