Innocent C. Nnorom

The challenge of electronic waste (e-waste) management in developing countries

Information and telecommunications technology (ICT) and computer Internet networking has penetrated nearly every aspect of modern life, and is positively affecting human life even in the most remote areas of the developing countries. The rapid growth in ICT has led to an improvement in the capacity of computers but simultaneously to a decrease in the products lifetime as a result of which increasingly large quantities of waste electrical and electronic equipment (e-waste) are generated annually. ICT development in most developing countries, particularly in Africa, depends more on secondhand or refurbished EEEs most of which are imported without confirmatory testing for functionality. As a result large quantities of e-waste are presently being managed in these countries. The challenges facing the developing countries in e-waste management include: an absence of infrastructure for appropriate waste management, an absence of legislation dealing specifically with e-waste, an absence of any framework for end-of-life (EoL) product take-back or implementation of extended producer responsibility (EPR). This study examines these issues as they relate to practices in developing countries with emphasis on the prevailing situation in Nigeria. Effective management of e-waste in the developing countries demands the implementation of EPR, the establishment of product reuse through remanufacturing and the introduction of efficient recycling facilities. The implementation of a global system for the standardization and certification/labelling of secondhand appliances intended for export to developing countries will be required to control the export of electronic recyclables (e-scarp) in the name of secondhand appliances.

TOXICITY CHARACTERIZATION OF WASTE MOBILE PHONE PLASTICS

Waste plastic housing units (N=60) of mobile phones (of different models, and brands), were collected and analyzed for lead, cadmium, nickel and silver using atomic absorption spectrophotometry after acid digestion using a 1:1 mixture of H2SO4 and HNO3. The mean (+/-S.D.) and range of the results are 58.3+/-50.4mg/kg (5.0-340mg/kg) for Pb, 69.9+/-145mg/kg (4.6-1005mg/kg) for Cd, 432+/-1905mg/kg (5.0-11,000mg/kg) for Ni, and 403+/-1888mg/kg (5.0-12,500mg/kg) for Ag. Approximately 90% of the results for the various metals were < or =100mg/kg. Results greater than 300mg/kg were generally less than 7% for each metal and could be attributed to exogenous contamination of the samples. These results suggest that there may not be any immediate danger from end-of-life (EoL) mobile phone plastic housing if appropriately treated/managed. However, considering the large quantities generated and the present low-end management practices in most developing countries, such as open burning, there appears a genuine concern over the potential for environmental pollution and toxicity to man and the ecology.

Heavy metal characterization of waste portable rechargeable batteries used in mobile phones

Ten brands of spent portable rechargeable batteries used in mobile phones (lithium-ion and nickel metal hydride) were collected and disassembled and the battery electrode and printed wiring board prepared using the EPA Method 3050B. The metal concentrations were determined by atomic absorption spectrometry. The mean (± standard deviation) concentrations and range of cobalt, chromium, nickel and cadmium in the battery electrodes were 361284±32281mg/kg (range 20870–575330 mg/kg); 25.3 ± 4.6 mg/kg (7.9–149 mg/kg); 75272 ± 14630 mg/kg (3589–266607 mg/kg) and 2.8 ± 0.6 mg/kg (0.2–16.3 mg/kg), respectively. Similarly, the mean values of cobalt, chromium, nickel and cadmium in the PWB were 564 ± 165 mg/kg (56.1–4068 mg/kg); 28.1 ± 4.0 mg/kg (ND-97.2 mg/kg); 735 ± 188 mg/kg (22.7–2727 mg/kg) and 1.8 ± 0.3 mg/kg (ND-7.2 mg/kg), respectively. The Li-ion battery electrodes contained significantly higher levels of cobalt (p < 0.01) whereas, the NiMH battery contained significantly higher nickel (P < 0.01). All the results for the cobalt and nickel levels in the battery electrodes exceeded the toxicity threshold limit concentration used in the toxicity characterization of solid wastes (cobalt, 8000 mg/kg; nickel, 2000 mg/kg). In fact, the mean cobalt level of the battery electrode is about 45 times the toxicity threshold limit concentration limit for cobalt while the mean nickel result is about 38 times the toxicity threshold limit concentration. Spent portable rechargeable batteries should be handled as toxic materials that require special treatment. Implementation of a well-coordinated management strategy for spent batteries is urgently required to check the dissipation of large doses of toxic heavy metals and rare earth into the environment.

Occurrence and accumulation of mercury in two species of wild grown Pleurotus mushrooms from Southeastern Nigeria.

The aim of this study was to evaluate the degree of contamination and intake rates, as well as the risk of Hg contained in two wild species of Pleurotus mushrooms--Oyster Mushroom (P. ostreatus) and King Tuber Mushroom (P. tuber-regium)--which are widely consumed in southeastern Nigeria; and to also assess their potential to accumulate Hg. The mean Hg concentrations in caps of P. ostreatus from distant sites of Ekeoba, Ntigha, and Ubakala in Abia State, were 31±11, 28±8, and 29±5 ng g(-1) dry weight, respectively; while the mean concentrations for stipes were 37±5, 36±17, and 28±6 ng g(-1) dw, in the respective communities. The caps and stipes were characterized by a mean bioconcentration factor value of ∼2, indicating that P. ostreatus is a very weak Hg accumulator and probably takes in Hg solely from the wooden substratum. Sclerotia of P. tuber-regium, purchased from five different regional markets: Ukwunwangwu (Uturu), Ekeama (Umuobiala), and Ahonta (Eluama) of Abia State; and from Abakpa market and Eke-Okigwe of Imo State; contained Hg in total range of 3.3 to 180 ng g(-1) dw. A meal consisting of 300 g of caps and stipes of P. ostreatus, or of fresh sclerotia of P. tuber-regium, would expose a consumer to <1.2, and between 0.39 and 1.2 μg Hg, respectively; and, if eaten daily for a week, would contribute less than 0.03%, and between 0.76% and 2.3% of the provisionally tolerable weekly intake (PTWI). The consumption of P. ostreatus and sclerotia of P. tuber-regium harvested from the areas investigated, therefore, poses no toxicological or health risks to the inhabitants.

Mercury in fruiting bodies of dark honey fungus (Armillaria solidipes) and beneath substratum soils collected from spatially distant areas.

BACKGROUND This paper reports data on bioconcentration potential and baseline mercury concentrations of fruiting bodies of dark honey fungus (Armillaria solidipes) Peck and soil substrate layer (0-10 cm) from 12 spatially distant sites across Poland. Mercury content of caps, stipes and soil samples were determined using validated analytical procedure including cold-vapor atomic absorption spectroscopy after thermal decomposition of the sample matrix and further amalgamation and desorption of mercury from gold wool. RESULTS Mean mercury concentrations ranged from 20 ± 8 to 300 ± 70 ng g(-1) dry weight (dw) in caps, from 20 ± 6 to 160 ± 40 ng g(-1) dw in stipes, and in underlying soil were from 20 ± 2 to 100 ± 130 ng g(-1) dw. The results showed that stipes mercury concentrations were 1.1- to 1.7-fold lower than those of caps. All caps and the majority of stipes were characterized by bioconcentration factor values > 1, indicating that dark honey fungus can be characterized as a moderate mercury accumulator. CONCLUSION Occasional or relatively frequent eating of meals including caps of dark honey fungus is considered safe in view of the low total mercury content, and the mercury intake rates are below the current reference dose and provisionally tolerable weekly intake limits for this hazardous metal.

Mercury in Russula mushrooms: Bioconcentration by Yellow-ocher Brittle Gills Russula ochroleuca

The purpose of this study was to examine the contamination and bioconcentration potential of mercury (Hg) in Yellow-ocher Brittle Gills known also as Yellow-ocher Brittle Gill or Common Russula (Russula ochroleuca) mushroom. Matured fruiting bodies of this fungus and soil samples were collected at ten spatially distant unpolluted sites in the northern part of Poland in 2004–2008. Total Hg content of fruiting bodies and soil were determined by cold-vapour atomic absorption spectroscopy (CV–AAS). The total Hg content of the Yellow-ocher Brittle Gills varied between 0.017 and 0.43 μg/g dry weights in individual caps and between 0.011 and 0.24 μg/g dw in the stipes. The mean mercury content of the mushroom varied spatially (p < 0.001) between the sites - in caps between 0.039 ± 0.024 and 0.18 ± 0.11 μg/g dw; and in stipes between 0.027 ± 0.014 and 0.13 ± 0.06 μg/g dw. The caps usually contained Hg in greater concentrations than stipes and the mean values of cap to stipe Hg concentration quotient (Qc/s) varied from 1.3 ± 0.4 to 1.9 ± 0.04. The range of Hg concentrations in the top soil layer (0–10 cm) varied from 0.011 to 0.51 μg/g dw (mean values varied between 0.025 ± 0.010 and 0.18 ± 0.13 μg/g dw). Mean Hg bioconcentration factor (BCF) varied between 0.57 ± 0.30 and 5.6 ± 1.7 for caps and 0.50 ± 0.49 and 3.3 ± 1.8 for stipes. Yellow-ocher Brittle Gills from Trójmiejski Landscape Park contained Hg at greater concentration compared to other sites. Also presented is a review of data on Hg contents of the genus Russula (41 species, both edible and inedible to man) collected from across the world.

Mercury in Yellow-cracking Boletes Xerocomus subtomentosus mushrooms and soils from spatially diverse sites: Assessment of bioconcentration potential by species and human intake

This study investigated the Hg concentrations in Yellow-cracking Boletes Xerocomus subtomentosus mushrooms and beneath soils collected from the wild at twelve sites across Poland. This mushroom species has some potential to bioconcentrate Hg in the fruiting bodies, and the amount of Hg sequestered, depending on geographical location, can pose health risk to consumers. The values of Hg bioconcentration factor (BCF) varied for the sites between 0.80 ± 0.20 and 17 ± 12 in caps and 0.50 ± 0.10 and 7.9 ± 6.6 in stipes of fruiting bodies but decreased as soil Hg content increased from 72 ± 32 to 570 ± 130 ng/g dry weight. The specimens collected from minerals rich area of Złotoryja contained the highest Hg concentration, which reached 630 ± 400 in caps and 420 ± 260 ng/g dw in stipes, while the lowest observed Hg concentrations at the other sites were 72 ± 32 and 57 ± 13 ng/g, for cap and stipes respectively. Available literature data on Hg in Yellow-cracking Boletes was also up-dated.

Mercury in the Grisette, Amanita vaginata Fr. and soil below the fruiting bodies

This study examined the mercury concentration in the Grisette Amanita vaginata Fr. and soil below the fruiting bodies collected between 2000 and 2008 from the wild at seven distant sites across Poland. The Hg content in samples was determined by cold atomic absorption method (CV-AAS) at a wavelength of 253.7 nm. Mean Hg contents varied from 0.096 ± 0.052 to 0.48 ± 0.13 mg kg−1 dry matter (dm) in caps (range, 0.043–0.73 mg kg−1), from 0.047 ± 0.02 to 0.23 ± 0.07 mg kg−1 dm (range, 0.028–0.47 mg kg−1) in stipes, and in underlying soil were from 0.035 ± 0.018 to 0.096 ± 0.036 mg kg−1 dm (range, 0.017 to 0.16 mg kg−1). The median Qc/s values ranged from 1.2 to 2.2 (mean 1.2 ± 0.4 to 2.1 ± 0.5) indicating that Hg content in stipes was generally lower than in caps. This mushroom species has some potential to bioconcentrate Hg in the fruiting bodies, as the values of the bioconcentration factor (BCF) varied for the sites between 1.2 ± 0.6 to 11 ± 5 for caps and 0.61 ± 0.26 to 7.4 ± 3.9 for stipes. Also available literature data on Hg in A. vaginata are reviewed and discussed.

Mercury in certain boletus mushrooms from Poland and Belarus

This paper reports the results of the study of Hg contents of four species of Boletus mushroom (Boletus reticulatus Schaeff. 1763, B. pinophilus Pilát & Dermek 1973, B. impolitus Fr. 1838 and B. luridus Schaeff. 1774) and the surface soils (0–10 cm layer, ∼100 g) samples beneath the mushrooms from ten forested areas in Poland and Belarus by cold-vapour atomic absorption spectroscopy. The ability of the species to bioconcentrate Hg was calculated (as the BCF) while Hg intakes from consumption of these mushroom species were also estimated. The median Hg content of the caps of the species varied between 0.38 and 4.7 mg kg−1 dm; in stipes between 0.13 and 2.5 mg kg−1 dm and in the mean Hg contents of soils varied from 0.020 ± 0.01 mg kg−1 dm to 0.17 ± 0.10 mg kg−1 dm which is considered as “background” Hg level. The median Hg content of caps of B. reticulatus and B. pinophilus were up to 4.7 and 3.6 mg kg−1 dm, respectively, and they very efficiently bioaccumulate Hg with median BCF values of up to 130 for caps and 58 for stipes. The caps and stipes of these mushrooms if eaten will expose consumer to elevated dose of total Hg estimated at 1.4 mg for caps of Boletus reticulatus from the Kacze Łęgi site, which is a nature reserve area. Nevertheless, the occasional consumption of the valued B. reticulatus and B. pinophilus mushrooms maybe safe.

Concentrations and Bioconcentration Factors of Minerals in Yellow‐Cracking Bolete (Xerocomus Subtomentosus) Mushroom Collected in Noteć Forest, Poland

UNLABELLED Yellow-cracking Bolete (Xerocomus subtomentosus) mushrooms and soil were collected from Noteć Forest--a large forested enclave in western part of Poland. Mercury was determined by cold vapour atomic absorption spectroscopy and the other elements by inductively coupled plasma atomic emission spectroscopy. K, P, and Mg were particularly abundant, with mean values of 46000, 8400, and 1100 mg/kg dry weight (dw) in caps followed by Na, Rb, Zn, and Ca with mean concentrations of 580, 350, 200, and 170 mg/kg dw, respectively. In descending order, the mean concentrations of Fe, Al, Cu, and Mn were 52, 49, 46, and 14 mg/kg dw, while the mean for the remaining elements was around 1.0 mg/kg dw or less. The elements such as Ca, Cu, Hg, K, Mg, Na, P, Rb, Zn, Ag, Cd, and Ni were accumulated (with bioconcentration factor (BCF) > 1), while Al, Ba, Fe, Mn, Sr, Co, Cr, and Pb were excluded (BCF < 1) in the fruiting bodies. The Pb and Cd content did not exceed the maximum levels set by the EU for cultivated mushrooms. Mercury in a conventional meal (300 g) portion of Yellow-cracking Bolete was far below the provisionally tolerable weekly intake of 0.004 mg/kg body weight (bw) as reevaluated recently by WHO. PRACTICAL APPLICATION The method presented in this study allows one to determine the content of 20 elements (Ag, Al, Ba, Ca, Cd, Co, Cr, Cu, Fe, Hg, K, Mg, Mn, Na, Ni, P, Pb, Rb, Sr, and Zn) in caps and stipes of Yellow-cracking Bolete (Xerocomus subtomentosus) mushrooms and soil samples collected from Poland. This study has revealed that the total Cd, Hg, and Pb dose provided to human body due to consumption of Yellow-cracking Bolete does not pose threat to a consumers health.