Distribution and Normalization of some Metals in Surface Sediments from South Caspian Sea

Surface sediments along the south of Caspian Sea were collected to evaluate the contamination of heavy metals. The result ranged (μg/g, Fe% dw): Pb(13.06–33.48); Ni(18.01–69.63); Cd(0.62–1.5); Zn(30.11–87.88); Cu(5.86–26.37) and Fe(1.8–4%) respectively. Cadmium showed higher EF when compared to other sites. Geoaccumulation Index value for Cd in most stations was classified as moderately contaminated and moderately to strongly contaminated, as well as the average of I_geo of Cd (1.77 ± 0.35) suggested that surface sediments of Caspian coast were moderately polluted by this metal. The result of the Pearson correlation showed that there were significant positive associations between Ni, Cd and Zn (r = 0.44–0.76; p < 0.01).     

Cadmium in the blood and seminal fluid of nonoccupationally exposed adult male subjects with regard to smoking habits

Blood cadmium (B-Cd) and seminal fluid cadmium (Sf-Cd) were measured in 120 adult male subjects not occupationally exposed to cadmium (Cd), comprising 42 nonsmokers (including nine former smokers) and 78 smokers. The respective median and range values were: 0.46 (0.19–1.49) μg/l of B-Cd and 0.54 (0.17–1.67) μg/l of Sf-Cd in nonsmokers, and 4.33 (0.49–13.33) μg/l of B-Cd and 0.85 (0.29–3.56) μg/l of Sf-Cd in smokers. Both indicators showed a highly significant difference in Cd exposure between the groups (P<0.0001), although the increase in B-Cd was considerably more pronounced than that of Sf-Cd in smokers compared with nonsmokers. The results suggest a nonlinear relationship (log Sf-Cd/log B-Cd: r=0.501, P<0.0001), rather than linear relationship (Sf-Cd/B-Cd: r=0.430, P<0.0001), between the indicators. Significant correlations were found between smoking habits, i.e., the number of cigarettes per day, and an increase in B-Cd in smokers (r=0.296, P<0.01) and in all 120 subjects (r=0.685, P<0.0001), as well as between smoking habits and an increase in Sf-Cd in smokers (r=0.378, P<0.001) and in all 120 subjects (r=0.488, P<0.0001). Both indicators are necessary for evaluation of individual internal Cd dose, since they appear to differ in reflecting recent and long-term cumulative Cd exposure and/or the amount of Cd at the site(s) of its effect(s) in the body. Received: 30 September 1996 / Accepted: 18 February 1997     

Exposure to methyl tert-butyl ether and tert-amyl methyl ether from gasoline during tank lorry loading and its measurement using biological monitoring

Objective and methods: The exposure of Finnish tank lorry drivers to methyl tert-butyl ether (MTBE) and tert-amyl methyl ether (TAME) during loading of gasoline was studied using biological and breathing-zone sampling. During the field measurements – in October 1994 and August 1995 – the gasolines (95, 98, 99 RON) contained MTBE to 5.2–11.8% and TAME to 0–6%. Results: The geometric mean (GM) breathing-zone concentration of MTBE was 4.3 mg/m³ (n= 15) in October and 6.4 mg/m³ (n= 20) in August. The GM concentration of TAME, measured only in August, was 0.98 mg/m³. The mean loading/sampling times were 37 and 35 min, the mean wind speeds were 0.8 and 0.6 m/s, and the mean air temperatures were −4.9° and +14.1 °C, respectively. Blood samples collected on average at 20 min after gasoline loading/exposure showed an MTBE concentration of 143 nmol/l (GM, n= 14) in October and 213 nmol/l (GM, n= 20) in August. Pearson's coefficient of correlation (r) between the MTBE breathing-zone concentrations and MTBE in blood was 0.86 (P= 0.0001) in October and 0.81 (P= 0.00001) in August. No correlation was found between MTBE in air and the metabolite tert-butanol (TBA) in blood. MTBE, but not TBA, in urine samples collected on average at 2.5 h after exposure showed a correlation with MTBE in air. The concentrations of TAME and its metabolite tert-amyl alcohol were below the quantitation limits (<7 and <100 nmol/l, respectively) in most blood and urine samples. Conclusions: The breathing-zone measurements showed low levels of exposure to the two oxygenates, the concentrations being well below the current hygienic standards for MTBE (250–360 mg/m³ for 15 min and 90–180 mg/m³ for 8 h). The linear correlations obtained for MTBE suggest that MTBE in blood or urine can be adopted as a valid biological exposure index. Received: 7 November 1997 / Accepted: 13 February 1998     

The Accumulation of Cadmium by the Yellow Pond Lily, Nuphar variegatum, in Ontario Peatlands

Cadmium concentrations of a common macrophyte, the yellow pond lily (Nuphar variegatum) were investigated from peatlands with a range in pH (4.4–6.3), alkalinity (0–181 μeq/L Ca), DOC (5.1–16.8 mg/L), and sediment organic content (20–88%). Cd concentrations in Nuphar ranged from 0.3 to 1.51 μg/g in the leaves and from 0.46 to 1.51 μg/g in the petioles, and was significantly higher in the petioles than in the leaves (p = 0.014; t-Test). Significant and negative correlations between Nuphar leaf Cd and pH (r²= 0.76; p < 0.001), alkalinity (r²= 0.41; p = 0.034), and DOC (r²= 0.46; p = 0.022) were obtained. In addition, a significant and negative correlation was found between Nuphar petiole Cd and pH (r²= 0.46; p = 0.023). These results indicate that the leaves of Nuphar found in peatlands of low pH, low alkalinity, and low DOC, and the petioles of Nuphar found in peatlands of low pH are more susceptible to accumulating potentially toxic levels of Cd. The organic content of the peatland sediments was not significantly correlated with either the leaf or petiole Cd concentration. Nuphar is an important food source for many wetland animals; any Cd that is present in these plants may be passed onto other trophic levels because diet is considered to be the major source of Cd to animals. Received: 5 December 1995/Revised: 13 June 1996     

Cadmium exposure of women in general populations in Japan during 1991–1997 compared with 1977–1981

Objectives: The Japanese people are known to have high environmental exposure to cadmium (Cd). The present survey was initiated to elucidate possible changes in the intensity of Cd exposure to the population by comparison of the present exposure level with the situation some 15 years ago. Methods: During 1991–1997, 24-h food-duplicate samples, peripheral blood specimens and morning spot urine samples were collected from 588 non smoking women from 27 survey sites in six regions, where food-duplicate and blood samples had also been obtained during 1977–1981 from 399 women. The samples were wet-ashed (after homogenization in the case of food-duplicates), and Cd in the wet-ashed samples was analyzed by inductively-coupled plasma mass spectrometry for Cd intake via foods (Cd-F), Cd concentration in blood (Cd-B) and Cd concentration in urine (Cd-U). The Cd-F and Cd-B were compared with the Cd-F and Cd-B obtained at the same sites in the 1977–1981 survey. Results: The exposure levels during 1991–1997 were such that Cd-F, Cd-B and Cd-Ucr (Cd–U after correction for creatinine concentration) were 25.5 μg/day, 1.90 μg/l and 4.39 μg/g creatinine. Comparison with the 1977–1981 survey results (i.e., 37.5 μg/day for Cd-F and 3.47 μg/l for Cd-B) showed that there were significant reductions (by 32 and 45%) in both parameters respectively during the last 15 years. The dietary route was an almost exclusive (i.e., 99% of the sum of dietary and respiratory uptake) route of Cd uptake, of which Cd in rice (11.7 μg/day) contributed about 40% of the total dietary intake. When compared among survey sites, inter-site variation in dietary Cd intake was primarily due to differences in the intake through boiled rice. Despite the recent reduction in Cd exposure, the current exposure level for Japanese people is still higher than the levels among other rice-dependent populations in Asia as well as in other parts of the world. Comparison was made between the present findings in general populations and observations among known Cd-pollution cases in Japan. Conclusions: Dietary uptake is an almost exclusive route of Cd exposure in the general Japanese population. Boiled rice is a strong determinant of variation in dietary Cd intake. Whereas there was a substantial reduction in Cd exposure among Japanese populations in the last 15 years, the current level is still high when compared internationally. Received: 1 March 1999 / Accepted: 17 July 1999     

Levels of Cd, Pb, As, Hg, and Se in Hair of Residents Living in Villages Around Fenghuang Polymetallic Mine, Southwestern China

Heavy metal levels in hair of residents living in villages around Fenghuang mine were investigated. Samples belonging to mine areas showed the highest values, with mean concentrations (mg kg⁻¹) of 0.17 for Cd, 8.67 for Pb, 0.11 for As, 2.19 for Hg, and 0.64 for Se. Significant correlations (p < 0.01) were found between Cd–Pb, Cd–As, Pb–As, and Se–Hg. There is no significant difference in any of the elements among age groups. However, significant differences in Cd and Pb levels were found between genders. Results revealed that children and females were more susceptible to Cd and Pb exposure.     

trans,trans-Muconic acid as a biomarker of non-occupational environmental exposure to benzene

 Excretion of trans,trans-muconic acid (2,4-hexadienedioic acid; t,t-MA), a potential biomarker of low-level exposure to benzene, was determined in 32 smokers and 82 nonsmokers. In smokers the median background excretion of t,t-MA was 0.13 (0.06–0.39) mg/g creatinine and was significantly higher (P<0.05) than the value of 0.065 (0.02–0.59) mg/g creatinine in nonsmokers. For nonsmokers, the correlation between t,t-MA excretion and environmental exposure to benzene in ambient air, which was determined during the 8-day study period by personal diffusion samplers, was not significant (r=0.164, P=0.18). Nonsmokers living in the city tended to have higher t,t-MA excretion rates than nonsmokers living in the suburbs. However, the difference was only significant for nonsmokers from nonsmoking homes. For the same location (suburb or city), smoking at home leads to a marginal increase in t,t-MA excretion of the nonsmoking members of the household. In a further study with eight nonsmokers we found that dietary supplementation with 500 mg sorbic acid significantly increased (P<0.001) the mean urinary t,t-MA excretion from 0.08 (0.04–0.12) to 0.88 (0.57–1.48) mg/24 h. Under study conditions 0.12% of the sorbic acid dose was excreted in urine as t,t-MA, thereby indicating that a typical dietary intake of 6–30 mg/day sorbic acid accounts for 10–50% of the background t,t-MA excretion in nonsmokers, and for 5–25% in smokers. As a consequence, sorbic acid in the diet is a significant confounding factor in assessing low-level benzene exposure if t,t-MA excretion in urine is used as a biomarker. Received: 10 October 1995 / Accepted: 26 February 1996     

The integrity of the liver among people environmentally exposed to cadmium at various levels

The objective of the present study was to examine if environmental exposure to cadmium (Cd) had any impact on the integrity of the liver among the general Japanese population. A nationwide survey was conducted in the winter seasons of 1991–1995 in 15 prefectures in Japan to collect 24-h food duplicates, peripheral blood samples, and morning spot urine samples from healthy nonsmoking adult women. The samples were analyzed for Cd by automated graphite furnace atomic absorption spectrometry. In total, 371 women offered food duplicate, blood, and urine samples. The dietary Cd intake was 17.3–79.4 μg/day, the level of Cd in blood was 1.58–3.82 ng/ml, and the urinary Cd concentration was 1.06–4.74 μg/g creatinine as geometric means calculated on a regional group basis. Analyses for correlation with liver function showed no Cd-exposure-related elevation in enzyme levels or reduction in albumin levels' in serum. The distribution of cases with enzyme levels above normal ranges (or below normal in the case of albumin) did not show any dose-related bias. The age of the subject, not the exposure to Cd, was the most influential factor in determining serum enzyme levels. Environmental exposure to Cd has not affected the integrity of the liver among the general population in Japan. Received: 8 August 1996 / Accepted: 8 November 1996     

Urinary lead as a possible surrogate of blood lead among workers occupationally exposed to lead

Objectives: The aim of the present study is to investigate whether lead (Pb) in urine (Pb-U) can be a valid surrogate of lead in blood (Pb-B), the traditional biomarker of exposure to lead in occupational health. Methods: Blood and spot urine samples were collected from 258 workers of both sexes occupationally exposed to lead. The samples were analyzed for lead by graphite furnace atomic absorption spectrometry, and the correlation between Pb-B and Pb-U was examined by linear regression analysis before and after logarithmic conversion. Results: The correlation coefficient (0.824; P < 0.01) was largest when the relationship between Pb-B and Pb-U was examined with 214 cases of one sex (i.e., men) after Pb-U was corrected for a specific gravity (1.016) of urine (Pb-Usg) and both Pb-B and Pb-Usg were converted to logarithms. The geometric means (GMs) of Pb-B and Pb-Usg for the 214 men were 489 μg/l and 81 μg/l, respectively. When Pb-Usg was assumed to be 100 μg/l in this set of correlations, the 95% confidence range of Pb-B for the group mean was narrow, i.e., 543–575 μg/l (with GM of 559 μg/l), whereas that for individual Pb-B values was as wide as 355–881 μg/l. Conclusions: The correlation of Pb-U with Pb-B among workers occupationally exposed to Pb was close enough to suggest that Pb-U may be a good alternative to Pb-B on a group basis, but not close enough to allow Pb-U to predict Pb-B on an individual basis. Received: 6 April 1999 / Accepted: 17 July 1999     

Metal and Metallothionein Concentrations in Scoter (Melanitta spp.) from the Pacific Northwest of Canada, 1989–1994

Eighty-six surf (Melanitta perspicillata) and nine white winged (M. fusca) scoters were collected from 1989–1994 at 11 locations in British Columbia and the Yukon. Their kidney and liver tissues were analyzed for cadmium (Cd), copper (Cu), zinc (Zn), and metallothionein (MT) concentrations. Individual kidney Cd values ranged from 2.4 μg/g dry weight (DW) in birds from northern Vancouver Island to 390.2 μg/g (DW) in birds from the Queen Charlotte Islands, which is in the range of values potentially associated with kidney damage. Birds from the Queen Charlotte Islands also had high kidney Zn concentrations, which were significantly higher than values in birds from Naniamo and Westham Island on the south coast of BC. Cd values were significantly (p < 0.001) correlated with both Zn and MT concentrations in kidney tissue (r = 0.66 and 0.62, respectively). Male surf scoters had significantly higher kidney Cd and Zn levels than females, with mean Cd values of 47.3 and 19.7 μg/g DW (p < 0.002) for males and females, respectively. Mean Zn values were 120.8 and 108.0 μg/g DW (p < 0.05) for males and females, respectively. However, no sex differences were observed for either Cu or MT concentrations in kidney tissue. Individual MT values ranged from 2.7 to 416.8 μg/g wet weight (WW). Individual kidney Cu values ranged from 15.1 to 48.4 μg/g DW for both sexes. Kidney and liver Cd concentrations were significantly correlated (r = 0.90, p < 0.05) with kidney levels almost always higher than liver values. Although Cd accumulation by the Skidegate scoters was high, comparable tissue Cd values have been documented in other seabirds collected from the same general area, indicating elevated Cd concentrations in marine food chains around the Queen Charlotte Islands (Haida Gwaii) region of the Pacific coast. Received: 17 January 2002/Accepted: 2 June 2002     

Normal liver function in women in the general Japanese population subjected to environmental exposure to cadmium at various levels

Objectives: Whereas it is well established that environmental exposure to cadmium (Cd) may induce kidney dysfunction, less attention has been paid to the possible disturbance of liver function by Cd exposure. The possibility that liver function is adversely affected by current levels of environmental exposure to Cd as investigated in women in the general population in Japan, where the background level of exposure to Cd is known to be high. Methods: From 1991 to 1997, 24-h food duplicate, peripheral blood and morning spot urine samples were collected from 607 non-smoking and non-habitually drinking women (age range 19–78 years) at 30 survey sites (with no known environmental pollution from heavy metals) throughout Japan. Liver function parameters in serum were examined by conventional methods. After wet-ashing, the food duplicate, blood and urine samples were analyzed for Cd intake via food (Cd-F), Cd in blood (Cd-B), and Cd in urine (Cd-U) by inductively-coupled plasma mass spectrometry. Results: The geometric mean values for Cd-F, Cd-B, and Cd-U were 24.7 (27.1) μg/day, 1.76 (2.07) μg/l, and 3.94 (4.61) μg/g creatinine (values in parentheses for 41- to 60 year-old women), respectively. It as found that the three parameters of ALP, ALT, and AST activity were positively and significantly related to the age of the subjects (whereas no association as detected in cases of γ-GTP, LAP, and albumin). Accordingly, a further analysis as made with 367 women selected by age (41–60 years; about 60% of the total population). Essentially, no Cd dose-dependent changes in liver function parameters were observed in the selected population of this narrower age range. Conclusions: Overall, it seemed prudent to conclude that liver function as not disturbed by the current environmental exposure to Cd in Japan. Received: 16 March 1999 / Accepted: 17 July 1999     

Nonessential Metals in Striped Marlin and Indo-Pacific Sailfish in the Southeast Gulf of California, Mexico: Concentration and Assessment of Human Health Risk

Seventeen sailfish (Istiophorus platypterus; 166–246 cm long) and 13 striped marlin (Tetrapturus audax; 159–254 cm long) specimens from the southern Gulf of California were analyzed for As, Cd, Hg, and Pb concentrations. More than 20% of the As and Cd levels exceeded the guideline levels of the World Health Organization (WHO), the U.S. Food and Drug Administration, and the European Union. About 65–90% of the specimens exceeded the limit value for Hg. Pb levels in billfish were significantly lower than guideline values. The intakes of As and Cd through billfish consumption by the population represented 20–40% of the provisional tolerable weekly intake (PTWI) values as recommended by the WHO. Levels of Hg exceeded the PTWI value. Pb intake represented <5% of the PTWI through these species in all age and gender groups. The target hazard quotients (THQs) for Cd and Pb were <1 in each group of interest. In contrast, THQ values based on As and Hg showed large variations, with the highest values for children, then pregnant women, and, finally, adults. Values of THQ >1 indicate risk for As and Hg; the risk from As was estimated assuming that 20% of the total As was inorganic. These metals can affect the nervous system and intellectual and physical development of unborn children and infants. A national moratorium on billfish consumption in México is recommended for children (0–6 years old), pregnant women, and women planning pregnancy.     

Mercury and Cadmium Contamination of Irrigation Water,Sediment, Soil and Shallow Groundwater in a Wastewater-Irrigated Field in Tianjin,China

We investigated the concentrations of Hg, Cd, Pb and As in samples of irrigation water, sediment, soil and groundwater from a field in Tianjin that was irrigated with wastewater. The results showed that the concentrations (Hg, 0.82 μg/L; Cd, 0.18 μg/L; Pb, 1.5 μg/L; As, 8.02 μg/L) in the irrigation water did not exceed the China Surface Water Quality Standard or the maximum concentrations in irrigation water recommended by the FAO. The concentrations of metals in the groundwater of wells (Hg, 0.016 μg/L; Cd, 0.128 μg/L; Pb, 0.25 μg/L; As, 4.65 μg/L) were lower than China Groundwater Quality Standard and the WHO guideline values for drinking water. The groundwater had not yet been contaminated through vertical infiltration-induced leaching. However, a substantial buildup of Hg and Cd in river sediments (I _geo for Hg and Cd; 5.24 and 3.04, respectively) and wastewater-irrigated soils (I _geo for Hg and Cd; 2.50 and 3.09, respectively) was observed. Taken together, these results indicated that irrigation with wastewater damaged the soil quality over the long term and that metals more easily accumulated in vegetable fields than rice fields.     

Animal Health Problems Attributed to Environmental Contamination in Lake Nakuru National Park,Kenya: A Case Study on Heavy Metal Poisoning in the Waterbuck <Emphasis Type="Italic">Kobus ellipsiprymnus defassa</Emphasis> (Ruppel 1835)

A study was conducted in which samples of soil, forage, as well as serum, bone, kidney, and liver of waterbuck were collected from Lake Nakuru National Park. The objective was to determine the ecosystem health status in order to establish the causes of animal health problems previously recorded in some sections of the Park. Trace element analysis in serum indicated occurrence of copper (Cu) deficiency in the north and eastern sections of the Park where mean values were marginal (range: 0.36–0.81, mean: 0.62 mg/l) compared to concentrations recorded in the western part of the Park (range: 0.69–1.48, mean: 1.22 mg/l). Bone analysis on dry matter basis (DM) indicated higher (p < 0.01) levels of cadmium (Cd, 0.437 mg/kg), fluoride (F, 3178 mg/kg), and lead (Pb, 20.62 mg/kg) in animals from the east compared to those from the west (0.002, 1492, 4.87 mg/kg, respectively), suggesting heavy exposure. In addition, samples from the east had much lower than normal calcium (Ca)-to-phosphorus (P) ratios (mean: 1.9:1) compared to those recorded in the west (2.2:1), suggesting poor bone mineralization. There was a higher concentration of Cd in the kidney (16.24 mg/kg, p < 0.05) and Pb in the liver (58.3 mg/kg, p < 0.01) in animals from the east compared to those in the west (12.92 and 36.2 mg/kg, respectively), but the converse was true of Cu. The liver Cu status was better in animals from the west with, concentrations (mean: 21.7 mg/kg) being about twice those recorded in the east (11.9 mg/kg DM). Forage analysis revealed prospects of Ca, P, and Cu deficiencies in the entire Park. However, in the northeastern section of the Park (measuring 50 ha) where waterbuck residence times are high, forage concentrations of Cd (0.31 mg/kg DM), molybdenum (Mo, 7.20 mg/kg DM), Pb (2.88 mg/kg DM), and zinc (Zn, 126 mg/kg DM) were an order of magnitude greater (p < 0.01) than the levels recorded in the rest of the Park (ranges: 0.133–0.165, 3.69–5.61, 0.485–0.621, 11.6–17.4 mg/kg DM, respectively). These disparities were attributed to a higher soil concentration of Cd (2.77 mg/kg DM), Pb (85.1 mg/k DM) and Zn (1414 mg/kg DM) in this section compared to the rest of the Park (ranges: 0.10–0.15, 5.02–6.26, 1.49–5.44 mg/kg DM, respectively), and strongly suggest heavy metal contamination as the source of animal health problems in the Park.     

Intercomparison Studies on Distribution and Coassociations of Heavy Metals in Liver, Kidney, and Muscle of Harbor Porpoise, Phocoena phocoena, from Southern Baltic Sea and Coastal Waters of Denmark and Greenland

The concentrations of selected metals such as Cd, Pb, Cu, Zn, Cr, Ni, Mn, and Fe were determined in liver, kidney, and muscle of harbor porpoise (Phocoena phocoena) from three geographical regions, i.e., the Baltic Sea and Danish and Greenland coastal waters. The concentrations of Cd in liver and kidney increased with age of the specimens analyzed. Significant interspatial variations in both hepatic and renal levels of Cd were also observed. Average hepatic levels of Cd in Baltic, Danish, and Greenland specimens were (age range) 0.05–0.09, 0.12–0.25, and 20.6–51.6 μg g⁻¹ dry weight, respectively. Such values for renal Cd were as follows: 0.55–0.71, 0.14–1.84, and 0.55–94.3 μg g⁻¹ dry weight. In contrast to Cd, concentrations of Cu in the liver and kidney of specimens from Baltic, Danish, and Greenland areas did not indicate such great interspatial variability. The average hepatic values amounted to (age range) 14.1–15.5, 22.1–63.6, and 16.3–25.9 μg g⁻¹ dry weight, and kidney contained on the average 7.83–8.80, 11.7–16.2, and 11.1–15.7 μg Cu g⁻¹ dry weight, respectively. The higher levels of hepatic and renal Cd in Greenland specimens than in Baltic ones could be explained by different food composition in the area studied. Baltic porpoises mainly feed on fish (cod, plaice) containing extremely low levels of muscle Cd, but an important diet component of Greenlandic individuals is squid, characterized by elevated levels of Cd. Received: 22 May 2001/Accepted: 11 November 2001     

Seasonal variability in cadmium, lead, copper, zinc and iron concentrations in the three major fish species, Oreochromis niloticus, Lates niloticus and Rastrineobola argentea in Winam Gulf, Lake Victoria: impact of wash-off into the lake

Trace metals Cadmium (Cd), Lead (Pb), Copper (Cu), Zinc (Zn) and Iron (Fe) were analyzed in edible portions of three main finfish species namely Lates niloticus, Oreochromis niloticus and Rastrineobola argentea sampled from various beaches of Winam Gulf, Lake Victoria, Kenya, in order to determine any seasonal and site variations and the results showed significantly (p < 0.05) higher mean concentrations of Cd, Cu, Zn and Fe during the wet season compared to the dry season for all the three species indicating the impact of wash-off into the lake during the rainy periods. The overall mean concentrations of the heavy metals (in μg/g dry weight) in all combined samples ranged from 0.17–0.40 (Cd), 0.47–2.53 (Pb), 2.13–8.74 (Cu), 28.9–409.3 (Zn) and 31.4–208.1 (Fe), respectively. It was found that consumption of Rastrineobola argentea can be a significant source of heavy metals especially Zn, to humans, compared with Lates niloticus and Oreochromis niloticus, if only the muscle parts of the latter two are consumed.     

Evaluation of urinary cadmium and lead as markers of background exposure of middle-aged women in Korea

Objective: The present study was initiated to investigate the validity of cadmium (Cd) and lead (Pb) in urine in comparison with the metals in blood as a biological marker of nonoccupational exposure of general populations to these metals as environmental pollutants. Design: Peripheral blood samples, morning spot-urine samples, and 24-h total food duplicate samples were collected from 107 nonsmoking women (aged 30–59 years) in four urban and rural survey sites in Korea. Methods: Portions of the samples were digested by heating in the presence of mineral acids, and the digests were analyzed for Cd and Pb by graphite furnace atomic absorption spectrophotometry. The metal concentrations in urine were adjusted for creatinine concentration and a specific gravity of 1.016. The analyte levels were evaluated on an individual basis (n = 107) and also on a group basis, i.e., in terms of geometric means for the survey sites (n = 4). Results: Cd in urine correlated with Cd in blood on an individual as well as survey-site basis and tended to correlate with Cd in food duplicates on a group basis. The correlation of Pb in urine with Pb in blood was weaker than that of Cd in urine with Cd in blood when evaluated on an individual and survey-site basis. Pb in urine correlated with Pb in food duplicates either weakly or even negatively when examined on a survey-site basis. Conclusions: Cd in urine proved to be valid as a biological marker of environmental exposure of general populations, whereas less support was obtained for Pb in urine as an exposure marker. Received: 5 May 1997 / Accepted: 28 August 1997     

Evaluation of urinary biomarkers of exposure to benzene: correlation with blood benzene and influence of confounding factors

Purpose   trans,trans-Muconic acid (t,t-MA) is generally considered as a useful biomarker of exposure to benzene. However, because of its lack of specificity, concerns about its value at low level of exposure have recently been raised. The aim of this study was (a) to compare t,t-MA, S-phenylmercapturic acid (SPMA) and benzene (B-U) as urinary biomarkers of exposure to low levels of benzene in petrochemical workers and, (b) to evaluate the influence of sorbic acid (SA) and genetic polymorphisms of biotransformation enzymes on the excretion of these biomarkers. Method  A total of 110 workers (including 24 smokers; 2–10 cigarettes/day) accepted to take part in the study. To assess external exposure to benzene, air samples were collected during the whole working period by a passive sampling device attached close to the breathing zone of 98 workers. Benzene was measured in blood (B-B) samples taken at the end of the shift, and was considered as the reference marker of internal dose. Urine was collected at the end of the shift for the determination of B-U, SPMA, t,t-MA, SA and creatinine (cr). B-U and B-B were determined by head-space/GC–MS, SPMA and SA by LC-MS, t,t-MA by HPLC-UV. Results  Most (89%) personal measurements of airborne benzene were below the limit of detection (0.1 ppm); B-B ranged from <0.10 to 13.58 μg/l (median 0.405 μg/l). The median (range) concentrations of the urinary biomarkers were as follows: B-U 0.27 μg/l (<0.10–5.35), t,t-MA 0.060 mg/l (<0.02–0.92), SPMA 1.40 μg/l (0.20–14.70). Urinary SA concentrations ranged between <3 and 2,211 μg/l (median 28.00). Benzene concentration in blood and in urine as well as SPMA, but not t,t-MA, were significantly higher in smokers than in non-smokers. The best correlation between B-B and urinary biomarkers of exposure were obtained with benzene in urine (μg/l r = 0.514, P < 0.001; μg/g cr r = 0.478, P < 0.001) and SPMA (μg/l r = 0.495, P < 0.001; μg/g cr r = 0.426, P < 0.001) followed by t,t-MA (mg/l r = 0.363, P < 0.001; mg/g cr r = 0.300, P = 0.002). SA and t,t-MA were highly correlated (r = 0.618, P < 0.001; corrected for cr r = 0.637). Multiple linear regression showed that the variation of t,t-MA was mostly explained by SA concentration in urine (30% of the explained variance) and by B-B (12%). Variations of SPMA and B-U were explained for 18 and 29%, respectively, by B-B. About 30% of the variance of B-U and SPMA were explained by B-B and smoking status. Genetic polymorphisms for biotransformation enzymes (CYP2E1, EPHX1, GSTM1, GSTT1, GSTP1) did not significantly influence the urinary concentration of any of the three urinary biomarkers at this low level of exposure. Conclusion  At low levels of benzene exposure (<0.1 ppm), (1) t,t-MA is definitely not a reliable biomarker of benzene exposure because of the clear influence of SA originating from food, (2) SPMA and B-U reflect the internal dose with almost similar accuracies, (3) genetically based inter-individual variability in urinary excretion of biomarkers seems negligible. It remains to assess which biomarker is the best predictor of health effects.     

Heavy Metal Levels in Suspended Sediments, Crassostrea gigas, and the Risk to Humans

Wild Pacific oyster (Crassostrea gigas) and sediment, both resuspended and suspended (RSS) samples (<53 μm), were collected over an 8-month period from a coastal estuary in Baynes Sound, BC, Canada. Stable isotope analysis (δ¹³C, δ¹⁵N) was used to determine, first, if RSS sediments was an important dietary source to C. gigas and, second, if so, whether it served as a significant dietary exposure route for Cd, Cu, Pb, and Zn. Although RSS sediments were high in trace metals such as Cd, Pb, Zn, and notably Cu, stable isotope signatures for oyster tissues did not correspond to those of RSS sediments. These results indicate that RSS sediments are not a significant source of metal to the oysters. In addition, we compared the potential risk to humans ingesting C. gigas with levels of Cd, Cu, Pb, and Zn from this study to the current Agency for Toxic Substances and Disease Registry (ATSDR) chronic oral minimal risk levels (MRLs) using current Canadian consumption guidelines of three oysters/week. Cu, Pb, and Zn levels were below MRL levels, with Cd exceeding the recommended 0.2 μg/kg/day MRL level fourfold. Total daily intake levels (TDI) for Cd were additionally calculated and either reached or exceeded the Food and Agriculture Organization/World Health Organization (FAP/WHO) reference dose of 1 μg/kg/day for Cd consumption in Canadians. Our results indicate that the current Canadian Cd consumption guidelines do not protect individuals consuming the maximum recommended levels of wild oysters.     

Heavy Metals in the Farming Environment and in some Selected Aquaculture Species in the Van Phong Bay and Nha Trang Bay of the Khanh Hoa Province in Vietnam

Aquaculture is currently one of the most rapidly growing production sectors in Vietnam. This publication describes the concentrations of heavy metals in the farming environment and some aquaculture species in the Khanh Hoa Province in Vietnam. The concentration of total As in the sediments ranged from 0.07 to 0.64 mg/kg, whereas the concentration of Hg varied from <0.0005 to 0.56 mg/kg. The corresponding concentration span for Cd and Pb, were 0.001–0.069 and 0.016–0.078 mg/kg, respectively. The concentrations of As in the aquaculture organisms spanned from 0.14 to 1.03 mg/kg. For Hg the concentrations varied from 0.1 to 0.45 mg/kg, for Cd from 0.02 to 0.10 mg/kg and for Pb from 0.07 to 0.37 mg/kg.