G. C. Lalor

Review of cadmium transfers from soil to humans and its health effects in the Jamaican environment

Concerns about the effects of cadmium on human health have led to numerous guidelines and regulations limiting its concentrations in soils and food and allowable human intakes. These have socio-economic consequences in terms of land use and the marketing of food. The bauxite soils in Jamaica, which are both aluminium ores and agricultural soils contain orders of magnitude higher than world normal concentrations of cadmium resulting in elevated Cd concentrations in several foodstuffs and significant transfers to humans, which would seem to represent a risk factor for increased mortality and/or morbidity in the local populations. But, as in Shipham and other examples, there is no evidence of cadmium-related human distress. Macro-indicators like life expectancy and median ages of death do not show cadmium related geographical distributions. The present review focuses on the soils and foods and illnesses of high incidence especially cancers and renal disease that have been traditionally associated with cadmium. In view of the remarkable concentrations of cadmium involved in Jamaica, and often contradictory reports in the literature, it appears that much remains to be learned about certain details of cadmium toxicity.

Levels of As, Cd, Pb, Cu, Se and Zn in bovine kidneys and livers in Jamaica

Paired liver and kidney samples from 100 free-range cattle in different parts of Jamaica were analyzed for essential and non-essential trace elements. We found significant enrichment of elements in the kidney (K) compared to the liver (L) with the K/L concentration ratios being 5.2 for Cd, 4.1 for Pb, 3.5 for Se and 2.1 for As, but the Cu contents of the kidney were significantly higher with the K/L ratio of 0.45. A large number of kidney and liver samples showed Cu concentrations in the ranges that were associated with deficiency effects in mammals. About 15% of the hepatic samples had Zn concentrations below 20 microg/g, suggesting that there might be zinc insufficiency in some of the animals. Positive associations were found between the metals in both the kidney and liver. On average, the intake of Cd from consumption of both bovine kidney and liver from the island was estimated to be 5.2 microg/day, equivalent to about 7% of the provisional tolerable daily intake (PTDI), although anyone who habitually consumed the few kidneys or livers with >40 microg/g cadmium may be at some risk of exceeding the PTDI. The consumption of offal from local animals did not appear to be an important dietary source of any of the essential microelements.

Heavy metals in surface water and stream sediments in Jamaica

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 Jamaicas 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 bio-availability of micropollutants such as heavy metals from the sediments can be expected to be relatively high.

Heavy metal pollution in Jamaica 1: Survey of cadmium, lead and zinc concentrations in the Kintyre and Hope Flat districts.

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−1 of lead and < 1–2 hg kg−1 of 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.

Blood lead levels in Jamaican school children

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 microg dl(-1), with a median of 9.2 microg dl(-1); the range and median in the urban schools were 4-34.7 and 16.6 microg 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 10 microg dl(-1). Except in the contaminated area, 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 microg dl(-1) with a median of 35 microg 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, remain higher than are desirable and unfortunately, all the sources of lead are not yet identified. The recent discontinuation of the use of leaded petrol is expected to result in significant reductions in exposure to lead.

Trace elements in Jamaican soils

The results of the analysis of approximately 100 soil samples for Na, Mg, Al, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, As, Sb, Ba, La, Sm, Eu, Dy, Lu, Hf, Th, and U by neutron activation analysis, in three soil horizons from four of the main agricultural parishes of Jamaica are presented. While there is some regional variation in the abundances, there are no statistically significant distributions of abundances across the horizons. The results for a few selected elements are compared with abundances in other countries.

Geochemical mapping in Jamaica.

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 γ-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.

Multivariate relationships and spatial distribution of geochemical features of soils in Jamaica

Abstract Concentrations of 31 chemical elements in 165 soil samples from the tropical island of Jamaica were analyzed during the island-wide soil survey. Multivariate outliers were detected and remedied for quality control of the database. Multivariate analyses including principal component analysis (PCA), cluster analysis, and analysis of variance (ANOVA), and a geographic information system (GIS) were applied to study the geochemical features of element associations and sample clusters. The results show that rare earth elements, most of the heavy metals and trace elements (including As, Al, Cd, Ce, Co, Cr, Dy, Eu, Fe, Hf, Hg, La, Lu, Mn, Pb, Sb, Sc, Sm, Th, Ti, U, V, Yb, Zn) are enriched in the bauxitic soils relative to the non-bauxitic soils, and closely correlated with one another. Negative correlations between the bauxite-enriched elements and the mobile alkali and alkaline earth elements including Ca, Sr, Mg and Na are observed, showing the opposite tendencies of enrichment of the immobile elements and leaching of the mobile elements during the soil formation processes. The halogen elements of Br and I are also relatively enriched in the bauxitic soils, but they appear to be rather affected by sea-spray. Copper has poor correlations with all the other elements, which is likely to be related to mineralization. Significantly different concentrations of the bauxite-enriched elements are observed between the bauxitic and non-bauxitic soils.

INAA of Trace Elements in Biological Materials Using the SLOWPOKE-2 Reactor in Jamaica

The biological standard reference materials Orchard Leaves SRM 1571 and Oyster Tissue SRM 1566a was analysed by instrumental neutron activation analysis (INAA) at the International Centre for Environmental and Nuclear Sciences, Jamaica at (ICEN) 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 are used to evaluate the possibilities of INAA for the analysis of biological samples at ICENS. The detection limits, the 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.

Lead in a residential environment in Jamaica

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 8 μg kg−1 in the water of the nearby Hope River. The blood lead levels of a sample of children were in the range 5.7–57 μg 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.