WHERE IS THE 40 YEARS OF RESEARCH PROVING SLUDGE IS SAFE ON FOOD CROPS?
Management: Health Aspects of Crop Uptake Sludge-Amended Soil and Recommendations M Sludge - Environmental Management - springerlink.com ... "Solid waste containing cadmium concentrations in excess of 25 mg/kg dry weight is not applied to sites where tobacco, leafy vegetables, or root crops are or ... Web Search
Environmental Management (Historical Archive) Publisher: Springer-Verlag New York ISSN: 0364-152X (Paper) 1432-1009 (Online) DOI: 10.1007/BF01867027 Issue: Volume 3, Number 2
Date: March 1979 Pages: 155 - 158 Research Municipal sludge management: Health aspects of crop uptake of cadmium from sludge-amended soil and recommendations for regulation William H. Hallenbeck1
(1) School of Public Health, University of Illinois at the Medical Center, P.O. Box 6998, 60680 Chicago, IL
Abstract Regulations have been proposed by the United States Environmental Protection Agency to promote the proper management of sludge disposal on croplands. The application of municipal sludge to croplands raises serious questions concerning the increase in dietary levels of metals resulting from metal uptake by crops. A model is presented that affords a quantitative estimate of the dietary increase of metals when foods are derived from sludge-amended soil. If a diet or part of a diet is derived completely from sludge-amended soil, it is likely to be excessive in cadmium and pose a clear health hazard. Recommendations designed to reduce the potential health threat of excessive metals in the diet are presented. Key words Sludge management - Sludge-amended soil - Crop uptake of cadmium - Cadmium toxicity
Cadmium exposure and nephropathy in a 28-year-old female metals worker.
Wittman R, Hu H.
Occupational Health Program, Department of Environmental Health, Harvard School of Public Health, Boston, Massachusetts, USA.
A 28-year-old female presented for evaluation of left flank pain and polyuria after having been exposed to cadmium in the jewelry manufacturing industry for approximately 3 years. This patient possessed both elevated 24-hr urinary ss2-microglobulin and elevated blood cadmium levels. Approximately 6 months after initial presentation, the patient resigned from her job due to shortness of breath, chest pain, and anxiety. Exposure to cadmium in the jewelry industry is a significant source of occupational cadmium exposure. Other occupational sources include the manufacture of nickel-cadmium batteries, metal plating, zinc and lead refining, smelting of cadmium and lead, and production of plastics. Cadmium is also an environmental pollutant that accumulates in leafy vegetables and plants, including tobacco. Major toxicities anticipated from cadmium exposure involve the renal, pulmonary, and, to a lesser extent, gastrointestinal systems. These include the development of renal proximal tubular dysfunction, glomerular damage with progressive renal disease, and respiratory symptoms including pneumonitis and emphysema. Low-level cadmium exposure has also been associated with increased urinary calcium excretion and direct bone toxicity, effects that recent research suggests may result in the development of osteoporosis. The body burden of cadmium, over half of which may reside in the kidneys, is most often measured through the use of urinary cadmium levels. Blood cadmium measurements generally reflect current or recent exposure and are especially useful in cases with a short exposure period and only minimal accumulation of cadmium in the kidneys. Both ss2- microglobulin and alpha1-microglobulin serve as organ-specific, early-effect biomarkers of tubular proteinuria and thus play a role in identifying early signs of cadmium-induced renal damage in those with potential exposures. In addition to ensuring workplace compliance with Occupational Safety and Health Administration-mandated monitoring and screening measures, it is prudent for those with cadmium exposure to maintain adequate intake of both iron and calcium, appropriate measures even in the absence of exposure. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=1
Safe levels of cadmium intake to prevent renal toxicity in human subjects Authors: Satarug S.1, *; Haswell-Elkins M.R.1; Moore M.R.1
Source: British Journal of Nutrition, Volume 84, Number 6, December 2000, pp. 791-802(12)
Publisher: CABI Publishing
next article > View Table of Contents
full text options
The present review attempts to provide an update of the scientific knowledge on the renal toxicity which occurs in human subjects as a result of chronic ingestion of low-level dietary Cd. It highlights important features of Cd toxicology and sources of uncertainty in the assessment of health risk due to dietary Cd. It also discusses potential mechanisms for increased susceptibility to Cd toxicity in individuals with diabetes. Exposure assessment on the basis of Cd levels in foodstuffs reveals that vegetables and cereals are the main sources of dietary Cd, although Cd is also found in meat, albeit to a lesser extent. Cd accumulates particularly in the kidney and liver, and hence offal contains relatively high amounts. Fish contains only small quantities of Cd, while crustaceans and molluscs may accumulate larger amounts from the aquatic environment. Data on Cd accumulation in human kidney and liver obtained from autopsy studies are presented, along with results of epidemiological studies showing the relationship between renal tubular dysfunction and kidney Cd burden. These findings suggest that a kidney Cd level of 50 g/g wet weight is a maximum tolerable level in order to avoid abnormal kidney function. This renal Cd burden corresponds to a urinary Cd excretion of 2 g/d. Accordingly, safe daily levels of Cd intake should be kept below 30 g per person. Individual variations in Cd absorption and sensitivity to toxicity predicts that a dietary Cd intake of 30 g/d may result in a slight renal dysfunction in about 1 % of the adult population. The previous guideline for a maximum recommended Cd intake of 1 g/kg body weight per d is thus shown to be too high to ensure that renal dysfunction does not occur as a result of dietary Cd intake.
Affiliations: 1: 1National Research Centre for Environmental Toxicology and 2Indigenous Primary Health Program, The University of Queensland, 39 Kessels Road, Coopers Plains, Brisbane 4108, Queensland, Australia
Applying biosolids to acid soils in NSW: Are guideline soil metal limits from other countries appropriate?
M. S. Whatmuff
In New South Wales (NSW) the use of biosolids (sewage sludge) as a soil amendment has become a major issue for regulatory authorities because of the potential impact of biosolids metal contaminants on agricultural produce. Although guidelines regulating the use of biosolids in other countries are based on extensive data sets, these were collected under different soil and climatic conditions than those found locally. This experiment was carried out to determine whether guideline soil metal limits from other countries are appropriate for regulating biosolids application under acid soil conditions that occur in NSW and whether a more intensive series of field experiments needed to be carried out. The uptake of biosolids Cd and Zn by silverbeet (swiss chard, Beta vulgaris) was assessed on soils differing in pHC (4.2-5.8) (pH measured in 0.01 M CaCl2) and soil metal loading (0.53-2.82 mg Cd/kg and 54- 159 mg Zn/kg) in the glasshouse and field. Metal uptake by our field-grown silverbeet was >10-fold higher for Cd and >20-fold higher for Zn than was predicted from the slope of the metal uptake response curve for leafy vegetables used in US EPA biosolids guidelines. For some treatments, leaf tissue Cd levels exceeded the maximum permissible concentration for Cd in foodstuffs, and Zn levels were above phytotoxicity thresholds (with some yield reduction) when silverbeet was grown on soils with Cd and Zn concentrations well below soil metal limit concentrations in the United States biosolids guidelines and equal to levels set in the United Kingdom. In addition, biosolids metal uptake under glasshouse conditions was more than twice that in field-grown plants. These results clearly demonstrate the importance of developing NSW-specific biosolids guidelines. Biosolids regulations in NSW should be based on uptake data for a wide range of important food chain and pasture crop species collected in the field and grown under local conditions.
Environment, Development and Sustainability Publisher: Springer Science+Business Media B.V., Formerly Kluwer Academic Publishers B.V. ISSN: 1387-585X (Paper) 1573-2975 (Online) DOI: 10.1023/A:1010061711331 Issue: Volume 2, Number 1
Date: March 2000 Pages: 13 - 21 Cadmium Concentration in Vegetables Grown on Urban Soils Irrigated with Untreated Municipal Sewage M. Qadir1, 2 , A. Ghafoor3, 2, G. Murtaza3, 2 and G. MURTAZA3, 2
(1) Department of Soil Science, University of Agriculture, Faisalabad-, 38040, Pakistan (2) Present address: Institut für Pflanzenernährung, Universität Giessen, Interdisziplinäres Forschungszentrum, Heinrich-Buff-Ring 26-32, 35392 Giessen, Germany (3) Department of Soil Science, University of Agriculture, Faisalabad-, 38040, Pakistan
Abstract Cadmium (Cd) is considered as a potential toxin that is principally dispersed in natural and agricultural environments through anthropogenic sources. Untreated municipal sewage, often a potential source of Cd, is generally used to irrigate urban agricultural soils in many developing countries. A study was carried out to determine Cd concentration in untreated municipal sewage and sewage-irrigated soils and vegetables. The metal ion concentration in municipal sewage was found 3- fold (0.03mgL-1) its permissible concentration in irrigation water (0.01mgL-1). Ammonium bicarbonate- diethylene triamine pentaacetic acid NH4HCO3-DTPA) extractable Cd concentration in top 0.15m soil ranged between 0.25 and 0.34mgkg-1. Soil Cd concentration was significantly correlated with soil clay content, pH, electrical conductivity, and cation exchange capacity. Cadmium availability index (CDI) decreased with an increase in soil depth. The metal ion was found in leaf (0.17-0.24mgkg-1 fresh weight) and fruit (0.07-0.18mgkg-1 fresh weight) portions of all the sampled vegetables: bitter gourd (Momordica charantia L.), cauliflower (Brassica oleracea L.), eggplant (Solanum melongena L.), fenugreek (Trigonella foenumgraecum L.), okra [Abelmoschus esculentus (L.) Moench], onion (Allium cepa L.), pumpkin (Cucurbita pepo L.), and spinach (Spinacia oleracea L.). Leafy tissue accumulated Cd about twice that of the fruit portion. Our results suggest that prolonged ingestion of sewage-irrigated leafy vegetables can develop such Cd levels in human body that may cause a number of illnesses. cadmium - human health - municipal sewage - soil contamination - vegetables
GROWING FOOD CROPS ON SLUDGE-AMENDED SOILS: PROBLEMS WITH THE U.S. ENVIRONMENTAL PROTECTION AGENCY METHOD OF ESTIMATING TOXIC METAL TRANSFER Issn: 1552-8618 Journal: Environmental Toxicology and Chemistry Volume: 17 Issue: 11 Pages: 2274-2281 Authors: McBride, Murray B. Article ID:10.1897/1551-5028(1998)017<2274:GFCOSA>2.3.CO;2
Abstract-The use of sewage sludges as farm fertilizers, encouraged in recent years by changes in U.S. Environmental Protection Agency (U.S. EPA) policy, has raised concerns among some scientists regarding food safety and long-term soil productivity. The U.S. EPA risk assessment for entry into the human diet of three of the most toxic metals, cadmium (Cd), mercury (Hg), and lead (Pb), utilized uptake coefficients (UCs) to calculate the amount of each metal that could enter food crops from the soil. Each UC was calculated as the increment of metal concentration in the edible part of the crop per unit increase of metal loading to the soil. However, the final UC estimates employed in the risk assessment are biased toward low values by a number of factors. These include the use of geometric means to obtain single-point averages of UCs for each crop group evaluated, rather than using arithmetic means or probabilistic methods, a systematic analytical or contamination error apparent in the reported metal concentrations of the control crops, and the fact that most of the UC values were derived for soils with pH 6 or higher. For more than 50% of all the soil and cropping conditions represented in the risk assessment, the geometrically averaged Cd UC values used by the U.S. EPA underestimated the actual risk posed by uptake into crops. The UC values for Pb and Hg are uncertain because of analytical or contamination errors, and because of the few data available for a number of crops. These uncertainties and biases in the risk assessment would advise a more cautious approach to agricultural and home garden use of sewage sludge than is permitted by the U.S. EPA 503 rule.
Cadmium Uptake by Lettuce from Soil Amended with Phosphorus and Trace Element Fertilizers B. Huang1 , S. Kuo1 and R. Bembenek1 (1) Department of Crop and Soil Science, Washington State University, Puyallup, WA, U.S.A
Abstract Some phosphorus and trace element fertilizers may contain elevatedamounts of toxic metals such as cadmium (Cd) and repeated uses of the fertilizers at high rates over time may increase Cd uptake by plants. This greenhouse study investigated the availability to leaf lettuce (Lactuca sativa L.) (Royal Green) of Cd in a western phosphate rock (PR), and a zinc (G-Zn) and an iron (IR) fertilizers that are by products of industrial wastes. The water-soluble CdCl2 was included in the study for comparison. Applications of Cd from the fertilizers orCdCl2 up to 16 times the Canadian Standards for maximum annual Cd loading limit increased soil total Cd. This was true also for the labileCd extractable by DTPA (diethylenetriaminepentaacetic acid) or 0.05 M CaCl2 for all Cd sources except IR. Lime and Cd source and rate allaffected Cd availability in the soil and accumulation by the plant. Theadded Cd from CdCl2 was more labile and readily available to the plant than the added Cd from the PR or G-Zn. Lettuce-Cd was best describedby CaCl2-Cd (r2 = 0.782), followed by DTPA-Cd (r2 = 0.686), with soil total Cd being least effective in predicting lettuce-Cd (r2 = 0.186). If soil total Cd has to be used in describing Cd accumulation bythe plant, it should be included with pH in a stepwise multiple regression. The Cd transfer coefficient for the fertilizers should be measured based on labile Cd extractable by CaCl2 or DPTA, instead of soil total Cd. The labile-based Cd transfer coefficient could improve the assessment ofthe risk of human exposure to the metal in the fertilizers through consumption of the food crop. cadmium - lettuce - phosphorus fertilizers - trace element fertilizers - cadmium transfer coefficient http://www.springerlink.com/(msxx3s45wslklg55zbz4ft45)/app/home/contribution.asp