Improving invasive species management by integrating priorities and contributions of scientists and decision makers

Managing invasive species is a major challenge for society. In the case of newly established invaders, rapid action is key for a successful management. Here, we develop, describe and recommend a three-step transdisciplinary process (the “butterfly model”) to rapidly initiate action for invasion management. In the framing of a case study, we present results from the first of these steps: assessing priorities and contributions of both scientists and decision makers. Both scientists and decision makers prioritise research on prevention. The available scientific knowledge contributions, however, are publications on impacts rather than prevention of the invasive species. The contribution of scientific knowledge does thus not reflect scientists’ perception of what is essentially needed. We argue that a more objective assessment and transparent communication of not only decision makers’ but also scientists’ priorities is an essential basis for a successful cooperation. Our three-step model can help achieve objectivity via transdisciplinary communication.     

C60 fullerene: a powerful antioxidant or a damaging agent? The importance of an in-depth material characterization prior to toxicity assays

Since the discovery of fullerenes in 1985, these carbon nanospheres have attracted attention regarding their physico/chemical properties. Despite little knowledge about their impact on the environment and human health, the production of fullerenes has already reached an industrial scale. However, the toxicity of C₆₀ is still controversially discussed.The aim of this study was to clarify the biological effects of tetrahydrofuran (THF) suspended C₆₀ fullerene in comparison to water stirred C₆₀ fullerene suspensions. Beyond that, we analyzed the effects on the Crustacea Daphnia magna an indicator for ecotoxicological effects and the human lung epithelial cell line A549 as a simplified model for the respiratory tract.We could demonstrate that water-soluble side products which were formed in THF nC₆₀ suspension were responsible for the observed acute toxic effects, whereas fullerenes themselves had no negative effect regardless of the preparative route on either A549 cell in vitro or D. magna in vivo.     

Sorption and mobility of pharmaceutical compounds in soil irrigated with reclaimed wastewater

Use of reclaimed wastewater for irrigation is an important route for the introduction of pharmaceutical compounds (PCs) into the environment. In this study, the mobility and sorption-desorption behavior of carbamazepine, naproxen and diclofenac were studied in soil layers sampled from a plot irrigated with secondary-treated wastewater (STWW). Carbamazepine and diclofenac were significantly retarded in the 0-5 cm soil sample rich in soil organic matter (SOM): carbamazepine was not affected by the water quality (freshwater versus STWW), whereas diclofenac exhibited a higher retardation factor (RF) in the freshwater system. Naproxen exhibited significantly lower RFs than diclofenac but with a similar trend - higher retardation in the freshwater versus STWW system. In the 5-15 cm soil sample containing low SOM, naproxen was highly mobile while carbamazepine and diclofenac were still retarded. In the 15-25 cm sample, all compounds exhibited their lowest RFs. Sorption data suggested that SOM governs the studied PCs' interactions with the soil samples. However, higher carbon-normalized sorption coefficients were measured for the PCs in the 15-25 cm sample, suggesting that both quantity and the physicochemical nature of SOM affect sorption interactions. While both naproxen and carbamazepine exhibited reversible sorption isotherms, diclofenac exhibited pronounced sorption-desorption hysteresis. This study suggests that carbamazepine and diclofenac can be classified as slow-mobile compounds in SOM-rich soil layers. When these compounds pass this layer and/or introduced into SOM-poor soils, their mobility increases significantly. This emphasizes the potential transport of PCs to groundwater in semiarid zones due to intensive irrigation with reclaimed wastewater in SOM-poor soils.     

Hydrologic modelling for Lake Basaka: development and application of a conceptual water budget model

Quantification of fluxes of water into and out of terminal lakes like Basaka has fundamental challenges. This is due to the fact that accurate measurement and quantification of most of the parameters of a lake’s hydrologic cycle are difficult. Furthermore, quantitative understanding of the hydrologic systems and hence, the data-intensive modelling is difficult in developing countries like Ethiopia due to limitation of sufficient recorded data. Therefore, formulation of a conceptual water balance model is extremely important as it presents a convenient analytical tool with simplified assumptions to simulate the magnitude of unknown fluxes. In the current study, a conceptual lake water balance model was systematically formulated, solved, calibrated, and validated successfully. Then, the surface water and groundwater interaction was quantified, and a mathematical relationship developed. The overall agreement between the observed and simulated lake stage at monthly time step was confirmed based on the standard performance parameters (R ², MAE, RMSE, E _f). The result showed that hydrological water balance of the lake is dominated by the groundwater (GW) component. The net GW flux in recent period (post-2000s) accounts about 56 % of the total water inflow. Hence, GW plays a leading role in the hydrodynamics and existence of Lake Basaka and is mostly responsible for the expansion of the lake. Thus, identification of the potential sources/causes for the GW flux plays a leading role in order to limit the further expansion of the lake. Measurement of GW movement and exchange in the area is a high priority for future research.     

Source characterization and risk of exposure to atmospheric polychlorinated biphenyls (PCBs) in Ghana

With recent evidence that persistent organic pollutants (POPs) such as polychlorinated biphenyls (PCBs) are emerging in environmental media in some developing countries that otherwise have sparing production and usage history, it has become important to identify such contemporary source factors of PCBs and the risks this may pose, in line with the global consensus on POP management and elimination. The present study investigated contaminations from atmospheric PCBs in Ghana, deciphered source factors, and accessed risk of exposure to dioxin-like PCBs (DL-PCBs). Atmospheric PCBs were monitored by deployment of PUF-disk passive air samplers (PAS) at several sites across Ghana for 56 days. Atmospheric ∑₁₉₀PCB concentration in Ghana ranged from 0.28 ng/m³ in Kumasi to 4.64 ng/m³ at Agbogbloshie, a suburb in Accra noted for informal electronic waste (e-waste) recycling activities. As high as 11.10 ng/m³ of PCB concentration was measured in plumes from uncontrolled open burning of e-wastes at Agbogbloshie. Applying statistical source characterization tools, it emerged that e-wastes were a major contributor to the environmental burden of atmospheric PCBs in Ghana. The risk of DL-PCB toxicity via inhalation in the Agbogbloshie area was 4.2 pg TEQ/day, within similar order of magnitude of an estimated risk of 3.85 pg TEQ/day faced by e-waste workers working averagely for 8 h per day. It is suggested that elimination of e-waste sites would help to significantly reduce PCB-related toxicity issues in Ghana.

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Urinary 8-oxo-7, 8-dihydro-2′-deoxyguanosine concentrations after frying of bacon,a pilot study

Cooking fumes contain compounds that may give rise to oxidative stress and mutations when inhaled. The aim of this study was to evaluate if cooking fumes from frying of bacon induce oxidative stress by measurement of urinary 8-oxo-7,8-dihydro-2 deoxyguanosine, a marker of oxidatively damaged DNA. Three non-smoking women fried bacon for 3 h. Urine samples were taken as early morning void at the same time on four days; the morning before frying, the morning after first frying, the morning after three days of frying and one week after first urine sample. 8-Oxo-7,8-dihydro-2 deoxyguanosine, 1-hydroxypyrene and 2-hydroxyphenanthrene, metabolites of polycyclic aromatic hydrocarbons, were measured by liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS). 8-Oxo-7,8-dihydro-2 deoxyguanosine correlated weakly with concentrations of 1-hydroxypyrene (r = 0.31, p = 0.042), but it did not correlate with 2-hydroxyphenanthrene (r = ?0.074; p = 0.64). Average urinary 8-oxo-7,8-dihydro-2 deoxyguanosine concentrations increased from the day before frying (16.3 ± 4.2 nmol/L) to the third day of frying (26.2 ± 10.2 nmol/L), although not statistically significantly. Our pilot study shows that frying of bacon may result in increased oxidative stress which further emphasises the possible carcinogenic potential of cooking fumes.     

Do EU pesticide standards promote environmentally-friendly production of fresh export vegetables in developing countries? The evidence from Kenyan green bean industry

Developed countries are major markets for developing country fresh produce. Demand by developed country consumers for spotless produce has encouraged developing country consumers to rely increasingly on pesticides in producing fresh export vegetables. However developed country pesticide standards enacted in response to reports of increased farmer and farm worker pesticide poisoning and the food safety scandals of the 1980s and 1990s require changes in the way growers use pesticides. The EU has especially developed stringent food safety standards relating to, among other things, pesticide usage. Under EU pesticide standards (EU-PS) farmers are trained by their buyers on safe use of pesticides and then closely monitored under contract. This paper looks at the impact of these standards on developing country farmers’ use of alternative pest management practices, pesticide protective clothing and the actual usage of pesticides. It finds that compliance with EU-PS increases the use of alternative pest management practices and protective clothing. However, EU-PS has mixed effect on the quantity of pesticides used. The paper also finds that farmer’s education and access to information play an important role in the use of alternative pest management practices. The paper concludes that EU-PS encourage the use of alternative pest management practices and pesticide protective gear in production of fresh export vegetables. The findings imply that EU-PS promote environmentally-friendly methods of production of fresh export vegetables in developing countries.     

Climate change and variability in Sub-Saharan Africa: a review of current and future trends and impacts on agriculture and food security

Sub-Saharan Africa has been portrayed as the most vulnerable region to the impacts of global climate change because of its reliance on agriculture which is highly sensitive to weather and climate variables such as temperature, precipitation, and light and extreme events and low capacity for adaptation. This article reviews evidence on the scope and nature of the climate change challenge; and assesses the impact of climate change on agriculture and food security in Sub-Saharan Africa. From the review, it is apparent that the climate in Africa is already exhibiting significant changes, evident by changes in average temperature, change in amount of rainfall and patterns and the prevalence of frequency and intensity of weather extremes. The review also revealed that although uncertainties exist with regards to the magnitude of impacts, climate will negatively affect agricultural production in Sub-Saharan Africa. Specifically, as result of current and expected climate change, the area suitable for agriculture, the length of growing seasons and yield potential, particularly along the margins of semi-arid and arid areas, are expected to decrease. These impacts will affect all components of food security: food availability, food accessibility, food utilisation and food stability and hence increase the risk of hunger in the region. The review thus confirms the general consensus that Sub-Saharan Africa is the most vulnerable region to climate change. It suggests that, policymakers and development agencies should focus on formulating and implementing policies and programmes that promote farm level adaptation strategies currently being practiced by farmers across the region.     

Regulatory context for cumulative impact research

Wetlands protection has become a topic of increased public attention and support, and regulation of wetlands loss under Section 404 of the Clean Water Act has received high priority within the US Environmental Protection Agency (EPA). Despite this, the nation is continuing to experience serious wetlands losses. This situation reflects the contentious nature of wetlands protection; it involves fundamental conflicts between environmental and development interests. Better information is needed to support regulatory decision making, including information on cumulative impacts. Currently, consideration of cumulative impacts, although required by various federal regulations, is limited. One reason is that most regulatory decisions are made on a permit-specific, site-specific basis, whereas cumulative impacts must be assessed on a broader, regional scale. In addition, scientific information and methods necessary to support cumulative impact assessment have been lacking. An anticipatory, planning-oriented framework to complement the existing site-specific permit review program is needed to support more effective consideration of cumulative impacts; such an effort is beginning to emerge. In addition, EPA is supporting research to provide better information on cumulative effects. It is recommended that the EPA program place initial emphasis on synthesis and analysis of existing information, on maximizing its use in decision making, and on information transfer. Recommended approaches include correlation of historic wetlands losses with loss of wetlands function and values, regional case studies, and development of indices of cumulative impact for use in permit review.Formerly Director, Office of Federal Activities, US Environmental Protection Agency     

STATISTICAL METHODS AND SAMPLING DESIGN FOR ESTIMATING STEP TRENDS IN SURFACE-WATER QUALITY1

ABSTRACT: This paper addresses two components of the problem of estimating the magnitude of step trends in surface water quality. The first is finding a robust estimator appropriate to the data characteristics expected in water-quality time series. The Hodges-Lehmann class of estimators is found to be robust in comparison to other nonparametric and moment-based estimators. A seasonal Hodges-Lehmann estimator is developed and shown to have desirable properties. Second, the effectiveness of various sampling strategies are examined using Monte Carlo simulation coupled with application of this estimator. The simulation is based on a large set of total phosphorus data from the Potomac River. To assure that the simulated records have realistic properties, the data are modeled in a multiplicative fashion incorporating flow, hysteresis, seasonal, and noise components. The results demonstrate the importance of balancing the length of the two sampling periods and balancing the number of data values between the two periods. The inefficiency of sampling at frequencies much in excess of 12 samples per year is demonstrated. Rotational sampling designs are discussed, and efficient designs, at least for this river and constituent, are shown to involve more than one year of active sampling at frequencies of about 12 per year.