Polychlorinated dibenzo-p-dioxins (PCDDs) and furans (PCDFs) in urban air and deposition in the United Kingdom

Polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs) have been monitored in air and deposition at four UK urban sites (London, Cardiff, Manchester and Stevenage) since the beginning of 1991; data from the first 2 years are presented here. Median Σ2,3,7,8-substituted PCDD/F concentrations in air were 3.2, 4.0, 3.5 and 2.6 pg/m³ respectively for London, Cardiff, Manchester and Stevenage. Median Σ2,3,7,8-substituted PCDD/F deposition fluxes were 1.5 ng/m²/day in London, 1.4 ng/m²/day in Cardiff and Manchester and 0.79 ng/m²/day in Stevenage. Seasonal variations in the PCDD/F concentrations were observed at all sites for both air and deposition, with concentrations/fluxes generally elevated during the winter.     

Inhibition of phosphoenolpyruvate carboxykinase activity appears to be the key biochemical lesion in the acute toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin in rats

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) exerts its acute toxicity by inducing a gradually increasing voluntary feed refusal. However, this seems not to be caused by a direct effect on the central nervous system, as far higher concentrations of TCDD were found in the brain after intracerebroventricular (i.c.v.) than after lethal intravenous (i.v.) injections, but were not accompanied by a wasting syndrome. TCDD causes inhibition of several key enzymes of gluconeogenesis, with phosphoenolpyruvate carboxykinase (PEPCK) responding earliest and strongest to the insult. Responses of pyruvate carboxylase (PC) and glucose-6-phosphatase (G-6-Pase) are less pronounced and begin at later time points. Blood and brain levels of tryptophan increase following TCDD treatment with a lag period of about three days, shortly after the decrease of PEPCK activity becomes apparent. Since thi samino acid is the precursor of the appetite suppressant neurotransmitter serotonin, and since it is normally degraded via gluconeogenesis, a series of events can be suggested to explain the TCDD-induced wasting syndrome. By an as yet unrevealed mechanism TCDD decreases the activity of PEPCK to about 40 percent of normal, leading to a back-up of gluconeogenic substrates, among them tryptophan, which in turn can further inhibit PEPCK activity in vivo. This causes an increase in serotonin turnover in brain and possibly in other tissues. Increased serotonergic activity in turn is likely to play an important role in the increasing feed refusal of TCDD-treated rats which eventually leads to death.     

Photolysis of polycyclic aromatic hydrocarbons adsorbed on spruce [Picea abies (L) Karst] needles under sunlight irradiation

Photolysis of polycyclic aromatic hydrocarbons (PAHs) sorbed on surfaces of spruce [Picea abies (L.) Karst.] needles under sunlight irradiation was investigated. PAHs were produced by combustion of polyvinyl chloride (PVC), wood, high-density polyethylene (HDPE), and styrene in a stove. The factors of sunlight irradiation on the surfaces of spruce needles were taken into consideration when investigating the kinetic parameters. The photolysis of the 18 PAHs under study follows first-order kinetics. The photolysis half-lives range from 15 h for dibenzo(a,h)anthracene to 75 h for phenanthrene. Photolysis of some PAHs on surfaces of spruce needles may play an important role on the fate of PAHs in the environment.     

Government policy influences on rangeland conditions in the United States: A case example

Since the early 1970s the Bureau of Land Management (BLM) and the Forest Service have emphasized the monitoring approach in managing their rangelands. After a 5-year period of intensive monitoring, stocking rate and other management actions are typically adjusted, depending on whether a definite downward or upward trend in range condition is observed. Examining the Afton Allotment on BLM land in southcentral New Mexico, we demonstrate serious flaws in the monitoring approach and other BLM grazing policies. Monitoring reflects past management but does not consider the future. Perverse incentives for permittees to maximize permit value rather than sustain the forage base still remain in place. The Range Reform '94 proposals by the U.S. Department of the Interior do not address these incentives and other flaws in public land policy. We would reform federal grazing land policy by coupling grazing fees to grazing intensity. Ranchers choosing conservative sustainable grazing intensities would pay low fees, whereas those choosing heavy grazing intensities would be charged higher rates. We would also implement other reforms: making livestock grazing permits transferable to other uses, discontinuing subsidies, eliminating restrictions on nonuse, offering incentives for public land investment, and establishing a biodiversity fund.This paper was supported by the New Mexico Agricultural Experiment Station, Las Cruces and was part of project 1-5-27417.     

The dilemma of the mining royalty: contractual or realty interest

At common law, the legal nature of a mining royalty between private parties will decide the respective rights of payor and recipient. In some circumstances, it will also determine whether the interest of the recipient will prevail or may be lost and ignored. Industry practices, even those of long standing, that are contrary to the law will not change the law or its effect to meet such concerns. This paper looks at the development of the mining royalty between private parties in Canada and the effect of the realization by recipients that contractual royalties, as opposed to royalties that are interests in the lands or product to which they relate, can be lost in certain circumstances. Suggestions are made for some features that may assist in transforming an otherwise contractual royalty into a real property interest. Some of the concerns for both payor and recipient with respect to the implementation of such suggestions are also discussed.
The article has two appendices attached. Appendix A is an extract from an article by the author discussing the concept of payment of a royalty in kind which is relevant to such suggestions. Appendix B contains some of the more lengthy explanatory notes referred to in the text of the article.