APPLICATION OF AN ENVIRONMENTAL AND ECONOMIC MODELING SYSTEM FOR WATERSHED ASSESSMENTS1

ABSTRACT: A National Pilot Project (NPP) on Livestock and the Environment was initiated in 1992 to help provide solutions to environmental problems associated with livestock production. A major development of the NPP was the Comprehensive Economic and Environmental Optimization Tool‐Livestock and Poultry (CEEOT‐LP), an integrated modeling system designed to produce economic and environmental indicators for alternative policy scenarios applied to intensive livestock production watersheds. The system consists of a farm‐level economic model (FEM) and two environmental models: the field‐scale APEX model and the watershed‐level SWAT model. To date, CEEOT‐LP has been applied to two watersheds in Texas and one in Iowa. Predicted reductions in P losses for two P‐based manure application rate scenarios, relative to baseline conditions, ranged from ?4 to ?54 percent across the three watersheds; however, N loss impacts ranged from a decrease of 34 percent to an increase of 79 percent. For five other alternative scenarios that were simulated for only one watershed, N and P loss impacts ranged between a reduction of 78 percent to an increase of 20 percent. Aggregate watershed‐level economic impacts of the seven scenarios spanned a spectrum of a 27 percent decrease to a 25 percent increase in profit, relative to the baseline.     

Levels and seasonal variations of organochlorine pesticides in urban and rural background air of southern Ghana

Urban, suburban and rural background air samples were collected in southern Ghana in 2008 employing polyurethane foam disc passive air samplers (PAS). PAS were analysed for organochlorine pesticides (OCPs), namely hexachlorocyclohexanes (α-, β-, γ- and δ-hexachlorocyclohexane), dichlorodiphenyltrichloroethane including metabolites (o,p'- and p,p'-DDT, DDE and DDD), hexachlorobenzene, pentachlorobenzene, aldrin, dieldrin, endrins (endrin, endrin aldehyde and endrin ketone), isodrin, heptachlors (heptachlor, heptachlor epoxide A and heptachlor epoxide B), chlordanes (α-, β-chlordane, oxychlordane and trans-nonachlor), endosulfans (α- and β-endosulfan and endosulfan sulphate), methoxychlor and mirex using a gas chromatograph coupled to a mass spectrometer. The levels of OCPs ranged for the individual pesticides from below limit of quantification to 750 pg m(-3) (for α-endosulfan), and current agricultural application seemed to be the main primary source of most abundant pesticides. Re-volatilization of previously used pesticides from contaminated soils could not be ruled out either as potential secondary source of contamination, especially in warm and dry seasons and periods of intensive agricultural activities. Higher atmospheric concentrations were observed in November and December during the dry season compared to lower concentrations observed in June, July and August when the country experiences heavy rains. The highest seasonal variation was observed for currently used pesticides as α-endosulfan. A p,p'-DDT/p,p'-DDE ratio suggested recent inputs of fresh technical DDT.     

Microbial pullulan for food,biomedicine, cosmetic,and water treatment: a review

Environmental Chemistry Letters - Most fossil fuel-derived polymers used for food packaging are non-biodegradable and induce pollution by microplastic, calling for safer material. Here we review...     

Status of the Riparian Ecosystem in the Upper San Pedro River, Arizona: Application of an Assessment Model

A portion of Arizona’s San Pedro River is managed as a National Riparian Conservation Area but is potentially affected by ground-water withdrawals beyond the conservation area borders. We applied an assessment model to the Conservation Area as a basis for monitoring long-term changes in riparian ecosystem condition resulting from changes in river water availability, and collected multi-year data on a subset of the most sensitive bioindicators. The assessment model is based on nine vegetation bioindicators that are sensitive to changes in surface water or ground water. Site index scores allow for placement into one of three condition classes, each reflecting particular ranges for site hydrology and vegetation structure. We collected the bioindicator data at 26 sites distributed among 14 reaches that had similar stream flow hydrology (spatial flow intermittency) and geomorphology (channel sinuosity, flood-plain width). Overall, 39% of the riparian corridor fell within condition class 3 (the wettest condition), 55% in condition class 2, and 6% in the driest condition class. Condition class 3 reaches have high cover of herbaceous wetland plants (e.g., Juncus and Schoenoplectus spp.) along the perennial stream channel and dense, multi-aged Populus-Salix woodlands in the flood plain, sustained by shallow ground water in the stream alluvium. In condition class 2, intermittent stream flows result in low cover of streamside wetland herbs, but Populus-Salix remain abundant in the flood plain. Perennial wetland plants are absent from condition class 1, reflecting highly intermittent stream flows; the flood plain is vegetated by Tamarixa small tree that tolerates the deep and fluctuating ground water levels that typify this reach type. Abundance of herbaceous wetland plants and growth rate of Salix gooddingii varied between years with different stream flow rates, indicating utility of these measures for tracking short-term responses to hydrologic change. Repeat measurement of all bioindicators will indicate long-term trends in hydro-vegetational condition.     

Socio-economic dynamics of forest loss in rural agro-ecosystems

Summary Agro-ecosystems in many of the developing economies are coming under increased pressure, especially in areas where population demands, weak economic growth, and debt burdens, are resulting in mass rural poverty and assault on environmental resources. The loss of forests is a double-edge blow for most rural and agricultural systems. The forests provide the resource substitutes for the many manufactured products which are scarce or physically and economically inaccessible, and they also provide congenial environments which support rural food systems by way of productive agricultural land opportunities.In many of the rural areas of Africa, in particular, forest stability is more threatened, and this requires both local and external responses to make sustainable development a possibility. This paper, which is based on a field study in Ghana by the author, identifies emerging socio-economic constraints in woodfuel systems in environments where demands on forest ecosystems are high. The degree to which such local socio-economic processes affect stability of forest ecosystems, and the conditions within which the research information could assist planners and resource managers towards sustainable use of forest ecosystems are analysed.Dr William Y. Osei was born in Ghana where he obtained a BA (Hons) Geography from the University of Ghana. He subsequently obtained an MA from Carleton University, Ottawa, Canada and a PhD from the University of Western Ontario, London, Canada. With teaching experience in Geography at the Canadian universities of Western Ontario, Brandon and Victoria, he currently holds the position of Assistant Professor in the Department of Geography at Algoma University College.     

Isolated Spring Wetlands in the Great Basin and Mojave Deserts,USA: Potential Response of Vegetation to Groundwater Withdrawal

Desert springs, often the sole sources of water for wildlife and cattle, support wetland and wetland/upland transition ecosystems including rare and endemic species. In the basin and range province in Nevada, USA, springs in the Great Basin and Mojave deserts are sustained by interconnected deep carbonate and shallow basin-fill aquifers which are threatened by proposed groundwater withdrawal to sustain rapidly expanding urban areas, a common problem in arid regions worldwide. This paper draws on historic groundwater data, groundwater modeling, and studies of environmental controls of spring ecosystems to speculate on the potential effects of groundwater withdrawal and water table decline on spring-supported vegetation. The focus is on springs in the Great Basin and Mojave deserts representative of those that may be affected by future, planned groundwater withdrawal. Groundwater withdrawal is expected to reduce spring discharge directly through reduced flows from the shallow basin-fill aquifer or through reduction of the hydraulic head of the deep carbonate aquifer. This flow reduction will truncate the outflow stream, reducing the areal cover of wetland and wetland/upland transition vegetation. Lowering the local water table may also reduce the amount of upland phreatophytic vegetation by causing water levels to drop below plant rooting depths. Percolation of salts to surface soils may be reduced, eventually altering desert shrub cover from halophytes to nonhalophytes. The extent of these effects will vary among springs, based on their distance from extraction sites and location relative to regional groundwater flow paths. On-site monitoring of biotic variables (including cover of selected hygrophytes and phreatophytes) should be a necessary complement to the planned monitoring of local hydrologic conditions.     

Procedures for ensuring community involvement in multijurisdictional river basins: a comparison of the Murray-Darling and Mekong river basins

Community involvement is fundamental to the management of multijurisdictional river basins but, in practice, is very difficult to achieve. The Murray-Darling basin, in Australia, and the Mekong River basin in Southeast Asia are both cooperatively managed multijurisdictional river basins where the management authorities have expressed an aim of community involvement. In the Murray-Darling basin vigorous efforts have promoted a culture of community consultation throughout each of the state jurisdictions involved, although true participation has not necessarily been achieved. In the Mekong basin the community is much more diverse and the successes so far have been largely at the local level, involving action in subsections of the basin. These case studies suggest that community involvement in the form of community consultation across large multijurisdictional river basins is achievable, but more comprehensive participation is not necessarily possible.     

Persistent organochlorine pesticide residues in fish, sediments and water from Lake Bosomtwi, Ghana

Some organochlorine pesticide residues in tilapia fish (Tilapiazilli), sediment and water samples from Lake Bosomtwi (the largest natural lake in Ghana) were determined to find out the extent of pesticide contamination and accumulation in the lake. The extracted residues were analyzed on a micro-capillary gas chromatograph equipped with electron capture detector. DDE (p,p'-1,1-dichloro-2,2-bis-(4-chlorophenyl)ethylene) was the predominant residue in all the samples analyzed; detected in 82% of water samples, 98% of sediment samples and 58% of fish samples at concentrations of 0.061+/-0.03 ng g(-1), 8.342+/-2.96 ng g(-1) and 5.232+/-1.30 ng g(-1), respectively. DDT (p,p'-1,1,1-trichloro-2,2-bis-(4-chlorophenyl)ethane) was detected in 78% at a mean concentration 0.012+/-0.62 ng g(-1) of water samples analyzed. The mean concentrations of DDT in sediments and fish were 4.41+/-1.54 ng g(-1) and 3.645+/-1.81 ng g(-1), respectively. The detection of lower levels of DDT than its metabolite, DDE, in the samples implies that the presence of these contaminants in the lake is as result of past usage of the pesticides.     

Uptake of heavy metals by some edible vegetables irrigated using wastewater: a preliminary study in Accra, Ghana

The heavy metals (Fe, Zn, Pb, Ni, Cr, Co, and Cd) burden in wastewater, soil, and vegetable samples from a wastewater irrigated farm located at KorleBu, Accra has been investigated. Flame atomic absorption spectrometry after microwave digestion using a combination of HNO₃, HCl, and H₂O₂ (for water), and HNO₃ and HCl (for soil and vegetables). The mean concentrations (in milligrams per kilogram) of heavy metals in the soil samples were in the order of Fe (171?±?5.22)?>?Zn (36.06?±?4.54)?>?Pb (33.35?±?35.62)?>?Ni (6.31?±?8.15)?>?Cr (3.40?±?3.63)?>?Co (1.36?±?0.31)?>?Cd (0.43?±?0.24), while the vegetables were in the order of Fe (183.11?±?161.2)?>?Zn (5.38?±?3.50)?>?Ni (3.52?±?1.27)?>?Pb (2.49?±?1.81)?>?Cr (1.46?±?0.51)?>?Co (0.66?±?0.25)?>?Cd (0.36?±?0.15). The bioconcentration factors suggest environmental monitoring for the heavy metals as follows: Cd (0.828), Cr (0.431), Ni (0.558), Co (0.485), and Fe (1.067). Estimated daily intakes were very low for both children and adults except Fe (0.767 mg/kg/day) in children. The population that consume vegetables from the study area were, however, estimated to be safe based on the results obtained from the health risk index, which were all?<?<1. The sodium absorption ratio according to FAO (1985) classifications indicate that the wastewater in the study area is unsuitable for irrigation purposes.