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Background:The economic growth and social interaction of many developing countries have been enhanced by vehicular transportation. However, this has come with considerable environmental cost. The vehicular emissions of gases such as carbon monoxide (CO), sulphur dioxide (SO 2 ), nitrogen oxide (NOx) and volatile organic compounds (VOC's) among others are associated with vehicular transportation. The resultant effect can lead to respiratory infections in humans, as well as growth inhibition and death of animals and plants. An investigation was conducted to evaluate the impact of vehicular air pollutants on some selected roadside tree species in the Kumasi Metropolis, Ghana. Ficus platyphylla, Mangifera indica, Polyalthia longifolia and Terminalia catappa, which were abundant and well distributed along the road sides, were selected for the study. Three arterial roads in the Kumasi Metropolis, namely Accra Road (Arterial I), Offinso Road (Arterial II) and Mampong Road (Arterial III), were considered as different traffic volumes experimental sites. The KNUST campus was selected as a control site. Diurnal analysis of CO, NO 2 , SO 2 and VOC was monitored in the sample sites. Three replicates of each tree species were defined at a distance 10 m away from the edge of the road. Physiologically active leaves (20 to 25) from each tree species replicate were harvested for physiological and biochemical determination. Results:The ambient air quality data showed higher levels at the arterial road sites, which were severely polluted based on air quality index. The biochemical studies revealed reductions in leaf total chlorophyll and leaf extract pH whilst leaf ascorbic acid and relative water contents increased at the arterial road sites.Conclusion: It was found that the plants' tolerant response level to vehicular air pollution was in the order T. catappa > F. platyphylla > M. indica and P. longifolia. Based on anticipated performance index, it was revealed that M. indica, F. platyphylla and T. catappa might be performing some level of air cleaning functions along the arterial roads. Whilst P. longifolia was poor and unsuitable as a pollution sink.

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The present study focused on cupric sulphate and cupric nitrate uptake in Typha latifolia and the impact of these copper species on the plant's detoxification capacity. When the plants were exposed to 10, 50 and 100 μM cupric sulphate or cupric nitrate, copper accumulation in T. latifolia roots and shoots increased with rising concentration of the salts. Shoot to root ratios differed significantly depending on the form of copper supplementation, e.g. if it was added as cupric (II) sulphate or cupric (II) nitrate. After incubation with 100 μM of cupric sulphate, up to 450 mg Cu/kg fresh weight (FW) was accumulated, whereas the same concentration of cupric nitrate resulted in accumulation of 580 mg/kg FW. Furthermore, significant differences in the activity of some antioxidative enzymes in Typha roots compared to the shoots, which are essential in the plant's reaction to cope with metal stress, were observed. The activity of peroxidase (POX) in roots was increased at intermediate concentrations (10 and 50 μM) of CuSO4, whereas it was inhibited at the same Cu(NO3)2 concentrations. Ascorbate peroxidase (APOX) and dehydroascorbate reductase (DHAR) increased their enzyme activity intensely, which may be an indication for copper toxicity in T. latifolia plants. Besides, fluorodifen conjugation by glutathione S-transferases (GSTs) was increased up to sixfold, especially in roots.

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One of the sources of air pollutants in the surrounding environment is the automobile emissions. Automobiles produce gaseous and particulate matters which are toxic and inflict damage to roadside plants. Roadside trees are notable for the absorption, sequestering of contaminants and the effective interceptor of airborne pollution. In view of this, the present work was based on investigating the macro-morphological and micro-morphological changes that boost the tolerance and continued existence of four roadside trees, namely Ficus platyphylla, Mangifera indica, Polyalthia longifolia and Terminalia cattapa in the incidence of vehicle exhaust emissions in Kumasi Metropolis, Ghana. Three arterial roads representing three different traffic volumes of extreme, heavy and severe were considered as observational sites. Kwame Nkrumah University of Science and Technology Campus was selected as the control site. The macro-morphological characteristics of the four tree species showed reduced leaf area, whilst the micro-morphological results revealed that stomata size, number and index were reduced at the arterial roadsides in all the four tree species. There was increased epidermal cell number and length and trichome length at the polluted arterial roadsides when compared to the control. These variations can be considered as pointers of environmental stress and could be used as indicators of urban air pollution.

Edge disturbance can drive liana community changes and alter liana-tree interaction networks, with ramifications for forest functioning. Understanding edge effects on liana community structure and liana-tree interactions is therefore essential for forest management and conservation. We evaluated the response patterns of liana community structure and liana-tree interaction structure to forest edge in two moist semideciduous forests in Ghana (Asenanyo and Suhuma Forest Reserves: AFR and SFR, respectively). Liana community structure and liana-tree interactions were assessed in 24 50 × 50 m randomly located plots in three forest sites (edge, interior and deepinterior) established at 0-50 m, 200 m and 400 m from edge. Edge effects positively and negatively influenced liana diversity in forest edges of AFR and SFR, respectively.There was a positive influence of edge disturbance on liana abundance in both forests.We observed anti-nested structure in all the liana-tree networks in AFR, while no nestedness was observed in the networks in SFR. The networks in both forests were less connected, and thus more modular and specialised than their null models. Many liana and tree species were specialised, with specialisation tending to be symmetrical.The plant species played different roles in relation to modularity. Most of the species acted as peripherals (specialists), with only a few species having structural importance to the networks. The latter species group consisted of connectors (generalists) and hubs (highly connected generalists). Some of the species showed consistency in their roles across the sites, while the roles of other species changed. Generally, liana species co-occurred randomly on tree species in all the forest sites, except edge site in AFR where lianas showed positive co-occurrence. Our findings deepen our understanding of the response of liana communities and liana-tree interactions to forest edge disturbance, which are useful for managing forest edge.

Lagoons are among the most important ecosystems in the world. To find out how activities around lagoons affect their physical and chemical properties, we assessed the physicochemical properties and concentrations of seven heavy metals from samples of sediments, Tilapia fish and water of Butuah Lagoon in Ghana, as an example. The lagoon was slightly alkaline with a fairly constant temperature but increased dissolved salts and inorganic materials that have resulted in higher electric conductivity than permissible for aquatic life. There was an indication of a large quantity of organic waste in the lagoon which reflected as high biological and chemical oxygen demand. We also recorded extremely high concentrations of oil and grease that negatively correlated with all physicochemical parameters measured. Lead (Pb) concentration in the three media was higher than the permissible limits while Zinc (Zn) and Cadmium (Cd) were higher in two except the water sample. Arsenic (As) concentrations were higher than the permissible limits only in the sediments. There is a significant anthropogenic impact on the lagoon, with the midstream having extremely high degree of contamination of most of the metals. The main pollutant in the sediment was Cadmium with high enrichment factor and geo-accumulation index value. Although, the concentrations of most metals in the fish were below the highest permissible level recommended, the higher levels in the water and sediment are of concern. It will be necessary to have a long-term monitoring programme for Butuah Lagoon to prevent it from further deterioration. Also, as bioaccumulation is a gradual process, having such programmes will prevent the risk of people eating and using fish and water contaminated with such deleterious metals.