Half-lives of tetra-, penta-, hexa-, hepta-, and octachlorodibenzo-p-dioxin in rats,monkeys, and humans--a critical review

The elimination half-lives (t1/2) in Sprague-Dawley rats for 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), 1,2, 3,7,8-pentachlorodibenzo-p-dioxin (PeCDD), 1,2,3,4,7,8-hexachlorodibenzo-p-dioxin (HxCDD), 1,2,3,4,6,7,8-heptachlorodibenzo-p-dioxin (HpCDD) and 1,2,3,4,6,7,8,9-octachlorodibenzo-p-dioxin (OCDD) were estimated in long-term studies by Schlatter, Poiger and others. Furthermore, there are some published half-lives of TCDD in adult humans. The average half-life of TCDD in adult humans is approximately 2840 days, while in Sprague-Dawley rats the average t1/2 of TCDD is 19 days. The t1/2 of TCDD in humans is about 150 times that of rats. This factor was used to calculate the t1/2 values of the other polychlorinated dibenzo-p-dioxins (PCDDs) in humans from the rat data. Furthermore, the terminal t1/2 values of PCDDs in adult humans were calculated from the regression equation: logt1/2H = 1.34 logt1/2R + 1.25 which was recently established for 50 xenobiotics (t1/2H = terminal half-lives in days for humans, t1/2R = terminal half-lives in days for rats). The following terminal half-lives in adult humans were obtained: 12.6 years for 1,2,3,7,8-PeCDD, 26-45 years for 1,2,3,4,7,8-HxCDD, 80-102 years for 1,2,3,4,6,7,8-HpCDD and ca. 112-132 years for OCDD. These half-lives of PCDDs are critically compared with measured t1/2 values of PCDDs and other persistent organic pollutants in rats, monkeys and humans.     

Toxicity, dioxin-like activities, and endocrine effects of DDT metabolites—DDA, DDMU, DDMS, and DDCN

Background, aim, and scope  

2,2-bis(chlorophenyl)-1,1,1-trichloroethane (DDT) metabolites, other than those routinely measured [i.e., 2,2-bis(chlorophenyl)-1,1-dichloroethylene (DDE) and 2,2-bis(chlorophenyl)-1,1-dichloroethane (DDD)], have recently been detected in elevated concentrations not only in the surface water of Teltow Canal, Berlin, but also in sediment samples from Elbe tributaries (e.g., Mulde and Havel/Spree). This was paralleled by recent reports that multiple other metabolites could emerge from the degradation of parent DDT by naturally occurring organisms or by interaction with some heavy metals. Nevertheless, only very few data on the biological activities of these metabolites are available to date. The objective of this communication is to evaluate, for the first time, the cytotoxicity, dioxin-like activity, and estrogenicity of the least-studied DDT metabolites.     

Physiology, morphology, and ozone uptake of leaves of black cherry seedlings, saplings, and canopy trees

Patterns of ozone uptake were related to physiological, morphological, and phenological characteristics of different-sized black cherry trees (Prunus serotina Ehrh.) at a site in central Pennsylvania. Calculated ozone uptake differed among open-grown seedlings, forest gap saplings, and canopy trees and between leaves in the upper and lower crown of saplings and canopy trees. On an instantaneous basis, seedling leaves had the greatest ozone uptake rates of all tree size classes due to greater stomatal conductance and higher concentrations of ozone in their local environment. A pattern of higher stomatal conductance of seedlings was consistent with higher incident photosynthetically-active radiation, stomatal density, and predawn xylem water potentials for seedlings relative to larger trees. However, seedlings displayed an indeterminate pattern of shoot growth, with the majority of their leaves produced after shoot growth had ceased for canopy and sapling trees. Full leaf expansion occurred by mid-June for sapling and canopy trees. Because many of their leaves were exposed to ozone for only part of the growing season, seedlings had a lower relative exposure over the course of the growing season, and subsequently lower cumulative uptake, of ozone than canopy trees and a level of uptake similar to upper canopy leaves of saplings. Visible injury symptoms were not always correlated with patterns in ozone uptake. Visible symptoms were more apparent on seedling leaves in concurrence with their high instantaneous uptake rates. However, visible injury was more prevalent on leaves in the lower versus upper crown of canopy trees and saplings, even though lower crown leaves had less ozone uptake. Lower crown leaves may be more sensitive to ozone per unit uptake than upper crown leaves because of their morphology. In addition, the lower net carbon uptake of lower crown leaves may limit repair and anti-oxidant defense processes.     

Sorption of lambda-cyhalothrin,cypermethrin, deltamethrin and fenvalerate to quartz,corundum, kaolinite and montmorillonite

Sorption to mineral surfaces may be important for retention and degradation of hydrophobic pesticides in subsoils and aquifers poor in organic matter. In this work the title pyrethroids have been used to investigate selective interactions with the surfaces of four minerals. Sorption of the four pyrethroids was quantified in batch experiments with initial pyrethroid concentrations of 1–100 μg/l. Sorption to centrifuge tubes used in the batch experiments accounted for 25–60% of total sorption. Net sorption was obtained from total sorption after subtracting the amounts of pyrethroids sorbed to centrifuge tubes used. All isotherms could be fitted by the Freundlich equation with n ranging between 0.9 and 1.1. Bonding affinities per unit surface area decreased in the order: corundum>quartz>montmorillonitekaolinite. A similar sequence as found for the total surface tension of the minerals. All minerals showed the same selectivity order with respect to sorption affinity of the four pyrethroids: lambda-cyhalothrin>deltamethrin>cypermethrin>fenvalerate, which shows that the most hydrophobic compound is sorbed most strongly. Stereochemical properties of the four pyrethroid formulations may also contribute to the selectivity pattern.     

Transformations,Lifetimes, and Sources of NO2, HONO,and HNO3 in Indoor Environments

Recent research has demonstrated that nitrogen oxides are transformed to nitrogen acids in indoor environments, and that significant concentrations of nitrous acid are present in indoor air. The purpose of the study reported in this paper has been to investigate the sources, chemical transformations and lifetimes of nitrogen oxides and nitrogen acids under the conditions existing in buildings. An unoccupied single family residence was instrumented for monitoring of NO, NO₂, NO_y, MONO, HNO₃, CO, temperature, relative humidity, and air exchange rate. For some experiments, NO₂ and HONO were injected into the house to determine their removal rates and lifetimes. Other experiments investigated the emissions and transformations of nitrogen species from unvented natural gas appliances. We determined that HONO is formed by both direct emissions from combustion processes and reaction of NO₂ with surfaces present indoors. Equilibrium considerations influence the relative contributions of these two sources to the indoor burden of HONO. We determined that the lifetimes of trace nitrogen species varied in the order NO ~ HONO > NO₂ >HNO₃. The lifetimes with respect to reactive processes are on the order of hours for NO and HONO, about an hour for NO₂, and 30 minutes or less for HNO3. The rapid removal of NO₂ and long lifetime of HONO suggest that HONO may represent a significant fraction of the oxidized nitrogen burden in indoor air.     

Effect of four alcohols on adsorption, desorption, and movement of cadmium, nickel, and zinc through soils

Miscible-displacement experiments were conducted to compare the effects of aqueous soil solutions with ethyl alcohol, ethylene glycol, diethylene glycol, and triethylene glycol on the movement of metals through soils. Aqueous or alcohol solutions containing 1 mM each Cd, Ni, and Zn and 5 mM Ca were perfused through columns containing River Sand, Canelo loam (Canelo 1) or Mohave sandy clay loam (Mohave scl) until effluent metal concentrations (C) equaled influent concentrations (C₀) or CC₀⁻¹ = 1. In general, the order of sorption was Zn > Ni > Cd in aqueous-perfused columns, while in alcohol-perfused columns sorption of Ni Cd ≥ Zn. In comparison to aqueous solutions, alcohols reduced total metal sorption by at least 25%. Metal sorption was best correlated to cation exchange capacity of the soil, sorption of metals being greatest in the Mohave scl and least in the River Sand. After CC₀⁻¹ = 1 was reached, columns were leached with deionized water. While leaching did not affect the sorption of metals in columns which had been perfused with aqueous solvents, sorption behavior of metals changed significantly in columns which had been perfused with alcohol solvents. Leaching caused desorption of 5 to 30% of the sorbed Ni. In general, Cd was desorbed (up to 45%) from the soils tested. The exceptions were River Sand columns perfused with diethylene and triethylene glycol in which additional Cd was sorbed to the soil from the soil solution. Additional Zn was sorbed in all columns tested with the exception of the Canelo 1 column perfused with ethyl alcohol.     

Cadmium,chromium and lead contamination of Athene noctua,the little owl,of Bologna and Parma,Italy

A study was conducted to determine cadmium, chromium and lead concentrations in liver and brain of 52 little owls (Athene noctua) from two provinces of Emilia Romagna region, with the aim of furnishing indirect information concerning contamination of their habitat, also considering possible environmental dispersion of the metals. Metal analysis was performed by atomic absorption spectrophotometry with graphite furnace. Variance analysis with sampling area, gender and age shows that no statistical difference was found for gender, while a significant difference (P<0.05) was found for cadmium and lead, but not for chromium, when sampling areas and age were of concern. For all metals highest mean concentrations were found in liver (170 ppb for cadmium, 297 ppb for chromium and 312 ppb for lead). These levels can be considered as indicative of chronic exposure to low and "background" amounts of pollutants and they are of no toxicological concern, as they are always well below the toxic thresholds defined for each metal. The present study can be considered as a starting point for further analyses, aimed to the definition of any possible subtle effect (e.g. effects on enzymes activity) and of any possible correlation between levels of pollutants and appearance of possible adverse effects. It also furnished useful data for diagnostic cases and potentially for monitoring local contamination.     

Adsorption of Pb,Cd, Cu,Zn, and Ni to titanium dioxide nanoparticles: effect of particle size,solid concentration,and exhaustion

Purpose  

Adsorption of metals (Pb, Cd, Cu, Ni, Zn) to TiO₂ nanoparticles and bulk particles was examined for use as a contaminant removal substrate as a function of particle size, sorbent concentration, and exhaustion.     

Impact of coexistence of carbendazim, atrazine, and imidacloprid on their adsorption, desorption, and mobility in soil

The effect of coexisting pesticide on adsorption/desorption and mobility of another one was investigated with carbendazim (CBD), imidacloprid (IDP), and atrazine (ATR). The data indicated that adsorption of CBD, ATR, and IDP on the tested soil was fitted well by Freundlich equation and increased with an order of IDP < ATR ? CBD. Adsorption of a pesticide was decreased by the coexistence of another one through their competitive adsorption. The presence of coexisting solute of the more adsorbability played a more important role than that of the lesser adsorbability. The adsorption of IDP and ATR was easier to be affected by 28.9–52.0 % and 31.1–60.7 % with the addition of CBD, while that of CBD was much less influenced by 3.4–18.1 % and 6.9–31.8 % with the presence of ATR and IDP, respectively. An adsorbability-related enhancement in desorption of the three pesticides by the co-adsorbed solute was also observed. As a result of competitive adsorption/desorption, the mobility of the pesticides estimated from soil thin-layer chromatography was altered. The results clearly illustrated that adsorbability and concentration-related alteration in adsorption/desorption and mobility will be caused by the coexistence of pesticides.     

杀虫剂十氯酮的多介质环境行为模拟

应用EQC模型模拟十氯酮在多介质环境中的归宿和迁移通量.结果表明:土壤是十氯酮最大的贮存库,在稳态平衡条件下,残留率达到95.0%;在稳态非平衡条件下,十氯酮单独排放到水体,有37.5%残留在于排放的水体中,其在大气的浓度水平和质量分布均很低,在沉积物中的质量则来自于水体向沉积物的沉降迁移;十氯酮主要通过水体的水平迁移和土壤的厌氧降解输出;十氯酮的主要界面迁移过程是大气向土壤的迁移,其次是水体向沉积物的沉降和大气向水体的迁移.     

Toxicity of carbaryl,diquat dibromide,and fluoranthene,individually and in mixture,to larval grass shrimp,Palaemonetes pugio

This study examined the toxicity of two pesticides (carbaryl and diquat dibromide) and one polycyclic aromatic hydrocarbon (fluoranthene), both singly and in mixture, to grass shrimp larvae (Palaemonetes pugio). These three chemicals are all present in coastal environments and can easily enter estuarine ecosystems. Fluoranthene was the most toxic chemical with a 96-h LC₅₀ value of 32.45 μ g/L, followed by carbaryl (43.02 μ g/L) and diquat dibromide (1624 μ g/L). In the chemical mixture tests, the binary carbaryl/diquat dibromide mixture and the ternary carbaryl/diquat dibromide/fluoranthene mixture had additive results.     

Toxicity of carbaryl, diquat dibromide, and fluoranthene, individually and in mixture, to larval grass shrimp, Palaemonetes pugio

This study examined the toxicity of two pesticides (carbaryl and diquat dibromide) and one polycyclic aromatic hydrocarbon (fluoranthene), both singly and in mixture, to grass shrimp larvae (Palaemonetes pugio). These three chemicals are all present in coastal environments and can easily enter estuarine ecosystems. Fluoranthene was the most toxic chemical with a 96-h LC50 value of 32.45 microg/L, followed by carbaryl (43.02 microg/L) and diquat dibromide (1624 microg/L). In the chemical mixture tests, the binary carbaryl/diquat dibromide mixture and the ternary carbaryl/diquat dibromide/fluoranthene mixture had additive results.     

Evaluation of the Stone and Marble Industry in Palestine: environmental,geological, health,socioeconomic, cultural,and legal perspectives,in view of sustainable development

The Stone (limestone) and Marble (trade name) Industry (SMI) is one of the most important and active industries in Palestine, as being economically and financially rewarding and greatly beneficial to the public and private sectors. This industry, which employs about 15,000–20,000 workers, contributes 20–25% to the total industrial revenues of Palestine, and 4.5% to the total gross national product. Despite its benefits, SMI has adverse effects on public health, the environment, biodiversity, water systems (both surface and underground), green cover, and ecosystems in general, as it is considered one of the most air- water-, soil-, and noise-polluting sources. To achieve the purpose of this research paper, available data and literature are analyzed, evaluated, and used, in order to provide a comprehensive understanding of the status of SMI, in light of sustainable development. This relates to various perspectives, including limestone geology, geopolitics, socioeconomics, culture, technology, legislation, as well as climate change, acid rain, and harmful effects of the SMI scale on public health and safety, environmental well-being, and challenges facing the industry. Two field studies, carried out in northern and southern West Bank, dealing with particulate matter (PM₁, PM_2.5, PM₇, PM₁₀, and TSP) and environmental pollution, were analyzed, and their results were compared with each other, as well as with the World Health Organization’s (WHO) guidelines. It is found that both West Bank’s areas are heavily polluted, resulting in considerable adverse impacts on public health, the environment, and green cover. Based on the findings of this paper, it is recommended that SMI should properly adhere to WHO guidelines and international standards to make the industry safer and more durable and sustainable, with fewer negative impacts on public health, the environment, and green cover.

     

Poverty, economic growth, deprivation, and water: the cases of Cambodia and Vietnam

Poverty reduction decorates all development agendas, but the complexity of the poverty issue is too often hidden behind simplistic indicators and development goals. Here, a closer look is taken at the concepts of "deprivation" and "vulnerability" as outcomes of poverty. Deprivation leads typically to social exclusion and marginalization; such groups are particularly weak in getting themselves out of poverty by "self-help," and economic growth does not trickle down to these people. When looking at the connections between poverty reduction and economic growth, special emphasis should be put on the differences between modern and more traditional sectors: development of the modern sector should not marginalize and exclude those dependent on more traditional livelihoods. Two case studies--The Tonle Sap area, Cambodia, and the Mekong Delta, Vietnam--reveal that investment in education, empowerment of small-scale entrepreneurship and other means of microeconomic environment, along with good governance, infrastructure, and income distribution can ensure that economic growth includes the poorer echelons of society.     

Accumulation of arsenic, lead, copper, and zinc, and synthesis of phytochelatins by indigenous plants of a mining impacted area

Several native plants, able to grow in an unconfined mining impacted area that is now in close vicinity with urban areas, were evaluated for their ability to accumulate heavy metals. The main soil contaminants were As, Pb, Cu, and Zn. Sampling of the rhizospheric metal polluted soil showed that Euphorbia prostrata Aiton, Parthenium incanum Kunth, and Zinnia acerosa (DC.) A. Gray were able to grow in the presence of high amounts of mixtures of these elements. The plants accumulated the metals in the above ground parts and increased the synthesis of thiol molecules. E. prostrata showed the highest capacity for accumulation of the mixture of elements (588 μg g DW^?1). Analysis of the thiol-molecules profile showed that these plants synthesized high amounts of long-chain phytochelatins, accompanied by low amounts of monothiol molecules, which may be related to their higher resistance to As and heavy metals. The three plants showed translocation factors from roots to leaves >1 for As, Pb, Cu, and Zn. Thus, by periodically removing aerial parts, these plants could be useful for the phytoremediation of semi-arid and arid mining impacted areas, in which metal hyper-accumulator plants are not able to grow.     

Assessment of the content,occurrence, and leachability of arsenic,lead, and thallium in wastes from coal cleaning processes

The aim of the study was to evaluate the content, occurrence, and leachability of arsenic (As), lead (Pb), and thallium (Tl) in wastes from coal cleaning processes with respect to the safe management of this waste. The study focused on wastes resulting from the wet gravitation and flotation processes employed for the purposes of coking coal cleaning in four coal mines situated in the Upper Silesian Coal Basin (Poland). The scope of the study included (i) determination of the content of these elements in the investigated wastes using atomic absorption spectrometry, (ii) evaluation of their mode of occurrence using electron microprobe analysis, and (iii) preliminary assessment of their leachability in deionized water. The content of the analyzed elements in the examined samples of coal waste was twice as high as the average content of these elements in the Earth’s crust. The contents of As and Pb, however, did not exceed their permissible contents in inert waste in accordance with Polish legal regulations based on EU directives. The limit on the content of Tl is not specified by these regulations, but its amount in the examined samples was similar to that occurring in the soils. Moreover, leaching tests have shown that these elements are hardly eluted from the analyzed material. Their content in the water leachates was generally lower than the detection limit of the analytical method, complying with the standards for good and very good water quality. Low leachability of these elements most probably results from their mode of occurrence in the investigated wastes. The chemical analysis using an electron microprobe and the analysis of the correlation between these elements, e.g., total and pyritic sulfur, have shown that Pb, As, and Tl are mainly found in sulfide minerals which are characterized by negligible solubility. In conclusion, the investigated hard coal processing waste does not constitute a threat to the environment and can be commercially used or safely neutralized, e.g., by landfilling.

     

Lead,mercury, cadmium,chromium, nickel,copper, zinc,calcium, iron,manganese and chromium (VI) levels in Nigeria and United States of America cement dust

This study was aimed at investigating the relative abundance of heavy metals in cement dust from different cement dust factories in order to predict their possible roles in the severity of cement dust toxicity. The concentrations of total mercury (Hg), copper (Cu), chromium (Cr), cadmium (Cd), nickel (Ni), manganese (Mn), lead (Pb), iron (Fe) and chromium (VI) (Cr (VI)) levels in cement dust and clinker samples from Nigeria and cement dust sample from the United States of America (USA) were determined using graphite furnace atomic absorption (GFAAS), while Zn and Ca were measured by flame atomic absorption spectrophotometry (FAAS), and Cr (VI) by colorimetric method. Total Cu, Ni and Mn were significantly higher in cement dust sample from USA (p < 0.05), also, both total Cr and Cr (VI) were 5.4–26 folds higher in USA cement dust compared with Nigeria cement dust or clinker (p < 0.001). Total Cd was higher in both Nigeria cement dust and clinker (p < 0.05 and p < 0.001), respectively. Mercury was more in both Nigeria cement dust and clinker (p < 0.05), while Pb was only significantly higher in clinker from Nigeria (p < 0.001). These results show that cement dust contain mixture of metals that are known human carcinogens and also have been implicated in other debilitating health conditions. Additionally, it revealed that metal content concentrations are factory dependent. This study appears to indicate the need for additional human studies relating the toxicity of these metals and their health impacts on cement factory workers.     

Modelling equilibrium adsorption of single,binary, and ternary combinations of Cu,Pb, and Zn onto granular activated carbon

Environmental Science and Pollution Research - Elevated concentrations of heavy metals in water can be toxic to humans, animals, and aquatic organisms. A study was conducted on the removal of Cu,...     

Physical and chemical separation of Ti,rare earth elements,Fe, and Al from red mud by carbothermal reduction,magnetic separation,and leaching

Environmental Science and Pollution Research - In this study, a combination of physical and chemical separation processes was used to recover the metallic components of red mud. At first, the...     

Radionuclides (lead-210, polonium-210, thorium-230, and -232) and thorium and uranium in water, sediments, and fish from lakes near the city of Elliot Lake, Ontario, Canada

Radionuclides (210Pb, 210Po, 230Th, and 232Th) and chemical Th and U were measured in water, sediments, and fish tissues (bone, muscle, and gut contents of laketrout, Salvelinus namaycush, whitefish, Coregonus clupeaformis and Prosopium cylindraceum) from four lakes in a watershed affected by U mining and milling operations at Elliot Lake, Ontario, and from control lakes in an adjacent, non-industrialized, watershed. Radionuclide concentration ratios between tissue levels and sediment and water levels were calculated. Annual radionuclide intakes and resulting doses were estimated for humans consuming fish from the watershed. Bone 210Pb levels were higher (186 mBq g(-1) dry wt in laketrout and 230 mBq g(-1) dry wt in one lake whitefish) than in muscle (< 50 mBq g(-1) dry wt in all cases), and generally higher in fish from study lakes than from controls, but no consistent differences were observed among fish species. Similarly, 210Po levels were higher in bone (208 +/- 33 mBq g(-1), in laketrout) than muscle (maximum 26 +/- 4 mBq g(-1), in laketrout), and in study lake populations compared to controls. Laketrout 210Po bone concentrations were higher than previously reported in Canada. Levels of 230Th, 232Th, and Th were below detection limits (20 mBq g(-1), 0.05 microg g(-1)) in body tissues in all fish species. Bone levels of U (14.6 +/- 3.0 microg g(-1), in lake whitefish) were higher than in muscle (most < 0.05 microg g(-1), except 0.12 +/- 0.04 and 0.08 +/- 0.03 microg g(-1) in lake whitefish) in fish from waters affected by industrial activity. In control lakes, bone and muscle levels were lower and not significantly different from each other. Muscle levels did not vary consistently with location. Concentration of 210Pb and U was seen from water and 'gut' material (taken as a surrogate for diet) to bone in laketrout and whitefish, and of U from water to muscle in whitefish, but in no case from sediments to tissues. Human intakes of 210Pb, 210Po, 230Th, 232Th, and U from consuming one meal of fish (375 g) per week could, in aggregate, represent an annual effective dose < 15% of the public dose limit (5 mSv). Monitoring biota living near the decommissioned Elliot Lake U operations, especially of 210Pb levels in fish muscle, with further assessment of human doses attributable to local fish and other animals in the diet, should continue. Because radionuclide effects on fish health (and on other non-human organisms) are of increasing concern, neoplasms, malformations, and reproductive anomalies in local fish deserve examination.