Physico-chemical characterization of grease interceptors with and without biological product addition

Hardened and insoluble fat, oil, and grease (FOG) deposits are the primary cause of sewer line blockages leading to sanitary sewer overflows (SSOs). However, there have been very few long-term assessments of the physico-chemical characteristics of full-scale grease interceptors (GIs), the first "line of defense" against FOG buildup in sewer lines. In this study, we assessed the physico-chemical characteristics of two full-scale GIs (at a restaurant and a retirement community kitchen) over a one-year period. Statistically significant differences between bioaugmented and untreated cycles were detected for several chemical and physical properties. The treated cycles had lower BOD and COD at the grease interceptor outlet. While the combined data for all treated cycles did not show lower FOG concentrations in the GI outlet compared to the combined data for all untreated cycles, comparison of specific individual treated and untreated cycles show a positive effect due to the addition of product.     

Polynomial response of 2,4-D mineralization to temperature in soils at varying soil moisture contents, slope positions and depths

The herbicide 2,4-D [2,4-(dichlorophenoxy) acetic acid] is a widely used broadleaf control agent in cereal production systems. Although 2,4-D soil-residual activity (half-lives) are typically less than 10 days, this herbicide also has as a short-term leaching potential due to its relatively weak retention by soil constituents. Herbicide residual effects and leaching are influenced by environmental variables such as soil moisture and temperature. The objective of this study was to determine impacts of these environmental variables on the magnitude and extent of 2,4-D mineralization in a cultivated undulating Manitoba prairie landscape. Microcosm incubation experiments were utilized to assess 2,4-D half-lives and total mineralization using a 4 × 4 × 3 × 2 factorial design (with soil temperature at 4 levels: 5, 10, 20 and 40°C; soil moisture at 4 levels: 60, 85, 110, 135 % of field capacity; slope position at 3 levels: upper-, mid- and lower-slopes; and soil depth at 2 levels: 0-5 cm and 5-15 cm). Half-lives (t(?)) varied from 3 days to 51 days with the total 2,4-D mineralization (M(T)) ranging from 5.8 to 50.9 %. The four-way interaction (temperature × moisture × slope × depth) significantly (p < 0.001) influenced both t(?) and M(T). Second-order polynomial equations best described the relations of temperature with t(?) and M(T) as was expected from a biological system. However, the interaction and variability of t(?) and M(T) among different temperatures, soil moistures, slope positions, and soil depth combinations indicates that the complex nature of these interacting factors should be considered when applying 2,4-D in agricultural fields and in utilizing these parameters in pesticide fate models.     

Investments in agricultural water management for poverty reduction in Africa: Case studies of Limpopo,Nile, and Volta river basins

Much of Sub‐Saharan Africa is burdened with water scarcity and poverty. Continentally, less than four percent of Africa's renewable water resources are withdrawn for agriculture and other uses. Investments in agricultural water management can contribute in several ways to achieving the Millennium Development Goals of eradicating extreme poverty and hunger and ensuring environmental sustainability. Increased yield and cropping area and shifts to higher valued crops could help boost the income of rural households, generate more employment, and lower consumer food prices. These investments can also stabilize output, income and employment, and have favourable impacts on education, nutrition and health, and social equity. Investments in agricultural water management can cut poverty by uplifting the entitlements and transforming the opportunity structure for the poor. The overall role of investments in agricultural water management in eradicating hunger and poverty is analyzed. This paper contributes to the present debate and efforts to identify strategies and interventions that can effectively contribute to poverty reduction in Africa. It provides an overview of population growth, malnutrition, income distribution and poverty for countries in three case study river basins — Limpopo, Nile, and Volta. With discussions on the contribution of agriculture to national income and employment generation, the paper explores the linkages among water resources investments, agricultural growth, employment, and poverty alleviation. It examines the potential for expansion in irrigation for vertical and horizontal growth in agricultural productivity, via gains in yield and cropping area to boost the agricultural output. Factors constraining such potential, in terms of scarcity and degradation of land and water resources, and poor governance and weak institutions, are also outlined. The paper argues that increased investments in land and water resources and related rural infrastructure are a key pathway to enhance agricultural productivity and to catalyze agricultural and economic growth for effective poverty alleviation.     

Ecological risk assessment of agricultural pesticides in the highly productive Ndop flood plain in Cameroon using the PRIMET model

Flood plains can make a significant contribution to food security due to their rich agricultural and aquaculture potentials but the misuse of pesticides in these ecosystems may seriously threaten their sustainability. We have assessed the risk of commonly used pesticides by rice and vegetable farmers on two major streams in the Ndop flood plain in Cameroon using the PRIMET model. Thirty pesticide formulations were identified containing 17 active ingredients belonging to fungicides (7), herbicides (3), and insecticides (7). Out of these, five posed acute and/or chronic risks to the streams. Chlorpyriphos-ethyl (ETR = 655), chlorothalonil (ETR = 250), and cypermethrin (ETR = 190) posed a definite acute risk to both streams. These pesticides also posed possible chronic risks with cypermethrin also posing a definite chronic risk (ETR = 1658) to fish in one of the streams. Mancozeb (ETR = 2.2) and λ-cyhalothrin (ETR = 2.8) posed a possible acute risk to both streams. It was interesting to note that most pesticides, including some of those that posed a risk, were applied at lower doses than their respective recommended doses. Differences in ETRs were also observed in the two streams with higher values occurring in the stream having a lower concentration of suspended solids. The higher velocity of the Ngwala-Mesaw stream did not affect the acute risk posed by pesticides. Pesticide toxicity was an important determinant in the risk posed and we recommend that appropriate mitigation measures be put in place to reduce the risk of these pesticides such as the implementation of an appropriate buffer zone between the edge of field and water body.

     

Urban green area provides refuge for native small mammal biodiversity in a rapidly expanding city in Ghana

Urbanization is a key driver of global biodiversity loss. Although sub-Saharan African countries are experiencing unprecedented urbanization and urban expansion, very little is known about how this impacts tropical biodiversity. Here, we assessed the effects of urban expansion and urban green space on local small mammal species diversity in Accra, Ghana. We surveyed small mammals in the University of Ghana botanical garden, an urban green area (UGA) and adjoining built-up environment (BE) and compared the results with baseline data (BLD) collected when large areas of the current city still remained mostly undeveloped. The methodology involved live-trapping using Sherman collapsible live-traps. Our data showed higher small mammal abundance and diversity in the UGA than BE. Similarity of species composition was higher between UGA and BLD than between BE and BLD. The small mammal species captured in BE (the rodents Mastomys erythroleucus, Rattus rattus, and Arvicanthis rufinus, and the shrew Crocidura olivieri) are known to easily adapt to human-modified landscapes. Our results suggest that urbanization negatively influenced the abundance, diversity, and community composition of small mammals. Efforts should be directed towards the integration of urban green areas into urban land development planning in developing countries in order to conserve local wildlife and ecological services that enhance the quality of urban life.     

Creating sense of community: The role of public space

A strong sense of community has been associated with improved wellbeing, increased feelings of safety and security, participation in community affairs and civic responsibility. Although interest in how the broader built environment influences sense of community is gaining momentum, there is a dearth of empirical research examining the association between sense of community and the quality of public space. This study investigates the relationship between four public spaces – Public Open Space (POS), community centres, schools and shops – and sense of community in residents of new housing developments in the Perth metropolitan area, Western Australia. Data was obtained from a cross-sectional survey (n = 911), a POS audit, and Geographical Information Systems, and analysed using linear regression. The perceived quality of neighbourhood POS and shops was significantly and positively associated with sense of community. This relationship appears to be unaffected by how frequently people use these spaces. High quality public spaces may be important settings for enhancing sense of community within residents of new housing developments.     

Adoption and adaptation of natural resource management innovations in smallholder agriculture: reflections on key lessons and best practices

Many smallholder farmers in vulnerable areas continue to face complex challenges in adoption and adaptation of resource management and conservation strategies. Although much has been learned from diverse experiences in sustainable resource management, there is still inadequate understanding of the market, policy and institutional failures that shape and structure farmer incentives and investment decisions. The policy and institutional failures exacerbate market failures, locking smallholder resource users into a low level equilibrium that perpetuates poverty and land degradation. Improved market access that raises the returns to land and labor is often the driving force for adoption of new practices in agriculture. Market linkages, access to credit and availability of pro-poor options for beneficial conservation are critical factors in stimulating livelihood and sustainability-enhancing investments. Future interventions need to promote joint innovations that ensure farmer experimentation and adaptation of new technologies and careful consideration of market, policy and institutional factors that stimulate widespread smallholder investments. Future projects should act as ‘toolboxes’, giving essential support to farmers to devise complementary solutions based on available options. Addressing the externalities and institutional failures that prevent private and joint investments for management of agricultural landscapes will require new kinds of institutional mechanisms for empowering communities through local collective action that would ensure broad participation and equitable distributions of the gains from joint conservation investments. Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue.     

Atrazine removal in agricultural infiltrate by bioaugmented polyvinyl alcohol immobilized and free Agrobacterium radiobacter J14a: a sand column study

Bench-scale sand column breakthrough experiments were conducted to examine atrazine removal in agricultural infiltrate by Agrobacterium radiobacter J14a (J14a) immobilized in phosphorylated-polyvinyl alcohol compared to free J14a cells. The effects of cell loading and infiltration rate on atrazine degradation and the loss of J14a were investigated. Four sets of experiments, (i) tracers, (ii) immobilized dead cells, (iii) immobilized cells, and (iv) free cells, were performed. The atrazine biodegradation at the cell loadings of 300, 600, and 900 mg dry cells L(-1) and the infiltration rates of 1, 3, and 6 cm d(-1) were tested for 5 column pore volumes (PV). The atrazine breakthrough results indicated that the immobilized dead cells significantly retarded atrazine transport. The atrazine removal efficiencies at the infiltration rates of 1, 3, and 6 cm d(-1) were 100%, 80-97%, and 50-70%, respectively. Atrazine degradation capacity for the immobilized cells was not significantly different from the free cells. Both infiltration rate and cell loading significantly affected atrazine removal for both cell systems. The bacterial loss from the immobilized cell system was 10-100 times less than that from the free cell system. For long-term tests at 50 PV, the immobilized cell system provided consistent atrazine removal efficiency while the atrazine removal by the free cells declined gradually because of the cell loss.     

U.S. Natural Resources and Climate Change: Concepts and Approaches for Management Adaptation

Public lands and waters in the United States traditionally have been managed using frameworks and objectives that were established under an implicit assumption of stable climatic conditions. However, projected climatic changes render this assumption invalid. Here, we summarize general principles for management adaptations that have emerged from a major literature review. These general principles cover many topics including: (1) how to assess climate impacts to ecosystem processes that are key to management goals; (2) using management practices to support ecosystem resilience; (3) converting barriers that may inhibit management responses into opportunities for successful implementation; and (4) promoting flexible decision making that takes into account challenges of scale and thresholds. To date, the literature on management adaptations to climate change has mostly focused on strategies for bolstering the resilience of ecosystems to persist in their current states. Yet in the longer term, it is anticipated that climate change will push certain ecosystems and species beyond their capacity to recover. When managing to support resilience becomes infeasible, adaptation may require more than simply changing management practices—it may require changing management goals and managing transitions to new ecosystem states. After transitions have occurred, management will again support resilience—this time for a new ecosystem state. Thus, successful management of natural resources in the context of climate change will require recognition on the part of managers and decisions makers of the need to cycle between “managing for resilience” and “managing for change.”     

Carbon, nitrogen balances and greenhouse gas emission during cattle feedlot manure composting

Carbon and N losses reduce the agronomic value of compost and contribute to greenhouse gas (GHG) emissions. This study investigated GHG emissions during composting of straw-bedded manure (SBM) and wood chip-bedded manure (WBM). For SBM, dry matter (DM) loss was 301 kg Mg(-1), total carbon (TC) loss was 174 kg Mg(-1), and total nitrogen (TN) loss was 8.3 kg Mg(-1). These correspond to 30.1% of initial DM, 52.8% of initial TC, and 41.6% of initial TN. For WBM, DM loss was 268 kg Mg(-1), TC loss was 154 kg Mg(-1), and TN loss was 1.40 kg Mg(-1), corresponding to 26.5, 34.5, and 11.8% of initial amounts. Most C was lost as CO2 with CH4 accounting for <6%. However, the net contribution to greenhouse gas emissions was greater for CH4 since it is 21 times more effective at trapping heat than CO2. Nitrous oxide (N2O) emissions were 0.077 kg N Mg(-1) for SBM and 0.084 kg N Mg(-1) for WBM, accounting for 1 to 6% of total N loss. Total GHG emissions as CO2-C equivalent were not significantly different between SBM (368.4 +/- 18.5 kg Mg(-1)) and WBM (349.2 +/- 24.3 kg Mg(-1)). However, emission of 368.4 kg C Mg(-1) (CO2-C equivalent) was greater than the initial TC content (330.5 kg Mg(-1)) of SBM, raising the question of the net benefits of composting on C sequestration. Further study is needed to evaluate the impact of composting on overall GHG emissions and C sequestration and to fully investigate livestock manure management options.