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F M Tack

Publications and source records attributed to F M Tack.

11 recordsLinked to original sources
PubMed2001

Guidelines for sampling in Flanders (Belgium).

In Flanders, sampling guidelines for investigations on contamination of soils are in development. One detailed sampling guideline is currently available with respect to the prospective investigation in the frame of the decree related to soil sanitation. Four strategies for sampling may be followed as a function of available information about pollution sources. Guidelines indicate what has to be sampled (top soil, deeper soil, soil water), how sampling points must be determined, how the number of samples and analyses is determined and what parameters need to be analysed. The example given shows that sampling guidelines will strongly depend on the ultimate goal of a particular sampling. A sampling procedure should be developed with close consideration of practical aspects and limitations, in order to be practical, realistic and cost-effective.

Accreditation↗
PubMed2001

Metal extraction from road sediment using different strength reagents: impact on anthropogenic contaminant signals.

Washoff of road deposited sediment into storm drain systems is one of the major contributors to nonpoint source pollution in urban fluvial networks. These sediments contain a variety of potentially toxic organic and inorganic contaminants. Road sediment from 13 locations in an urban (non-industrialized) drainage basin, and soil from 10 background (control) locations were collected to assess total and labile fractions of Al, Co, Cu, Fe, Mn, Ni, Pb and Zn. Four digestions, of varying strength, were used to assess contaminant levels, these included: a total four-acid digestion, a microwave-assisted digestion with concentrated nitric acid (USEPA Method 3051), a 0.5 M 'cold' HCl, and a 0.05 M EDTA (pH 7). Road sediment data indicate that Al, Co, Fe, Mn and Ni were primarily lithogenic in origin, while Cu, Pb and Zn showed very significant anthropogenic signals, most probably from vehicle-related sources. Median Pb concentration enrichment ratios for the EDTA extraction were about 42, indicating an extreme anthropogenic signal. The weak extractants (HCI and EDTA) are considered in this study to be superior in their ability to characterize the degree of anthropogenic contamination and should be utilized more widely in environmental contaminant studies.

Chelating Agents↗
PubMed2000

Metal phase associations in soils from an urban watershed, Honolulu, Hawaii.

Soils of Manoa watershed, Hawaii, have received varying inputs of anthropogenic trace metals, with roadside soils primarily influenced by automobile contributions. A four-stage sequential extraction procedure was used to fractionate 13 topsoil (0-2.5 cm) and 13 subsoil (7.5-10.0 cm) samples into: (i) an adsorbed, exchangeable and carbonate (AEC) phase; (ii) a reducible phase; (iii) an oxidizable phase; and (iv) a residual phase. Phases (i)-(iii) were considered 'labile', with the residual fraction 'non-labile' under normal circumstances. An examination of eight elements (Al, Co, Cu, Fe, Mn, Ni, Pb and Zn) indicated that Pb was the trace metal most impacted by anthropogenic inputs. Roadside soil Pb enrichment was apparent with data from a 0.5 M HCI leach exhibiting a maximum concentration of 1000 mg/kg compared with a median background value of 12 mg/kg. Sequential extraction results indicated the following order with respect to phase dominance for Pb: reducible > residual > oxidizable > AEC. The identification of the reducible phase as the primary pool of available Pb supports previous work from temperate roadside soil environments. The reducible phase is characterized by hydrous Fe and Mn oxides and mobilization of fixed elements can occur with decreases in pH and redox potential. Iron was the least labile of the elements examined with only 5-6% of total Fe removed by the first three steps of the extraction procedure. Lead had the highest labile percentage with average values between 74 and 81%. Therefore, results from this study support earlier research in this watershed which identified Pb as the primary trace metal of concern from a contamination perspective.

Humans↗
PubMed2000

Calculation and mapping of critical loads of sulfur and nitrogen in Flanders, Belgium.

Up to now, critical loads calculations for the Flemish Region were based on European background data of surrounding countries. A first attempt has been made to calculate and map critical loads for forest ecosystems in Flanders using available site-specific information. Values of current deposition were used to calculate and map exceedances. The lowest critical loads for acidification (697 eq ha(-1)year(-1)) occur in the Campine and the north of Limburg where ecosystems largely consist of coniferous forests on poor sandy soils. The dominance of coniferous forest types in the Campine is also responsible for low critical load values for eutrophication (between 536 and 971 eq ha(-1)year(-1)). In 75% of the receptor points that have been considered an exceedance of the critical load for acidification is noted, primarily in areas with high SO2 and NOx depositions, such as the north of the provinces East and West Flanders and Antwerp. The critical load for eutrophication is exceeded in all points considered. Exceedances are particularly high in coniferous forests in West Flanders, and in the north of the provinces of Antwerp and Limburg, where especially NHx depositions amount to high values. Data needed for the calculation of critical loads are still sparse in Flanders, e.g. for: (1) weathering rates of soil minerals; (2) interception and evaporation of forest ecosystems; and (3) uptake of N and basic cations by vegetation. This supplementary information will contribute to a further refining of the calculated critical loads, which constitute indispensable information in developing an emission abatement policy.

Acid Rain↗
PubMed2000

Characterization of selected element concentrations and enrichment ratios in background and anthropogenically impacted roadside areas.

Previous research by the National Contaminant Biomonitoring Program found fish from Manoa Stream, Hawaii, to have the highest concentrations of Pb in the nation. To explore possible source linkages we sampled background (uncontaminated) soil, roadside soil, and road deposited sediment in Manoa watershed and analyzed them for total and extractable concentrations of Al, Co, Cu, Fe, Mn, Ni, Pb, and Zn. Our concentration and enrichment ratio data indicate that Al, Co, Fe, Mn, and Ni were controlled by natural source variations, and Cu, Zn, and particularly Pb were anthropogenically enhanced. Labile Pb concentrations, extracted with either dilute HCl or EDTA, reached a maximum of 3,560 mg/kg compared to background values of <10 mg/kg. Additionally, 25% of the 169 contaminated samples analyzed had EDTA-extractable Pb enrichment ratios > or =11.5, where a value of 1 separates uncontaminated from contaminated media. Given the proximity of most samples to roadways it is reasonable to conclude that automotive emissions plus vehicle wear were the primary contributors of trace metals to the roadside system. These data are discussed in context with previous work on the fluvial bed sediments in this watershed in an attempt to examine the potential linkage with the biological accumulation of Pb in fish from Manoa watershed.

Animals↗
PubMed1999

Leaching behaviour of Cd, Cu, Pb and Zn in surface soils derived from dredged sediments.

Leaching of heavy metals from land-disposed dredged sediment spoils is a potential environmental hazard. The leaching behavior of Cd, Cu, Pb and Zn in surface soils sampled from abandoned dredged sediment disposal sites was assessed. Using simple mass-balance calculations, the significance of the leaching test results with respect to metal migration into underlying clean soil was appraised. The potential leachability, defined as the amounts released at constant pH 4, decreased in the order (% of total contents): Zn (58%) approximately equal to Cd (49%)>Cu (5%) approximately equal to Pb (2%). The kinetics of metal release were determined in a cascade shaking test using de-mineralized water acidified to pH 4 (HNO(3)). Metal concentrations in the leachates were low and metal migration was, assuming uniform convective flow, predicted to be of no environmental concern. It is emphasized that any long-term prediction of metal migration is uncertain.

Journal Article↗
PubMed1996

Metal solubility as a function of pH in a contaminated, dredged sediment affected by oxidation.

The solubility as a function of pH for metals in a reduced dredged sediment, subjected to different redox conditions, was studied in a laboratory experiment. The redox conditions imposed simulated (i) the undisturbed sediment (flooded), (ii) a dredged material stored in a confined pond (aerated once and then flooded), (iii) an upland stored dredged material (drained and dried), and (iv) an upland stored sediment subjected to tillage (drained, dried and mixed). Minor differences in the solubility as a function of pH were observed between the treatments after two weeks. After three months, the solubility of Cd, Cu, Pb and Zn increased strongly in the oxidized sediments. Leachability of Fe decreased, while Mn, Ni and Co were mostly unaffected. Both short- and long-term mobility of metals (except Fe) is expected to be lowest when a reduced sediment remains in reduced conditions. Studying the solubility as a function of pH may provide additional information on the chemical association of metals in sediments.

Journal Article↗