Areas were sampled in the White Rock Creek Watershed to examine sediment bound trace metal distributions and sorption relationships. A Kruskal-Wallis AOV found significant among area differences for most metals, and SNK-like multiple comparisons were used to group these areas. Kruskal-Wallis AOVs similarly found among area differences for sediment components that bind trace metals (Fe and Mn oxides and organic carbon) and physicochemical conditions that influence metal sorption (particle size and pH). Multiple correlation found numerous relationships among trace metals, sediment components, and physicochemical conditions. Statistical relationships indicate that metal partitioning to various sorption factors is metal specific. White Rock Creek Watershed trace metal concentrations are comparable to those in many urban watersheds.

Thesis (M. Sc. Agriculture (Animal Production)) -- University of Limpopo, 2021 / The study was carried out to determine the concentration levels of mercury (Hg), lead (Pb), cadmium (Cd), chromium (Cr), nickel (Ni) and zinc (Zn) in water, soil, witbuffels grass and meat of goats reared along the river banks of Middle Olifants (Mogalatsana village) and Mogalakwena (Papegaai village) rivers. The samples were collected from the river water, soils along the river banks, grass grown along the river banks and male Pedi goats reared in Mogalatsana and Papegaai villages. The samples were analysed for the selected heavy metals with an inductively coupled plasma mass spectroscopy (ICP-MS). Data was analysed as in a complete randomised design. The results of selected heavy metals in water of both rivers ranged from 0.00 mg/litre of water (Ni and Cr) to 0.04 mg/litre of water (Hg). The concentration levels of selected heavy metals in water were similar (P>0.05) for Middle Olifants and Mogalakwena rivers. The concentration levels of selected heavy metals in the soils along the banks of Middle Olifants and Mogalakwena rivers ranged from 0.00 mg/kg DM soil (Hg and Cd) to 63.70 mg/kg DM soil (Cr). There were similar (P>0.05) concentration levels of selected heavy metals in the soils along the banks of Middle Olifants and Mogalakwena rivers. Heavy metal concentration levels in the witbuffels grass grown along the banks of Middle Olifants and Mogalakwena rivers ranged from 0.00 mg/kg DM of grass (Hg and Cd) to 5.05 mg/kg DM of grass (Zn). Similar (P>0.05) concentrations of selected heavy metals were observed in witbuffels grass grown along the banks of Middle Olifants and Mogalakwena rivers. However, the concentration levels of Zn, Pb and Cd in water from both sites were above internationally maximum permissible levels, indicating that the water from these rivers was not safe for drinking by humans and animals. The concentration levels of Ni and Pb in soils from both sites were above internationally recommended maximum permissible limits. Similarly, chromium concentration levels in witbuffels grass from both sites were above the recommended maximum permissible limits for livestock, indicating that the grass was not safe for consumption by livestock. It is recommended that further studies be conducted to ascertain these findings. Blood, liver, kidney and meat samples of yearling male Pedi goats grazing along the banks of Middle Olifants river (Mogalatsana village) had similar (P>0.05) Cr, Cd, Hg, Ni and Pb concentration levels, respectively. However, goat liver samples had higher (P<0.05) Zn concentrations than meat, kidney and blood samples. Samples of goat v meat contained higher (P<0.05) Zn concentrations than those of kidneys and blood. Similarly, goat kidney samples contained more (P<0.05) Zn than blood samples. Blood, liver, kidney and meat samples of Pedi goats grazing along the banks of Mogalakwena river (Papegaai village) contained similar (P>0.05) concentration levels of Cr, Cd, Hg, Ni and Pb, respectively. However, goat meat samples contained higher (P<0.05) Zn concentrations than liver, kidney and blood samples. Samples of goat liver contained higher (P<0.05) Zn concentration levels than kidney and blood samples. Similarly, goat kidney samples contained more (P<0.05) Zn than blood samples. Meat, blood, liver and kidney samples of male Pedi goats raised in Mogalatsana and Papegaai villages had similar (P>0.05) chromium, cadmium, mercury, nickel and lead concentrations, respectively. However, liver and kidney samples of goats from Mogalatsana village had higher (P<0.05) zinc levels than those from Papegaai village. Blood and meat samples of goats from Papegaai village had higher (P<0.05) zinc levels than those from Mogalatsana village. The concentration levels of Zn, Ni, Pb, Cr and Cd in the blood, liver, kidney and meat samples of male Pedi goats reared along the banks of Middle Olifants and Mogalakwena rivers were within the maximum permissible levels for human consumption. Mercury concentration levels in liver, kidney and meat samples of the goats were within the maximum permissible levels for human consumption. However, mercury concentration levels in the blood of goats grazing along the banks of Middle Olifants and Mogalakwena rivers were above the maximum permissible limit of 0.2 mg/litre of blood. It was concluded that meat, livers and kidneys of the goats were fit for human consumption. However, blood from these goats was not fit for human consumption.

About 27 million metric tons of municipal solid waste are used annually as fuel in U.S. Waste-to-Energy (WTE) power plants, which annually generate seven million tons of bottom ash (BA) and fly ash (FA). In the U.S., bottom ash and fly ash residues are mixed to “combined ash” (CA) in the approximate ratio of 6 to 1, and are disposed in landfills after metal separation. The disposal of WTE ash is a significant cost and land use item of waste management. This dissertation aims to (i) comprehensively understand the characterization and properties of WTE ash; (ii) provide practical and economic stabilization technologies to reduce the leachability of heavy metals in WTE ash and assessing whether it can be further beneficially used as secondary materials; (iii) utilize the stabilized/processed WTE ash as secondary construction materials in civil engineering applications, thus diverting materials from landfills and contributing to the circular economy. The Characterization section provides a comprehensive assessment of WTE bottom ash, fly ash, and combined ash, including chemical composition (XRF, ICP-OES, IC), mineral composition (X-ray diffraction-XRD quantification), thermogravimetric analysis (TGA), particle size distribution, and scanning electron microscopy (SEM). The physical properties of WTE residues were also investigated, including moisture, bulk density, specific gravity, void content, and water absorption. Leaching Environmental Assessment Framework (LEAF) Method 1313 of the U.S. Environmental Protection Agency (EPA) was used to understand the effect of eluate pH on the leachability of heavy metals. Combination of the above methods was applied to quantify the crystalline and amorphous phases present in WTE residues and produced specimens. In the U.S., WTE BA is discharged from the combustion chamber into a water tank. The BA includes 50-70% mineral fraction, 15-30% glass and ceramics, 5-13% ferrous metals, 2-5% non-ferrous metals, and 1-5% unburned organics. This thesis received the BA samples after ferrous and non-ferrous metal recycling. The major chemical composition includes SiO2 (34%), CaO (21%), Al2O3 (9%), and Fe2O3 (11%). According to XRD quantification results, BA consists of 76% amorphous phases (glass and metastable minerals), and the dominant crystalline mineral is quartz (SiO2, 12%). The calcium silicate (aluminate) hydrates (C-S-(A)-H) gel formed during the water quenching process embeds fine particles in the amorphous phases. The U.S. WTE air pollution control systems commonly include semi-dry scrubbers, with a few plants using dry scrubbers. FA consists of two kinds of particles: the furnace particles carried in the process gas and the newly-formed particles in the scrubber. The major chemical composition in FA includes CaO (40%), Cl (15%), SO3 (8%), CO2 (8%), and activated carbon/organic matter (3%) due to the injection of absorbents (hydrated lime and activated carbon) and the effects of flue gas scrubbing. The empirical formulae of the constituent crystalline (40-50%) and amorphous (50-60%) phases were derived. The excess water in semi-dry scrubbers improved the hydration reaction between newly-formed particles and furnace particles and resulted in the transformation of amorphous phase to calcium silicate hydrates (C-S-H) phase. The hydration products of semi-dry FA immobilized some heavy metals and reduced their leachability to below the levels of the Resource Conservation and Recovery Act (RCRA) by Toxic Characteristic Leaching Procedure (TCLP) test, as compared to dry scrubber FA, which exceeded the limits of RCRA. The U.S. combined ash can pass the TCLP test and comply with the RCRA standards for non-hazardous landfill disposal. The Stabilization section examines the effects of processing combined ash. CA undergoes water washing, crushing, and size separation processes to three fractions: coarse (27%, CCA, 9.5-25 mm), medium (37%, MCA, 2-9.5 mm), and fine (25%, FCA, < 2 mm), identified by particle size distribution results. The by-products of the washing process are extra fine filter cake ash (EFFCA, 8% of CA) collected from the water treatment system and ash dissolved in the wastewater (3% of CA). The characterization (chemical composition, mineral composition, and leachability) of ash the fractions (CCA, MCA, and FCA) showed that their mineral changed during the processing and exhibited significantly lower leachability (LEAF Method 1313-pH dependence), in comparison to as-received CA. The processed ash fractions with reduced leachability of heavy metals, can be further beneficially used as secondary materials. The effect of pH of the washing agents (water, acid and alkaline solutions) on the chemical/mineral transformation and the heavy metals leachability of the FA, BA, and CA was assessed. A novel technique of determining the distribution of various elements in washed ash (product), filter cake (by-product), and wastewater (dissolution) during ash processing was developed to compare the effectiveness of the washing process, which is dominated by dissolution and precipitation reactions. As-received FA, BA, and CA contained 50-75% of amorphous phases in metastable status, which are transformed to crystalline phases during the washing process. It was concluded that water washing is the most practical method for transforming WTE CA to construction material. The Utilization section examined the use of WTE ash in civil engineering applications, i.e. (i) Using the CCA and MCA fractions as stone aggregate substitute in structural concrete; (ii) Using FCA as sand substitute or using the milled FCA (MFCA) powder as mineral addition in cement mortar; (iii) Using FCA and EFFCA powder as metakaolin substitute in artificial aggregate; (iv) Using FA and phosphate FA (PFA) as cement substitute in cement mortar. In conclusion, the CA size fractions, i.e., MCA and CCA, are suitable for use as aggregate substitutes in the production of structural concrete. Up to 100 wt.% of stone aggregate in concrete can be substituted by MCA and CCA. The compressive strength of the optimal products exceeds 28 MPa after 28 days of curing, which is comparable to commercial concrete products using natural stone aggregate. The optimum concrete mixture composition was 40 wt.% of MCA or CCA, 30 wt.% sand, 20 wt.% cement, 10 wt.% water, and superplasticizer, with compressive strength of 28-30 MPa and elastic modulus of 6,300-6,600 MPa. The optimal products complied with stringent leaching standards, and the properties of the final products were comparable to the conventional civil engineering materials. All FCA or MFCA products were effectively stabilized/solidified and transformed to non-hazardous material that can be used in construction. The main challenge in the utilization of FCA or MFCA in cement mortar is the cementitious phase expansion due to the metallic aluminum present in FCA or MFCA. It was concluded that up to 50 vol.% of sand in cement mortar can be directly substituted by FCA, and up to 25 vol.% of MFCA can be utilized as mineral addition to replace cement in the production of cement mortar. In the production of artificial aggregates, up to 15% of FCA or up to 10% of EFFCA can replace metakaolin by volume. The produced samples indicated crushing strength of 4 and 1.5 MPa, respectively. The specific gravity and water absorption of optimal ash aggregate is 1.3 and 30%. The FCA and EFFCA aggregates exhibited good chemical stability and reduced the cracks observed in the fire resistance test. The ash aggregates can be used as a lightweight aggregate for non-structural applications. FCA can improve the workability of the metakaolin mixture and extend the setting time, which is beneficial for geopolymer aggregate manufacturing. The heavy metals from FCA and EFFCA can be effectively stabilized/solidified in artificial aggregate. Phosphoric acid can effectively stabilize the as-received FA, so that the dry scrubber FA passes the TCLP test and complies with the RCRA standards. The mineral transformations of individual ash and ash-cement paste were investigated by the XRD quantification analysis. FA and PFA enhanced the hydration degree of cement, and received higher mechanical performance than reference in 0-25 vol.% cement replacement. The leachability of heavy metals was effectively reduced in a wide leaching range (eluate pH 0-12.5), realized the stabilization/solidification purposes under restricted non-hazardous landfill standards.

No description available.

<p dir="ltr">The Northwest Atlantic Ocean, which surrounds the US eastern coastline, is an area rich in marine life. The US eastern coastline is also highly urbanized, resulting in a lot of pollutants (like heavy metals) entering the marine environment. This is of concern for long-lived marine species like sea turtles. Since sea turtles are long-lived and highly migratory, their tissues can often incorporate these pollutants through environmental and dietary exposure. I collected tissue samples from 5 different sea turtle populations in the Northwest Atlantic and analyzed them for concentrations of silver (Ag), aluminum (Al), arsenic (As), cadmium (Cd), cobalt (Co), chromium (Cr), iron (Fe), manganese (Mn), nickel (Ni), lead (Pb), selenium (Se) and zinc (Zn) using an Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The first chapter looks at skin (reflects exposure ~1 year ago) and scute (reflects exposure from 4-6 years ago) samples collected during necropsies of juvenile green (<i>Chelonia mydas</i>) (n=8), Kemp’s ridley (<i>Lepidochelys kempii</i>) (n=30) and loggerhead (<i>Caretta caretta</i>) (n=17) turtles that were found cold-stunned in Cape Cod Bay, Massachusetts. In scute samples, the heavy metal with the highest concentration for green turtles was iron, zinc for loggerhead turtles, and arsenic for Kemp’s ridley turtles. In skin samples, the heavy metal with the highest concentration for green turtles was iron, arsenic for loggerhead turtles, and aluminum for Kemp’s ridley turtles. Overall, I found scute samples to have higher heavy metal concentrations than skin samples. The second chapter looks at scute samples collected from loggerhead turtles of different life stages. These samples were collected during necropsies of cold-stunned loggerhead turtles from Cape Cod Bay, Massachusetts (CCB; n=17), as well as from live loggerhead turtles in the Mid-Atlantic Bight (MAB; n=37) and off the coast of North Carolina (NC; n=9). We also collected commonly known loggerhead turtle prey items including whelk (<i>Buccinum undatum</i>) (n=12), Atlantic scallop (<i>Placopecten magellanicus)</i> (n=10) and Jonah crab (<i>Cancer borealis</i>) (n=5) from the Mid-Atlantic Bight region to study the occurrence of biomagnification through trophic pathways. NC loggerhead turtles had higher heavy metal concentrations than other locations except for cadmium and zinc, where CCB loggerhead turtles were higher. I found that all heavy metals except silver, cadmium, and lead appear to be biomagnified (TTF>1) in loggerhead turtles. These two chapters provided baseline information on heavy metal concentrations in sea turtles in east coast US.</p>

Due to mining activities, the natural vegetation cover in Gatumba area was removed and replaced either by crops or bare wasteland with reduced available arable land. The main aim of the study was to assess the impact of the mining activities on the plant mineral uptake and the dynamics of the vegetation. The vegetation in this area under investigation was diversified and heterogeneous. Trace element concentrations in soils were similar to those in plant parts but some elements were highly concentrated in soils than in plants. According to the bioaccumulation factors of the analyzed trace elements in plant parts, two categories of plants were identified, and these are excluders and accumulators. No toxic levels of the evaluated trace elements were found in the analyzed plant samples. As a recommendation for the adaptation of plants to Gatumba mining environment, the most useful plant species for the revegetation/restitution of the technosols should be Sesbania sesban, Crotalaria dewildemaniana and Tithonia diversifolia subject to further experiments on trace elements bioaccumulation and organic matter production / Environmental Sciences / M.A. Science (Environmental Sciences)

Thesis (MScAgric (Zoology))--University of Stellenbosch, 1996. / A number of studies on the general physico-chemical character of the Eerste River, Western Cape, had previously been done, but the problem of heavy metal pollution had, by 1993, not been addressed. A study was therefore undertaken from 1993-1995 in order to investigate these aspects. Since several researchers have shown that freshwater crabs accumulate certain heavy metals in their bodies and may therefore be used as monitors of environmental heavy metal pollution, the present study concentrated mainly on metal concentrations (Mn, Zn, Cu, Pb and Cd) in the local freshwater crab species, Potamonautes perlatus, and its possible use as biomonitor in the Eerste River. Two localities in the Eerste River were chosen,. in order to make comparisons, namely a relatively uncontaminated site in the Assegaaibosch Nature Reserve, Jonkershoek, and a visibly polluted site downstream from Stellenbosch, behind Stellenbosch Farmers' Winery (SFW). Crabs, water and sediment samples were collected seasonally at both localities, and metal concentrations thereof determined by atomic absorption spectrophotometry. The results showed that the Eerste River down to the SFW locality is still relatively unpolluted in terms of heavy metals. It was, however, clear that runoff from the Stellenbosch municipal, industrial and agricultural areas do have an influence on other physico-chemical features of the river. The concentrations of heavy metals in whole crabs, tissues and carapace showed that Zn concentration was well regulated in P. perlatus from both localities, Mn and Cu were accumulated in individuals from SFW, and Pb and Cd accumulated in both populations. Compartmentalization of heavy metals was shown to occur in P. perlatus: the carapace was found to be the most important storage site for Mn, Zn and Pb, the carapace and gonads equally important for Cd storage, and the digestive gland the most important site for Cu storage. Whereas gender was shown, generally, to be of little importance in heavy metal uptake in P. perlatus, crab body size and seasonality were both shown to influence heavy metal uptake to some extent. However, only summer peaks in whole crab, carapace and tissue manganese concentrations were shown to correlate with peaks in environmental Mn concentrations. It was concluded that P. perlatus would possibly only be a Suitable monitor of environmental Mn, Pb and Cd pollution, although there is no guarantee that the crab body would accurately reflect environmental concentrations. It was also ascertained that, since a study of the sperm ultrastructure of P. perlatus showed a significantly larger number of abnormal spermatozoa in male crabs from ,SFW, and since these observed differences could possibly be related to heavy metal exposure, the sperm of this species might be a more reliable indicator of heavy metal pollution. It was finally concluded that more intensive research need to be undertaken on various aspects, especially the use of the spermatozoon as indicator of environmental heavy metal pollution, and that the results of the present study could serve as a basis for future studies.

The aim of this study was to use plants to determine the degree of heavy metal contamination in water and sediments in order to effectively monitor and provide possible recommendation to improve the water quality in the aquatic ecosystem of the Bottelary River.

Copper and zinc are heavy metals commonly present in highway stormwater runoff. Discharge of these metals to surface waters inhabited by sensitive aquatic species including threatened and endangered salmonids has necessitated the need for improved treatment techniques. Although copper is of the greater toxicological concern, zinc is often present at concentrations several times higher than copper and may compete with copper during adsorptive treatment processes. In the current study, the ability biogenic fish-bone based alternative adsorbent, Apatite II™, for copper and zinc removal from synthetic stormwater runoff was evaluated. Batch experiments were employed to examine equilibrium removal and rapid small scale column tests (RSSCT) were used to simulate dynamic operation in continuous systems. In both batch and continuous systems, the release of phosphate and calcium were observed, and Apatite II™ achieved high removal efficiencies. The removal of copper and zinc was likely due to a combination of processes including adsorption, ion exchange and precipitation. Precipitation played a dominant role in copper removal and the release of phosphate and pH buffering appear to drive this process. While precipitation was also quite important for zinc removal, adsorptive removal also played a role. The findings from the current study provide a general understanding of the performance of copper and zinc removal from stormwater runoff using Apatite II™. / Graduation date: 2012

The aim of this study was to use plants to determine the degree of heavy metal contamination in water and sediments in order to effectively monitor and provide possible recommendation to improve the water quality in the aquatic ecosystem of the Bottelary River.