Global NEST Journal

Associations between bivariate variables relative to the unexplained relationships of height-Dbh (diameter
at breast height) models were investigated. Seven permanent sample plots measuring 40m by 250m at
Omo Forest Reserve were used to assess the relationships between height and diameter at breast height of
three tree species as affected by the variables of neighbouring trees. The result showed differences in the
coefficient of determination of the bivariate models and multivariate models. The models arrived at for
each of the species and for the bivariate models are:
Scottelia coriaceae: Ht = 2.59 + 0.473D+ 0.0012D2 for 5cm ≤ D ≤100cm (R2 = 0.70)
Sterculia rhinopetala: Ht = 5.96 + 0.467D+ 0.00296D2 for 5cm ≤ D ≤100cm (R2 = 0.77)
Strombosia pustulata: Ht = 2.02 + 0.722D+ 0.00581D2 for 5cm ≤ D ≤ 60cm (R2 = 0.81)
Where both Ht and D are height and Diameter at breast height.
While on the other hand the multivariate models that considered the effect of neighbouring trees are:
Scottelia coriaceae: 2
1 2 3 4 Ht = 3.74 + 0.41x −1.14x + 0.205x +1.278x (R = 0.723)
Sterculia rhnopetala: 2
1 2 3 4 Ht = 6.18 + 0.2601x +1.163x + 0.438x − 0.442x (R = 0.608)
Strombosia pustalata: 2
1 2 3 4 Ht = 6.84 + 0.399x − 0.318x − 0.138x − 0.838x (R = 0.650)
x1 = diameter at breast height, x2 = Mean neighbouring tree distance, x3 = Frequency of the neighbouring
tree and x4 = Position of the crown.

Effluents from five major textile industries in Kaduna (Nigeria) were characterized for a proposed
central effluent treatment plant. Seven of the measured parameters exceeded the limit set by the
Federal Ministry of Environment. Colour intensity exceeded it in all the samples (Mills 1 – 5) by about
350 folds on the average while COD, TSS, NH3, BOD5, and S2- were by 24, 13, 8, 7 and 3 folds
respectively. TDS was detected in all samples with limit exceeded only in Mill 2. Nitrate, oil and
grease were detected in Mills 1 and 2 and within the limit. Al, Mn, and Zn were detected in 80% and
within the limit while Fe was detected in 60 %. Cu was detected in 80 % with limit exceeded about 3
folds on the average. The present study is focused on the pollution implications of these effluents from
textile operations in the city; important because of the risk of human exposure to them.

The Cost-Effectiveness Analysis (CEA) is the method most commonly used for the assessment of the
costs and effectiveness of alternative policy options on the environment.
The objective of this paper is to describe the priority of the policy area “coastal water pollution control
from land uses, in catchment area” in the frame of an Integrated Coastal Zone Management (ICZM).
The evaluation of related ICZM options is effected through use of the CEA; this policy area can be a
distinct study, on which other seafront management ICZM policy areas can be based.
This is also based on the fact that the indicators used in the Coastal water pollution control from land
uses policy area are different from the indicators for seafront management. The differences in ICZM
indicators result to a lower number of variables, and consequently to a better development and use of
all the data. In the present work the indicators needed for the application of the CEA in the water
quality policy area are identified.

(NMEA) and N-nitrosodiethylamine (NDEA) are highly mutagenic compounds that are
suspected of carcinogenic activity to the human body.
The aim of the paper is the evaluation of the possibility of N-nitrosomethylethylamine and
N-nitrosodiethylamine formation as a result of the reaction of methylethylamine (MEA) or
diethylamine (DEA) respectively with chlorine in the presence of ammonia ions. The
optimal conditions of NMEA and NDEA formation were identified as a result of an
experiment carried out using different molar ratios of the substrates of reaction.
As the primary aim of the research was the evaluation of the possibility of NMEA and
NDEA formation as a result of the reaction of methylethylamine or diethylamine
respectively with chlorine in the presence of ammonia ions, a successful result obtained
after GC-LRMS analysis was fundamental to the further research. Analytes from postreaction
mixtures were concentrated, according to the modified procedure proposed by
Mitch et al., by means of liquid/liquid extraction with the usage of methylene chloride. The
N-nitrosomethylethylamine and N-nitrosodiethylamine were found in the analyzed
extracts of post-reaction mixtures. Apart from NMEA and NDEA identification, the
verification of other products with the usage of mass spectra library was also undertaken.
The results indicated that the changes in the relative ratio of the substrates influence the
concentration of NMEA and NDEA.
The obtained results revealed that NMEA and NDEA are only two of the many products
of the reaction taking place in the aqueous solution, which contained methylethylamine or
diethylamine and ammonia ions, and was disinfected with chlorine. The other identified
products are: ethyl(methyl)formamide and 3-ethyl(methyl)aminopropanenitrile. Therefore
N-nitrosomethylethylamine and N-nitrosodiethylamine can be treated as new disinfection
by-products similar to THMs, HAAs, MX or NDMA.