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Heffes, T-A.P., P. L. Coates-Beckford and H. Robotham. 1992.  Effects of Meloidogyne Incognita and Rotylenchulus reniformis on Growth and Content of Vigna unguiculata and Zea mays.  Nematropica, 22(2).

In a greenhouse experiment,seedlings of cowpea (Vigna unguiculata cv.Yvon Clay) and corn (Zea mays cv. X306B) were grown for weeks in pots receiving initial inoculum (Pi) of 0, 100, 1000, or 10 000 eggs of Meloidogyne incognita race 1 or immature, vermiform Rotylenchulus reniformis race A. Final nematode populations, plant growth, and concentrations of 11 plant nutrients within shoots and roots were measured. Each nematode reproduced on both hosts but final populations were larger on cowpea than on corn. Both nematodes stunted the growth of each host. Leaves of corn plants inoculated with 1 000 M. incognita eggs or with 10 000 vermiform R. reniformis showed symptoms of nutrient deficiency.  For each host-parasite combination, there were more differences in nutrient concentrations in roots than in shoots, when infected and non-infected plants were compared. Specific effects of nematode parasitism on host nutrient concentrations differed with the host and the parasite. However, when affected, concentrations of potassium were always lower and those of aluminium and vanadium were always higher in nematode-infected than in noninfected plants. In most cases, nematode infection resulted in a decrease in the concentration of iron in roots and shoots.

Matthews, K.D., R.A. Fairman, A. Johnson, K.V.N. Spence, I. Kahwa, G.L. McPherson and H. Robotham.  1993. The Preparation and Luminescence Decay Dynamics of Coupled Heterolanthanide (III) Cations in Dinuclear Schiff-base Complexes. Journal Chemical Society Dalton Transactions, 1719-1723.

Molecular recognition events in which lanthanide(III) (Ln³⁺) cation pairs formed have been studied using the template condensation crystalline products (Ln_1-xEu_x)₂L(NO₃)₄·H₂O and (Ln_1-xTb_x)₂L(NO₃)₄·H₂O (where H₂L is the [2 + 2] macrocyclic Schiff base obtained from 2,6-diformyl-p-cresol and 3,6-dioxaoctane-1,8-diamine). The observed relationship between the concentrations of Eu³⁺ (or Tb³⁺) in the reaction mixture X_Eu or X_Tb (from neutron activation analyses) with corresponding concentrations in the crystalline products (x) suggests that formation of LnEuL(NO₃)₄·H₂O heteromolecules is more favourable than that of LnTbL(NO₃)₄·H₂O. In both cases the cation discrimination index, computed as the ratio of probabilities of Ln³⁺ incorporation into the crystalline heterolanthanide compounds, is in favour of the larger Ln³⁺ ion.  However indiscriminate complexation of Nd³⁺ and Eu³⁺ in the (Nd_1-xEu_x)₂L(NO₃)₄·H₂O system is unusual and reflects the importance of co-operative heteropair effects.

Luminescence decay dynamics of the (Sm_1-xEu_x)₂L(NO₃)₄·H₂O and (Pr_1-xTb_x)₂L(NO₃)₄·H₂O systems (O < x < 1) reveal two microscopic environments for Eu³⁺ and Tb³⁺ which were attributed to homodinuclear molecules, Ln₂L(NO₃)₄·H₂O (Ln = Eu or Tb) (slow component) and heterodinuclear molecules SmEuL(NO₃)₄·H₂O and PrTbL(NO₃)₄·H₂O (fast component). The luminescence decay rate constants for intramolecularly coupled Eu-Sm and Pr-Tb pairs are 8200 and 12 500s^-1, which yield coupling constants ( alpha) of 2.9 x 10^-53 and 4.7 x10^-53 m⁶ s^-1 respectively when dominant dipolar interactions are assumed. No exchange interactions are evident despite the presence of a phenolate linkage shared by the heteroatoms only ~4 A apart. The ratio of Eu-Eu to Eu-Sm 'cation pairing selectivity' constants of 1 :1.5 (expected ratio for random pairing is 1 :2) supports the intervention of molecular recognition processes favouring the homo- to hetero-paired species in the ion pairing events leading to (Sm_1-xEu_x)2L(NO₃)₄·H₂O compounds.

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Lalor, G.C. and H. Robotham. 1994.  Multi-Disciplinary Facilities at The Centre For Nuclear Science,U.W.I. Journal of Radioanalytical and Nuclear Chemistry, 180(2), 319-323.

The Centre for Nuclear Sciences was established in 1984 with the mandate to introduce Caribbean scientists to the application of nuclear technology in multi-disciplinary studies, and to carry out research in areas of national and regional importance. This paper describes the present facilities and the major programmes being carried out at the Centre.

Anglin-Brown, B., A. Armour-Brown and G.C. Lalor.  1995. Heavy MetalPpollution in Jamaica 1: Survey of Cadmium, Lead and Zinc Concentrations in the Kintyre and Hope Flat Districts. Environmental Geochemistry and Health, 17, 51-56.

Despite its being highly mineralised, the Hope Mine area has become a residential district. Composite soil samples taken from 91 allotments show values for cadmium: < 2-220 mg kg^-1 , lead: 6-38,000 mg kg^-1,and zinc: 66-40,000 mg kg^-1. Water samples from adits contain 52-86 µg kg^-1of lead and < 1-2 µg kg^-1of cadmium . The soil contents of cadmium and lead in at least two areas suggest that remedial actions should be considered . Blood lead levels for 33 children aged between ten months and seven years are in the range 5.7-57 µg dl^-1; haemoglobin levels vary between 9.7 and 12.7 mg dl^-1. There is no obvious relationship between Pb and haemoglobin levels. Further geochemical work to define fully the spatial extent of the polluted region and epidemiological studies including intelligence testing to define further the effects of lead on children in this environment would be valuable.

Harty, E.M., G.C. Lalor and H. Robotham.   1995. Elemental Concentrations in Jamaican Peat. Environmental Geochemistry and Health, 13(4), 197-202.

The peat of the Negril Morass in Western Jamaica was sampled at depths down to 7 m in directions parallel and perpendicular to the seashore , and the samples were analysed for Al, As, B, Br, Ca, Ce, Cl, Co, Cr, Cs, Dy, Eu, Fe, Hf, I, La, Mg, Mn, Na, Sb, Sc, Sm, Sr, Ti, U and V by instrumental neutron activation analysis and by spectrophotometry. The peat is high in ash content, but the concentrations of most elements are below crustal abundances and therefore provide no evidence of nearby mineralisation . The elemental concentrations indicate that no particular environmental hazards are to be expected from the use of this peat in electricity generation.

Robotham, H., M. Wong, C. Thompson and M. Golden.  1994. The Identification Of Geographia by Neutron Activation Analysis. Journal of Radioanalytical and Nuclear Chemistry, 179(2), 341-347.

Chemical markers for use as indicators of geophagia in Jamaica are reported. Five volunteers each ingested 10g of each of three common soils of Jamaica to which carmine (an inert gastrointestinal dye) had been added. A pre-ingestion faecal sample and all post-ingestion faecal samples were collected until no more carmine was seen. The faecal and soil samples were analysed by instrumental neutron activation analysis. Of the 14 elements quantified Dy, Eu, Ce, Hf, and Th were consistently detected in the post-ingestion but not in the pre-ingestion faecals. These elements should therefore be excellent markers of geophagia as they are present in insignificant levels in food compared to soils. Because of high sensitivity and short throughput times, Dy and Eu appear to be the most promising elements for the detection of the occurence of geophagia.

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Lalor, G.C.  1996. Geochemical Mapping of Soils in Jamaica. Environmental Geochemistry and Health, 18(4), 89-97.

A high-precision regional geochemical data base of Jamaica is being developed as a basis for a wide variety of economic and environmental applications. These include pollution studies, resource identification and management, agriculture, land use, and the relationship between geochemistry and the health of crops, animals, and man. The acquisition of analytical data is mainly by instrumental neutron activation analysis using a SLOWPOKE reactor and by energy dispersive X-ray fluorescence. Concentration ranges and means in soil are presented for 31 elements and maps illustrating the distributions of Al, Br, Co, and the gamma-ray intensities are presented as examples. Compared with world averages the levels of many heavy metals in Jamaican soils are found to be relatively high and in the main strongly correlated with bauxite occurrences. The high content of bromine in the soils appears to reflect the impact of sea-spray.

Preston, J., B. Engel, G.C. Lalor and M. Vutchkov.   1996. The Application of Geographic Information Systems to Geochemical Studies in Jamaica. Environmental Geochemistry and Health, 18(4), 99-104

The Centre for Nuclear Sciences (CNS) uses a raster based geographic information systems (GIS), integrated with a relational database to store information on point sampled data, including concentrations of over 50 elements and/or ions in a variety of sample materials. These data are filtered in the GIS to create surface layers and are assigned colours according to percentile ranges allowing visual inspection to be used to identify significant features and trends. The database currently contains raster map layers for soils and geologic features, point site data for water and air, and vector data for roads, rivers and streams. While data are still being added to the database interesting results are already being obtained and a few instances where the GIS was used to assist in the data interpretation are reported.

Engel, B., G.C. Lalor and M.K. Vutchkov. 1996.  Spatial Pattern of Arsenic and Lead Distributions in Jamaican soils. Environmental Geochemistry and Health, 18, 105-111.

The spatial patterns of arsenic and lead distribution in Jamaican soils were studied using the Geographical Resources Analysis Support System (GRASS) and data from an island wide soil survey. Arsenic and lead were analysed by instrumental neutron activation analysis (INAA) and energy-dispersive X-ray fluorescence (EDXRF) techniques. The frequency distribution of each element is discussed in relation to major lithological groups. The As-Pb background levels for different areas in Jamaica were estimated.

Johnson, A.H.M., G.C.Lalor, J. Preston, H. Robotham, C. Thompson and M.K. Vutchkov. 1996.  Heavy Metals in Jamaican Surface Soils. Environmental Geochemistry and Health, 18, 113-121.  

A regional survey of Jamaican surface soils has been conducted in which more than 200 samples were collected at a sample density of 1 per 64 km² across the island and analysed for total concentrations of 31 elements by instrumental neutron activation analysis (INAA), energy dispersive X-ray fluorescence (EDXRF) analysis and atomic absorption spectrophotometry (AAS). The aim of the survey was to begin the construction of a high-precision geochemical database to provide information on elemental levels in soils for application to environmental studies, agriculture, and human and animal health. Results on the regional scale are presented for As, Cd, Cu, Hg and Pb. Although Jamaican surface soils are enriched in several heavy metals compared with world soil means and crustal abundances, lead is of particular importance at this stage because of its occurrence in residential areas. Except for Cu, the distribution maps of these elements are highly correlated with bauxite which in Jamaica is associated with white limestone geology and residual terra rossa soils.

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Anglin-Brown, B., A. Armour-Brown, G.C. Lalor, J.A. Preston and M.K. Vutchkov.  1996. Lead in a Residential Environment in Jamaica. Environmental Geochemistry and Health, 18, 129-133.

The background levels of lead in Jamaica in soils and sediments, estimated at 37 mg kg^-1,are relatively high compared with world averages. Several areas have values in excess of this due to mineralisation and pollution. One such is the residential Hope Flats/Kintyre area in which levels of lead up to 2.5% are found in the soils and up to 8µg kg-1 in the water of the nearby Hope River. The blood lead levels of a sample of children were in the range 5.7- 57µg dl^-1. The high lead levels suggest a potential health risk, particularly for the children. This can be minimised by programmes which include community education, case management and abatement to reduce the lead exposure.

Johnson, A., G.C. Lalor, J. Preston and M.K. Vutchkov. 1996.  Heavy Metal Pollution In Jamaica 2: Background Levels of Lead in Jamaican Soils. Jamaican Journal of Science and Technology, 7 & 8 (1-12).

The island-wide distribution of lead (Pb) in Jamaican soils is presented and discussed. The lead content in Jamaican rocks is close to the crustal average of 13 mg kg^-1 but some soils are enriched in lead with respect to the bed-rock by a factor of up to 9. Except for contaminated and mineralised areas ( and which have some very high values), the range observed in this study is 6 - 897 mg kg^-1, with the highest concentrations in the soils overlying the white limestone formations. The frequency distribution of the soil lead concentrations with respect to the underlying geology and the geochemical mapping for soil lead are discussed. The mean lead concentration of the soils is 45 mg kg^-1 which is high relative to the crustal average of 13 mg kg^-1, but is not atypical of tropical lateritic soils such as Jamaican bauxites. The data presented on the blood lead levels of children in the Kintyre area suggest that, at this time, lead is the primary heavy metal hazard in Jamaica.

Johnson, A., G.C. Lalor, H. Robotham and M.K. Vutchkov.  1996. Analysis of Jamaican Soils and Sediments by Energy-Dispersive X-Ray Fluorescence Spectrometry. Journal of Radioanalytical and Nuclear Chemistry, 209(1), 101-111.

The calibration of a tube excited Energy-Dispersive X-Ray Fluorescence spectrometer for routine geochemical analyses of Ca, Ti, V, Cr, Mn, Fe, Cu, Zn, Rb, Sr and Pb in Jamaican soils and sediments is described. Simple linear and parabolic regression models using scattered radiation and an element as internal standards were applied. The analysis of over 200 samples from a regional soil survey has been used to contribute to a database on the geochemistry of Jamaican soils and sediments. An application example of the Zn distribution map in Jamaican soils is presented.

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