Adapting a rapid assessment protocol to environmentally assess palm swamp (Veredas) springs in the Cerrado biome,Brazil

The exploitation and degradation of natural environments exert intense pressure on important ecosystems worldwide. Thus, it is necessary developing or adapting assessment methods to monitor environmental changes and to generate results to be applied to environmental management programs. The Brazilian Veredas (phytophysiognomies typical to the Cerrado biome) are threatened by several human activities; thus, the aim of the present study is to adapt a rapid assessment protocol (RAP) to be applied to Veredas springs, by using the upper course of the Vai-e-Vem stream watershed (Ipameri County, Goiás State, Brazil). Therefore, several springs in the study site were visited and 11 of them were considered Veredas springs. After the RAP was adapted, the instrument was validated and used to environmentally assess the springs in order to demonstrate its applicability. The present study has provided an instrument of option to monitor Veredas springs.     

Cytotoxic and genotoxic effects of silver nanoparticle/carboxymethyl cellulose on <Emphasis Type="Italic">Allium cepa</Emphasis>

Several mutagenic agents may be present in substances released in the environment, which may cause serious environmental impacts. Among these substances, there is a special concern regarding the widespread use of silver nanoparticles (AgNP) in several products due to their widely known bactericidal properties, including in the medical field and the food industry (e.g., active packaging). The assessment of the effects of AgNP released in the environment, having different concentrations, sizes, and being associated or not to other types of materials, including polymers, is therefore essential. In this research, the objective was to evaluate the genotoxic and cytotoxic effects of AgNP (size range between 2 and 8 nm) on root meristematic cells of Allium cepa (A. cepa). Tests were carried out in the presence of colloidal solution of AgNP and AgNP mixed with carboxymethylcellulose (CMC), using distinct concentrations of AgNP. As a result, when compared to control samples, AgNP induced a mitotic index decrease and an increase of chromosomal aberration number for two studied concentrations. When AgNP was in the presence of CMC, no cytotoxic potential was verified, but only the genotoxic potential for AgNP dispersion having concentration of 12.4 ppm.     

Detection of hormones in surface and drinking water in Brazil by LC-ESI-MS/MS and ecotoxicological assessment with <Emphasis Type="Italic">Daphnia magna</Emphasis>

The growing use of pharmaceutical drug is mainly due to several diseases in human and in animal husbandry. As these drugs are discharged into waterways via wastewater, they cause a major impact on the environment. Many of these drugs are hormones; in which even at low concentrations can alter metabolic and physiological functions in many organisms. Hormones were found in surface water, groundwater, soil, and sediment at concentrations from nanograms to milligrams per liter of volume—quantities known to cause changes in the endocrine system of aquatic organisms. This study aimed to develop a methodology for hormone detection (estriol, estrone, 17β-estradiol, 17α-ethinylestradiol, progesterone, and testosterone) on surface and treated water samples. Sample toxicity was assessed by ecotoxicology tests using Daphnia magna. A liquid chromatograph coupled to a mass spectrometer with an electrospray ionization source (LC-ESI-MS/MS) was used for the analysis. The results showed that samples were contaminated by the hormones estriol, estrone, progesterone, 17β-estradiol, and 17α-ethinylestradiol during the sampling period, and the highest concentrations measured were 90, 28, 26, 137, and 194 ng·L^?1, respectively. This indicates the inflow of sewage containing these hormones at some points in the Piracicaba River in the State of Sao Paulo—Brazil. Results indicated little toxicity of the hormone estriol in D. magna, indicating that chronic studies with this microcrustacean are necessary.     

Factors influencing the food transition in riverine communities in the Brazilian Amazon

The objective of this study was to determine the main patterns and factors influencing food transition in riverine people in the Brazilian Amazon. Through interviews with a semi-structured questionnaire, we inferred their food habits and provide information about general demographic, socioeconomic, resource use and environmental context. Data from the questionnaires were categorized and analyzed using a logistic regression model to assess the relative influence of socioeconomic and environment factors on the local diet. Based on a logistic regression data analysis, it was found a greater consumption of processed food significantly associated with multiple factors such as market participation, sex (female and male), government aid to forest conservation and environment context (upland and wetland). Although the local diet is composed mainly of local resources such as fish and cassava flour, increasing incomes due to direct government subsidy programs and marketing of cassava flour have influenced these local practices and habits. Through the analysis of factors influencing food transition, it was possible to evaluate those having the greatest effect on this Amazon region and propose an alternative method to subsidy food policy grounded in local opinion surveys.     

Herbicide leaching on a recharge area of the Guarany aquifer in Brazil

The region of Ribeir?o Preto City, located in Southeast of Brazil, S?o Paulo State, is an important sugarcane, soybean, and corn producing area with a high level of pesticides utilization. This region is also an important recharge area for groundwater supply of the Guarany aquifer. Since the past ten years atrazine, simazine, ametryn, tebuthiuron, diuron, 2,4-D, picloram, and hexazinone are the main herbicides used in this area. In order to study a possible leaching of some of these herbicides into the aquifer, surface, and groundwater samples were collected in a watershed during the years of 1996 to 2003, from different locations. To detect and quantify the herbicides a GC-MS (gas chromatograph/mass spectrometry) method was used. The response of the herbicides analyzed was linear over the concentration range of 0.02 to 2.0 microg/L. Analysis of groundwater revealed that the herbicides tebuthiuron, diuron, atrazine, simazine, and ametryn were not present in the samples. In the surface water collected in 1997, ametryn was present in two out of nine locations with concentrations ranging from 0.17 and 0.23 microg/L, which is above the allowable 0.1 microg/L according to the European safety level. The leaching potential of tebuthiuron, diuron, atrazine, simazine, 2,4-D, picloram, and hexazinone has been evaluated using CMLS-94, "Chemical Movement in Layered Soil," as simulation model. No leaching into the depth of the water table at 40 m was found.     

Kinetics of carbosulfan hydrolysis to carbofuran and the subsequent degradation of this last compound in irrigated rice fields

The objectives of this work were estimate the reaction rates of hydrolysis of carbosulfan to carbofuran and subsequent degradation of this last compound in irrigated rice fields, and the respective half life, in aquatic environment and soil solution, by mean of numerical solution of differential ordinary linear equations system that describes the kinetics of insecticide concentrations. The results indicated that the carbosulfan and carbofuran have low persistence in water and medium persistence in soil solution of tropical irrigated rice fields. However, both compounds can be found in laminar water and soil solution in concentration above environmental and human safety limits.     

Bioaccumulation and critical body residue of PAHs in the amphipod,Diporeia spp: additional evidence to support toxicity additivity for PAH mixtures

Polycyclic aromatic hydrocarbons (PAHs) are considered to act additively when exposed as congener mixtures. Additive internal concentrations at the site of toxic action is the basis for recent efforts to establish a sum PAH guideline for sediment-associated PAH toxicity. This study determined the toxicity of several PAH congeners on a body residue basis in Diporeia spp. These values were compared to the previously established LR(50) value for a PAH mixture based on the molar sum of PAH congeners and demonstrated similar LR(50) values for individual PAH. These results support the contention that the PAH act at the same molar concentration whether present as individual compounds or in mixture. Aqueous exposures were conducted for 28 d, and the water was exchanged daily to maintain the exposure concentration. The concentration in the exposures declined by an average of 22% between water exchanges across all compounds, and ranged from 11% to 32%. The toxicokinetics were determined using both time-weighted-average (TWA) and time-variable water concentrations and were not statistically different between the two source functions. Toxicity was determined for both mortality and immobility (failure to swim on prodding) and on both a TWA water concentration and a body residue basis. The LC(50) values ranged from 1757 microg l(-1) for naphthalene after 10 d exposure to 79.1 microg l(-1) for pyrene after 28 d exposure, and the EC(50) ranged from 1587 microg l(-1) for naphthalene after 10 d exposure to 38.2 microg l(-1) for pyrene after 28 d exposure. The LR(50) values for all congeners at all lengths of exposure were essentially constant and averaged 7.5+/-2.6 micromol g(-1), while the ER(50) for immobility averaged 2.6+/-0.6 micromol g(-1). The bioconcentration factor declined with increasing exposure concentration and was driven primarily by a lower uptake rate with increasing dose, while the elimination remained essentially constant for each compound.