Atrazine degradation and residues distribution in two acid soils from temperate humid zone

Mineralization of atrazine and formation of extractable and non-extractable "bound" residues were followed under laboratory conditions in two contrasting soils (organic C, texture, and atrazine application history) from northern Spain. The soils, a Humic Cambisol (MP) and a Gleyic Cambisol (G) were incubated with labeled atrazine (ring-13C atrazine) at field application dose and measurements were made at different time intervals during 3 mo. Fate and behavior of atrazine along the incubation showed different patterns between the two soils, the time taken for degradation of 50% (DT50) being 9 and 44 d for MP and G soils, respectively. In MP soil, with 40 yr of atrazine application and lower organic C and clay content, more than 89% of U-13C-atrazine added was mineralized after 12 wk, with most mineralization occurring within the first 2 wk. G soil, with 10 yr of atrazine application, exhibited a more progressive U-13C-atrazine mineralization, reaching 54% of initially added atrazine at 12 wk. Hydroxyatrazine and deisopropylatrazine were the metabolites founded in the extractable fraction, demonstrating that both chemical and biological processes are involved in atrazine degradation. Soil G showed during all the incubation times an extractable residues fraction greater than that in MP soil, indicating a high potential risk of soil and water contamination. Rapid microbial degradation through s-triazine ring cleavage was proposed to be the main decomposition pathway of atrazine for the two soils studied. Bound residues pool also differed notably between soils accounting for 9 and 41% of initially added atrazine, the higher values shown by soil with higher organic matter and clay content (G soil).     

Overcoming environmental deterioration through defensive expenditures: field evidence from Bahía del Tóbari (Sonora, México) and implications for coastal impact assessment

The costs of the maneuvers that fishermen and shrimp farmers have to undertake in a coastal scenario where both the access to navigable waters and water quality have decreased were interpreted as defensive expenditures. Maneuvers were prompted by profound changes in water circulation and siltation mode imposed by major shifts in regional and local land-use patterns. In coastal scenarios under heavy land-based discharges and local geomorphic modifications, local users with little chance to move away may modify their routines in order to maintain existing levels of utility. The concept of defensive expenditures could be used to assess social responses to adverse changes in environmental and resource conditions, as a means to distinguish stages in which local sectors respond individually from qualitatively different stages in which intersectoral events are more conspicuous.     

Modelling built-up land take in Europe to 2020: an assessment of the Resource Efficiency Roadmap measure on land

Land taken by artificial surfaces has an impact on the quality of life and ecosystems. To reduce possible negative impacts of land take, the European Commission proposed setting a milestone objective for 2020 in terms of future rates of land take.

This paper describes a methodology to model the impacts of the 2020 land-take milestone proposed in the RERM in the European Union 27 MS. An integrated modelling framework was configured to assess the spatial impact of two land-take scenarios: a ‘Reference’ scenario, which is driven by demographic and economic trends, and a ‘Target 0’ scenario that follows the 2020 land-take milestone proposed in the RERM. We conclude that the implementation of the 2020 land-take milestone, by reducing future land take in Europe, will foster more efficient use of land (less land taken for the same activity levels) and minimise negative impacts on non-artificial land uses.     

Synergies and trade-offs among integrated conservation approaches in Mexico

Integrated conservation approaches (ICAs) are employed by governments, communities, and nongovernmental organizations worldwide seeking to achieve outcomes with dual benefits for biodiversity conservation and poverty alleviation. Although ICAs are frequently implemented concurrently, interactions among ICAs and the synergies or trade-offs that result are rarely considered during program design, implementation, and evaluation. In support of more deliberate and effective use of ICAs, we examined interactions among four well-known strategies: biosphere reserves (BRs), voluntary protected areas (VPAs), payments for ecosystem services (PES), and community forest management (CFM). Through a comparative case study, we analyzed interactions among spatially or temporally clustered ICAs implemented on communally held and managed lands in three ecologically and socioeconomically distinct regions of Mexico. Our research methods combined policy analysis with data gathered through participant observation and semistructured interviews (n = 78) and focus groups (n = 5) with government officials, implementers, and participants involved in ICAs in 28 communities. Despite the significant differences among the regions in which they were implemented, we found that key actors at each level of involvement generally perceived interactions among ICAs as synergistic. The PES programs were perceived to strengthen protected areas by reducing forest cover loss in and around BRs, fostering proconservation attitudes, and incentivizing the establishment of VPAs. Communities that invested PES income in CFM were motivated to conserve forests beyond the duration of PES programs, and CFM in buffer zones was perceived to strengthen BRs by maintaining forest cover and generating income for communities. We also identified key social and environmental factors that can influence these interaction effects among ICAs. Based on these findings, we recommend further study of ICA interactions and intentionally complementary policy design to maximize positive environmental and social outcomes.     

Arsenic and subclinical vascular damage in a sample of Italian young adults: a cross-sectional analysis

Environmental Science and Pollution Research - Exposure to arsenic (As) increases cardiovascular risk. The purpose of this study was to evaluate the relationship between As and intima-media...     

Summer cover crops reduce atrazine leaching to shallow groundwater in southern Florida

At Florida's southeastern tip, sweet corn (Zea Mays) is grown commercially during winter months. Most fields are treated with atrazine (6-chloro-N-ethyl-N'-[1-methylethyl]-1,3,5-triazine-2,4-diamine). Hydrogeologic conditions indicate a potential for shallow groundwater contamination. This was investigated by measuring the parent compound and three degradates--DEA (6-chloro-N-[1-methylethyl]-1,3,5-triazine-2,4-diamine), DIA (6-chloro-N-ethyl)-1,3,5-triazine-2,4-diamine, and HA (6-hydroxy-N-[1-methylethyl]-1,3,5-triazine-2,4-diamine)--in water samples collected beneath sweet corn plots treated annually with the herbicide. During the study, a potential mitigation measure (i.e., the use of a cover crop, Sunn Hemp [Crotalaria juncea L.], during summer fallow periods followed by chopping and turning the crop into soil before planting the next crop) was evaluated. Over 3.5 yr and production of four corn crops, groundwater monitoring indicated leaching of atrazine, DIA, and DEA, with DEA accounting for more than half of all residues in most samples. Predominance of DEA, which increased after the second atrazine application, was interpreted as an indication of rapid and extensive atrazine degradation in soil and indicated that an adapted community of atrazine degrading organisms had developed. A companion laboratory study found a sixfold increase in atrazine degradation rate in soil after three applications. Groundwater data also revealed that atrazine and degradates concentrations were significantly lower in samples collected beneath cover crop plots when compared with concentrations below fallow plots. Together, these findings demonstrated a relatively small although potentially significant risk for leaching of atrazine and its dealkylated degradates to groundwater and that the use of a cover crop like Sunn Hemp during summer months may be an effective mitigation measure.     

Total and partial digestion of sediments for the evaluation of trace element environmental pollution

Four different sample treatment methods for the determination of trace elements have been compared: a total digestion with HNO3-H2O2-HF using microwave, and three different standardized methods of fractionation: BCR three-steps sequential extraction, USEPA standard 3050B and ISO standard 11466. The four treatment methods were applied to the determination of Cu and Ni in four samples collected in different areas of Cienfuegos Bay (Cuba). The location of samples and the analytes were selected on the basis of results obtained by previous studies. Analyses following total digestion and BCR three-steps procedure were performed by inductively coupled plasma mass spectroscopy whereas analyses following EPA and ISO procedures were performed by flame atomic absorption spectroscopy. The results obtained have been compared with an estimated anthropic fraction evaluated in each sampling point as the difference between the total concentration and an estimated background concentration level. The BCR three-steps provided the best approximation of the estimated anthropic fraction and was therefore applied also in the determination of Pb and Cd for further consideration.     

确认制是预防事故的好方法

１确认是避免失误的有效方法一名泵工开泵送焦油,开泵以前先用蒸汽清扫泵出口管道,然后开泵送焦油。由于泵出口焦油压力比蒸汽压力大,焦油被压入蒸汽管道,又从蒸汽管道进入锅炉,由锅炉随蒸汽送往全厂。一时食堂的馒头上有了焦油,浴室的热水中有了焦油,洗衣房的水中...     

Adsorption of chloridazon from aqueous solution on modified kerolite-rich materials

The adsorption of chloridazon (5-amine-4-chloro-2-phenylpyridazin-3(2H)-one) on kerolite samples heated at 110°C (K-110), 200°C (K-200), 400°C (K-400), 600°C (K-600) and acid-treated with H₂SO₄ solutions of two different concentrations (0.25 and 0.5 M) (K-0.25 and K-0.5, respectively) from pure water at 25°C has been studied by using batch and column experiments. The adsorption experimental data points were fitted to the Freundlich equation in order to calculate the adsorption capacities (K_f) of the samples; K_f values ranged from 184.7 mg kg^?1 (K-0.5) up to 2253 mg kg^?1 (K-600). This indicated that the heat treatment given to the kerolite greatly increases its adsorption capacity for the herbicide whereas the acid treatment produces a clear decrease in the amount of chloridazon adsorbed. The removal efficiency (R) was also calculated; R values ranging from 52.8% (K-0.5) up to 88.3% (K-600). Thus, the results showed that the 600°C heat-treated kerolite was more effective in relation to adsorption of chloridazon and it might be reasonably used in removing this herbicide from water.     

Efficiency of a blast furnace slag cement for immobilizing simulated borate radioactive liquid waste

The efficiency of a blast furnace slag cement (Spanish CEM III/B) for immobilizing simulated radioactive borate liquid waste [containing H3BO3, NaCl, Na2SO4 and Na(OH)] has been evaluated by means of a leaching attack in de-mineralized water at the temperature of 40 degrees C over 180 days. The leaching was carried out according to the ANSI/ANS-16.1-1986 test. Moreover, changes of the matrix microstructure were characterized through porosity and pore-size distribution analysis carried out by mercury intrusion porosimetry (MIP), X-ray diffraction (XRD) and thermal analysis (TG). The results were compared with those obtained from a calcium aluminate cement matrix, previously published.