Chelating reagents impregnated or incorporated into solid sorbents have been widely used in the preconcentration of metal species. In this work, polystyrene-divinylbenzene functionalized with 2-hydroxyacetophenone was used for the preconcentration and determination of cadmium, cobalt, and nickel in sediment samples by flame atomic absorption spectrometry. The sorbent was characterized by infrared spectroscopy and scanning electron microscopy. The influence of variables on the extraction of the metal ions was studied. Under optimized conditions, the method showed enrichment factors of 20 (Cd), 37 (Co), and 32 (Ni) and detection limits of 0.1 (Cd), 0.8 (Co), and 0.6 μg L⁻¹(Ni). The accuracy of the method was tested by analysis of a certified reference material composed of inorganics in marine sediment (NIST 2702). The method was applied to the determination of cadmium, cobalt, and nickel in real sediment samples. Cadmium and cobalt were not found in the sediment samples. Nickel was found in two samples (5.2 and 8.2 μg g⁻¹).

The ability of untreated and acid-treated biomass from Pistia stratiotes (PL and APL, respectively) and Eichhornia crassipes (ELS and AELS, respectively) to remove color from anaerobically digested sugar cane stillage (ADS) was investigated. The effects of pH (3–8), particle size (< 0.75, 0.75–1, 1–4 mm), and biomass concentration (5–15 g/L) on decolorization of ADS were assessed using untreated biomass. After acid modification of biomass (acid-treated), the effects of pH (3–8), biomass concentration (6–10 g/L), time (20–480 min), and ADS dilution (non-diluted, 1:2, 1:10, 1:20) on color removal from ADS were evaluated. Scanning electron microscopy and Fourier transform infrared spectroscopy (FTIR) analyses were also performed. A clear effect of particle size on ADS decolorization was found (21.04 ± 0.75 and 27.87 ± 0.30 % for 0.75–1 and <0.75 mm, respectively, for ELS; 31.65 ± 0.23 and 37.82 ± 0.53 for 1–4 and 0.75–1 mm, respectively, for PL). Decolorization also increased when the untreated biomass concentration was higher (15.41 ± 0.3 and 27.89 ± 0.2 % for 5 and 10 g/L, respectively, for ELS; 15.61 ± 0.11 and 33.06 ± 1.09 % for 5 and 10 g/L, respectively, for PL). The use of acid-treated biomass enhanced the effect of pH on color removal (48.30 ± 1.27 and 12.96 ± 0.27 % for pH of 3 and 7, respectively, for AELS; 47.11 ± 1.72 and 6.62 ± 0.21 % for pH of 3 and 7, respectively, for APL). The highest rate of color removal obtained using acid-treated biomass was 55.58 ± 1.82 and 56 ± 0.77 % for AELS and APL, respectively. The FTIR spectra analysis suggested the electrostatic attraction between protonated carboxylic groups on biomass and anionic colored compounds as being one of the adsorption mechanisms for ADS decolorization. The use of dry biomass from invasive macrophytes is an effective alternative for color removal from ADS.

Background. Ghana, like many countries in Africa, has a history of heavy metal pollution largely emanating from industrial effluent discharges and anthropogenic deposits on prevailing winds of pollutants from industrial activities. One of the biggest contributors to pollution in the Ghanaian environment is mineral mining. Objectives. The aim of this study was to determine the distribution and health risks of heavy metals in surface water from both pristine environments and major mining areas in Ghana. Methods. A total of 32 composite samples were collected between September and October, 2014 to assess concentrations of heavy metals and pollution levels, as well as cancer and non-cancer risks to human health from exposure to heavy metals from four major mining regions and four rain forest reserves in the Western, Ashanti, Brong Ahafo and Eastern regions of Ghana. Samples were analyzed using atomic absorption spectrometry. Results. The mean concentrations (mg/L) of heavy metals at the pristine sites ranged from 1.747 for iron (Fe) to 0.001 for mercury (Hg) and 0.453 for Fe to 0.002 for Hg at the mining sites. All the metals were found to be below World Health Organization (WHO) and United States Environmental Protection Agency (USEPA) recommended limits except for Hg, which was at the USEPA guideline limit. However, the concentrations of the metals from the mining sites were found to be slightly higher than those from the pristine sites. Conclusions. The concentrations of heavy metals in the Nyam, Subri, Bonsa and Birim Rivers from the mining sites and the Atiwa Range, Oda, Ankasa and Bosomkese Rivers from the pristine sites were found to be either below or within the USEPA and WHO's recommended limits for surface water. The health risk assessment values for the hazard quotient for ingestion of water (HQing), dermal contact (HQderm) and chronic daily intake (CDI) indicated no adverse effects as a result of ingestion or dermal contact from the rivers. However, arsenic (As) in both the pristine and mining sites and chromium (Cr) in the pristine sites pose a carcinogenic threat to the local residents.

Background. Mining activity in the catchment area of Tanzania’s Lake Rukwa is suspected of adding to the lake and connected rivers’ heavy metal load. There has been no study done, however, on the levels of mercury (Hg) and lead (Pb) in lake sediment and fish muscle, and what the results could mean for human health. Objectives. This study investigated the concentration of Hg and Pb in lake sediment and in the muscles of African sharptooth catfish (Clarias gariepinus), Lake Rukwa tilapia (Oreochromis rukwaensis) and Singida tilapia (Oreochromis esculentus) from Tanzania’s Lake Rukwa and connected rivers. Methods. Concentrations of Hg and Pb in fish muscle and lake sediment were measured using inductively coupled plasma atomic emission spectroscopy (ICP-AES) and mercury analyzers, respectively. Results. Levels of Pb and Hg from C. gariepinus ranged between 0.01 to 1.9 μg/g and 0.03 to 0.33 μg/g, respectively. Pb and Hg in O. esculentus varied between 0.02 to 1.4 μg/g and <0.01 to 0.29 μg/g, respectively. Pb and Hg levels in O. rukwaensis ranged from 0.12 to 0.88 μg/g and 0.12 to 0.88 μg/g, respectively. On the other hand, concentrations of Pb and Hg in the sediment samples ranged between 0.02 to 16.23 μg/g and from 0.01 to 1.43 μg/g, respectively. Concentrations of Hg in the muscles of C. gariepinus and O. esculentus were above World Health Organization (WHO) permissible limits, indicating that they are not safe for human consumption. Concentrations of Pb in fish muscle samples were below WHO permissible limits and United States Environmental Protection Agency (USAEPA) provisional tolerable weekly intake (PTWI) standards. Furthermore, Hg and Pb in sediment were below the threshold value of Environment Canada and Florida’s ‘No effect level’. Conclusions. Although levels of Pb in fish samples and Hg and Pb levels in sediment were below international standards, it is important to consider that fish forms an important source of animal protein for local inhabitants, who are likely to consume more fish than considered by these standards. The study recommends further research on the levels of mercury and lead in humans, especially children and pregnant women. Competing Interests. The authors declare no competing financial interests.

Background. India has a well-defined deposit refund system (DRS) based on the principles of extended producer responsibility (EPR) for recycling used lead acid batteries (ULABs). However, the presence of an informal sector and lack of monitoring have resulted in an ineffective system of recycling mainly driven by the interests of the informal sector. Objectives. The present study attempts to understand the existing recycling mechanism and comparatively analyses a base case and three alternative scenarios developed taking into consideration the existence of a very active informal recycling sector. Materials and Methods. A base case and three alternative scenarios which were developed for this study were evaluated. Scenario I is the base case scenario representing the existing system. Scenarios II and III integrate informal recycling with the mainstream recycling system through a separate collection agency. Scenario IV proposes a strong upstream-defined deposit refund where the manufacturer pays a ‘green tax’ and receives a refund on green recycling of ULABs. The major gains and losses both upstream and downstream in the recycling chain are analysed for all of the scenarios. Results. Scenario II was determined to be the most effective, as it takes care of the interests of both the formal and informal stakeholders. By using the services of the itinerant collectors and eliminating informal smelters, Scenario II strengthens formal recycling. The introduction of a separate collection agency in Scenarios II and III benefits almost all of the major stakeholders in the system. Scenario IV gives the manufacturer more responsibility for used batteries. In all four scenarios, the downstream stakeholders of the EPR-DRS were the major beneficiaries. Conclusions. A successful EPR-DRS for ULABs in India can be achieved by integrating informal recycling through the introduction of a separate collection agency, strengthening the upstream DRS, completely eliminating informal recycling, and effective compliance monitoring. Competing Interests. The authors declare no competing financial interests.

Background. Mancozeb belongs to a group of pesticides known as dithiocarbamates (DTC) that are a non-systemic group of pesticides extensively used in Uganda to protect crops from fungal diseases. Objectives. This study was done in 5 selected districts of Central Uganda with a focus on markets and farms to investigate the current mancozeb concentrations on tomatoes and identify key areas of improvement to minimize human exposure. Methods. Tomato samples were analyzed for mancozeb residue determined as carbon disulfide (CS2) by gas chromatography—mass spectrometer (GC-MS). Results. All the samples analyzed had detectable concentrations of mancozeb residue. It was observed that farm samples had mean concentrations of 1.03±0.28 mg/kg, while market samples had 0.77±0.49 mg/kg. The study also found that farmers applied 3–6 times the dosage of mancozeb recommended by manufacturers. Furthermore, the observed pre-harvest interval after application of mancozeb was 1–2 days as opposed to 3–7 days set by manufacturers. Conclusions. The observed practices at farms are likely to put farmers and final consumers at a risk of exposure to dithiocarbamates. Competing Interests. The authors declare no competing financial interests.

Four kinds of surfactants were used to increase accessibility of pyrene and cadmium (Cd) in simulated pyrene, Cd, and pyrene-Cd soils in this study. Tea saponin (TS) at 40 mg L⁻¹groups (exchangeable fraction of Cd and bioaccessible fraction of pyrene were 8.96 and 36.93 mg kg⁻¹) showed more preferable potential application in improving solubilization capability than other surfactants. The morphology of Cd was transformed from Fe-Mn oxides (8.86 to 7.61 and 8.67 to 7.99 mg kg⁻¹in Cd and pyrene-Cd soil) and associated to carbonates fractions (4.46 to 4.36 and 4.28 to 4.36 mg kg⁻¹in Cd and pyrene-Cd soil) to exchangeable fraction with adding TS. These two morphological changes were important processes in the solubilization of Cd. The morphology of pyrene was transformed from associated fraction (72.15 to 61.95 and 71.02 to 63.48 mg kg⁻¹in pyrene and pyrene-Cd soil) to bioaccessible fraction (26.66 to 33.71 and 26.91 to 36.93 mg kg⁻¹in pyrene and pyrene-Cd soil) with adding TS. This morphological transformation was important in the improving of solubilization capacity of pyrene. In contrast, the solubilization of pyrene was promoted in the presence of Cd in pyrene-Cd soil (the bioaccessible fractions were 33.71 and 36.93 mg kg⁻¹in pyrene and pyrene-Cd soil), but the solubilization of Cd was hindered in the presence of pyrene (the exchangeable fractions of Cd were 8.86 and 8.67 mg kg⁻¹in Cd and pyrene-Cd soil). These findings will be beneficial for application of surfactants in soil remediation.

Malathion is an organophosphate insecticide registered for use in cities throughout North America to control adult mosquitoes. The objective of this study was to determine the impact of urban malathion applications on the levels of malathion detected in bulk deposition. In 2010, malathion was applied by the City of Winnipeg’s Insect Control Branch for a total amount of 6632 kg in the city, as well as by the general public in relatively small amounts. In 2011, no malathion was applied by the city. Malathion was detected in 41 % of the samples in 2010 with deposition rates ranging from 0.5 to 107.7 μg/m²/week. Only 9 % of the samples contained malathion in 2011 with deposition rates always being <0.4 μg/m²/week. Between 6 and 25 % of the samples in 2010 exceeded the toxicological threshold levels of malathion to a range of freshwater amphipods, water fleas, and stoneflies, including Daphnia magna which is a bioindicator of good environmental health. The weekly maximum malathion concentration detected in this study (5.2 μg/L for a week in June 2010) was at least 26 times greater than the maximum concentration of malathion reported in other atmospheric deposition studies. For the two insect management areas (7.4 and 37.6 km²) where the bulk deposition samplers had been placed, calculations suggested that between 1.2 and 5.1 % of the malathion applied by the city became bulk deposition. Percutaneous absorption by humans of malathion in rainfall is unknown.

The internal concentration represented by the critical body residue (CBR) is an ideal indicator to reflect the intrinsic toxicity of a chemical. Whilst some studies have been performed on CBR, the effect of exposure route on internal toxicity has not been investigated for fish. In this paper, acute toxicity data to fish comprising LC₅₀ and LD₅₀ values were used to investigate CBR. The results showed that exposure route can significantly affect the internal concentration. LD₅₀ and CBR calculated from LC₅₀ and BCF both vary independently of hydrophobicity as expressed by log Kₒw; conversely, LC₅₀ is related to log Kₒw. A poor relationship was observed between LC₅₀ and LD₅₀, but the relationship can be improved significantly by introduction of log Kₒw because log CBR is positively related to log LD₅₀. The parallel relationship of log CBR-log Kₒw and log LD₅₀-log Kₒw indicates that LD₅₀ does not reflect the actual internal concentration. The average LD₅₀ is close to the average CBR for less inert and reactive compounds, but greater than the average CBR for baseline compounds. This difference is due to the lipid fraction being the major storage site for most of the baseline compounds. Investigation on the calculated and observed CBRs shows that calculated CBRs are close to observed CBRs for most of compounds. However, systemic deviations of calculated CBRs have been observed for some compounds. The reasons for these systemic deviations may be attributed to BCF, equilibrium time and experimental error of LC₅₀. These factors are important and should be considered in the calculation of CBRs.

The paper presents the results of antimony removal from the Dúbrava water resource using a pilot plant system capable of taking samples from different heights of adsorption materials. The adsorbents GEH, CFH12, CFH18, and Bayoxide E33 and two experimental stainless columns with bleeder valves located at heights of 20, 45, and 70 cm of the adsorption media and 91 cm (GEH), 94 cm (CFH18), 87 cm (CFH12), and 87 cm (Bayoxide E33) filter media high were used. The results of the experiments show that the most suitable material for removing antimony from water is GEH. For an antimony concentration of 78.4–108.0 μg/L in raw water and a filtration rate of 5.6–5.9 m/h, the limit concentration of 5 μg/L at the outlet of the 70-cm high adsorption media was reached at the bed volume 1788. In a case when the media height was 91 cm, the antimony concentration in the treated water would reach the limit value of 5 μg/L after a 672-h operation of the stainless column at the bed volume 4256. Under these conditions, the adsorption capacity was calculated at 184 μg/g. The adsorption capacities and bed volumes of the other adsorbents were lower in comparison to GEH.