Model Evaluation of Dry Deposition to Vegetation for Volatile and Semi-Volatile Organic Compounds in a Multimedia Environment

Gas-phase atmospheric deposition wasevaluated in a screening level model of themultimedia environmental distribution of toxics(MEND-TOX). Algorithmic additions to MEND-TOXfor the estimation of gas-phase depositionvelocity over vegetated surfaces were analyzedusing recently published dry deposition fluxmeasurements for nitric acid. Model outputs arecompared to similar estimates from the NOAAmultilayer dry deposition model. Results of theevaluation indicate that MEND-TOX performs wellas a screening level model for the estimation ofgas-phase dry deposition velocity of nitric acidover soybeans. The present study expandsprevious laboratory results for organic speciesto include an inorganic species and open fieldand dry leaf, conditions.(On assignment to the National Exposure Research Laboratory, U.S. Environmental Protection Agency); (author for correspondence, e-mail     

Much Ado: How Big Is the Problem of Hydrolysis of Methyl Tertiary Butyl Ether (MtBE) to Form Tertiary Butyl Alcohol (tBA)?

Groundwater contaminated by the gasoline additive methyl tertiary butyl ether (MtBE) is also frequently impacted by tertiary butyl alcohol (tBA). The USEPA recently sponsored a study that discusses the possibility of hydrolysis of MtBE to form tBA during analytical procedures. This finding is important because it suggests that existing tBA data may not accurately depict tBA or MtBE concentrations in groundwater. This article discusses the mechanism and kinetics of MtBE hydrolysis, then presents three case studies of analytical results from sites in California, USA. Although these case studies are limited in scope, the data do not support the occurrence of the hydrolysis of MtBE to form tBA due to acid preservation of groundwater samples. At a minimum, this suggests that MtBE hydrolysis may not be as pervasive a problem as suggested in USEPA's study; therefore, concerns about the validity of historical tBA data may not be warranted. The reason for this result may be simple: there are two necessary factors that promote hydrolysis: low pH and high temperature (above 40°C). Although the static headspace analysis method used to obtain the data in the White et al. study may require heating to achieve adequate sensitivity, many laboratories perform purge-and-trap analyses without heating. Under those conditions, hydrolysis may not occur. However, it may be prudent to preserve samples with alkaline preservatives, to eschew high temperatures during the analysis of groundwater samples, or to neutralize the sample pH before heating.     

Species of Trace Metals,Organic Residues and Humic Substances in Sediments From the Taiwan Erhjin River and Coastal Areas

Abstract

Total organic carbon, humic substances, and the species of trace metals (including Cu, Zn, Pb, Cd, Cr, Mn and Fe) in six and seven phases, such as bioexchangeable (P1), skeletal (carbonates, P2), easily reducible (Fe and Mn oxides, P3), moderately reducible (crystalline Mn oxides, P4), organic matters with sulphides (P5), and detritus with minerals (P6) as well as organic with humic substances (PB4) and organic residues (PB6), were analyzed in sediments from the Taiwan Erhjin coastal (including river and estuarine) area, where places we found the copper pollution. Results indicate that higher percentages of P1 and P2 for copper, zinc, lead, cadmium and manganese in samples collected in March and September of 1990 were much higher than those in P3-P6. High percentages of chromium and iron in samples respectively collected in March and September of 1990 were found in P6. for the seven phase analysis, higher percentages of copper species in PB4 and PB6 as well as iron species in PB7 were observed. On the other hand, purified humic acid with the high contents of manganese and iron in humic acid as well as purified fulvic acids were generally found at the upstream stations; and low values at coastal stations. However, extremely high copper (as high as 1750μg g^?1, dry weight in fulvic acid and 820μg g^?1 in humic acid) and lead (821μg g^?1 in humic acid) concentrations with relatively high manganese and iron concentrations were observed in humic substances from the station near the copper recycling area. Comparing the results obtained from the Antarctic Ocean sediments with those from the Taiwan Erhjin Chi coastal sediments, the human impacts on the latter are evaluated.     

Evaluation of soil characteristics potentially affecting arsenic concentration in paddy rice (Oryza sativa L.)

Paddy rice may contribute considerably to the human intake of As. The knowledge of soil characteristics affecting the As content of the rice plant enables the development of agricultural measures for controlling As uptake.During field surveys in 2004 and 2006, plant samples from 68 fields (Italy, Po-area) revealed markedly differing As concentration in polished rice. The soil factors total As_{(aqua regia)}, pH, grain size fractions, total C, plant available P_(CAL), poorly crystalline Fe_(oxal.) and plant available Si_(Na-acetate) content that potentially affect As content of rice were determined.A multiple linear regression analysis showed a significant positive influence of the total As_{(aqua regia)} and plant available P_(CAL) content and a negative influence of the poorly crystalline Fe_(oxal.) content of the soil on the As content in polished rice and rice straw.Si concentration in rice straw varied widely and was negatively related to As content in straw and polished rice.     

酸性矿井水的治理方法研究进展

酸性矿井水污染已成为全球范围内较为严重的环境污染问题之一,其污染范围广泛,诱因复杂,性质多变,危害深远。酸性矿井水未经处理排放造成江湖河流酸化,地表土壤板结,水中及土壤中的重金属含量超标,导致生物体内重金属过量富集,作物死亡,从而严重地危害了人类的健康和生命安全。对于酸性矿井水的治理意义重大,刻不容缓。讨论了目前国内外常见的酸性矿井水污染的治理技术方法,并对各种方法进行了比较。     

Thermal treatments of industrial wastes in controlled atmospheres for the elimination of As, Hg, Cd, Se and the concentration of Pb, Cu and Zn

Thermal treatments of five different types of non-ferrous metallurgical wastes, under a controlled atmosphere, were carried out at temperatures lower than 800°C for the separation of their toxic compounds and the concentration of valuable metals in the treatments residues. The best results were obtained by the treatments in air or hydrogen, or both successively. Simple treatments, using air or hydrogen, of three samples allowed the elimination of more than 95% of their toxic elements and almost doubled their valuable metals concentration. For the rest of the samples, a combined treatment was necessary for their efficient decontamination. In this case, the valuable metals content in the treatment's residue was increased to a reasonable value. Most of the solids issuing from these treatments can be recycled in current non-ferrous metallurgical processes.     

Induction of glutathione reductase enzyme activity by β‐aminobutyric acid in plant leaves

Abstract

Treatment of pea and tobacco leaf discs with the resistance inducer DL‐β‐amino‐n‐butyric acid (BABA) led to a substantial induction of glutathione reductase (GR, E.C. 1.6.4.2.) enzyme activity. After exposure to 1 mM BABA for 96 hrs, the GR activities were 3.2‐fold and 2.9‐fold higher in pea and tobacco leaf discs, respectively, than GR activities in untreated controls. Elevated GR levels may contribute to the antioxidative protection of plants during pathogen attack.     

Metabolic effects of diazinon on the European eel

Abstract

Eels were exposed to a sublethal diazinon concentration of 0.042 mg/L for exposure times of 6, 24, 48, 72 and 96 hours. Biochemical analyses of blood composition, such as plasma glucose, total plasma cholesterol and triglycerides, plasma lactate, plasma urea and uric acid, showed significant differences between treated and control animals. Plasma glucose and lactate increased after 6 hours exposure to the insecticide. Plasma cholesterol and triglycerides content decreased during 96 hours treatment. Urea levels increased at 72 hours while uric acid content decreased significantly at 24, 72 and 96 hours exposure to the pesticide.

The observed effects of diazinon on eel metabolism suggested that the treated fish was faced with a serious metabolic crisis, and the fish looked for alternative methods of metabolism to overcome the toxic stress.     

Species of Trace Metals, Organic Residues and Humic Substances in Sediments From the Taiwan Erhjin River and Coastal Areas

Total organic carbon, humic substances, and the species of trace metals (including Cu, Zn, Pb, Cd, Cr, Mn and Fe) in six and seven phases, such as bioexchangeable (P1), skeletal (carbonates, P2), easily reducible (Fe and Mn oxides, P3), moderately reducible (crystalline Mn oxides, P4), organic matters with sulphides (P5), and detritus with minerals (P6) as well as organic with humic substances (PB4) and organic residues (PB6), were analyzed in sediments from the Taiwan Erhjin coastal (including river and estuarine) area, where places we found the copper pollution. Results indicate that higher percentages of P1 and P2 for copper, zinc, lead, cadmium and manganese in samples collected in March and September of 1990 were much higher than those in P3-P6. High percentages of chromium and iron in samples respectively collected in March and September of 1990 were found in P6. for the seven phase analysis, higher percentages of copper species in PB4 and PB6 as well as iron species in PB7 were observed. On the other hand, purified humic acid with the high contents of manganese and iron in humic acid as well as purified fulvic acids were generally found at the upstream stations; and low values at coastal stations. However, extremely high copper (as high as 1750μg g^-1, dry weight in fulvic acid and 820μg g^-1 in humic acid) and lead (821μg g^-1 in humic acid) concentrations with relatively high manganese and iron concentrations were observed in humic substances from the station near the copper recycling area. Comparing the results obtained from the Antarctic Ocean sediments with those from the Taiwan Erhjin Chi coastal sediments, the human impacts on the latter are evaluated.     

The relationship between metal composition,phenolic acid and flavonoid content in Imleria badia from non-polluted and polluted areas

ABSTRACT

The aim of this study was to determine the elemental composition, phenolic content and composition and antioxidant properties of Imleria badia (Fr.) Vizzini (former names Boletus badius (Fr.) Fr., and Xerocomus badius (Fr.) E.-J. Gilbert) fruiting bodies collected from sites with different levels of pollution. Imleria badia was relatively tolerant to soil contamination with toxic elements and was able to grow in As, Cd, Hg and Pb concentrations exceeding 15, 2.9, 0.4 and 77 mg kg^?1, respectively. The concentration of elements in soil was reflected in the element content in I. badia. The fruiting bodies from polluted sites exhibited significantly higher content of all the analyzed elements. Among 21 individual phenolic compounds only protocatechiuc and caffeic acids, and quercetin were determined in fruiting bodies of I. badia. The differences between the concentration of the quantified phenolic compounds and the total flavonoid content in fruiting bodies of I. badia from unpolluted and polluted sites were not significant. However, the greatest total phenolic content was found in fruiting bodies from the polluted areas. The antioxidative capacity of mushrooms collected from heavily polluted sites was lower than those growing in unpolluted areas. The concentrations of some metals in soil and fruiting soil were positively correlated with phenolic content and IC₅₀.