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Davis, M., C. Grant, G. Ho-Yorck-Krui, A. Johnson, G.C.  Lalor, H. Robotham and M. Vutchkov.   1997.  Suspended Particulates in the Jamaican Atmosphere.  Environmental Geochemistry and Health, 19(1), 23-28.

The results of a survey of air particulates at 23 sites across Jamaica for total suspended particulates (TSP), Al, Br, Cl, Na, Pb, and V, by instrumental neutron activation analysis (INAA) and X-ray fluorescence analysis (XRF) are reported. The geometric mean of TSP values, 35µg m^-3, is well within the World Health Organisation's standard of 60µg m^-3 for TSP, but in areas of high vehicular traffic density the TSP values exceeded this limit. The correlation coefficient between Br and Pb concentrations in the particulates was 0.92 and the Br/Pb ratio of 0.38 compares well with a ratio of 0.39 found in commercial petrol indicating that the exhaust from vehicular traffic is the major source of Pb in atmospheric particulate matter in Jamaica.

Knight, C., J. Kaiser, G.C. Lalor, H. Robotham and J.V. Witter.  Heavy Metals in Surface Water and Stream Sediments in Jamaica. Environmental Geochemistry and Health, 19(2), 63-66, 1997.

The levels of heavy metals in water and stream sediments in Jamaica are presented and compared to levels in soils and environmental standards. Heavy metals (cadmium, chromium, copper, mercury, nickel, lead and zinc) appear to be less of a problem to Jamaica's freshwater environment than might be expected given the concentrations in soils. This can be explained by taking into account the dynamics of the Jamaican water environment and the relative absence of anthropogenic sources. The dynamics of the freshwater system on the other hand, could pass any environmental threat to the coastal environment. Because the stream sediments are relatively coarse and contain little organic material the bioavailability of micropollutants such as heavy metals from the sediments can be expected to be relatively high.

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Davis, M., G.C. Lalor, R. Rattray and T. Loder.  1998. Nutrient Status of the Black River System, St. Elizabeth, Jamaica.  Jamaica Journal of Science and Technology, 9, 45-62.

The nutrient status of water samples from the Black River watershed with respect to nitrate+nitrite, orthophosphate, silicate and ammonia is reported. Nitrate+nitrite concentrations in the Black River are highest in the upper section of the river and decline downstream. Fertilizer runoff is a likely source of this dissolved inorganic nitrogen. The Elim River, which is polluted by ammonia and orthophosphate in wastewater effluent from the nearby sugar factory and ammonia from an aquaculture operation, is a major contributor to the nutrient load entering the Upper Morass. Below Lacovia, all nutrient levels in the Black River decrease. This may be partially due to the presence of large quantities of water hyacinth, pointing to the importance of preserving this vegetation. On the Broad River the seasonal saline wedge was evident  6.3 km upstream, producing low silicate and inorganic nitrogen in samples collected near the bottom of the river. A relatively high ammonia concentration was observed in samples collected near the bottom of a section of this river. Nutrients in the plume of the Black River are conservatively diluted at least 1.2 km into the saline water of the bay.

Fowles, R.G., K.O. Pascoe, R. Rattray. 1998.  Characterization of Exoskeleton Composition of Jamaican Crustaceans for Chitin Isolation. Jamaican Journal of Science and Technology, Vol. 9:3-9.

Neutron Activation Analysis of the shells of the Jamaican marine spiny lobster, land crab, marine blue crab and the giant Malaysian fresh water prawn shows that they contain 42%, 70%, 65% and 47% calcium respectively, expressed as calcium carbonate. The digestion efficiency for extraction of calcium varies significantly; not only with species, but also with the strength of the acid used and the digestion time. Standard acid hydrolysis is not effective in removing all calcium compounds from the shells of some species of crustaceans. The inorganic composition of the shells has been partially characterized by Neutron Activation Analysis (NAA).

Gardner J.M., S.P. Walker, S.M. Chang, M. Vutchkov and G.C. Lalor. 1998.  Undernutrition and Elevated Blood Lead Levels: Effects on Psychomotor Development among Jamaican Children.  Public Health Nutr, 1(3), 177-179.

OBJECTIVE: We examined whether or not the effect of elevated blood lead levels on children's psychomotor development was modified by their nutritional status.

DESIGN: Anthropometry, developmental quotients (DQs), blood lead levels and haemoglobin were measured in lead exposed and unexposed children with different levels of nutritional status. Social background and maternal height and verbal intelligence were also measured. Testers, anthropometrists and interviewers established reliabilities with a trainer before the study began.

SETTING: Children were from two suburban areas in Kingston, Jamaica. All measurements on the children were carried out at a research unit. Social background and maternal measurements were carried out at the children's homes.

SUBJECTS: The exposed group comprised 58 children (3-6 years) attending the same preschool which was situated in a lead contaminated environment. The unexposed group comprised 53 children attending a nearby preschool without lead contamination.

RESULTS: The exposed children had significantly higher blood lead levels and lower DQs, and their homes had poorer facilities than the unexposed children. The deficit in DQ was greater (10.6 points) among children with weight for height less than -1 SD (National Center for Health Statistics references) than among better nourished children (2 points).

CONCLUSIONS: Undernourished children exposed to lead may have more serious developmental deficits than better nourished children

Grant, C., G.C. Lalor, J. Preston, R. Rattray and M.K. Vutchkov. 1998.  Neutron Activation Analysis with the Slowpoke Reactor in Jamaica. Jamaican Journal of Science and Technology Vol. 9:63-77

The International Centre for Environmental and Nuclear Sciences (ICENS) operates a small nuclear reactor, the Canadian-made SLOWPOKE 2, with a maximum operating flux of 1x10¹² neutrons cm^-2 s^-1. The flux is remarkable stable. The reactor is being used mainly for Neutron Activation Analysis (NAA) and the system now has the capability of determining 55 elements with useful detection limits. The data are being applied as part of a programme to develop computer readable geochemical databases for applications which include: agriculture, animal and human health, land use planning, and the assessment of natural resources. The methodology is described and the distributions of aluminium, chromium, iodine and zinc in Jamaican soils are presented as examples of typical results.

Grant, C.N., G.C. Lalor and M.K. Vutchkov. 1998.  Neutron Activation Analysis of Cadmium in Jamaican Soils. Journal of Radioanalytical and Nuclear Chemistry, 237(1-2), 109-112.

A procedure for the instrumental neutron activation analysis of Cd in soils with relatively high Cd content and possible interferences is reported. Cadmium concentrations in Jamaican soils above 4mg.kg-1 can now be reliably determined by multielemental instrumental activation analysis with an accuracy ±10% and the reasonably high throughput of 30 samples per day. Over 600 geochemical survey samples were analysed for Cd along with some 20 other long-lived elements.

Lalor, G.C., R. Rattray, P. Simpson and M.K. Vutchkov. 1998.  Heavy Metals In Jamaica. Part 3: The Distribution of Cadmium In Jamaican Soils. Revista Internacional de Contaminacion Ambiental, 14(1), 7-12.

The distribution of cadmium in soils across Jamaica is reported. The island-wide average is 20 mg kg^-1 and concentrations as high as 409 mg kg^-1 have been observed in some of the Terra rosa soils overlying Tertiary Limestones in central Jamaica and in a smaller region in a residential district near to a disused mine. In certain areas the enrichment is up to three orders of magnitude with respect to bedrock. The cadmium and zinc concentrations are highly correlated. Despite the high concentrations of cadmium found in certain localities, no cases of cadmium poisoning have been recognized in Jamaica, probably because the neutral and slightly alkaline soils and the underlying limestone help to fix the cadmium and thus maintain low concentrations in the underground and surface waters. However, changes in land use or other conditions may increase the risk.

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Lalor, G., R. Rattray, P. Simpson and M.K. Vutchkov. 1999.  Geochemistry of an Arsenic Anomaly In St. Elizabeth, Jamaica. Environmental Geochemistry and Health, 21(1), 3-11.

A soil arsenic anomaly with concentrations up to 400 µg As g^-1 was discovered near Maggotty, St. Elizabeth, during an island-wide geochemical survey of Jamaica. Detailed sampling and chemical analysis of soil samples confirmed the arsenic levels and led to a better definition of the size of the anomaly. The area exceeding the 95th percentile (> 65 µg As g^-1) of the island-wide concentrations has been determined to be at least 10km². The anomalous values may be the result of an ancient hot spring environment which was responsible for the introduction and deposition of Fe-As-S as pyrite and arsenopyrite in the limestone bedrock, which were subsequently oxidised and weathered to yield the arsenic rich soils. These soils were also enhanced in elements such as Sb, Fe and Co. Despite the high soil arsenic content, the arsenic concentration in the surface water is low and there seems to be no immediate health risk to the residents. The area, however, does present a potential hazard with changing land use.

Lalor, G.C., J. Preston, R. Rattray, M. Vutchkov.  1999. Heavy Metals in Jamaican Soils Part 4: Some Potentially Hazardous Elements.  Jamaican Journal of Science and Technology 10, 1-5.

Soil is the basis of terrestrial life and contains a very large number of elements which are biologically active.  Some of these elements are essential to life while others, for example, arsenic and heavy metals, are hazardous even at low concentrations.  Many Jamaican soils contain relatively high concentrations of potentially hazardous elements associated to a large extent with terra rossa and bauxitic soils that overlie the White limestone group. Among these elements are antimony, arsenic, cadmium, lead and mercury, the island-wide concentration distributions of which are reported and discussed. Antimony and arsenic are not considered to be environmental problems under the present conditions of land use.  While the concentrations of cadmium in some soils are extraordinarliy high there is no evidence that there are medical problems caused by cadmium ingestion.  Toxicity from naturally occurring lead is unlikely to be of concern except in the Hope River Valley, where very high concentrations are associated with galena in mine waste and ore residues from the old Hope Mine. These concentrations are also reflected in the blood lead levels of school children and the levels were high enough so that mitigation was carried out. The terra rossa and the morass soils are enhanced in mercury and more detailed work on the distribution and bioavailability of this element is recommended.

Lalor, G.C., M.K. Vutchkov, C. Grant, J. Preston, A.M.G. Figueiredo and D.I.T. Favaro. 2000.  INAA of Trace Elements in Biological Materials using the SLOWPOKE-2 Reactor in Jamaica. Journal of Radioanalytical and Nuclear Chemistry, 244(2), 263-266.

The biological standard reference materials Orchard Leaves SRM 1571 and Oyster Tissue SRM 1566a were analysed by instrumental neutron activation analysis (INAA) at the International Centre for Environmental and Nuclear Sciences, Jamaica at (ICENS) and at the Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), Brazil. The comparison of the results with those obtained with the more powerful reactor is used to evaluate the possibilities of INAA for the analysis of biological samples at ICENS. The detection limits, precision and accuracy of the results obtained in both laboratories are compared. The advantages and disadvantages of the different irradiation facilities are discussed. Some results obtained for Jamaican biological samples are also presented.

Vutchkov, M., C. Grant, G.C. Lalor and J. Preston. 2000.  Standardization of the SLOWPOKE-2 Reactor in Jamaica for Routine NAA. Journal of Radioanalytical and Nuclear Chemistry, 244(2), 355-359.

The International Centre for Environmental and Nuclear Sciences (ICENS) has been involved in conducting multipurpose geochemical surveys, the results of which were published in "A Geochemical Atlas of Jamaica". The primary analytical tool for these studies was neutron activation analysis (NAA) using the SLOWPOKE-2 reactor at the Centre. The neutron flux of the SLOWPOKE-2 reactor is extremely stable, thus allowing a semi-absolute method for quantitative NAA. This has several advantages, but requires preparation and measurement of the single- or multi-element standards for each gamma-spectroscopy syste../icens_slim2.jpgm (GSS). The NAA laboratory at ICENS operates three GSSs. The primary ("master") GSS was standardized using single element standards for over 50 elements, naturally occurring in most geological and biological materials. The standardization of the secondary GSS's was achieved by transferring the elemental sensitivities of the master GSS using an instrumentation-free standardization approach. The paper describes the implementation of this methodology and its utilization in the routine analytical work.

Lalor, G.C. and  M. Vutchkov.  2000. Heavy Metals in Jamaica Part 5: Reduction of Blood Lead Levels of Children in a Mine-Waste Contaminated Area.  Jamaican Journal of Science and Technology Vol. 11 Issue 1016-2054, 23-35.

 Blood lead levels in children in the age group 27-81 months who have been exposed to lead in a mine-waste contaminated area have been examined. The original levels of 15 - >60 µg dL^-1 (mean >37) were reduced to 7 - 27 µg dL^-1 (mean >15) ten months after the isolation of the mine-waste and lead contaminated soil in the school yard, improved sanitation, education of teachers, parents and the children, supported by a feeding programme. The lower lead values are similar to levels observed among children of similar ages in rural district in Jamaica.

This work has confirmed the effectiveness of the interventions: the present cohort of schoolchildren that have never been so exposed to lead, have blood lead levels that average a greatly improved 8.3 µg dL^-1 with 82% of them below the defined level of 10 µg dL^-1 for lead poisoning. The highest value observed in these children was 20 µgdL^-1 for 2 of the cohort. The main source of lead was the mine-waste; neither food nor water appears to be important contributors to the lead exposure but during this study lead has been observed in paint on older houses. This introduces a new dimension that might well be of concern islandwide.

G. Kennedy, J. St-Pierre, K. Wang, Y. Zhang, J. Preston, C. Grant, M. Vutchkov.  2000. Activation Constants for Slowpoke and MNS Reactors Calculated from the Neutron Spectrum and k₀ and Q₀ Values. Journal of Radioanalytical and Nuclear Chemistry, 245(1), 167-172.

The relative thermal, epithermal and fast neutron fluxes were measured in the inner and outer irradiation sites of three Slowpoke reactors and one Miniature Neutron Source (MNS) reactor by the bare triple monitor method. Using the measured neutron spectrum parameters and a compilation of published k₀ and Q₀ values, activation constants were calculated for the most intense gamma-rays of all nuclides commonly used in NAA. The resulting table of constants can be used to standardize NAA measurements for all elements when combined with relative efficiency measurements and the measurement of the thermal neutron flux with one standard. The observed constancy of the neutron spectra suggests that these activation constants are valid for all 14 Slowpoke and MNS reactors.

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Grant, C.N., G.C.Lalor and M.K.Vutchkov. 2001.  Radon Mapping of Soils in St. Elizabeth Jamaica. Journal of Radioanalytical and Nuclear Chemistry, Vol. 250(2), 295-302.

Soil gas measurements of radon were made in St. Elizabeth, Jamaica using nuclear track etch detectors. The results were compared to gamma spectroscopy measurements made in the laboratory on soil samples collected at the radon measurement sites. An assessment of the degree of disequilibrium of uranium and thorium was also made by comparison with neutron activation analysis, delayed neutron counting and equivalent uranium and thorium measurements. The results to date for equivalent uranium and radon show a strong correlation and indicate the possibility of soil radon mapping in Jamaica using gamma spectroscopy. Three anomalous sites have been identified.

Lalor, G., R. Rattray, M. Vutchkov, B. Campbell, and K. Lewis-Bell.   2001. Blood Lead Levels in Jamaican School Children. The Science of the Total Environment 269, 171-181.

Blood lead levels are reported for a total of 421 schoolchildren in 13 schools in rural and urban environments in Jamaica, including one highly contaminated community.In the rural areas blood lead levels ranged from 3 to 28.5 µg dl^-1, with a median of 9.2µg dl^-1;the range and median in the urban schools were 4-34.7 and 16.6µg dl^-1,respectively. Forty-two percent of the rural and 71% of the urban blood lead levels exceeded the US Centers for Disease Control and Prevention intervention level of 10µg dl^-1. Except in the contaminated areas,the relationship between soil lead levels,which in Jamaica are in general typical of tropical lateritic soils, and blood lead levels is not clear-cut. Very high blood lead levels of 18 to > 60 µg dl^-1 with a median of 35 µg dl^-1 were observed among children in the contaminated area, the site of a former lead ore processing plant. These high blood lead levels were significantly reduced, by the implementation of relatively simple mitigation strategies which involved isolation of the lead, education, and a food supplementation programme, to levels similar to those observed in the urban schools. These values, however, remained higher than are desirable and unfortunately, all the sources of lead are not yet identified.  The recent discontinuation of the use of petrol is expected to result in significant reduction in exposure to lead.

Lalor, G. and C. Zhang.  2001. Multivariate Outlier Detection and Remediation in Geochemical Databases. The Science of the Total Environment 281, 99 - 109.

In this study, outliers are classified into three types: (1) range outliers; (2) spatial outliers; and (3) relationship outliers, defined as observations that fall outside of the values expected from correlation within the dataset.  The multivariate methods of principal component analysis (PCA), multiple regression analysis (MRA) and an autoassociation neural network (AutoNN) method are applied to a dataset comprising 203 samples of rare earth element (REE) concentrations in soils of Jamaica which shows the expected good correlations between the elements. PCA is shown to be effective in detection of high value range outliers, while AutoNN and MRA are effective in detection of relationship outliers. A backpropagation neural networkwas used to predict the 'expected values' of the outliers.  Four obvious relationship outliers with unexpected low Sm concentrations were selected as an example for remediation. The predicted Sm values were confirmed on remeasurement. Neural network methods, with the advantages of being model-free and effective in solving non-linear relationship problems, appear to provide and automated and effective way for the quality of environmental databases.

Lalor, G.C. and M.K. Vutchkov. 2002.  Essential Elements in Jamaican Soils Part 2: Cobalt.  Jamaican Journal of Science and Technology, 2001 & 2002, Vols. 12 & 13 35-47.

The distribution of cobalt in Jamaican soils island-wide at a sample density of 1 in 64 km², shows a range of 4.7 - 105 mg kg^-1 and a mean of 28 mg kg^-1. The higher values are found mainly in central Jamaica, and are significantly greater than those reported for contaminated soils worldwide. In the absence of anthropogenic sources these are presumed to be a consequence of the natural geochemistry of the country. The soil cobalt concentrations island-wide are well correlated with Al, Fe (R² > 0.7) less well so with As, Mn, Th, V, Cr, Ti, Zn, Sb (R² = 0.47 - 0.38) but poorly with Cu, frequently occurs in cobalt ores.  At the more intensive sampling density of one sample in 4 km2 in the parishes of St. Elizabeth and Manchester the range and mean were 1 - 112 mg kg^-1 and 34 mg kg^-1 respectively. The soils generally contain adequate amounts of this essential element for proper animal nutrition, and cobalt deficiency in farm anumals ought not to be a problem but in some areas the high cobalt concentrations could contribute to deficiencies in other metals. Geochemical maps based on these data allow prediction of cobalt concentrations at any arbitrary point within the two parishes, with an accuracy of about + 50%.  Such maps should be useful in land use planning for agriculture.

The cobalt concentrations in 54 samples of a range of foods (condiments, fruits, root crops and vegetables), grown in St. Elizabeth and Manchester, appear higher than similar values reported in the United Kingdom, but insufficient data are now available to quantitatively examine the food/soil relationships for this element.

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