Iowa Statewide Stream Nitrate Load Calculated Using In Situ Sensor Network

Various techniques exist to estimate stream nitrate loads when measured concentration data are sparse. The inherent uncertainty associated with load estimation, however, makes tracking progress toward water quality goals more difficult. We used high‐frequency, in situ nitrate sensors strategically deployed across the agricultural state of Iowa to evaluate 2016 stream concentrations at 60 sites and loads at 35 sites. The generated data, collected at an average of 225 days per site, show daily average nitrate‐N yields ranging from 12 to 198 g/ha, with annual yields as high as 53 kg/ha from the intensely drained Des Moines Lobe. Thirteen of the sites that capture water from 82.5% of Iowa's area show statewide nitrate‐N loading in 2016 totaled 477 million kg, or 41% of the load delivered to the Mississippi–Atchafalaya River Basin (MARB). Considering the substantial private and public investment being made to reduce nitrate loading in many states within the MARB, networks of continuous, in situ measurement devices as described here can inform efforts to track year‐to‐year changes in nitrate load related to weather and conservation implementation. Nitrate and other data from the sensor network described in this study are made publicly available in real time through the Iowa Water Quality Information System.     

Estimation of pyrethroid pesticide intake using regression modeling of food groups based on composite dietary samples

Population-based estimates of pesticide intake are needed to characterize exposure for particular demographic groups based on their dietary behaviors. Regression modeling performed on measurements of selected pesticides in composited duplicate diet samples allowed (1) estimation of pesticide intakes for a defined demographic community, and (2) comparison of dietary pesticide intakes between the composite and individual samples. Extant databases were useful for assigning individual samples to composites, but they could not provide the breadth of information needed to facilitate measurable levels in every composite. Composite sample measurements were found to be good predictors of pyrethroid pesticide levels in their individual sample constituents where sufficient measurements are available above the method detection limit. Statistical inference shows little evidence of differences between individual and composite measurements and suggests that regression modeling of food groups based on composite dietary samples may provide an effective tool for estimating dietary pesticide intake for a defined population.     

Not seeing is not believing: volunteer beliefs about Burmese pythons in Florida and implications for public participation in invasive species removal

Public engagement is important to invasive species management, and recreational harvest programs are one way agencies seek to involve the public and raise awareness. We surveyed participants (n = 660) and non-participants (n = 77) in the 2013 Python Challenge^TM to understand whether this event achieved its primary goal of raising awareness of the ecological impact of Burmese pythons (Python molurus bivittatus) in south Florida. Respondents indicated a high level of ‘concern’ about the seriousness of the python problem and the need for management actions. Concern was affected positively by environmental motivations, experience of seeing pythons in the wild, older age, and female sex, but negatively by level of Python Challenge involvement. Results suggest that ‘proximate’ experience of not seeing a python may reduce concern, whereas ‘ongoing’ experience may temper concern without diminishing involvement. This research highlights the role of experience in shaping beliefs and advises diligence in public participation programs.     

Life cycle assessment of mine tailings management in Canada

The effective management of mine tailings involves the control of several environmental impacts and legal requirements. Six tailings site management and closure scenarios were developed for a copper zinc underground mine located in Quebec (Canada) and compared using life cycle assessment (LCA). Two options are considered for the mine operation: tailings can be sent to the tailings disposal area where they are submerged or they can be partly used for backfilling. For each of these two operation options, three alternatives are presented for mine closure: (a) submerged tailings, (b) partial desulphurization with a cover of desulphurized material and (c) a cover with capillary barrier effects (CCBE) made of natural soils followed by revegetation. The goals of the study were to draw the inventory of these management scenarios from the development to the post-closure phase, to assess and compare their environmental impacts and to determine the importance of the land-use impact category. The potential impacts for each scenario were evaluated using the IMPACT 2002+ LCIA method. The results of the performed LCA indicate that for mine development and operation, scenarios where tailings are partly used as backfill for underground stopes appear to lead to larger impacts in 11 of the 14 midpoint categories since the backfill plant operation consumes a greater amount of material and energy. For a site closure period of 2 years, the CCBE option creates the greatest impacts, since it requires much more effort than the other techniques. The results for the post-closure phase have been analysed separately since they have a larger uncertainty. They appear to modify the comparative assessment results. The various results presented in the paper show the importance of taking land-use impacts into account.     

Including adaptation costs and climate change damages in evaluating post-2012 burden-sharing regimes

Many studies have been published to evaluate the consequences of different post-2012 emission allocation regimes on regional mitigation costs. This paper goes one step further and evaluates not only mitigation costs, but also adaptation costs and climate change damages. Three post-2012 emission allocation regimes (Contraction & Convergence, Multistage and Common but differentiated convergence) and two climate targets (2°C and 3°C above the pre-industrial level) are considered. This explorative analysis shows that including these other cost categories could lead to different perspectives on the outcomes of allocation regimes. Up to 2050, the poorest regions have negative mitigation costs under all allocation regimes considered, as they benefit from emission trading. However, these regions also suffer from the most severe climate impacts. As such, the financial flows due to emission trading from developed to developing countries created under these allocation regimes could also be interpreted as compensation of climate change damages and adaptation costs. In the longer run, the sum of climate change damages, adaptation costs and mitigation costs are the highest in the poorest regions of Sub-Saharan Africa and South Asia, for both climate targets and practically all emission allocation regimes.     

An integrated environmental approach to investigate biomarker fluctuations in the blue mussel Mytilus edulis L. in the Vilaine estuary, France

Estuarine areas represent complex and highly changing environments at the interface between freshwater and marine aquatic ecosystems. Therefore, the aquatic organisms living in estuaries have to face highly variable environmental conditions. The aim of this work was to study the influence of environmental changes from either natural or anthropogenic origins on the physiological responses of Mytilus edulis. Mussels were collected in the Vilaine estuary during early summer because this season represents a critical period of active reproduction in mussels and of increased anthropogenic inputs from agricultural and boating activities into the estuary. The physiological status of the mussel M. edulis was evaluated through measurements of a suite of biomarkers related to: oxidative stress (catalase, malondialdehyde), detoxication (benzopyrene hydroxylase, carboxylesterase), neurotoxicity (acetylcholinesterase), reproductive cycle (vitelline, condition index, maturation stages), immunotoxicity (hemocyte concentration, granulocyte percentage, phagocytosis, reactive oxygen species production, oxidative burst), and general physiological stress (lysosomal stability). A selection of relevant organic contaminant (pesticides, (polycyclic aromatic hydrocarbons, polychlorobiphenyls) was measured as well as environmental parameters (water temperature, salinity, total suspended solids, turbidity, chlorophyll a, pheopigments) and mussel phycotoxin contamination. Two locations differently exposed to the plume of the Vilaine River were compared. Both temporal and inter-site variations of these biomarkers were studied. Our results show that reproduction cycle and environmental parameters such as temperature, organic ontaminants, and algal blooms could strongly influence the biomarker responses. These observations highlight the necessity to conduct integrated environmental approaches in order to better understand the causes of biomarker variations.     

The effect of cadmium upon the structure of the olfactory nerve in the young pike †

Some recent experiments have shown with autoradiographic methods the axonal transport of cadmium along the olfactory nerve of the salmon trout.² We should determine in our experiments the effect of cadmium upon the olfactory nerve at histological level using optical microscopy technics.