The impact of cow dung augmentation on soil restoration and bio-accumulation of metals (Lead and Cadmium) in Pheretima posthuma (Annelida: Clitellata)

To investigate the role of cow dung in soil reclamation and bio assimilation along with bio accumulation of heavy metals in earthworm (P. posthuma) (N=900) earthworms were used and treatment groups of CD-soil mixture of different proportion of cow dung were designed. Nonlethal doses of lead acetate and cadmium chloride were added in treatment groups. Mature P. posthuma were released in each experimental pot maintaining the favorable conditions. The pH, carbon, nitrogen, phosphorus, exchangeable cations, and heavy metal level of each mixture was evaluated. The results indicated that bio-assimilation of Pb and Cd by P. posthuma were significantly (P ˂ 0.01) higher in different soil-CD treatments compared to control. Highest bio-assimilation of both metals was observed in T1 of both groups (Pb = 563.8 mg/kg and Cd = 42.95 mg/kg). The contents of both metals were significantly (P ˂ 0.05) lowered in casting. The nutrient concentration in the final castings of all soil-CD treatments were also equally transformed from less or insoluble to more soluble and available for plants, except for carbon level which increased with CD proportion. It is concluded that cow dung as organic matter has a positive effect on soil reclamation and bio-assimilation of metals by P. posthuma.

Quantification of Some Metals in Commonly Consumed Canned Foods in South-west Nigeria: Probable Pointer to Metal Toxicity

Canned foods are one of the most commonly consumed products, due to benefits like the taste, handiness and convenience derived from them. On the other hand, these dietary products may be a means of heavy metal exposure and toxicant. This study aimed to quantify metals content in some frequently consumed canned foods in Nigeria as a possible source of toxicity. Twenty-two different commonly consumed brands of canned foods (Sweet corn, Green peas, Corned beef, Hotdog, Mushroom, Tin tomato, Mixed fruit, Baked beans, Mackerel (tomato sauce canned fish), Sardine (canned fish in vegetable oil) and Red kidney were analyzed for Ni, Cr, Cu, Pb and Al using Atomic Absorption Spectrophotometer after wet digestion. The results showed that the heavy metals concentration in the samples under study ranged from 0.55 to 0.86mg/kg (Ni), 0.00 to 0.41mg/kg (Cr), 1.40 to 1.76 mg/kg (Pb), 0.07 to 0.2mg/kg (Cu) and 4.71 to 16.4mg/kg (Al). The levels of Pb, Ni and Al were above FAO/WHO recommended limit of 0.01mg/kg, 0.05mg/kg and 7mg/kg respectively. The presence of heavy metals like lead (Pb) above the permissible limit calls for caution during production and in the frequent consumption of canned foods which may lead to accumulation of metals, toxicity and the sequelae.

Changes in Anatomical Features of Chromolaena Odorata during Phytoaccumulation of Heavy Metals

The present study investigated the accumulation of selected HMs by Chromolaena odorata and the concomitant effects on leaf anatomical features. Top soils were collected from a marked plot and pooled together to obtain a composite sample. The soil was sun-dried to constant weight and measured into experimental pots at 20kg each). The pots were divided into 5 metal groups with 3 sub-groups each. Each group was polluted with Manganese (Mn), Cadmium (Cd), Copper (Cu), Lead (Pb) and Zinc (Zn) in their respective chloride forms. Concentrations of the metals in the soil were initially based on their respective ecological screening value/benchmark (ESV). The ESV values for the 5 HMs were 50, 4, 100, 50 and 50 mg/kg respectively. Within each group, the respective HMs was applied in 3 concentrations of 1ESV, 3ESV and 5ESV. The control experiment consisted of plants grown in soils with no exogenous application of the test metals. The experiment was triplicated. Twenty hours later, equal sized stem cuttings of C. odorata (2.0 – 2.3cm in thickness, 30 cm in length) were planted per experimental pot. Six months later, results showed significant accumulation of metals in plant stem, leaves, and most especially the root. Mn was the most accumulated HM in all plant parts (9.22 – 17.86 mg/kg), compared to Cd (0.85 – 1.66 mg/kg).Significant changes in folial anatomy were reported in HM-impacted plants compared to the control. There were more upper epidermal stomata (270 – 353 mm2) in Mn-exposed plants compared to the others. Increase in vascular bundle thickness (p<0.01) was reported in HM-exposed plants compared to control. Highly significant decrease in stem parenchyma thickness (p<0.01) never the less parenchyma thickness of HM-exposed plants ranged from 46.37 – 49.53 µm in Zn and Pb-exposed plants compared to 79.23 µm in the control.

Crustal-scale transport of nanoparticle emulsion forms ore deposits

A 10- to 10 000-fold enrichment is required to form economic metal deposits. Such enrichment is achieved through the accumulation of metals transported in hydrothermal fluids from their source to the deposit. The contribution of gold nanoparticle suspensions in fluids is required to form bonanza gold grades. However, as the source of gold is spatially disconnected from the deposit location, it is not known how the transport of gold nanoparticles is achieved. Here we show that metal nanoparticles (Au, AgO, AuAg Cu) are stabilised by colloidal silica in nanoparticle emulsion and transported with the aid of low-density carbonic phases. We document systematic occurrence of metals nanoparticle in five deposits that show a previously unrecognized association with amorphous silica and carbon. Our results demonstrate that stabilisation of metal nanoparticles may be achieved over kilometres through the Earth’s upper crust and offers a step change in our understanding of metalliferous deposit formation.

Differences in the Content of Zn Fractions in the Profiles of Soils from Allotment and Domestic Gardens in South-Eastern Poland

The aim of the research was to show the distribution of fractions as well as bioavailability and the total forms of Zn in the profiles of soils from domestic gardens and family allotment gardens in six cities in south-eastern Poland. Results found that the level of Zn total form varied in the ranges from A horizon: 12.75–154.75 mg·kg−1 in sandy soils and 18.20–104.00 mg·kg−1 in silty soils. Accumulation of metals was assessed using concentration indices, Igeo, and the Cav/Ct and BF indices of bioavailable forms. The analysis took into account the role of organic matter as an important component in binding the analyzed metals in soil horizons subjected to long-term horticultural cultivation. In the two groups of sandy and silty soils distinguished according to their particle size distribution, horticultural treatments were found to exert a greater impact on sandy soils. Additionally, higher contents of the examined element were stated in the humus horizons, as indicated by the high values of concentration and Igeo indices showing high Zn pollution in the soils. The content of bioavailable zinc forms was significantly high, especially in soils with a higher metal content.

Heavy metals in the green-lipped mussel Perna viridis: Are they safe as animal feeds?

The objective of this study was to compare the cited data of Cd and Pb levels in the green-lipped mussels (Perna viridis) with established maximum limits of both metals by European Union (EU) legislation for animal feeds. It was found that most mussel populations from Malaysia (90% for Cd; 87.5% for Pb) and Hong Kong (96.2% for Cd; 100% for Pb) were found to have lower levels of Cd and Pb than the maximum limits for animal feeds by EU. Therefore, both toxic metals based on the feeds of mussel meats on the animals should not pose serious toxicological effects. However, the meat of P. viridis are potential animal feeds similarly to the fish meal. Considering the accumulation of metals in the long term, future biomonitoring of Cd and Pb should focus on animal feed materials on mussel-based origins. Keywords: Animal Feed; Mussels; Safety

Effect of Soil Degradation and Remediation in Technogenic Barrens on the Uptake of Nutrients and Heavy Metals by Plants in the Kola Subarctic

To assess the state of plants and their response to changes in soil properties, the elemental composition of leaves of widespread and pollution-tolerant species Betula pubescens Ehrh. and Salix caprea L. has been studied near the nonferrous metallurgy enterprises in the Kola Peninsula. The content of nutrients and heavy metals in the leaves of undergrowth on technogenic barrens and remediation sites differing in remediation technologies has been analyzed. According to the results of leaf diagnostics, both species under barren conditions are characterized by a noticeable deficiency of K, Ca, P, and, especially, Mn and Zn. The leaves of both species accumulate Ni, Cu, Co, As, Cr, Fe, Al, Pb, V, and S. Willow leaves contain more Cd, Co, Cr, Ni, Cu, Al, Fe, As, S, Ca, K and less Mn than birch leaves. Chemophytostabilization has little effect, and the covering of contaminated soils with a constructed fertile layer leads to the enrichment of birch and willow leaves with Ca, K, and P. Under conditions of continuing atmospheric emissions and gradual accumulation of bioavailable heavy metals in soils after the remediation, the accumulation of metals in leaves is largely determined by the distance from the pollution source, reflecting the possibility of both root and foliar uptake. The concentrations of Ni and Cu in leaves in 2018 did not decrease compared to 2011. The low, albeit varying, ratios of the contents of heavy metals in undergrowth leaves and in the soil and weak correlation of heavy metal contents in these media indicated that B. pubescens and S. caprea retain their ability to regulate their chemical composition even under extreme conditions of technogenic barrens. At the same time, supporting the protective capabilities of plants via optimizing mineral nutrition and soil acidity in combination with a reduction in atmospheric pollution is a prerequisite for efficient remediation of technogenic territories in the Far North.

Gold mining’s toxic legacy: Pollutant transport and accumulation in the Klip River catchment, Johannesburg

Waste from gold mines is considered to constitute the largest single source of waste pollution in South Africa and contributes significantly to acid mine drainage, which remains one of the country’s most serious environmental and socio-economic issues. Run-off from the Central Rand Goldfield discharges into wetlands along the Klip River, which are known to be important sinks for toxic pollutants. The aim of this study was to examine the transport, migration and sequestration of metal pollutants in the upper Klip River catchment in further detail. Analyses reveal that the majority of pollutants are associated with contaminant plumes that emanate from mine dumps and enter the wetland via groundwater recharge. This water carries highly elevated concentrations of Co, Ni, Zn, U and rare earth elements, which are naturally sequestered within the wetland, largely through precipitation and adsorption. While surface run-off from mine dumps severely contaminates watercourses within the upper catchment, surface inputs are considered relatively minor contributors to the overall pollutant load entering the Klip River wetland, although aerosol fallout is an important source of Pb. The extensive accumulation of metals within the Klip River wetland reflects the contaminant legacy associated with gold mining on the Witwatersrand and highlights the vital role this natural system has played in trapping vast quantities of toxic pollutants and remediating downstream waters. Contaminant plumes associated with mine dumps will likely persist for decades; preventing further deterioration of the Klip River wetlands is thus critical for safeguarding water sources in the region.

The impact of sediment, fresh and marine water on the concentration of chemical elements in water of the ice-covered lagoon

The common use of chemical elements by man has been contributing to their extraction for centuries. As a consequence, they have been directly or indirectly introduced into the biogeochemical cycle. In the framework of many conventions, mining and processing of elements are currently subject to many restrictions. However, their large load that has already been deposited in the soil and bottom sediments can be remobilised and enter the food chain. The identification of factors favouring this process is very important, especially during the period of adopting new legal regulations on limiting the emission of pollutants. It became possible in February 2018 during the persistence of ice cover on the lagoon’s surface. This allowed observation of processes, the effect of which in the absence of ice is blurred by wind mixing water. Therefore, an investigation of sources of 25 elements in a lagoon of the southern Baltic has been undertaken, based on the example of the Vistula Lagoon. The results point to the remobilisation of chemical elements (including the toxic ones) from land and bottom sediments, where they have been deposited for decades. These processes led to the accumulation of metals in certain areas of the lagoon. It may result in their uptake and accumulation in the benthic organisms inhabiting the lagoon and further transfer in the food chain. It is of major importance as the lagoons in the southern Baltic fulfil many essential functions in the scope of tourism, economy, and fishery. Thanks to restrictions on the quality of wastewater and the emission of pollutants, it has been noticed a substantial “purifying” effect of rivers, too.

Differentiation of Trace Metal Contamination Level between Different Urban Functional Zones in Permafrost Affected Soils (the Example of Several Cities in the Yamal Region, Russian Arctic)

Dynamically developing urbanization causes a number of environmental effects, including those related to the chemical transformation of soils. Relatively less information about the urban areas of the Arctic and Subarctic zones, constructed mostly on permafrost and intensively populated areas can be found. By the example of the analysis of basic soil properties and concentrations of trace metals in the soils of the cities of Salekhard, Urengoy, Nadym, Novy Urengoy and Gaz Sale (the Yamalo-Nenets Autonomous District), as well as various functional zones within the cities, the relationship between the age of the cities, the level of anthropogenic pressure and the type of parent materials and the character of accumulation of metals in the soil profile of urban soils have been described. The direct correlation was found between the content of Pb, Cr, Ni, As and soil sorption characteristics. In young cities built on sandy sediments, there is less accumulation of heavy metals in the topsoil horizons. Relatively higher concentrations of Cu and Cd were noted in soils of industrialized cities, regardless of functional zones. The higher content of Cr, Ni, Cu, Zn, As and Pb has been registered in older zones also frequently used for residential purposes. The calculated values of the PI index for some functional zones of young cities show the medium and high content of heavy metals. The analysis of Igeo and PLI indices shows a large diversity both in relation to individual cities and their functional zones. Soil quality, in spite of the high level of anthropogenic load, was assessed as mostly satisfactory.