PREP-PAC: a nutrient replenishment product designed for smallholders in western Kenya

Continuous cropping in the absence of external nutrient inputs to soils has led to the expression of poorly productive patches in farmers’ fields of western Kenya. Farmers attempting to correct these conditions are often confused by the spatial and symptomatic irregularity of affected plants and, until recently, no soil management product was commercially available that is specifically formulated to restore soil fertility to these patches. PREP-PAC consists of 2.0 kg of Minjingu rock phosphate (RP), 200 g of urea, seeds of various symbiotic nitrogen-fixing food legumes, rhizobial inoculant, gum arabic seed adhesive, lime for seed pelleting, and instructions for the use of these materials. It is intended for addition to 25 m² and produced at a cost of $ 0.56 per unit. The general principle is to apply slowly available RP sufficient for several cropping seasons with readily available nitrogenous fertilizer and to intercrop farmer’s maize (Zea mays) with a legume that provides residual fixed-nitrogen and organic inputs to the soil. This approach was tested in on-farm experiments conducted in collaboration with several grassroots rural development organizations. An experiment examined interactions between PREP-PAC components in a maize–soybean (Glycine max) intercrop in nutrient-depleted soils with sandy and clayey surface horizons. The treatments included ±RP, ±urea, and ±inoculants arranged as a 2³ factorial with four replicates at each location. Total value of the intercrops ranged between $ 0.83 in the unamended plots and $ 2.44 in plots treated with PREP-PAC. Significant positive effects were observed with the addition of RP (P<0.001), urea (P=0.04), and inoculant (P=0.01) and in interactions between RP and urea (P=0.02) or inoculant (P=0.07). The return ratio to PREP-PAC investment was 2.6 in the sandy soil and 3.7 in the clay. PREP-PACs were tested on-farm in 52 symptomatic patches containing maize–bean intercrops with and without an improved variety of climbing Phaseolus vulgaris cv. Flora. Unamended patches (25 m²=0.0025 ha) produced 1.6 kg maize and 0.08 kg bean. With addition of PREP-PAC containing Flora, yields increased to 4.1 kg maize and 1.1 kg bean (P<0.001 for both crops). Improvement in bean yield during the first cropping season nearly offset PREP-PAC’s investment costs. PREP-PAC is a strategic approach because all of its ingredients, except for urea, originate from East Africa, and are relatively inexpensive; the product is intended for distribution through existing retail and development networks.     

Microbial Contamination of Groundwater at Small Community Water Supplies in Finland

The raw water quality and associations between the factors considered as threats to water safety were studied in 20 groundwater supplies in central Finland in 2002-2004. Faecal contaminations indicated by the appearance of Escherichia coli or intestinal enterococci were present in five small community water supplies, all these managed by local water cooperatives. Elevated concentrations of nutrients in raw water were linked with the presence of faecal bacteria. The presence of on-site technical hazards to water safety, such as inadequate well construction and maintenance enabling surface water to enter into the well and the insufficient depth of protective soil layers above the groundwater table, showed the vulnerability of the quality of groundwater used for drinking purposes. To minimize the risk of waterborne illnesses, the vulnerable water supplies need to be identified and appropriate prevention measures such as disinfection should be applied.     

No bioavailability of 17α-ethinylestradiol when associated with nC60 aggregates during dietary exposure in adult male zebrafish (Danio rerio)

The C(60) fullerene is a manufactured carbon nanoparticle (CNP) that could pose a risk to humans and other organisms after release into the environment. In surface waters, C(60) is likely to be present as aggregates of nC(60) and these aggregates can associate with other substances that are toxic. Our goal was to evaluate the association of a model contaminant [17α-ethinylestradiol (EE2)] with nC(60) and determine bioavailability of EE2 after accumulation by a filter feeding organism [Brine shrimp (BS) Artemia sp.] and subsequent dietary exposure in zebrafish. Aqueous suspensions of nC(60) were prepared (600 mg C(60)/900 mL, 6-month water stirred method) with/without EE2 (1 μg/L) and BS were exposed to these preparations. Accumulation of nC(60) in gut of BS was assessed by light microscopy, and C(60) were extracted from BS and concentration analyzed by HPLC. Adult male zebrafish were fed (5d) live BS according to the following treatments: BS (control); BS containing nC(60); BS containing nC(60)+EE2; or BS containing EE2. Liver was excised from exposed fish and total RNA was extracted for assessment of vitellogenin gene (vtg1A/B) expression. The vtg1A/B was highly up-regulated in fish exposed to BS containing EE2, but expression of vtg1A/B did not differ from controls in other treatments. The EE2 associated with nC(60) did not become bioavailable in zebrafish during passage through the intestinal tract of zebrafish. Results have implications on the effect of nC(60) on the bioavailability of co-contaminants in organisms during dietary exposure.     

Statistical Analysis of Trends in Urban Ozone Air Quality

The purpose of this paper is to demonstrate the use of some statistical methods for examining trends in ambient ozone air quality downwind of major urban areas. To this end, daily maximum 1 -hr ozone concentrations measured over New Jersey, metropolitan New York City and Connecticut for the period 1980 to 1989 were assembled and analyzed. This paper discusses the application of the bootstrap method, extreme value statistics and a nonparametric test for evaluating trends in urban ozone air quality. The results indicate that although there is an improvement in ozone air quality downwind of New York City, there has been little change in ozone levels upwind of New York City during this ten-year period.     

Comparative study of biochemical and immunological biomarkers in three marine bivalves exposed at a polluted site

A battery of biochemical and immunological biomarkers used for pollution assessment were measured for first time in the clams Venus verrucosa and Callista chione and were compared with those of the mussel Mytilus galloprovincialis, a well-established indicator organism utilized in numerous environmental monitoring programs. Clams and mussel were transplanted at a polluted and a reference site or maintained at the laboratory. Among biochemical biomarkers, acetylcholinesterase did not differ at the polluted site in all species, but there was a significant difference between the mussel and the clams, glutathione S-transferase showed a clear inhibition at the polluted site in all species and a significant difference between the two clams was also indicated, while catalase activities were increased only in V. verrucosa at the polluted site and not in mussel or the other clam. Immunological biomarkers responses were also pronounced at the polluted site. Lysozyme activity was species-dependent whereas respiratory burst activity measured as luminol-dependent chemiluminescence (CL) was site and stimulus dependent, and it was evident in M. galloprovincialis and V. verrucosa and not in C. chione. Further investigation focused on biochemical and immunological biomarkers related with the oxidative mechanisms in clams will strengthen and expand their use as bioindicators for pollution assessment.     

Reduction of Tobacco Smoking Health Risk Through an Appropriate Media Based Communication Strategy in Uganda

The health impacts of tobacco consumption are well documented and have gained acceptance worldwide. Today, a substantial, preventable burden of tobacco attributable diseases exists in most countries, though in most of the cases, unknown. Smoking accounts for almost half of the deaths in middle age in some regions. In Uganda, translating findings into policy action is slow and involves several stakeholders. It will continue to require support from tobacco control campaign groups. This paper analyses secondar...     

Baseflow nitrate in relation to stream order and agricultural land use

Management of agricultural nonpoint-source pollution continues to be a challenge because of spatial and temporal variability. Using stream order as an index, we explored the distribution of nitrate concentration and load along the stream network of a large agricultural watershed in Pennsylvania-the East Mahantango Creek Watershed and two of its sub-watersheds. To understand nitrate concentration variation in the stream water contributed from ground water, this study focused on baseflow. Impacts of agricultural land use area on baseflow nitrate in the stream network were investigated. Nitrate concentration showed a general decreasing trend with increasing stream order based on stream order averaged values; however, considerable spatial and temporal variability existed within each snapshot sampling. Nitrate loads increased with stream order in a power function because of the dominant effect of stream flow rate over the nitrate concentration. Within delineated sub-watersheds based on stream orders, positive linear functions were found between agricultural land use area percentage and the baseflow nitrate concentration and between agricultural drainage area and the nitrate load. The slope of the positive linear regression between the baseflow nitrate concentration and percent agricultural land area seems to be a valuable indicator of a watershed's water quality as influenced by agricultural practices, watershed size, and specific physiographic setting. Stream order seems to integrate, to a certain degree, the source and transport aspects of nonpoint-source pollution on a yearly averaged basis and thus might provide a quick estimate of the overall trend in baseflow nitrate concentration and load distribution along complex stream networks in agricultural watersheds.     

Public preferences for environmental management practices at DOE's nuclear waste sites

Residents who lived within 50 miles of one of six major US Department of Energy nuclear waste sites were asked in 2005 and again in 2010 to rate environmental management options. Respondents expressed strong preference for continuously sampling the air and water, monitoring worker health, and providing training and equipment to local responders. They strongly supported some site restrictions, such as making sure that the federal government owns the site until no more hazards are present, keeping visitors and recreational users off the site, and requiring government officials to report information to community representatives. The public was much more equivocal about other options, such as restricting new nuclear‐related activities and requiring site managers to live near sites. The authors summarize factors that lead to these public preferences and discuss five population types encountered at these and perhaps other waste management sites. © 2011 Wiley Periodicals, Inc.