Richard M. Jacobs

EFFECTS OF VITAMIN C AND IRON ON CADMIUM METABOLISM

Toxic levels of dietary cadmium (5-200 ppm) interfered with iron absorption and produced an iron deficiency. Supplements of iron (particularly the divalent form) and ascorbic acid protected against the cadmium. With very low levels of dietary cadmium (about 0.06-0.08 ppm), typical of those in the diets of humans, supplements of iron(II) and ascorbic acid markedly decreased cadmium concentrations in the liver, kidney, and small intestine. Iron deficiency changed the distribution of cadmium within the body. The effect of ascorbic acid on cadmium metabolism appears to depend primarily, if not entirely, on its influence in improving iron absorption. Maintenance of modest iron stores appears to be very important in minimizing cadmium absorption.

Effects of Dietary Zinc, Manganese, and Copper on Tissue Accumulation of Cadmium by Japanese Quail

Abstract The beneficial effects of a combined dietary supplement of Zn, Cu, and Mn in decreasing Cd absorption was previously reported. The purpose of this study was to investigate the individual and combined effects of these three elements. In the first two experiments, day-old Japanese quail were fed basal diets containing either requirement amounts of Zn (30 ppm) and Mn (12 ppm) and slightly above requirement levels of Cu (5 ppm). From Day 7 birds were fed either the basal diet or diets containing combinations at twice these concentrations; a 2 × 2 × 2 factorial design was used. 109Cd content and Cd concentration of these diets were 100 μCi and 145 μg/kg, respectively. In the third experiment, day-old birds were fed either the basal diet or a basal diet containing 109Cd and single additional supplements of either Zn, Cu, or Mn. All birds were killed at 14 days of age. The Cd concentration was determined for the duodenum, jejunum-ileum, liver, and kidney. When the experimental diets were fed for 7 days, only Zn had a protective effect against Cd. Whereas none of the elements reduced the Cd concentration of the duodenum, Zn reduced the Cd in the jejunum-ileum, liver, and kidney by approximately 66, 21, and 11%, respectively. Cu and Mn caused occasional increases of Cd in some tissues. Feeding the experimental diets for 2 weeks resulted in similar responses. Zn nutrition appears to play an important role in protecting against dietary Cd absorption.

Mineral composition of brains of normal and multiple sclerosis victims.

Abstract Elemental contents of human brain samples were determined using plasma emission spectroscopy. White matter samples from brains of multiple sclerosis (MS) victims had significantly greater concentrations of calcium, iron, manganese, and zinc, and significantly less phosphorus, as compared with controls. Whether these differences in elemental concentrations indicate an etiogenic or pathogenic relationship between these elements and MS is not known.

Preliminary assessment of potential health hazards associated with barium leached from glazed ceramicware

Ceramic glazes contain several elements which have the potential to leach into food or beverages that are held or stored in ceramicware. Recently, barium salts have been investigated as one of the alternatives to lead in frit formulations for glazes. This preliminary evaluation addresses the potential health hazards associated with barium at levels that might leach from glazed ceramicware. A set of specialty ceramicware, consisting of five teacups and a pitcher, was examined for extractable barium. Exposure to barium that adults (18-44 years) might encounter using the vessels for coffee, tea, or orange juice was estimated. The exposure estimate was derived from values for intakes of the beverages and for the barium migration from glazed ceramicware test samples. An established reference dose (RfD) for barium exposure for the critical effect of hypertension was identified. The potential hazard associated with the leaching of barium from glazed ceramicware varied with the level of use. Consuming beverages in amounts up to the 95th percentile would not result in total barium intake in amounts that exceed the RfD; consuming large quantities (> 95th percentile) of beverages such as tea or coffee from glazed vessels might. This suggests that for a small portion of the population of users, intake of barium may be in quantities that warrant further consideration as a potential health hazard. Analyses of a broad sample of ceramicware and study of barium leaching behaviour under actual use conditions are needed to assess further the significance of these findings.

Survey of imported green coffee beans for pesticide residues

The US Food and Drug Administration carries out incidence/level monitoring in order to acquire data on the presence and amounts of pesticide residues in particular commodity/chemical combinations. In the survey reported here, imported green coffee beans were analysed for a variety of pesticide chemicals. A total of 60 green coffee samples were collected from 21 countries that are major exporters of coffee to the United States. The samples were analysed for organochlorine/organophosphorus, N-methyl carbamate, benomyl group and EBDC residues. Four samples had detectable residues: chlorpyrifos, 0.01, 0.02 and 0.04 ppm and pirimiphos-methyl, 0.01 ppm. The majority (93%) of the green coffee samples analysed in this survey had no detectable pesticide residues.

Copper, Iron, Manganese, and Zinc Content of Hair from Two Populations of Rhesus Monkeys**

The concentrations of the elements copper (Cu), iron (Fe), manganese (Mn), and zinc (Zn) in hair of caged (in Maryland) and freeranging (in Puerto Rico) rhesus monkey populations were determined. Significant chronological age-related decreases were evident for the trace elements Mn and Zn in both populations (P<0.01) and for Cu and Fe in free-ranging monkeys (P<0.005). The only overall gender difference was higher hair Mn concentration in freeranging males than in females (P<0.03). There were no significant differences in hair Cu, Fe, or Mn related to pregnancy status. Hair Zn was lower in samples from pregnant than from nonpregnant monkeys from the caged monkeys (P≤0.05), but did not differe in the freeranging monkeys. Comparison of the two populations revealed that hair Zn levels were significantly higher in caged vs free-ranging animals (P<0.001). We attribute this higher hair Zn in the caged monkeys to contact and ingestion of Zn from their galvanized enclosures. Hair iron levels were significantly higher (P<0.001) in free-ranging monkeys, possibly as a result of Fe-rich soil ingestion from their environment. These data support continued investigation of the use of hair as an indicator of the exposure of large groups or populations to potentially high levels of specific minerals, and the use of nonhuman primates as models for the study of trace element deficiency and/or toxicity in humans.