钢铁企业固体废弃物资源化利用浅析

固体废物做到资源化即通过综合利用,使有利用价值的固体废物变废为宝,实现资源的再循环利用,是固体废物污染控制一直努力方向。钢铁联合企业生产过程中产生的固体废弃物量大、面广,如对其进行资源化利用不仅可获得好的效益,同时也解决了环保难题。通过借鉴国内外钢铁企业固体废弃物资源化利用成功技术,使我们在开展环境影响评价工作中对钢铁企业固废的资源化利用提出一些切实可行的控制措施。     

Prevalence of chromosomal aberrations in Argentinean agricultural workers

Environmental Science and Pollution Research - Little is known about biosecurity measures and toxic effects during pesticide application in the province of Jujuy, Argentina, particularly concerning...     

Adsorption of a dye on clay and sand. Use of cyclodextrins as solubility-enhancement agents

Laboratory-scale studies were aimed at elucidating the physico-chemical aspects on the removal process of crystal violet (CV) from waters and solid substrates. The laponite clay (RD) and sand were chosen for the double aim at investigating them as CV adsorbents for water treatment and as substrates which mime the soil components. Sand is very effective in removing CV from waters. The cyclodextrins (CDs) were exploited as solubility-enhancement agents to remove CV from the solid substrates. They are powerful solvent media because they extract the CV from sand forming water-soluble CV/CD inclusion complexes and do not show affinity for sand. Optimum performance was shown by the modified CDs (i.e. hydroxypropyl-β-cyclodextrin and methyl-β-cyclodextrin). A linear correlation between the logarithm of the equilibrium constant for the CV/CD inclusion complexes formation (K_cpx) and the maximum amount of CV extracted from sand in the columns experiments at a flow rate of 1.5 ml min⁻¹ was drawn. This relationship predicts that CDs with K_cpx < 180 M⁻¹ are not suitable for CV removal from sand. CDs failed to displace CV from RD because they generate the formation of RD clusters where CV remains entrapped.     

Nitrogen cycling through swine production systems: ammonia, dinitrogen, and nitrous oxide emissions

Ammonia (NH(3)) emissions from animal systems have become a primary concern for all of livestock production. The purpose of this research was to establish the relationship of nitrogen (N) emissions to specific components of swine production systems and to determine accurate NH(3) emission factors appropriate for the regional climate, geography, and production systems. Micrometeorological instrumentation and gas sensors were placed over two lagoons in North Carolina during 1997-1999 to obtain information for determining ammonia emissions over extended periods and without interfering with the surrounding climate. Ammonia emissions varied diurnally and seasonally and were related to lagoon ammonium concentration, acidity, temperature, and wind turbulence. Conversion of significant quantities of ammonium NH(4)(+) to dinitrogen gas (N(2)) were measured in all lagoons with the emission rate largely dependent on NH(4)(+) concentration. Lagoon NH(4)(+) conversion to N(2) accounted for the largest loss component of the N entering the farm (43% as N(2)); however, small amounts of N(2)O were emitted from the lagoon (0.1%) and from field applications (0.05%) when effluent was applied nearby. In disagreement with previous and current estimates of NH(3) emissions from confined animal feeding operation (CAFO) systems, and invalidating current assumptions that most or all emissions are in the form of NH(3), we found much smaller NH(3) emissions from animal housing (7%), lagoons (8%), and fields (2%) using independent measurements of N transformation and transport. Nitrogen input and output in the production system were evaluated, and 95% of input N was accounted for as output N from the system.     

Economic Failures in French Recreational Fishing Management

In France, freshwater recreational fishing management does not sufficiently satisfy anglers. Fishing effort is too high creating congestion costs and environmental quality is low while there is a positive willingness-to-pay for improvements. These inefficiencies are explained by three phenomena. First, private property rights are attenuated under institutional pressure. Second, recreational fishing is managed as an open access resource over the whole territory. Finally, halieutic policies focus on the protection of environmental resources and are inefficient at maximizing the social rent provided by recreational fisheries. Fishing effort regulation and environmental services provision following the beneficiary-pays principle could improve collective welfare. Social pricing could ensure equity in access to the resource.     

Reproduction and biochemical responses in Enchytraeus albidus (Oligochaeta) to zinc or cadmium exposures

To better understand chemical modes of action, emphasis has been given to stress responses at lower levels of biological organization. Cholinesterases and antioxidant defenses are among the most used biomarkers due to their crucial role in the neurocholinergic transmission and in cell homeostasis preventing DNA damage, enzymatic inactivation and lipid peroxidation. The main goal of this study was to investigate the effects of zinc and cadmium on survival and reproduction of E. albidus and to assess metals oxidative stress potential and neurotoxic effects at concentrations that affected reproduction. Both metals affected the enchytraeids’ survival and reproduction and induced significant changes in the antioxidant defenses as well as increased lipid peroxidation, indicating oxidative damage. This study demonstrates that determining effects at different levels of biological organization can give better information on the physiological responses of enchytraeids in metal contamination events and further unravel the mechanistic processes dealing with metal stress.     

The relation between Acid Volatile Sulfides (AVS) and metal accumulation in aquatic invertebrates: Implications of feeding behavior and ecology

The present study evaluates the relationship between Acid Volatile Sulfides (AVS) and metal accumulation in invertebrates with different feeding behavior and ecological preferences. Natural sediments, pore water and surface water, together with benthic and epibenthic invertebrates were sampled at 28 Flemish lowland rivers. Different metals as well as metal binding sediment characteristics including AVS were measured and multiple regression was used to study their relationship with accumulated metals in the invertebrates taxa.Bioaccumulation in the benthic taxa was primarily influenced by total metal concentrations in the sediment. Regarding the epibenthic taxa metal accumulation was mostly explained by the more bioavailable metal fractions in both the sediment and the water. AVS concentrations were generally better correlated with metal accumulation in the epibenthic invertebrates, rather than with the benthic taxa. Our results indicated that the relation between AVS and metal accumulation in aquatic invertebrates is highly dependent on feeding behavior and ecology.     

Photodegradation of the steroid hormones 17beta-estradiol (E2) and 17alpha-ethinylestradiol (EE2) in dilute aqueous solution

The photochemical transformation of natural estrogenic steroid 17beta-estradiol (E2) and the synthetic oral contraceptive 17alpha-ethinylestradiol (EE2) has been studied in dilute non buffered aqueous solution (pH 5.5-6.0) upon monochromatic (254 nm) and polychromatic (lambda>290 nm) irradiation. Upon irradiation at 254 nm, the quantum yields of E2 and EE2 photolysis were similar and evaluated to be 0.067+/-0.007 and 0.062+/-0.007, respectively. Upon polychromatic excitation, and by using phenol as chemical actinometer, the photolysis efficiencies have been determined to be 0.07+/-0.01 and 0.08+/-0.01 for E2 and EE2, respectively. For both estrogens, photodegradation by-products were identified with GC/MS and LC/MS. In a first step, a model compound--5,6,7,8-tetrahydro-2-naphthol (THN)--, which represents the photoactive phenolic group, was used to obtain basic photoproduct structural informations. Numerous primary and secondary products were observed, corresponding to hydroxylated phenolic- or quinone-type compounds.     

Ecotoxicity interspecies study of ionic liquids based on phosphonium and ammonium cations

Environmental Science and Pollution Research - This work studies the effects of different bromide-based ionic liquids, with phosphonium and ammonium cations, towards several environmental...