Chemical Time Bombs Research Articles

Soil Contamination in the Problem Areas of Agrarian Slovakia

Landfills, old and abandoned mines, industrial sites, heaps, sludge ponds and other sources of pollution represent environmental threats and are characterized as chemical time bombs. This work is focused on the evaluation of soil contamination by risk elements using various indices (geoaccumulation index—Igeo, enrichment factor—EF, contamination factor—Cif and degree of contamination—Cd). These selected agrarian problem areas are located in Slovakia, especially in the air pollution field of landfills consisting of power plant fly ash, tannery and footwear wastes, leachate (lúženec), iron ore slag, waste from metallurgy and sludge ponds in which coal sludge waste is deposited and waste from ore treatment. Nine research sites in the agrarian region of Slovak Republic were monitored. Ten risk elements (Fe, Mn, Zn, Cu, Co, Ni, Cr, Pb, Cd and Hg) and pH/H2O were included in this study and were determined in surface soils (of 0.05 m to 0.15 m) using atomic absorption spectrometry (AAS). Our study showed the highest exceedance of the limit values of risk elements in the order Ni (51.85 times) > Co (25.47 times) > Cd (13.70 times) > Cu (12.78 times) > Cr (8.37 times) > Fe (8.26 times) > Hg (7.94 times) > Zn (5.71 times) > Pb (4.63 times). The content of risk elements increased based on the average values of Igeo in the order of Cr < Hg < Zn < Pb < Ni < Cu < Cd. Igeo values for cadmium indicated mild-to-extreme contamination at all sites. We found the most significant enrichment in the order of Cd > Cu > Pb > Ni > Zn > Hg > Cr. EF values for cadmium indicated extremely high enrichment; the Cif and Cd values indicated a very high degree of soil contamination near the nickel smelter landfill, an industrial metallurgical plant and old but active mines. The studied areas pose a serious danger not only to the soil but also to groundwater and biota due to the prevailing low soil reaction, which increases the mobility of toxic elements. The study provides important results for the development of effective strategies for the control and remediation of endangered areas.

Sustainable utilization of a recovered struvite/diatomite compound for lead immobilization in contaminated soil: potential, mechanism, efficiency, and risk assessment.

A waste-struvite/diatomite compound (MAP@Dia) recovered from nutrient-rich wastewater treated by MgO-modified diatomite (MgO@Dia) was provided to immobilize lead in aqueous solution and contaminated soil. The mechanism and effectiveness of lead immobilization was investigated, and the pHstat leaching test and fixed-bed column experiments were carried out to assess the risk of MAP@Dia reuse for lead immobilization. The results showed that MAP@Dia were effective in immobilizing lead in aqueous solution with adsorption capacity of 832.47-946.50mg/g. The main mechanism of Pb immobilization by MAP@Dia could be contributed by surface complexation and dissolution of struvite followed by precipitation of hydroxypyromorphite Pb10(PO4)6(OH)2. Lead(II) concentration reduced from 269.61 to 78.26mg/kg, and residual lead(II) increased to 53.14% in contaminated soil when the MAP@Dia application rate was 5%. The increased neutralization capacity (ANC) and lower lead extraction yields in pHstat leaching test in amended soil suggested 5 times of buffering capacity against potential acidic stresses and delayed triggering of "chemical time bombs." The results of column studies demonstrated that amendment with MAP@Dia could reduce the risk of lead and phosphorus (P) leaching. This study revealed that MAP@Dia could provide an effective solution for both P recycling and lead immobilization in contaminated soil.

Phosphate mineral fertilizers, trace metals and human health

Fertilizers, indispensable as they may seem, are nevertheless materials that also clearly cause serious environmental contamination notably in the agricultural soils. The dire necessity for increased food production has been more marked than ever before. Mineral fertilizers, which are indeed an important nutrient source used for enhanced food production, have unfortunately now become a 'necessary evil'. Excessive and continuous use of nitrogen and phosphorous fertilizers for decades have converted the agricultural soils into virtual chemical time bombs. Phosphate rocks by their very geological and mineralogical nature contain a host of environmentally hazardous chemical elements such as Cd, Pb, Hg, U Cr and As among others. The superphosphates are particularly abundant in these hazardous elements and they contaminate the agricultural soils through the use of fertilizer. The leachability and dispersion of some of these toxic elements are most pronounced in some types of soils such as andisols. After the discovery of the dreaded disease ' Itai-Itai ' cadmium has been listed as one of the most potentially dangerous elements found in phosphate fertilizers. Uranium, apart from its radiotoxicity, is chemotoxic and on account of these two properties, it is considered as a disease causing element. The geochemical pathways lead these toxic elements into food crops, soil, water, air and ultimately the human body tissues via the food chain. Several diseases are known to be caused by the excessive presence of the toxic elements and among them gastrointestinal, pulmonary and kidney ailments are most noteworthy.

Dredged River Sediments: Potential Chemical Time Bombs? a Case Study

The influence of dredging and land-disposal of a severely polluted river sediment on the release of heavy metals was studied. During the first 20 days of sediment oxidation and ripening, the pH of the sediment decreased from 8.0 to 3.5

ChemInform Abstract: Contaminated Aquatic Sediments and Waste Sites as Toxic Chemical Time Bombs

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Project tocoen ‐ the fate of selected organic pollutants in the environment part XXI. ‐ The contents of PAHs, PCBs, PCDDs/Fs in sediments from Danube river catchment area

As a part of cooperation between Chemical Time Bombs Program and Project TOCOEN, the contamination of sediments in Moravian and Slovakian part of Danube river catchment area by PAHs, PCBs, PCDDs/Fs was determined. The total contents of PAHs ranged between 25.5 and 4,690.3 ng•g‐1, PCBs between 4.9 and 232 ng•g‐1 and PCDDs/Fs were detected at one site in concentration 0.0005 pg•g‐1 TEQ.

Report of the closing session at the set ac conference, potsdam, germany, 24 june, 1992: chemical time bombs

Land Degradation & DevelopmentVolume 4, Issue 4 p. 199-206 Closing Session Report of the closing session at the set ac conference, potsdam, germany, 24 june, 1992: chemical time bombs G. P. Hekstra, G. P. HekstraSearch for more papers by this authorW. M. Stigliani, W. M. Stigliani ChairmenSearch for more papers by this authorG. R. B. Ter Meulen-Smidt, G. R. B. Ter Meulen-Smidt RapporteurSearch for more papers by this author G. P. Hekstra, G. P. HekstraSearch for more papers by this authorW. M. Stigliani, W. M. Stigliani ChairmenSearch for more papers by this authorG. R. B. Ter Meulen-Smidt, G. R. B. Ter Meulen-Smidt RapporteurSearch for more papers by this author First published: December 1993 https://doi.org/10.1002/ldr.3400040403Citations: 1AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume4, Issue4December 1993Pages 199-206 RelatedInformation

Ecological sustainability and the use of chemicals: Is ecotoxicological risk assessment doing its job properly? An introduction to chemical time bombs

AbstractTen million chemical substances are registered scientifically, but only 1 per cent, 100000, are known to be traded internationally, and only a fraction of these are assessed to establish (eco)toxicological risks through international and national authorities. Only a few of the substances are natural or systemic; most are xenobiotic and poorly evaluated with respect to their environmental effects. It is not only the chemical accidents that make newspaper headlines, but the creeping accumulation of pollutants in soils, sediments and groundwater which degrade the environment for future generations. Ecotoxicological risk assessment still neglects this ‘hidden pollution’, as it usually deals only with the bioavailable fractions of chemicals in the environment. the ‘lost’ (residue) fractions, however, can have non‐linear and time‐delayed effects (chemical time bombs).As governments need to protect their natural resources (soils, sediments, groundwaters) against negative impacts from chemicals, an ecosystem approach May, help them to overcome the shortsightedness of current ‘acute’ ecotoxico‐logical risk assessments. the Netherlands' risk philosophy on chemicals in the environment is discussed as an example. the National Environmental Policy Plan‐2 (1994) stresses the chain of events associated with a chemical from the raw material, The side effects of its transport, production, use and disposal, to its final effects in the ecosystem, including the time‐delayed responses of pollution. a revised ecotoxicological assessment policy under the new NEPP will have to take account of such chemical time bombs.

Long‐term environmental risks for soils, groundwaters and sediments in the danube catchment area: The danube chemical time bombs project

AbstractThe accumulation of pollutants in soils, sediments and groundwaters due to natural causes or as a consequence of human activities is a serious problem in the Danube region. the sudden release of the (temporarily) immobilized pollutants as a consequence of various soil degradation processes (acidification, salinization or alkalinization, The destruction of the soil structure and clay minerals, a decrease in the organic matter content and the buffering capacity) is even more harmful. This chemical time bomb phenomena significantly influences the present and future land and water use in the whole Danube catchment area and therefore has great practical significance. the aim of this project, as the first phase of an integrated environmental master plan, is to identify the problems, to delineate problem areas, to analyse the natural system (present status, vulnerability, future risks) and to develop the scientific tools and infrastructure for long‐term environmental risk assessment, which will be the scientific basis for the plan of action to prevent, eliminate or, at least, reduce the harmful side‐effects and the unfavourable ecological and economic consequences of the chemical time bomb in the Danube catchment area.

Chemical time bombs from landfills: Appraisal and modelling

AbstractAbout 240 x 106 tonnes of industrial waste, 104 x 106 tonnes of municipal waste and more than 60 x 106 tonnes of sediment sludge are landfilled (65 per cent), incinerated (24 per cent) and partly recycled in Europe annually. About 60000‐120000 landfill sites, occupying 800‐1700 km2, are recorded in the EEC, of which a limited number are in operation. These sites generate 12.5 x 109 m3 of landfill gas annually, of which about 755 x 106 m3 are presently recovered, and 0‐1‐4‐0 x 106 m3 of heavily polluted leachate, which is dispersed to ground and surface waters. the area with polluted groundwater increases annually by 1‐10 per cent (1200‐12000 km2 of contaminated land). Landfill gas contains carcinogenic and pathogenic components and contributes 2 per cent of the total emission of greenhouse gases; locally it is a potential hazard. Incinerators reduce the solid volume to about 30 per cent of the original but cause the atmospheric deposition of acids and dioxins. Emissions of landfill gas, leachate and atmospheric deposition have been recognized as potential chemical time bombs (CTBs). Models are currently available for the estimation of the time at which the effects of these CTBs will become manifest. It is recommended that an inventory of all landfills should be made to assess the potential hazards in detail, to encourage institutions to initiate the clean‐up of contaminated sites and the aftercare of closed sites, and to set up a co‐operative network within the EEC.

Chemical time bombs related to forestry practice: Distribution and behaviour of pollutants in forest soils

AbstractHeavy metals and persistent organic pollutants from atmospheric deposition and from fertilizer and pesticide applications are important hazardous substances in forest soils. Data are presented showing that these substances preferentially accumulate in the upper humic horizons of the soils. Another group of substances to be considered in relation to the chemical time bomb concept are the components of humus and soil minerals, mainly nitrogen and metals, which May, be mobilized and thus threaten groundwater quality. Forestry management practices such as thinning, cropping, fertilization and liming are discussed as potential triggers for the mobilization of harmful substances. in this context, The turnover (build‐up and mineralization) of organic matter plays a crucial part. It will be shown, however, that even more danger arises from soil acidification induced by the atmospheric deposition of acidifying pollutants such as sulphates and nitrates.

Environmental conditions and chemical time bomb hazards in Poland

AbstractObservations on the state of the environment, soil properties, soil hazards and some possible changes in soil parameters are discussed. Sandy and light loamy soils cover more than 50 per cent of the arable land in Poland. About 58 per cent of soils are acid (pH<5‐5) in the surface layer and 25 per cent in the layer from 100 to 150 cm. About 51‐3 per cent of soils are very vulnerable to pollution. According to a BIGLEB‐SOWEP prognosis, in the year 2000 about 13 per cent of soils will be seriously at risk from chemical degradation. Acidification will proceed due to increases in the emission of SO2 and NOx, and the end of liming. the environmental conditions in Poland favour delayed responses to environmental hazards: chemical time bombs.

Potential chemical time bombs in the schelde estuary

AbstractThe Schelde estuary is heavily polluted with many different (micro)pollutants. This results in high concentrations in the abiotic and biotic compartments of the Schelde estuary and in various effects. the present day suboxic and anoxic conditions in the upper estuary are probably responsible for the high distribution coefficients for some trace metals in the lower Schelde estuary (Western Schelde). a future reduction in discharges with a high biological oxygen demand will therefore not only result in higher oxygen concentrations, but probably also in lower distribution coefficients for trace metals in the Western Schelde. Simulations show that lower trace metal distribution coefficients will probably result in higher concentrations of dissolved (bioavailable) trace metals, even with substantially reduced discharge rates, due to the desorption of trace metals from resuspended bottom sediments.

Technical, policy and legal aspects of chemical time bombs with emphasis on the institutional action required in eastern Europe

AbstractTechnical, economic and institutional conditions are changing rapidly in Eastern Europe. the area has inherited a high level of chemical pollution of soil and water resources, leading to grave risks of chemical time bomb effects. With the current financial and manpower constraints and the general stress on the new economies of the subregion, any substantial environmental improvements reversing past trends will require considerable time, during which chemical pollutants will continue to accumulate in soils and waters. Special emphasis is given to diffuse and accelerated pollution from inappropriate or changed land uses. It is suggested on the basis of recent legislation on transboundary and national chemical pollution in Europe that national policies, priorities and legislation shoud be developed throughout Eastern Europe.

Contribution of Czecho‐Slovakia to the chemical time bombs study in the danube catchment area

AbstractAn overview is given of the activities of Czecho‐Slovak institutes within the project ‘Long‐term risks for soils, sediments and groundwater in the Danube catchment area,’ as accepted in 1991 by six riparian countries from the Danube basin. the project is divided into: screening maps; analytical methodology; (bio)monitoring; use of geographical information systems (GIS) for data storage and presentation of results; soil vulnerability studies; modelling of processes; and case studies. Twenty‐six tasks are listed, together with authors and addresses of co‐operating organizations included in the Czecho‐Slovakian project. in the initial stages information was gathered to produce maps of hot‐spots in the Czecho‐Slovakian territory of the Danube catchment area. a list of landfill sites is almost ready; surface water pollution for the Danube itself and for the Hron tributary has been evaluated and some proposals for the presentation of the results have been considered. the methodological part of the project summarizes the analytical methods for the groundwater study. Base levels and standards for the comparison of quality have been completed. At present the Water Research Institute is planning to process the results using ILWIS (Integrated Land and Water Information System), which is distributed by ITC (Enschede, The Netherlands) and VITUKI (Hungary). Some administrative and budgetary aspects of the task are considered and the acute need for closer international cooperation is emphasized.

Salinization of groundwater and the mobilization of micropollutants: Effect on the food chain

AbstractAlthough the development of salinization in European soils and waters is less of a problem than in Asia, Africa and Australia, The impact in Europe is likely to be worse because of the much greater interference with stored pollutants. Three types of salinization are discussed here: salinization caused by faulty irrigation, increased evapotranspiration and rises in sea‐level. the potential activation of the chemical time bombs due to climatic changes and the development of the co‐tolerance of plants to metal pollution and increased salinity is considered.

Riverine and estuarine sedimentation of pollutants and leaks from sludges and wastes: Analytical, prognostic, experimental and remedial approaches

AbstractThe effects of chemical time bombs are typically discontinuous and non‐linear. Once a certain threshold has been passed, The system starts to behave differently from before (Stigliani, 1991). a typical example is the consumption of a certain buffer capacity in a system, and the subsequent breakthrough of parameters such as pH values and metal concentrations. the mobilization of metals from different types of waste materials, after the depletion of typical barriers (mechanical or chemical) or after an increase of accelerating factors such as the lowering of pH values, was studied. the release of metals from sediments, leaks of pollutants from sludges and wastes, and some remedial approaches are discussed.

Soil vulnerability to pollution in Europe

Abstract. Pollution by inorganic and organic substances is increasingly disrupting the natural functions of soils. Some soils seem capable of receiving and holding chemical compounds, at the same time retaining their ecological flexibility, but others are readily damaged and should be regarded as vulnerable to particular pollution scenarios.At the request of the Chemical Time Bombs (CTB) Project, the International Soil Reference and Information Centre (ISRIC) organized an international workshop to assess the feasibility of increasing awareness of ‘soil vulnerability’ by a mapping exercise for Europe (SOVEUR), at a scale of 1:5 M, with reference to selected organic and inorganic contaminants. The workshop participants outlined procedures for a GIS‐based approach to determining areas where vulnerable soils occur, and formulated proposals for the implementation phase of the SOVEUR programme. Funding is now sought for continuation of the work outlined in this paper.

Summary of the workshop on delayed effects of chemicals in soils and sediments (Chemical Time Bombs), with emphasis on the Scandinavian region

The expression Chemical Time Bombs refers to a chain of events resulting in the delayed and sudden occurrence of harmful environmental effects due to the mobilization of chemicals stored in soils and sediments in response to slow alterations in environmental conditions. This workshop was part of a series of workshops in which basic ideas were developed and regional awareness promoted. The International Workshop on Delayed Environmental Effects of Chemical Pollution with Focus on the Nordic Countries was held in Uppsala, Sweden on 14 and 15 September 1991. A brief account of the discussions and the main conclusions are presented here. It was concluded that the effects in Nordic countries could be extended to areas with similar climate and bedrock conditions. These include the northern parts of Canada and Russia, Scotland, Iceland and Greenland. Fundamentally, Chemical Time Bombs in the Nordic and other cold climate areas do not differ from those in warmer areas. Conditions specific to cold climate areas are generally a thin soil cover, extensive occurrence of peat, and prolonged periods of frost and snow cover. Processes determining the buildup and triggering of Chemical Time Bombs differ only in rate and intensity as far as they are dependent on temperature and daylight. Loads of contaminants identified as being specific to Scandinavia are Hg and potentially toxic organic outputs of papers mills which threaten inland water ecosystems, as well as the Gulf of Bothnia and the Baltic Sea ecosystems. Assessment of risks from Chemical Time Bombs is still in its infancy. Quantitative risk assessment models for the accumulation in soils and sediments of heavy metals and toxic organic pollutants are still lacking.

Chemical Time Bombs: Predicting the Unpredictable

(1991). Chemical Time Bombs: Predicting the Unpredictable. Environment: Science and Policy for Sustainable Development: Vol. 33, No. 4, pp. 4-30.