Effluents are wastes produced from industries and they vary depending on the human activities that produce them. Production of these wastes is an integral part of industrial activities but unfortunately our inability to anticipate or predict the types and magnitude of undesired consequences of unbridled release of effluents in our environment, coupled with the growth of industrialization have resulted in massive and destructive operations in our ecosystem. Although industrial processes are desirable at the same time, the serious and irreversible damage due to the environment through their apparently innocuous discharges of effluents are unquantifiable.
Until now, effluents are discharge into rivers, estuaries, lagoons, or the sea without any form of treatment. However, despite the treatment being employed by some industries, it is still impossible to remove all undesirable properties from effluents.
Since commercial exploration of petroleum started in Nigeria in 1958 (Okoh, 2003), petroleum has continuously grown to be ministry of the Nigerian economy. The exploration of petroleum has led to the pollution of land and weather ways. The agricultural lands have become less productive and the creeks and the fishing water have become more or less dead. Several civil unrests due to environmental degradation due to oil exploration have also been witnessed in the Niger Delta Region of Nigeria (Inoni et al, 2006).
Studies have revealed that the occurrence of large amount of hydrocarbons in the soil leads to a nitrogen deficiency and hence upsets the carbon-nitrogen ratio of the spill site thereby threatening the survival of soil biota (Johnson et al, 1974). Moreover, the infiltration of the containment into soil pores leads to the expulsion of air thus depleting oxygen reserves in the soil and impeding its diffusion into the deeper layers (Ayotamuno et al., 2006a). Thereafter as microbial activities, increase available oxygen diminishes in the soil environment (Ayotamuno et al, 2006). Thus limits the survival of plants as they then lack essential elements for their growth.
Furthermore, research on the remediation of crude oil contaminated soils using plant (phytoremediation) has shown that certain plants could contain, translocate and/or volatilize petroleum-hydrocarbons, as they grow on crude contaminated soil, although not without constraints like leaf burn, witting and stunted growth (Ayotammunno et al., 2006C). However, the exact level(s) of contaminant concentration which they can tolerate and give beneficial yield remains not well understood.
Moreover, oil interference with structure or functions of the various organs of plants and animals and may directly kill them. Oil contaminated soils generally cause delayed in seed emergence. This is due to poor wet ability and aeration of the soil and loss of seed viability. Change in soil condition. Causes progressive depression in height, numbers of leaves and other parameters which implies stressful conditions.
These stress condition interferes water uptake and gaseous exchange. This may create a condition of physiological. This may create a condition of physiological drought (Mc Cown et al, 1992).
1.1 African Yam Bean (Sphenostylis Stenocarpa)
African yam bean (Sphenostylis stenocarpa) (Hochst. EXA Rich) Harms, belong to the legume family. It is cultivated in Nigeria mainly for seeds and also grown for tubers in Cote d’Ivoire, Ghana Ethiopia part of East Africa, Malawi, and Zimbabwe (Utter, 2007). It is vigorous vine twines and climbs to the height of about sun and requires staking. It flowers profusely in 100-150 days producing brightly coloured flowers which may be pink, purple or greenish writer. The slightly woody pods contain 20-30 seeds, they are up to 30cm long and mature within 120 days. The plant produces underground tubers that are used as food in some parts of Africa and that serves as organs of perenation of the wild. African yam Tuber (AYB) seeds are highly rich in Vitamin C, dietary fibre, vitamin B6, potassium and magnesium. While being low in saturated fat, sodium and cholesterol.
The AYB tubers are regarded as an important source of starch and protein in tropical African and the plant is potentially important as a pulse legume (Busson, 2001). The amino acid content of the seeds per long dry matter is 1,640kg. AYB products generally have a lower glycine index than other legume products, which means that they will provide a more sustained form of energy. Most rural communities cannot afford animal proteins and over three million children lack sufficient proteins within the last decade and therefore suffer grossly retarded physical growth and development. The African Yam bean is one of the tuber known as legumes (NAS, 1979) and they are cheaper than animal products such as fish, meat and egg. Therefore, they consumed worldwide as major source of cheap and especially in developing or poor countries where consumption of annual protein may be limited as a result of economic, social cultural or religious factor (Olayide, 1982). Global food security however is becoming shaky with increasing dependence on a few major staple crops. Thus has resulted in an alarming reduction not only in crop diversity but also in the variability within crops.
1.2 Biology of Sphenostylis Stanocarpa
Afrcian yam bean (AYB) sphenostylis stenocarpa is a vigorous, herbaceous, climbing vine reaching 1.5-2m in height, with trifoliate leaves, the leaflets being up to 14cm in length and 5cm broad. The flowers are mauvish-pink, purple or greenish-white in colour, about 2.5cm in length and borne on stout auxiliary peducles. It is glabrous seed pods which are linear, flat, with margins raised, 25-30cm long and 1-1.5cm broad, containing 20-30. Seeds which may be ellipsoid, rounded or truncated, and show considerable variation in size and colour, the largest are usually about 1cm long and 0.7cm wide. Seed colour may vary from creamy-white or brownish-yellow to dark brown, sometimes with black marbling, and there appear to be a number of types according to seed colour. The plant produces small spindle-shaped tubers, about 5-7.5cm long.
There is some evidence that yields of seeds and tubers are in versely related.
Plate 1: Typical African yam Bean seeds
Plate2: A Typical Yam Bean tuber
1.3 Uses of African Yam Bean
The seeds and tubers are the two organs of economic important providing food for both humans and livestock. However, there is a cultural and regional preference for each, West African prefer the seeds to the tubers, while tubers are highly relished by the East and Central Africans.
Thus, exceptional nutritional pulse has a very significant link with African socio-cultural life for instance, there are times in Ghana when they prepare a special mean from African yam bean sees during the celebration of puberty rites in adolescent girls (Potter, 1992).
The seeds of African yam bean are cooked and eaten as food, however, it is sometimes neglected in most Nigerian homes because of long hours cooking (4-6hours) after removal of skin coat and soaking in water.
The tubers are cooked and eaten in the same manner as potatoes which it resembles in flavour. Extract of African yam bean also have medical values such as its ability to inhibit haemoglobin polymerization and improve the Fe2+/Fe3+ ratio of sickle cell blood (Nwaoguikpe and Uwakwe, 2005).
The crop has not received adequate research attention up till now, it is classified as a neglected under-utilization species (Bioversity, 2009). At present African yam bean has been relegated to an unimportant position as it is grown predominantly by the older generation of farmers. The bulk of genetic resources to this crop are in the hands of these farmers which threatens its survival. There is therefore a need for germplasm collection, characterization and conservation to prevent it from being extinct.
1.5 Objective of Study
The main aim of this study is to determine the growth performance of African yam bean (AYB) Sphenostylis stenocarpa on rubber dump sties soil.