Macrophage activity and histopathology of the lymphohematopoietic organs in male Wistar rats orally exposed to single or mixed pesticides

The noxious effects of low or effective dose exposure to single or mixed pesticides on macrophage activity and the lymphohematopoietic organs were investigated. Male Wistar rats were orally exposed to dichlorvos, dicofol, endosulfan, dieldrin and permethrin, either as single or combined mixtures during a 28-day study containing eight groups: one group received a semipurified diet (non-treated); two groups received a semipurified diet containing low dose mixture (dieldrin 0.025 mg/kg, endosulfan, 0.6 mg/kg, dicofol 0.22 mg/kg, dichlorvos 0.23 mg/kg, permethrin 5 mg/kg) or an effective dose mixture (dichlorvos 2.3 mg/kg, dicofol 2.5 mg/kg, endosulfan 2.9 mg/kg, dieldrin 0.05 mg/kg and permethrin 25.0 mg/kg), respectively; the other five groups received a semipurified diet containing each single pesticide in effective doses. At sacrifice, the thymus, spleen, mesenteric lymph nodes, Payer's patches and bone marrow were removed for histological analysis. Peritoneal macrophages were obtained to determine the phagocytosis and spreading indexes and tumoral necrosis factor alpha (TNF-α), nitric oxide (NO) and H₂O₂ production. Exposure to pesticide mixtures did not alter the percentage of macrophage phagocytosis and spreading, TNF-α production or the NO and H₂O₂ release when compared to the non-treated group. Neither was there any apparent evidence that a pesticide mixture at low or effective doses altered the histological structure of the lymphohematopoietic organs. The findings indicate that short-term treatment with pesticide mixtures did not induce an apparent immunotoxic effect in male Wistar rats.     

Accumulation,biotransformation, and biochemical responses after exposure to arsenite and arsenate in the estuarine polychaete <Emphasis Type="BoldItalic">Laeonereis acuta</Emphasis> (Nereididae)

Introduction  

This study aimed to analyze antioxidant responses and oxidative damage induced by two inorganic forms of arsenic (As; As^III and As^V) in an estuarine polychaete species, Laeonereis acuta (Nereididae). The capacity of arsenic biotransformation was also evaluated through the methylation process considering the activity of a key enzyme involved in the metabolization process.     

Enhanced solubilization of arsenic and 2,3,4,6 tetrachlorophenol from soils by a cyclodextrin derivative

The application of extracting aqueous solutions with cyclodextrins in several soil remediation technologies has been increasingly studied but little is known about their removal capacities toward the inorganic species. Herein, the effectiveness of cyclodextrins (CDs) in extracting arsenic, copper, and iron from a mining soil is presented. In a preliminary test of four types of CD aqueous solutions, only the addition of carboxylmethyl-beta-cyclodextrin CMCD (a cyclodextrin derivative) led to a significant enhancement in arsenic removal. An increase in the concentration of copper and iron in the leachates was also observed with CMCD. Kinetic study of arsenic release was carried out at two temperatures (20 and 35 degrees C). The arsenic concentration in the leachates increases with increasing cyclodextrin concentration. At an 80 mM CMCD concentration, arsenic, copper, and iron released in filtrates were about 20-, 1,000-, and 4,000-fold greater, respectively, than that obtained using deionized water. In the soil system, the CMCD capacity removal was found to be higher for cations than for arsenic. Because the tetrachlorophenol can co-occur with arsenic and copper in several contaminated sites, its solubilization by CMCD was also investigated. Extraction experiments were performed to extract 2,3,4,6 tetrachlorophenol (TeCP) in spiked soil with CMCD. The results of batch experiments have shown that CMCD could significantly increase the TeCP extraction from soil. CD sorption on soils as quantified by a fluorescence technique was low, indicating no significant loss of CD during the leaching experiments. The use of CMCD as a flushing agent to enhance the removal of both inorganic and organic pollutants from mixed-contaminated soils appears as a promising remediation method.     

Biomass consumption and CO2, CO and main hydrocarbon gas emissions in an Amazonian forest clearing fire

Biomass consumption and CO₂, CO and hydrocarbon gas emissions in an Amazonian forest clearing fire are presented and discussed. The experiment was conducted in the arc of deforestation, near the city of Alta Floresta, state of Mato Grosso, Brazil. The average carbon content of dry biomass was 48% and the estimated average moisture content of fresh biomass was 42% on wet weight basis. The fresh biomass and the amount of carbon on the ground before burning were estimated as 528 t ha^?1 and 147 t ha^?1, respectively. The overall biomass consumption for the experiment was estimated as 23.9%. A series of experiment in the same region resulted in average efficiency of 40% for areas of same size and 50% for larger areas. The lower efficiency obtained in the burn reported here occurred possibly due to rain before the experiment. Excess mixing ratios were measured for CO₂, CO, CH₄, C₂–C₃ aliphatic hydrocarbons, and PM_2.5. Excess mixing ratios of CH₄ and C₂–C₃ hydrocarbons were linearly correlated with those of CO. The average emission factors of CO₂, CO, CH₄, NMHC, and PM_2.5 were 1,599, 111.3, 9.2, 5.6, and 4.8 g kg^?1 of burned dry biomass, respectively. One hectare of burned forest released about 117,000 kg of CO₂, 8100 kg of CO, 675 kg of CH₄, 407 kg of NMHC and 354 kg of PM_2.5.     

Revisiting the plant hyperaccumulation criteria to rare plants and earth abundant elements

The several established criteria to define a hyperaccumulator plant were applied to a rare and endangered species, Plantago almogravensis, and to the 3rd most abundant element in the earth crust, Al. Using the most common criteria, P. almogravensis undoubtedly is an Al hyperaccumulator plant. If the recent proposed requirements were considered, most of them matching those for a plant to be used in phytoextraction, it can only be considered an unusual accumulator of Al. A discussion is made concerning the several criteria of a hyperaccumulator plant in order to include rare and endemic ones and abundant elements. In ecological terms, the enrichment in Al and Fe observed may account for the differences in the vegetation pattern. Due to the rarity and endangered nature of this plant, the contribution of this work is also relevant for the ecological understanding and the development of conservation options of this endemic species.     

Biodegradability of the anticancer drug etoposide and identification of the transformation products

Etoposide susceptibility to microbiological breakdown was studied in a batch biotransformation system, in the presence or absence of artificial wastewater containing nutrients, salts and activated sludge at two concentration levels. The primary focus of the present study was to study etoposide transformation products by ultra-high performance liquid chromatography coupled to high-resolution hybrid quadrupole-Orbitrap tandem mass spectrometry (MS/MS). Data-dependent experiments combining full-scan MS data with product ion spectra were acquired to identify the molecular ions of etoposide transformation products, to propose the molecular formulae and to elucidate their chemical structures. Due to the complexity of the matrix, visual inspection of the chromatograms showed no clear differences between the controls and the treated samples. Therefore, the software package MZmine was used to facilitate the identification of the transformation products and speed up the data analysis. In total, we propose five transformation products; among them, four are described as etoposide transformation products for the first time. Even though the chemical structures of these new compounds cannot be confirmed due to the lack of standards, their molecular formulae can be used to target them in monitoring studies.     

Effect of variations in the redox potential of Gleysol on barium mobility and absorption in rice plants

Two assays were designed to obtain information about the influence of redox potential variations on barium mobility and bioavailability in soil. One assay was undertaken in leaching columns, and the other was conducted in pots cultivated with rice (Oryza sativa) using soil samples collected from the surface of Gleysol in both assays. Three doses of barium (100,300 mg kg⁻¹ and 3000 mg kg⁻¹-soil dry weight) and two redox potential values (oxidizing and reducing) were evaluated. During the incubation period, the redox potential (Eh) was monitored in columns and pots until values of −250 mV were reached. After the incubation period, geochemical partitioning was conducted on the barium using the European Communities Bureau of Reference (BCR) method. Rainfall of 200 mm d⁻¹ was simulated in the columns and in the planting of rice seedlings in the pots. The results of the geochemical partitioning demonstrated that the condition of reduction favors increased barium concentrations in the more labile chemical forms and decreased levels in the chemical forms related to oxides. The highest barium concentrations in leached extracts (3.36 mg L⁻¹) were observed at the highest dose and condition of reduction at approximately five times above the drinking water standard. The high concentrations of barium in the soil did not affect plant dry matter production. The highest levels and accumulation of barium in roots, leaves, and grains of rice were found at the highest dose and condition of reduction. These results demonstrate that reduction leads to solubilization of barium sulfate, thereby favoring greater mobility and bioavailability of this element.     

Estimation of uncertainty arising from different soil sampling devices: the use of variogram parameters

In the frame of the international SOILSAMP project, funded and coordinated by the National Environmental Protection Agency of Italy (APAT), uncertainties due to field soil sampling were assessed. Three different sampling devices were applied in an agricultural area using the same sampling protocol. Cr, Sc and Zn mass fractions in the collected soil samples were measured by k(0)-instrumental neutron activation analysis (k(0)-INAA). For each element-device combination the experimental variograms were calculated using geostatistical tools. The variogram parameters were used to estimate the standard uncertainty arising from sampling. The sampling component represents the dominant contribution of the measurement uncertainty with a sampling uncertainty to measurement uncertainty ratio ranging between 0.6 and 0.9. The approach based on the use of variogram parameters leads to uncertainty values of the sampling component in agreement with those estimated by replicate sampling approach.     

Concentrations and specific loads of brominated flame retardants in sewage sludge

Many substances related to human activities end up in wastewater and accumulate in sewage sludge. The present study focuses on two classes of brominated flame retardants: polybrominated diphenyl ethers (BDE28, BDE47, BDE49, BDE66, BDE85, BDE99, BDE100, BDE119, BDE138, BDE153, BDE154, BDE183, BDE209) and hexabromocyclododecane (HBCD) detected in sewage sludge collected from a monitoring network in Switzerland. Mean concentrations (n=16 wastewater treatment plants) were 310, 149, 95 and 17microg per kg dry matter for decaBDE, HBCD, penta- and octaBDE, respectively. These numbers correspond well with other studies from European countries. DecaBDE, HBCD, penta- and octaBDE showed average specific loads (load per connected inhabitant per year) in sludge of 6.1, 3.3, 2.0 and 0.3mgcap(-1)yr(-1), respectively. This is in line with consumption and storage of the compounds in the environment and the anthroposphere. Discrepancies observed for octaBDE and HBCD can be explained by the release from materials where these compounds are incorporated in and/or their degradation during anaerobic sludge treatment. Loads from different types of monitoring sites showed that brominated flame retardants ending up in sewage sludge originate mainly from surface runoff, industrial and domestic wastewater.     

New and versatile optical-immunoassay instrumentation for water monitoring

This article is a review of new and versatile optical-immunoassay instrumentation for water monitoring developed through two European Union projects, RIver ANAlyser (RIANA) and Automated Water Analyser Computer Supported System (AWACSS). Both projects utilise immunoassay techniques to isolate the analytes and Total Internal Reflection Fluorescence (TIRF) to quantify them. Completed in 1999, the RIANA project developed a sensitive and cost-effective analytical system capable of simultaneous detection of multiple-analytes in real-world water samples. The AWACSS project has been in progress since 2001 and is developing rugged-but-sensitive instrumentation that will detect up to 30 analytes simultaneously, will operate unattended, and will have networking capability.