Garnering support for Pigouvian taxation with tax return: a lab experiment

Environmental Economics and Policy Studies - To test if tax return can effectively and efficiently increase the acceptance of externality taxation, a laboratory experiment with a negative...     

Manganese in the urban atmosphere: identifying anomalous concentrations and sources

Purpose  

Industrial emissions can raise urban background levels of inhalable Mn particles in an order of magnitude above normal, eclipsing the contribution made by natural sources and traffic.     

Vertical and horizontal distributions of microbial abundances and enzymatic activities in propylene-glycol-affected soils

The natural microbial activity in the unsaturated soil is vital for protecting groundwater in areas where high loads of biodegradable contaminants are supplied to the surface, which usually is the case for airports using aircraft de-icing fluids (ADF) in the cold season. Horizontal and vertical distributions of microbial abundance were assessed along the western runway of Oslo Airport (Gardermoen, Norway) to monitor the effect of ADF dispersion with special reference to the component with the highest chemical oxygen demand (COD), propylene glycol (PG). Microbial abundance was evaluated by several biondicators: colony-forming units (CFU) of some physiological groups (aerobic and anaerobic heterotrophs and microscopic fungi), most probable numbers (MPN) of PG degraders, selected catabolic enzymatic activities (fluorescein diacetate (FDA) hydrolase, dehydrogenase, and β-glucosidase). High correlations were found between the enzymatic activities and microbial counts in vertical soil profiles. All microbial abundance indicators showed a steep drop in the first meter of soil depth. The vertical distribution of microbial abundance can be correlated by a decreasing exponential function of depth. The horizontal trend of microbial abundance (evaluated as total aerobic CFU, MPN of PG-degraders, and FDA hydrolase activity) assessed in the surface soil at an increasing distance from the runway is correlated negatively with the PG and COD loads, suggesting the relevance of other chemicals in the modulation of microbial growth. The possible role of potassium formate, component of runway de-icers, has been tested in the laboratory by using mixed cultures of Pseudomonas spp., obtained by enrichment with a selective PG medium from soil samples taken at the most contaminated area near the runway. The inhibitory effect of formate on the growth of PG degraders is proven by the reduction of biomass yield on PG in the presence of formate.     

Effects of induced paralysis on hemocytes and tissues of the giant lions-paw scallop by paralyzing shellfish poison

In general, bivalves are not affected by exposure to toxic dinoflagellates that produce paralyzing shellfish poisons (PSP). After injection with PSP extracted from the Gymnodinium catenatum, Nodipecten subnodosus is paralyzed, indicating that PSP provokes effects similar to what is observed in vertebrates, including paralysis and metabolic stress. To investigate the processes involved in poisoning by PSP, lions-paw scallops were injected with gonyautoxin (GTX) 2/3 epimers in the adductor muscle. Mild doses provoked adductor muscle contractions and paralysis, mantle retraction, and incapacity of shell closure, but scallops gradually recovered in a clear, dose-time recovery pattern. With high doses of GTX 2/3, scallops were permanently paralyzed, and hemocytes in hemolymph were reduced. Surprisingly, under these conditions, scallops continued normal feeding and did not show any microscopic defect in intestine or gills, but hemocytes infiltrated the adductor muscle and abnormal vitellogenesis and mantle melanization occurred. Paralysis stress was accompanied by negative scallop responses, based on visible effects, generation of nitric oxide, lipid peroxidation, and changes in antioxidant and hydrolytic enzymes in hemocytes and tissues. These data can be used to understand potential side effects of PSP in bivalves.     

Transfer of pesticides to the brew during mate drinking process and their relationship with physicochemical properties

In order to evaluate the extraction of pesticide residues that are transferred to the brew during mate drinking process of P.U.1 yerba mate leaves (Ilex paraguariensis), a special device to simulate the way in which mate is drunk in Uruguay was developed. The transfer to the brew of 12 organophosphates, 5 synthethic pyrethroids and one organochlorine pesticide from spiked samples was studied. The relationship between the transfer data thus obtained and physicochemical properties like water solubility (Ws), octanol-water coefficient (Kow) and Henry's constant (H) was evaluated. The extractability of the pesticide residues from yerba mate can be correlated with log Ws and log Kow. These transfer values allowed the calculation of ARLs (acceptable residue level) for the pesticides following Food and Agriculture Organization (FAO), World Health Organizaion (WHO) guidelines. These results can help the future establishment of maximum residue levels (MRLs)     

Evaluation of landfill leachate treatment by advanced oxidative process by Fenton’s reagent combined with membrane separation system

A high content of refractory organic matter, ammonia and toxic compounds is characteristic of landfill leachate. Advanced oxidative processes (AOPs) are an attractive alternative for landfill leachate treatment. However, when applied as a unique process treatment, they do not provide a complete solution for the effluent treatment. Combining AOP with a membrane separation process (MSP) presents a number of benefits and provides an adequate solution for this problem. With this in mind, the present work aims to evaluate, using a bench scale, leachate treatability through AOP by Fenton’s reagent (AOP/Fenton) combined with microfiltration (MF) and nanofiltration (NF). A high efficient removal of COD (63%), true color (76%) and humic substances (50%) was observed during AOP/Fenton under optimized conditions (1.7 g H₂O₂/g COD_{raw leachate}; FeSO₄·7H₂O:H₂O₂ = 1:5.3; pH = 3.8; reaction conditions = 115 rpm/28 min). According to the evaluated parameters, MSP presented an efficient complementary treatment, in which the integrity of the stages was sufficient for reaching regulatory levels in the effluent (Deliberação Normativa Conjunta COPAM/CERH-MG N^o. 1, May 5, 2008).