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
Integrated
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
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