Acid Rain in Downtown São Paulo City, Brazil

During the period from July 2002 to June 2004, the chemical characteristics of the rainwater samples collected in downtown São Paulo were investigated. The analysis of 224 wet-only precipitation samples included pH and electrical conductivity, as well as major ions (Na⁺, $ \rm NH^{ + }_{4} During the period from July 2002 to June 2004, the chemical characteristics of the rainwater samples collected in downtown S?o Paulo were investigated. The analysis of 224 wet-only precipitation samples included pH and electrical conductivity, as well as major ions (Na⁺, , K⁺, Ca²⁺, Mg²⁺, Cl⁻, , ) and carboxylic acids (acetic, formic and oxalic) using ion chromatography. The volume weighted mean, VWM, of the anions , and Cl⁻ was, respectively, 20.3, 12.1 and 10.7 μmol l⁻¹. Rainwater in S?o Paulo was acidic, with 55% of the samples exhibiting a pH below 5.6. The VWM of the free H⁺ was 6.27 μmol l⁻¹), corresponding to a pH of 5.20. Ammonia (NH₃), determined as (VWM = 32.8 μmol l⁻¹), was the main acidity neutralizing agent. Considering that the H⁺ ion is the only counter ion produced from the non-sea-salt fraction of the dissociated anions, the contribution of each anion to the free acidity potential has the following profile: (31.1%), (26.0%), CH₃COO⁻ (22.0%), Cl⁻ (13.7%), HCOO⁻ (5.4%) and (1.8%). The precipitation chemistry showed seasonal differences, with higher concentrations of ammonium and calcium during autumn and winter (dry period). The marine contribution was not significant, while the direct vehicular emission showed to be relevant in the ionic composition of precipitation.     

Reusing fly ash in glass fibre reinforced cement: a new generation of high-quality GRC composites

New composite materials based on an alkali-resistant glass-fibre reinforced cement (AR-GRC) system are being developed by using fly ash (FA) produced at coal thermoelectric power plants, and fluid catalytic cracking catalyst residue (FC3R) from the petrol industry as cement replacement materials. These wastes are reactive from the pozzolanic viewpoint, and modify the nature and the microstructure of the cement matrix when a part of the Portland cement is replaced in the formulation of GRC. Several microstructural and mechanical aspects are being studied for AR-GRC systems. The behaviour of composites exposed to ageing shows that the pozzolanic activity of the ground FA added in high amounts and its mixture with the FC3R increase the flexural strength and no evidences of strength decay are observed. Additionally, the fibres due to the high alkalinity of the cementing matrix can be deteriorated. Fibres in the control (only Portland cement) and FC3R containing composites were attacked, whereas composites with FA and their mixture with FC3R show that the fibres have not been attacked, due to the pozzolanic activity of replacing materials that reduce the calcium hydroxide content in the cementing matrix.     

Determination of selenium by GFAAS in slurries of fish feces to estimate the bioavailability of this micronutrient in feed used in pisciculture

This paper presents a simple, fast and sensitive method to determine selenium in samples of feces and of fish feed by graphite furnace atomic absorption spectrometry (GFAAS) through the direct introduction of slurries of the samples into the spectrometer's graphite tube. The limits of detection (LOD) and quantification (LOQ) calculated for 20 readings of the blank of the standard slurries (0.50% m/v of feces or feed devoid of selenium) were 0.31 microg l(-1) and 1.03 microg l(-1), respectively, for the standard feces slurries and 0.35 microg l(-1) and 1.16 microg l(-1), respectively, for the standard feed slurries. The proposed method was applied in studies of bioavailability of selenium in different fish feeds and the results proved consistent with that obtained from samples mineralized by acid digestion using the microwave oven.     

Changes in hematological and serum biochemical values in jundiá Rhamdia quelen due to sub-lethal toxicity of cypermethrin

Jundiá (Rhamdia quelen, Quoy and Gaimard), a South American teleostean fish, was exposed to sub-lethal concentrations of cypermethrin (30% and 45% of the 48-h LC(50) value of 0.265 ppm) for 2, 4 or 8 days. Serum biochemical and hematological values and behavioral changes were studied. The 30% LC(50), 0.08 ppm, produced significant increases in Mg(2+), P, K(+), creatinine, urea, glucose, cholesterol, aspartate aminotransferase and alkaline phosphatase levels, and reduction in total proteins and triglycerides in serum. The 45% LC(50), 0.12 ppm, produced significant increase in Na(+), Mg(2+), P, K(+), creatinine, urea, glucose, cholesterol, and alkaline phosphatase, and reduction in triglycerides and alanine aminotransferase levels in serum. At this concentration, the fish showed behavior changes such as hyper-excitability, asphyxia, and widening of mouth and operculum. The hematological values remained normal, except for hemoglobin concentrations and the mean corpuscular hemoglobin concentration, which increased with exposure to 0.08 ppm and 0.12 ppm cypermethrin. Results of the present work show that biochemical analysis of serum can be useful to detect incipient cypermethrin intoxication of the shoal.     

Mobility of dimethoate residues from spring broccoli field

Dimethoate [O, O-dimethyl-S-(N-methylcarbamoyl-methyl) phosphorodithioate] is a broad-spectrum systemic insecticide currently used worldwide and on many vegetables in Kentucky. Dimethoate is a hydrophilic compound (log KOW = 0.7) and has the potential of offsite movement from the application site into runoff and infiltration water. The dissipation patterns of dimethoate residues were studied on spring broccoli leaves and heads under field conditions. Following foliar application of Dimethoate 4E on broccoli foliage at the rate of 0.47 L acre(-1), dimethoate residues were monitored in soil, runoff water collected down the land slope, and in infiltration water collected from the vadose zone. The study was conducted on a Lowell silty loam soil (pH 6.9) planted with broccoli under three soil management practices: (i) soil mixed with municipal sewage sludge, (ii) soil mixed with yard waste compost, and (iii) no-mulch rototilled bare soil. The main objective of this investigation was to study the effect of mixing native soil with municipal sewage sludge or yard waste compost, having considerable amounts of organic matter, on off-site movement of dimethoate residues into runoff and infiltration water following spring rainfall. The initial deposits of dimethoate were 6.2 and 21.4 micro g g(-1) on broccoli heads and leaves, respectively. These residues dissipated rapidly and fell below the maximum residue limit of 2 micro g g(-1) on the heads and leaves after 10 and 14 d, respectively, with half-lives of 5.7 d on broccoli heads and 3.9 d on the leaves. Dimethoate residues detected in top 15 cm of soil (due to droplet drift and wash off residues from broccoli foliage) one day (d) following spraying, were 30.5 ng g(-1) dry soil in the sewage sludge treatment, and 46.1 and 134.5 ng g(-1) dry soil in the yard waste and no mulch treatments, respectively. Water infiltration was greater from yard waste compost treatment than from no mulch treatment, however concentrations of dimethoate in the vadose zone of the three soil treatments did not differ.     

Gas chromatographic methods for monitoring of wastewater chlorophenol degradation in anaerobic reactors

Wastewater samples from an anaerobic reactor were extracted with hexane and derivatized with diazomethane (method 1) and with acetic anidride (method 2). Gas chromatography with electron-capture detection (ECD) was employed for separating the parent compound and intermediates trichlorophenols (TCP) and dichlorophenols (DCP) which originated from the penta chlorophenol (PCP) degradation process. The relations between concentrations of PCP, TCP and DCP areas were linear in the range of concentrations of 0.2 to 8 mg/L and 0.025 mg/L to 5 mg/L for methods 1 and 2, respectively. The repeatability of the extraction methods was satisfactory, with variation coefficients lower than 11%. For method 1, at the fortification level of 0.2 mg/L, recovery of PCP, TCP, and DCP was 112%, 74% and 45%, respectively. For method 2, the corresponding recovery values at the fortification level of 0.1 mg/L were 91%, 93% and 103%, respectively. Storage of the frozen samples did not alter their PCP determination properties. The chromatographic methods adapted for chlorophenol determination in wastewater were suitable with relatively simple manipulation techniques. The obtained results were reproducible and allowed identification of intermediates formed during the PCP degradation process.     

Leaching of seven pesticides currently used in cotton crop in Mato Grosso State-Brazil

This study aimed to evaluate the leaching of pesticides and the applicability of the Attenuation Factor (AF) Model to predict their leaching. The leaching of carbofuran, carbendazim, diuron, metolachlor, alpha and beta endosulfan and chlorpyrifos was studied in an Oxisol using a field experiment lysimeter located in Dom Aquino-Mato Grosso. The samples of percolated water were collected by rain event and analyzed. Chemical and physical soil attributes were determined before pesticide application to the plots. The results showed that carbofuran was the pesticide that presented a higher leaching rate in the studied soil, so was the one representing the highest contamination potential. From the total carbofuran applied in the soil surface, around 6% leached below 50 cm. The other pesticides showed lower mobility in the studied soil. The calculated values to AF were 7.06E-12 (carbendazim), 5.08E-03 (carbofuran), 3.12E-17 (diuron), 6.66E-345 (alpha-endosulfan), 1.47E-162 (beta-endosulfan), 1.50E-06 (metolachlor), 3.51E-155 (chlorpyrifos). AF Model was useful to classify the pesticides' potential for contamination; however, that model underestimated pesticide leaching.     

Multiresidue analysis of pesticides in fruits and vegetables by gas chromatography-mass spectrometry

A multiresidue method was assessed for the determination of several pesticides (organochlorine, organophosphorus, pyrethroids, triazole, amidine) using gas chromatography/mass spectrometry. The extraction of pesticides was carried out by liquid-liquid extraction (LLE) and solid-phase extraction (SPE) using two types of columns (CN and C18). The extracts were cleaned by the addition of florisil, the pesticides were separated by capillary column gas chromatography and detected by mass spectrometry in the electron impact mode. The extraction using C18 column provided the best results for most of the analyzed pesticides. The majority of pesticides recoveries from the four fruits and vegetables (apples, pears, tomatoes and pepper) were greater than 60%. Linearity and precision were satisfactory. The estimated limits of detection and limits of quantification ranged from 0.01 to 0.1 mg/kg and from 0.02 to 0.3 mg/kg, respectively. The proposed procedure was found to be useful for the multiresidue analyses of pesticides in agricultural products for routine monitoring programs.     

A two-generational reproductive toxicity study of zinc in rats

A two-generation reproductive toxicity study of zinc chloride (ZnCl(2)) was conducted in rats. F(o) male and female rats were administered 0.00 (control), 7.50 (low), 15.00 (mid) and 30.00 (high) mg/kg/day of ZnCl(2). Selected F(1) male and female rats were exposed to the same doses received by their parents (F(o)). Exposure of F(0) parental rats to ZnCl(2) showed significant reduction in fertility, viability (days 0 and 4), and the body weight of F(1) pups from the high-dose group but caused no effects on litter size, weaning index, and sex ratio. Similarly, the continued exposure of F(1) parental rats to ZnCl(2) also reduced fertility, liter size, viability (day 0), and the body weight of F(2) pups within the high-dose group but caused no effects on weaning index and sex ratio. Exposure of ZnCl(2) to F(0) and F(1) parental males resulted in a significant reduction in their body weights, and the F(0) and F(1) parental females did not show any significant difference in their body weights compared to their control groups. However, the postpartum dam weights of both F(0) and F(1) female rats were significantly reduced compared to their controls. Exposure of ZnCl(2) to F(o) and F(1) generation parental rats did not produce any significant change of their clinical signs as well as their clinical pathology parameters, except the alkaline phosphotase (ALK) level, which showed an upward trend in both sexes of both generations. Exposure of ZnCl(2) to F(0) rats resulted in a reduction of brain, liver, kidney, spleen and seminal vesicles weights of males and in the spleen and uterus of females. Similarly, exposure of F(1) rats to ZnCl(2) also resulted in reduction of brain, liver, kidney, adrenal, spleen, prostate and seminal vesicles weights of males and in spleen and uterus of females. ZnCl(2) exposure resulted in grossly observed gastro-intestianla (GI) tract, lymphoreticular/hematopoietic, and reproductive tract lesions in parental rats in both generations. Reduced body fat was also recorded in F(1) parental rats.     

The use of NTA and EDDS for enhanced phytoextraction of metals from a multiply contaminated soil by Brassica carinata

The potential of nine different species to grow in the presence of metals (As, Cd, Cu, Pb and Zn) and to accumulate them in the shoots was assessed for each metal separately by germination and root length tests, and successively by hydroponic experiments. Of the nine species tested, Brassica carinata was the species that accumulated the highest amounts of metals in shoots without suffering a significant biomass reduction. To further evaluate the potential of B. carinata for chelant-enhanced phytoextraction of a natural, multiply metal-polluted soil (As, Cd, Cu, Pb and Zn), both hydroponic and pot experiments were carried out with nitrilotriacetic acid (NTA) or (S,S)-ethylenediamine disuccinic acid (EDDS) as complexing agents. The hydroponic study with solutions containing the five metals together showed that accumulation of Cd, Cu, Pb and Zn in shoots was higher following EDDS addition compared to NTA. EDDS was more effective than NTA in desorbing Cu, Pb and Zn from the soil, whereas As and Cd were poorly extracted. B. carinata plants were grown for 4 weeks in the multiply metal-contaminated soil and then the soil was amended with 5 mmol kg(-1) NTA or EDDS. All plants were harvested 1 week after amendment. In comparison to NTA, EDDS was more effective in enhancing the concentrations of Cu, Pb and Zn in B. carinata shoots (2- to 4-fold increase compared to the control). One week after chelant addition, the DTPA-extractable metal concentrations in the polluted soil were lower in the EDDS treatment in comparison with the NTA amendment. Even though B. carinata showed a reduced growth and a relatively low metal uptake, it demonstrated the ability to survive and tolerate the presence of more metals simultaneously.