ISSN 1556-6757


SJI 


 

 

 

 

 
 
Volume 1, Issue 2, 2007

Assessing indigenous knowledge of forest and lake resources degradation: a case of Chisi Island, Lake Chilwa, Zomba, Malawi, Central Africa.    Miriam Dalitso Kalanda-Sabola
 

Abstract

A study was carried out on Chisi Island to examine the indigenous people’s knowledge of forest and lake resources degradation and factors that lead to the degradation. A structured household questionnaire, key informants, focus group discussions, historical matrices and transect walks were used to examine the people’s knowledge of the indicators and causes of resources degradation or factors that affect the status of the resources at a particular time. The results indicated growth of secondary colonizers, scarcity of medicinal plants and migration of wild pigs as indicators of forest degradation. Low fish catches and declining numbers of waterfowl were also reported as indicators of lake resources degradation. Forest degradation resulted from

poverty and famine. Low fish catches and presence of Hippopotamus amphibious and Typha domingensis in the lake was determined by the water level. Use of seine nets also contributed to fish degradation. These results show that local people have the potential to provide accurate ecological knowledge. This study therefore, argues that scientific studies on Chisi Island should integrate local ecological knowledge in determining resources degradation and monitoring resources population in management projects. Full Article



Biosorption of lead from aqueous solutions of varied pH by kale plants (Brasicca oleraceae var acephala)   
V. Emongor

Abstract
This study was undertaken to evaluate the effect of irrigating kale plants (Brassica oleraceae var acephala) with water of variable pH on lead uptake and partitioning. Lead was applied as lead nitrate (300 mg/kg). Kale plants were irrigated with water having pH values of 4.5, 5.5, 6.5, 7.1 (tap water, used as control), 7.5 and 8.5, respectively, throughout the experimental period. The results showed that lead accumulated more in kale roots, followed by the stem, leaf blade and leaf petiole. Irrigating kale plants with acidic water (pH 4.5-6.5) increased lead accumulation in kale roots, stem, and leaf petioles and blades. As the pH of the irrigation water became more alkaline (pH 7.1-8.5), there was a significant (P<0.0001) decrease in lead accumulation in kale leaf petiole, leaf blade, stem and roots. The results also showed that irrigating kale plants with water of pH 6.5 increased kale leaf size, fresh leaf yield and dry matter accumulation. It was concluded that lead uptake was significantly (P<0.0001) increased when the medium of growth pH was acidic (pH 4.5-6.5). Therefore, to minimize lead uptake and optimize growth and fresh leaf yield of kale plants, the pH of the medium should be between 6.5 and 7.0. Full Article



Concentration and Speciation of Arsenic in South African Soil Contaminated by Historically Cattle Tick Dip Operations   Billy A. Moremedi and Jonathan O. Okonkwo

Abstract

Concentration and speciation of arsenic in South African soil contaminated by historically cattle

tick dip operations was determined. High total arsenic levels (1033-1369 mg/L) were detected

in the soil. Two-Way ANOVA indicated a significant difference (p<0.05) between arsenic levels in

soils obtained from the contaminated sites and control site (0.15 mg/L). A decrease in the total

arsenic with increased depth was observed. The greatest arsenic value (1369 mg/L) was

obtained at the surface, indicating that arsenic was still abundant at the surface even though

the dip is no longer in operation. The total arsenic recorded for different depths were

significantly higher than the target value of 40 mg/kg. The distribution of arsenic in the different

fractions indicated that arsenic was mostly bound to Fe and Al hydroxides (21%) and in the

residual fractions (52%). A low arsenic proportion was present in the most labile fractions,

soluble (3%), exchangeable (14%) and carbonates (10%). The results obtained in the present

study suggest that the study area is grossly contaminated by arsenic. This means that the site

has the potential to contaminate groundwater over a period of time if no remediation or

reclamation is carried out. However, the low total arsenic values obtained for the sites closer to

the river suggest that arsenic movement towards the river has been slow. There is an urgent

need, therefore, to conduct risk assessment of the site in order to ascertain the overall risk

posed to the immediate environment, water resources and vegetation. Full Article
 




Pulp mill effluent is a source of environmental estrogens on Alabama’s Coosa River
Quentin Felty

Abstract
Alkylphenols are degradation by-products of detergents used to disperse tacky deposits on equipment in the paper industry. β-sitosterol is a phytosterol from pine trees used in the pulping industry. Both of these compounds are reported to be endocrine disrupting chemicals (EDCs). The goal of this study was to monitor a combination of EDCs in pulp mill effluent. Water samples collected from a pulp mill were derivatized and analyzed for trimethylsilyl derivatives by GC/MS. Mean concentrations of 4-tert-octylphenol, 4-nonylphenol, and β-sitosterol in the effluent were 3.45, 6.62, and 19.92μg/L, respectively. We detected a 1.4-fold higher level of 4-t-OP and showed β-sitosterol to be 2.8-fold higher than reports in the literature. The presence of alkyphenols and β-sitosterol in pulp mill effluent show that Alabama’s water sources are being contaminated by EDCs. The concentrations we detected are individually capable of inducing an adverse effect which indicates a need for a human risk assessment. Full Article


 


I
ntegrated pest management for African bollworm (Helicoverpa armigera (Hubner) in Botswana: review of past research and future perspectives Motshwari Obopile and Keatametse T. Mosinkie


Abstract
African bollworm or Old World bollworm (Helicoverpa armigera Hubner, Lepidoptera: Noctuidae) is an extremely polyphagous and major pest of many crops in Botswana. The damage to most crops results in reduction of yields. H. armigera is estimated to cause yield loss of 15 to 30% on sorghum in Botswana. Despite its importance, research on H. armigera has not been carried out in Botswana since 1979. This paper reviews the research on management of H. armigera that was undertaken in Botswana from the late sixties to late seventies (1967 to 1979). The research focused on developing various pest management methods that would be packaged into an integrated pest management strategy to manage H. armigera in field crops. The major findings were that microbial control (using nuclear polyhedrosis virus and Bacillus thuringiensis Berliner), enhancing natural enemies, cultural control and the use of insecticides had potential in management of H. armigera. These findings are discussed in comparison with other studies done in Asia, Australia and other parts of Africa where African bollworm is a major pest of field crops. The primary objective of this paper is to review the research that had been undertaken on H. armigera in Botswana and propose future research needs and directions. Full Article


 

Evaluating a Chlorophyll Content Meter on Three Coastal Wetland Plant Species

Patrick D. Biber

Abstract
The aim was to determine chlorophyll content index (CCI) and leaf chlorophyll (Chl a) content of a

rush, Juncus roemerianus, a grass Spartina alterniflora, and a tree, Rhizophora mangle,

occurring in coastal wetlands. Mean CCI values were 11.98 in J. roemerianus, 29.87 in S.

alterniflora, and 30.68 in R. mangle. Mean chlorophyll content was 8.85 mg/cm2 in J. roemerianus, 9.72 mg/cm2 in S. alterniflora, and 4.68 mg/cm2 in R. mangle. Positive correlations between CCI and Chl a content were found for J. roemerianus (Chl a = 4.936 + 0.396 CCI), for S. alterniflora (Chl a = 3.429 + 0.208 CCI), and for R. mangle (Chl a = 1.406 + 0.099 CCI). The grass and mangrove with flat leaves showed better correlation between the CCI and Chl a content than the rush with cylindrical leaves.  Full Article

 



Phytochemical Distribution Among Selected Advanced Apple Genotypes Developed for Fresh Market and Processing    Shahrokh Khanizadeh, Li Ding, Rong Tsao, Djamila Rekika, Raymond Yang, Marie-Thérèse Charles, Clément Vigneault, H. P. Vasantha Rupasinghe

 

Abstract

The phenolic composition of the flesh and peel of five advanced apple genotypes developed for

processing and 14 cultivars was investigated using high-performance liquid chromatography

(HPLC). The total phenolic content (TPC) was investigated using the Folin-Ciocalteu method, and the total antioxidant capacity (TAC) was investigated using a ferric reducing antioxidant power (FRAP) assay. ‘Floribunda Rosea’ was found to possess the highest TPC, total phenolic index (TPI) and TAC values, whereas ‘Eden™’ (also known as ‘SJCA38R6A74’) had the lowest. The profiles of the phenolic compounds varied among the 19 genotypes, and the peel showed higher concentrations than the flesh. The apples studied were found to contain 14 individual phenolic compounds, with epicatechin and procyanidin B2 being the most abundant phenolic compounds in the peel, and chlorogenic acid being the most abundant phenolic compound in the flesh. Procyanidins were the most predominant group in both the flesh and the peel, and ‘Eden™’ was the only apple selection that did not contain any procyanidins in its flesh. No flavonols were detected in the flesh of some genotypes (‘Cortland’, ‘McIntosh Summerland’ and ‘Spartan’). Cyanidins were found essentially in red apple peels (‘Cortland’, ‘Primevert’, ‘SJC649’ and SJC7123-1’). The significant variation in antioxidant capacity and total phenolic compounds

clearly shows the potential value of certain new cultivars and advanced lines as parents in a

breeding program.  Full Article