Trace elements and stable isotopes (delta13C and delta15N) in shallow and deep-water organisms from the East China Sea

Trace elements (22) and stable isotope ratios (δ¹⁵N and δ¹³C) were analyzed in marine organisms from shallow (SW) and deep-water (DW) of the East China Sea to understand biomagnification and prey source of trace elements. In the benthic marine organisms from DW, δ¹⁵N values were negatively correlated with Ba, Cu, Ag, Mo, Sr, As, and Co concentrations. This may be due to the specific accumulation in lower trophic animals and/or the biodilution through the food web in DW. Relationships between δ¹⁵N and concentrations of Co, Cr, Bi, and Tl in fish and Ag, Bi, V, Hg, and Tl in crustaceans showed positive correlations, suggesting that trophic position was affecting the concentrations of those elements in phyla, with higher trophic animals retaining higher concentrations than the lower trophic animals. Positive correlations between δ¹³C and Rb were observed in marine organisms. Therefore, Rb may be a possible substitute of δ¹³C as tracer of prey source in the East China Sea although further investigation is required.     

Monitoring of pesticide residues of five notable vegetables at Agbogbloshie market in Accra,Ghana

The study monitored the concentrations of pesticide residues in vegetables arriving at Agbogbloshie, a central market in the Accra Metropolis from different parts of Ghana and beyond. A total of 810 samples of 5 different vegetables from Central, Volta, Greater Accra, Ashanti, Eastern Regions, and neighboring country (Togo) were collected from January 2009 through to December 2011. In all, 18 % of the samples had no detectable residues, 62 % were below the maximum residue limits (MRLs), and 20 % also exceeded the EU (MRLs) adopted values. Overall, lettuce contained the highest number of residues above their MRLs besides cucumber and cabbage. The pesticide residues were mainly organophosphates and synthetic pyrethroids. The results demonstrate the need for continuous monitoring of pesticide residues in vegetables arriving at the various major markets in Ghana.     

El Niño‐Southern Oscillation,rainfall variability and sustainable agricultural development in the Ho Municipality,Ghana

El Niño‐Southern Oscillation (ENSO), which occurs in the Equatorial Pacific Ocean, has been identified to have significant influence on rainfall variability throughout the world, especially in the tropics. Such variability in rainfall has implications for agrarian economies, such as that in Ghana. This study therefore sought to demonstrate the effect of ENSO‐induced variability in annual and seasonal rainfall on the development of sustainable agriculture in the Ho Municipality of Ghana. Using 61 years of monthly rainfall data (1955–2015) for the Ho Municipality and ENSO indices, this study showed that 15% of the variability in total annual rainfall is explained by the ENSO phenomena. Mean annual rainfall and rainfall in the major rainy season decreased for El Niño years, in addition to a more variable rainfall compared to that received in La Niña years. The major growing season was observed to be longer in La Niña years and shorter in El Niño years. This means that the potential for crop cultivation will be severely hampered in an El Niño year. Farmers within the municipality are therefore encouraged to harness other complementary water sources for farming activities and also employ water management strategies during El Niño years.     

Polychlorinated biphenyls (PCBs) in Africa: a review of environmental levels

Several studies have shown an increase in PCB sources in Africa due to leakage and wrongly disposed transformers, continuing import of e-waste from countries of the North, shipwreck, and biomass burning. Techniques used in the recycling of waste such as melting and open burning to recover precious metals make PCBs contained in waste and other semivolatile organic substances prone to volatilization, which has resulted in an increase of PCB levels in air, blood, breast milk, and fish in several regions of Africa. Consequences for workers performing these activities without adequate measures of protection could result in adverse human health effects. Recent biodegradation studies in Africa have revealed the existence of exotic bacterial strains exhibiting unique and unusual PCB metabolic capability in terms of array of congeners that can serve as carbon source and diversity of congeners attacked, marking considerable progress in the development of effective bioremediation strategies for PCB-contaminated matrices such as sediments and soils in tropical regions. Action must be taken to find and deal with the major African sources of these pollutants. The precise sources of the PCB plume should be pinned down and used to complete the pollutant inventories of African countries. These nations must then be helped to safely dispose of the potentially dangerous chemicals.     

Contamination status of arsenic and other trace elements in drinking water and residents from Tarkwa, a historic mining township in Ghana

This study was conducted to assess the contamination status of 22 trace elements, especially As in water and residents in Tarkwa, a historic mining town in Ghana. Drinking water and human urine samples were collected from Tarkwa in addition to control samples taken from Accra, the capital of Ghana in March, 2004. Concentrations of As and Mn in some drinking water samples from Tarkwa were found above the WHO drinking water guidelines posing a potential health risk for the people. A potential health risk of As and Mn is a concern for the people consuming the contaminated water in this area. No significant difference of As concentrations in human urine between mining town (Tarkwa) and control site (Accra) was observed. Although As concentrations in drinking water in Tarkwa were low, urinary As levels were comparable to those reported in highly As-affected areas in the world. These results suggest the presence of other sources of As contamination in Ghana. This is the first study on multi-elemental contamination in drinking water and human from a mining town in Ghana.     

The connection between urbanization and carbon emissions: a panel evidence from West Africa

Environment, Development and Sustainability - This study examined the nexus between urbanization and carbon emissions in West Africa. Second-generation econometric techniques that are robust to...     

Participatory incremental slum upgrading towards sustainability: an assessment of slum dwellers’ willingness and ability to pay for utility services

The concept of participatory slum upgrading has received attention in the conventional literature because it ensures and promotes the sustainability of slum-upgrading programmes. In participatory slum-upgrading programmes, slum dwellers are treated as partners, instead of recipients of the services that are provided to mitigate their deprivations. The concept thrives on the willingness and ability of slum dwellers to pay for the services. The ability of slum dwellers to pay for services, unlike their willingness to pay, has received limited research attentions. Therefore, the purpose of this study was to assess the willingness and ability of residents of a slum settlement in Kumasi in Ghana to pay for utility services. Semi-structured interview schedules were used to gather primary data from a total of 276 households. The survey data were supplemented with data from key informant interviews and focus group discussions. The results show that almost nine out of every ten households were willing to pay for water and electricity services, if these services would be supplied to them directly by the state providers. The exploitation of the residents by unregulated utility services providers partly explains their willingness to pay for the utility services. These service providers charged almost 14 times the official tariffs. The results further show that all the households who were willing to pay were also capable of paying for the services without compromising their ability to afford other life essentials. The study concludes that slum regularisation policies, programmes and projects could be designed to be incremental and participatory by making the slum dwellers, partners and drivers of the upgrading process.     

Human exposure to PCBs, PBDEs and HBCDs in Ghana: Temporal variation, sources of exposure and estimation of daily intakes by infants

Human exposure to polychlorinated biphenyls (PCBs) and brominated flame retardants (BFRs) such as polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecanes (HBCDs) was evaluated in Ghana using breast milk samples collected in 2004 and 2009. Mean levels and ranges of PBDEs (4.5; 0.86-18 ng/g lw) and PCBs (62; 15-160 ng/g lw) observed in the present study were unexpectedly high, in spite of the fact that Ghana is a non-industrialized country when compared with many of the Asian and European countries. Significant increases were found in the concentrations of PCBs and PBDEs over the years, while no significant increase was observed for HBCDs. Estimated hazard quotient (HQ) showed that all the mothers had HQ values exceeding the threshold of 1 for PCBs, indicating potential health risk for their children. PCBs in dirty oils and obsolete equipment should be of concern as potential sources in Ghana, and e-waste recycling with little or no experience in safe handling could be a threat to this sub-region noted for unregulated disposal of e-waste. The results may point towards an increase in trends in human milk in Ghana, especially in the larger cities but further analysis would be required to confirm this upward trend in levels. This is the first study to report BFRs in human breast milk from Africa, and undoubtedly from Ghana.     

Soil contamination by halogenated polycyclic aromatic hydrocarbons from open burning of e-waste in Agbogbloshie (Accra,Ghana)

Detailed composition of chlorinated and brominated polycyclic aromatic hydrocarbons (Cl-PAHs and Br-PAHs) generated during informal recycling of e-waste and their toxic relevance are still poorly understood. This study investigated the occurrence of Cl-PAHs and Br-PAHs in surface soil samples from the Agbogbloshie e-waste recycling site (Accra, Ghana) using quantitative gas chromatography–mass spectrometry (GC–MS) and comprehensive two-dimensional GC–time-of-flight mass spectrometry (GC × GC–ToFMS) profiling. The results of GC–MS analysis showed elevated concentrations in open e-waste burning areas (160–220 and 19–46 ng/g dry weight for Cl- and Br-PAHs, respectively) with substantial contribution from unidentified compounds (respectively, more than 36 and 70%, based on the total areas of potential peaks). Cl- and Br-PAHs from e-waste burning had a distinctive composition dominated by ring–ring compounds. Several homologue groups not monitored with GC–MS were found using GC × GC–ToFMS: PAHs with up to 5Cl or 3Br, mixed halogenated PAHs and chlorinated methylPAHs. The dioxin-like toxic equivalents of the identified Cl-/Br-PAHs in soils, estimated from their in vitro AhR agonist potencies relative to 2,3,7,8-tetrachlorodibenzo-p-dioxin, were much lower than the range reported for chlorinated and brominated dioxins. However, the toxicity of the unidentified halogenated PAHs remained unclear.     

Validation of QuEChERS method for the determination of 36 pesticide residues in fruits and vegetables from Ghana,using gas chromatography with electron capture and pulsed flame photometric detectors

In this study, “Quick, Easy, Cheap, Effective, Rugged and Safe” ‘QuEChERS’ method was modified for the determination of 36 pesticides fortified at (0.01–1.0) mg kg^?1 in three vegetables and a fruit (lettuce, carrot, tomatoes and pineapples respectively) from Ghana. The method involved extraction with acetonitrile, phase separation with primary secondary amine and magnesium sulfate; the final injection solution was reconstituted in ethyl acetate. Organochlorine and synthetic pyrethroids residues were detected with electron capture detector whereas organophosphorus, pulsed flame photometric detector was used. The recoveries at different concentration levels (0.01, 0.1 and 1.0 mg kg^?1) were in the range of 83% and 93% with relative standard deviation ranging from 2% to 10% (n = 5) and the coefficient of determination (R²) was greater than 0.99 for all the 36 pesticides. The method was successfully tested on 120 real samples from Accra markets and this proved to be useful for monitoring purposes particularly in laboratories that have no gas chromatography-mass spectrometry and liquid chromatography-mass spectrometry.