Study Groups Versus Commodity Agreements: An Appraisal*

Since World War II there have been several attempts to establish intergovernmental mineral commodity arrangements involving both the producing and consuming countries. Two different forms have been used, the consultative forum and the commodity agreement (with binding economic provisions). The two different approaches are compared using as examples the six post-World War II International Tin Agreements and the International Lead and Zinc Study Group. The study group or consultative forum appears to work better.     

Developments and prospects of world lead and zinc mining

World developments in lead and zinc are examined for 1970-90 and projections presented for 1995. Although lead consumption has Increased during the period under review, lead mine production has been on a decline, the differences being made up from secondary lead sources. Lead mine production is projected to be steady to 1995, with increased consumption continuing to be met from secondary sources. Zinc mine production increased at a trend rate of about 1% per year between 1970 and 1990, but for 1991-95, production is expected to grow at a lower rate. For 1990-95 zinc consumption is expected to grow at a rate of 2.3%. This modest mine production increase to 1995 is unlikely to be adequate to meet growth in MEC zinc consumption.     

Dynamic material flow analysis of zinc resources in China

Zinc is one of the most widely applied nonferrous metals in China. Study on the applications and recurrent situation of zinc resources is of great strategic importance for the sustainable development of China's economy. In this paper, a dynamic material flow analysis (MFA) method has been adopted to analyze quantificationally zinc resources in China, as well as to analyze and predict the quantity of zinc product scrap and their recycling situation. The weighted average method was applied to calculate average lifetimes of six major zinc products in China. The average lifetimes of battery, zinc oxide, zinc die-casting alloys, zinc material products, galvanized zinc and brass are 0.17, 5.3, 11.1, 12, 21 and 30 years, respectively. Assuming the lifetime of zinc product group obeys the Weibull distribution and the consumption of zinc products varies linearly with time, the future consumption and scrap generation of zinc products will increase continuously. It is expected that they would increase from 49% to 76% during 2004–2020, respectively. Assuming the recycling rate remains unchanged with time, the zinc old scrap index, both the theoretical and actual values, would continue increasing in China. The values are expected to reach 0.402 and 0.076 by 2020, respectively. Therefore, the regeneration resource of depreciated zinc is actually insufficient in China. According to the scenario analysis, the actual value of old scrap indexes is positively correlated with the recycling rate of zinc products. Because galvanized products are the largest consumption area of zinc products in China, the influence of their recycling rate on old scrap index is obviously larger than other zinc products. Through the analysis, this paper suggests that the increase of the recycling rate of zinc products could not only improve to a certain degree China's relative shortage of zinc resources, but greatly relive the supply pressure of zinc in the world.     

ACCUMULATION OF SELECTED TRACE METALS IN SOILS OF URBAN RUNOFF SWALE DRAINS1

ABSTRACT: Field investigations were conducted at three sites in the Washington, D.C., area to detect the accumulation patterns of the trace metals, cadmium, copper, lead and zinc in the soils of roadside grassed swale drains that had been receiving urban stormwater runoff. Two sites were residential areas and one site was an intensively used highway. The research results seem to indicate that the use of swale drains to control urban stormwater runoff had few harmful effects to fine textured soils with respect to the study metals. With the exception of zinc, typical roadside patterns of decreasing metal concentrations with increasing distance from roads were observed for the upper 5 cm of study soils. Zinc accumulated in residential grassed swales due to leachate from galvanized curverts. Sampling to a depth of 60 cm revealed no evidence of subsurface trace metal enrichment in the study swales. Although the percentage of soil zinc in leachable form was as high as 20 percent of total zinc concentrations, the other study metals had small leachable components. Leachable lead was always less than 1 percent of the total lead.     

AQUATIC ORGANISMS AND HEAVY METALS IN MISSOURI'S NEW LEAD BELT1

The New Lead. Belt of southeastern Missouri has recently become the largest lead producing region of the world. The impact of this rapid development on the previously rural and undeveloped region of the Missouri Ozarks is the subject of a continuing interdisciplinary study. Since the industrial development began, there have been a number of nuisance biological blooms in several of the small streams receiving effluent from the mines and mills. The major constituents of the problem algal growths were identified and found to include: Cladophora, Oscillatoria, Mougeotia, Zygnema, Spirogyra, Cymbella, and a variety of other stalked and non-stalked diatoms. Secondary blooms of Sphaerotilus were observed to reach problem proportions in some streams, particularly in the autumn. Finely ground rock flour and mineral particles escaping from tailings dams were found to be trapped by the stream vegetation. Concentrations of lead, zinc, copper, and manganese in the algal and bacterial mats were found to be inversely related to distance downstream from the tailings dams. Consumer organisms, including crayfish, snails, aquatic insects, tadpoles, minnows and larger sunfish were analyzed to determine the extent of dissemination and concentration of the heavy metals through food chains. Preliminary results indicated insignificant concentrations of heavy metals in those consumer organisms studied, though in at least one problem stream the normal consumer organisms mentioned were markedly reduced in numbers.     

Time-series analysis of global zinc demand associated with steel

This study aimed to analyze the global-scale substance flow of zinc associated with steel in order to discuss the sustainable use of zinc resources in the future. The relationship between the demand for steel and zinc was characterized in terms of zinc intensity for galvanized steel and the percentage of galvanized steel that accounts for the total steel demand. Zinc consumption for steel was divided into end uses according to the statistics on steel. Zinc demand in the future was forecasted with three scenarios for zinc intensity. Future steel demand was estimated using the stocks-drive-flows model, in which the demand is determined by the change in stock. The growth of in-use stock of galvanized steel in the future was estimated by considering economic growth on the basis of the transition of in-use stock of galvanized steel in the past. The cumulative zinc demand for galvanized steel up to the year 2050 was compared with the zinc reserves. It was found that the global average recovery rate of zinc was estimated at approximately 20% by the dynamic substance flow analysis for zinc. It is hoped that the recovery rate will increase. Even if zinc intensity is continuously reduced according to an experience curve based on technological development, a large portion of the current reserves will be consumed for galvanized steel. It was concluded that technological development in reducing zinc intensity will play a significant role in zinc resource conservation.     

鲫鱼对铜和锌的吸收蓄积研究

用原子吸收分光光度法研究铜和锌在鲫鱼体内积累行为,结果表明,溶解态和颗粒态铜和锌在鱼鳃、肌肉中的积累量随其浓度的增加而增加。铜和锌积累能力的大小顺序为锌〉铜。鱼鳃和肌肉对溶解态和颗粒态重金属的积累能力为鱼鳃大于肌肉,蓄积曲线表现为逐渐趋向平缓的形式。颗粒态鱼鳃积累尤其大于肌肉,说明鱼在对颗粒态铜和锌的积累过程中,部分颗粒态金属是吸附在鱼鳃上的。由于生理功能不同,鲫鱼对锌需要量比铜多。     

Technological improvements in automotive battery recycling

Recycling of automotive batteries for the recovery of secondary lead is extremely important in Brazil, for the country does not possess large reserves of this metal. Lead is one of the most widely used metals in the world, but it is highly toxic, posing risks for humans and for the environment if not utilized or treated adequately. Industrial waste containing lead in Brazil are classified by the Brazilian Residue Code (NBR—10004:2004) as hazardous. The lead recycling process employed by the recycling industry in Brazil is the pyrometallurgical process in a rotary furnace. This process consists of four stages: (1) grinding of the battery to separate plastic, electrolyte and lead plates; (2) lead reduction in a rotary furnace; (3) separation of metallic lead from slag; and (4) refining of recycled lead. The purpose of this work is to propose process improvements aimed primarily at increasing production output by reducing the loss of lead in slag and particulates, thereby providing a healthier work environment in line with Brazilian environmental and labor laws.     

Achieving uniform regulation of environmental lead exposure and poisoning in wildlife and humans

Lead from spent ammunition causes preventable lead exposure in wildlife and humans that may ingest it. Nontoxic substitutes for lead ammunition exist but are not adopted widely because of hunter opposition. Other forms of lead exposure in the human environment have been heavily regulated because there is no safe level of exposure. The use of lead ammunition should be regulated similarly to protect wildlife from this common disease.     

原子荧光光谱法测定蔬菜样品中铅

铅作为一种对人体有害元素,在蔬菜样品中必须被检测。应用原子荧光光度计检测铅的含量,具有取样量少、灵敏度高、检出限低等优点,适合于环境样品的分析检测。     

Management of the zinc chain

In this study, a substance chain approach as a tool contributing to a sustainable development has been tested by applying it to zinc. An analysis of the western world zinc substance chain has been made in order to identify the main routes of zinc losses from the chain. Technologically feasible options to improve the management of the chain have been selected and applied to a modelled chain. With the emphasis on resource management, the model has been designed to evaluate the impact of options on the input of primary zinc into the chain. The consequences of the options for the energy resources have been analyzed.Redesigning the global zinc chain using the chosen technologically feasible options has lead to a lower primary zinc input when compared to the present chain, but a 45% primary zinc input is still needed, while the improved chain requires 8% less energy. To obtain a further decrease of primary zinc input in the chain, research should focus on emission abatement during zinc usage, where especially corrosion of galvanized steel forms a problem, and on the prevention of mixed-product waste streams with a low average zinc concentration. The energy analysis shows that options to improve the zinc chain should be carried out carefully, avoiding extra demands on the energy resources.The study indicates that designing a substance chain, along with even simple modelling, results in a good tool to calculate the impact of different kinds of options on the total chain.     

The environmental and ethical implications of lead shot contamination of rural lands in North America

Lead shot deposited in fields and woodlands near shooting rangesand intense, upland, hunting adds an enormous tonnage of lead toenvironments, worldwide. This contamination is not remedied bybanning lead shot use only for waterfowl hunting. Lead pelletsdisintegrate extremely slowly, during which time they may beingested from the soil by wild birds, livestock, or silage-makingmachinery, and cause sublethal or fatal lead poisoning. Leadpellet corrosion products contaminate soil, surface waters, andground waters, often exceeding permissible levels. Plants do notconcentrate much lead from the soil, except when grown in acidicsoils of heavily-contaminated shooting ranges. Inheavily-contaminated sites, earthworms ingest leadcompounds which are bioaccumulated in higher consumersof food webs. Non-toxic substitutes made from steelor bismuth are available internationally and areeffective for all types of hunting and targetshooting. Many nations are slow to require their use,despite the marked awareness of the problems of leadshot contamination and toxicosis. This is due tohunters and international sport shooting organizationsopposing the use of non-toxic substitutes and overtemphasis by government agencies on the burden ofscientific proof for every situation, rather thantaking preventative action according to thePrecautionary Principle. The ethical approach ofDenmark and The Netherlands, which banned all uses oflead shot, is advocated as a precedent for othernations to adopt.     

Implicit beliefs about self and nature: Evidence from an IAT game

Recent psychological research has examined the beliefs that individuals hold about their relationship with the natural world. This article builds on the previous literature on connectedness with nature and we introduce a new game version of the Implicit Association Test (IAT), known as FlexiTwins. The game is intended to facilitate research using the IAT and provides a flexible platform for measuring implicit associations. In this paper, we report three studies in which we use the game to measure self-nature associations. Study 1 reports the development and validation of FlexiTwins with a college sample. Study 2 further validates the game using a known-groups sample of environmental activists. Finally, Study 3 examines the implicit connectedness of a sample of 30 grade school children. Across all three studies, we find good evidence for reliability, as well as theoretically meaningful results.     

Copper, zinc, and arsenic in soil surrounding Douglas-fir poles treated with ammoniacal copper zinc arsenate (ACZA)

The levels of copper, zinc, and arsenic in soil surrounding Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] utility poles treated with ammoniacal copper zinc arsenate (ACZA) were investigated at sites in Florida, Virginia, and New York. Copper levels were elevated near the poles and declined with both horizontal distance away from the pole and depth beneath the soil surface. Zinc levels were also elevated next to the poles, but the levels declined more slowly than did those of copper. Arsenic levels were elevated in soil immediately next to the poles but declined to near background levels farther away. The results indicate that metals can leach from ACZA-treated poles, but do not migrate far in the soil, and thus the levels decline sharply with distance from the poles.     

Characterization of pollutants in Florida street sweepings for management and reuse

Disposal and beneficial-use options for street sweeping residuals collected as part of routine roadway maintenance activities in Florida, USA, were assessed by characterizing approximately 200 samples collected from 20 municipalities. Total concentrations (mg/kg or μg/kg) and leachable concentrations (mg/L or μg/L) of 11 metals and a number of organic pollutant groups (volatile organics, semi-volatile organics, pesticides, herbicides, carbamates) in the samples were measured. The synthetic precipitation leaching procedure (SPLP) was performed to evaluate the leachability of the pollutants. From the total metal analysis, several metals (e.g., arsenic, barium, chromium, copper, nickel, lead, and zinc) were commonly found above their detection limits. Zinc was found to have the highest mean concentration of all metals measured (46.7 mg/kg), followed by copper (10.7 mg/kg) and barium (10.5 mg/kg). The metal with the smallest mean concentration was arsenic (0.48 mg/kg). A small fraction of the total arsenic, barium, lead, and zinc leached in some samples using the SPLP; leached concentrations were relatively low. A few organic compounds (e.g., 4,4′-DDT, endrin, and endosulfan II) were detected in a limited number of samples. When the total and leaching results were compared to risk-based Florida soil cleanup target levels and groundwater cleanup target levels, the street sweepings were not found to pose a significant human-health risk via direct exposure or groundwater contamination.     

Lead in particulate deposits and in leaves of roadside plants, Karachi, Pakistan

Lead concentrations were determined for particulates which were deposited during one year on the leaves of roadside plants in Karachi. The particulates were collected from the leaves at a height of one metre. The lead accumulated by the leaves of different species was also measured. A statistically significant correlation was found between the number of passing petrol driven vehicles and the lead concentration in the deposits at different designated sites. However, no significant correlation was found between the concentration in the deposits and the lead accumulated by the leaves. A lead concentration of 30.00±6.6 ppm was recorded as the highest concentration in the particulate deposits, while maximum lead accumulated by the leaves was noted as 3.12±1.09 ppm.     

The USSR, China, India and the world metals industry to 2010

Remarkable changes are occurring within the economies of the USSR, China and India that are influencing mineral industry activities. These three countries account for a major share of world minerals production and consumption. Their domestic reforms may ultimately have a serious impact on the global mining industry. This paper examines the present status of the Soviet, Chinese and Indian mineral industries, and forecasts conditions to 2010. Long-term characteristics analysed include industrial production, intensity of use, consumption, mine and plant expansion and trade policy. Six metals are highlighted in the study – aluminium, copper, lead, nickel, steel and zinc.     

Hazard and Effects of Pollution by Lead on Vegetable Crops

Lead (Pb) contamination of the environment is an important human health problem. Children are vulnerable to Pb toxicity; it causes damage to the central nervous system and, in some extreme cases, can cause death. Lead is widespread, especially in the urban environment, and is present in the atmosphere, soil, water and food. Pb tends to accumulate in surface soil because of its low solubility, mobility, and relative freedom from microbial degradation of this element in the soil. Lead is present in soil as a result to weathering and other pedogenic processes acting on the soil parent material; or from pollution arising caused by the anthropogenic activities; such as mining, smelting and waste disposal; or through the adoption of the unsafe and unethical agricultural practices such as using of sewage sludge, and waste water in production of vegetable crops or cultivation of vegetables near highways and industry regions. Lead concentrations are generally higher in the leafy vegetables than the other vegetables. Factors affecting lead uptake included its concentration in the soil, soil pH, soil type, organic matter content, plant species, and unsafe agriculture practices. Generally, as Pb concentration increased; dry matter yields of roots, stems and leaves as well as total yield decreased. The mechanism of growth inhibition by lead involve: a decrease in number of dividing cells, a reduction on chlorophyll synthesis, induced water stress to plants, and decreased NO ₃ ^- uptake, reduced nitrate and nitrite reductase activity, a direct effect of lead on protein synthesis, a decrease on the uptake and concentration of nutrients in plants. The strategies to minimize Pb hazard can be represented in: (a) Phytoremediation, through natural plants are able to bio-accumulate Pb in their above–ground parts, which are then harvested for removal such as, using Indian Mustard (Brassica juncea), Ragweed (Ambrosia artemisiifolia), Hemp Dogbane (Apocynum cannabium), or Poplar trees, which sequester lead in its biomass. (b) Good and ethical agricultural practices such as cultivation of vegetables crops as far from busy streets or highways and industry regions as well as nonuse of sewage sludge and waste water in cultivated soils. (c) Increasing the absorptive capacity of the soil by adding organic matter and humic acid. (d) Growing vegetable crops and cultivars with a low potential to accumulate lead, especially in soils exposed to atmospheric pollution. (e) Washing of leafy vegetables by water containing 1 % vinegar or peeling roots, tubers, and some fruits of vegetables before consumption may be an important factor in reducing the lead concentration.     

Price and volatility transmission between primary and scrap metal markets

The relationship between primary and scrap prices has been hypothesized for the most part as unidirectional, characterized by spillovers from primary to scrap prices. The purpose of this study is to evaluate empirically the dynamic interactions between primary and scrap metal prices through multivariate time series methods. In addition, the study expands the investigation at the level of volatility transmission, which has not been previously examined. The metal prices utilized are for copper, lead, and zinc for the period 1984–2001. The paper demonstrates differing long run and short run links. Scrap prices do not improve the long run interpretation of primary prices, but information flows from the scrap to the primary markets exist in the short run. Additionally, the copper and lead markets exhibit bidirectional information flows in terms of volatility transmission. The analysis provides valuable insight into the interactions of the primary and scrap metal sectors which can be used to improve forecasting and planning.     

Price and volatility transmission between primary and scrap metal markets

The relationship between primary and scrap prices has been hypothesized for the most part as unidirectional, characterized by spillovers from primary to scrap prices. The purpose of this study is to evaluate empirically the dynamic interactions between primary and scrap metal prices through multivariate time series methods. In addition, the study expands the investigation at the level of volatility transmission, which has not been previously examined. The metal prices utilized are for copper, lead, and zinc for the period 1984–2001. The paper demonstrates differing long run and short run links. Scrap prices do not improve the long run interpretation of primary prices, but information flows from the scrap to the primary markets exist in the short run. Additionally, the copper and lead markets exhibit bidirectional information flows in terms of volatility transmission. The analysis provides valuable insight into the interactions of the primary and scrap metal sectors which can be used to improve forecasting and planning.