HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Figures Only Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in ISI Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (12) Citing Articles via Google Scholar Google Scholar Articles by He, Z. L. Articles by Yu, S. Search for Related Content PubMed Articles by He, Z. L. Articles by Yu, S. GeoRef GeoRef Citation Agricola Articles by He, Z. L. Articles by Yu, S. Related Collections Surface Water Quality Toxic Trace Metals Soil Chemistry

DIVISION S-6—SOIL & WATER MANAGEMENT & CONSERVATION

Transport of Heavy Metals in Surface Runoff from Vegetable and Citrus Fields

^a Univ. of Florida, Institute of Food and Agricultural Sciences, Indian River Research and Education Center, 2199 South Rock Road, Fort Pierce, FL 34945
^b College of Natural Resource and Environmental Sciences, Zhejiang Univ., Huajiachi Campus, Hangzhou 310029, P.R. China

^* Corresponding author (zhe{at}mail.ifas.ufl.edu)

	ABSTRACT

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS NOTES RESULTS AND DISCUSSION DISCUSSION CONCLUSIONS REFERENCES

 
Heavy metal accumulation in agricultural soils increases export potential of the metals to the environment. The concentrations of dissolved heavy metals (Cd, Co, Cr, Cu, Fe, Ni, Pb, Zn, Mn, and Mo) in surface runoff were monitored over a 2-yr period at 11 sites of vegetable farms and citrus groves in Florida. A total of 1277 surface runoff samples were analyzed for dissolved metals and extractable metals in the surface soils of each field site were determined. Concentrations of the metals in the runoff ranged widely from nondetectable level to 2.80, 18.5, 14.1, 1475, 9227, 39.3, 30.4, 1401, 2118, and 15.0 µg L^–1 for Cd, Co, Cr, Cu, Fe, Ni, Pb, Zn, Mn, and Mo, respectively. Spatial and temporal variations in the concentrations of heavy metals and runoff discharge were noted among the different sites. Ninety-four, 96, 55, 32, 93, and 61% of the samples had metal concentrations below the detection limits for Cd, Co, Cr, Ni, Pb, and Mo, respectively, whereas 0.62, 30, and 23% of the samples had Cu, Fe, and Mn higher than their drinking water standards. Annual loads of dissolved metals in the runoff varied widely among monitoring sites and were different between the year 2001 and 2002. The concentrations of heavy metals in the surface runoff were associated with the accumulation of the metals in the soils. The 0.01 M CaCl₂ extractable Cu, Fe, Zn, and Mn in soil were found to significantly correlate with Cu, Fe, Zn, and Mn concentrations in the surface runoff.

Abbreviations: Ac, acetate • ICP-AES, inductively coupled plasma atomic emission spectrometer

	INTRODUCTION

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS NOTES RESULTS AND DISCUSSION DISCUSSION CONCLUSIONS REFERENCES

 
INCREASED ANTHROPOGENIC inputs of heavy metals in soils have received considerable attention, since transport of the metals may result in increased contents of heavy metals in the ground water or surface water (Purves, 1985; Alloway, 1995; Moore et al., 1998). High Cu and Zn concentrations were detected in the sediments of St. Lucie Estuary in South Florida (Haunert, 1988; He et al., 2003). Heavy metal inputs included those from commercial fertilizers, liming materials and agrochemicals, sewage sludges and other wastes used as soil amendments, irrigation waters, and atmospheric deposition (Senesi et al., 1999). Soils receiving repeated applications of organic manures, fungicides, and pesticides have exhibited high concentrations of extractable heavy metals (Payne et al., 1988; Kingery et al., 1994; Sims and Wolf, 1994; van der Watt et al., 1994; Li et al., 1997; Moore et al., 1998; Han et al., 2000) and subsequently resulted in increased heavy metal concentrations in runoff (Moore et al., 1998). The mobility of heavy metals depends not only on the total concentration in soil but also on soil properties, metal properties, and environmental factors. Heavy metals accumulate in soils in various forms: water soluble, exchangeable, carbonate associated, oxide associated, organic associated, and residual. The metals present in these categories have different mobility (Iyengar et al., 1981; Sims and Kline, 1991; Moore et al., 1998). Water-soluble and exchangeable fractions readily release to the environment, whereas the residual fractions are immobile under natural conditions. Dowdy and Volk (1983) suggested that the movement of heavy metals in soils could occur in sandy, acid, low organic matter soil if subjected to heavy rainfall or irrigation. Although many studies were conducted on vertical movement and leaching of heavy metals in the soils (Scokart et al., 1983; Maskall et al., 1995; Sawhney et al., 1995; Kabala and Singh, 2001), minimal information is available on runoff losses of dissolved heavy metals in agricultural soils. The objective of this study was to investigate heavy metal losses in surface runoff and its relation with metal accumulation in Florida sandy agricultural soils used for citrus fruits and vegetables.

	MATERIALS AND METHODS

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS NOTES RESULTS AND DISCUSSION DISCUSSION CONCLUSIONS REFERENCES

 
Eleven field sites (seven at commercial citrus groves and four at vegetable production farms) in St. Lucie and Martin Counties, Florida were selected to monitor heavy metal losses in surface runoff from the beginning of 2001 to the end of 2002 (Table 1). SIGMA 900MAX portable autosamplers¹ (American Sigma, Loveland, CO) were installed at the drainage outlet for each site. Rainfall was measured by a rain gauge and runoff flow rate was measured by a flow meter, data were recorded in the autosampler every 10 min. All sites were located in the Indian River area of Florida with flat landscape (<5% slope) and shallow water tables (30–80 cm) where the dominant hydrological pathways were extensive networks of artificial drainage ditches. The soils of the experiment sites were representative for commercial citrus and vegetable production systems in the Indian River area. They included Wabasso sand (sandy, siliceous, hyperthermic Alfic Alaquods), Waveland fine sand (sandy, siliceous, hyperthermic, ortstein Arenic Alaquods), Ankona sand (sandy, siliceous, hyperthermic, ortstein Arenic Ultic Alaquods), Winder variant sand (fine-loamy, siliceous, hyperthermic Typic Glossaquods), and Nettles sand (sandy, siliceous, hyperthermic, ortstein Alfic Arenic Haplaquods). General characteristics of the study sites are given in Table 1. In addition to application of N, P, and K, micronutrient fertilizers were applied for the citrus and vegetable production in the areas. Annual foliar application of Cu and Zn ranged from 2.2 to 5.6 kg ha^–1 as copper sulfate, 2.2 to 4.5 kg ha^–1 as zinc sulfate or 0.8 to 1.1 kg ha^–1 as chelated zinc, and Cu- and Zn-containing pesticides/fungicides (such as copper hydroxide) that accelerated Cu and Zn accumulation in the soils (Simonne and Hochmuth, 2001).

For each site, two composite soil samples were taken across each experimental field in July 2001. Each composite sample was composed of a mixture of four samples taken at a depth of 0 to 150 mm from four locations within each field. All soil samples were air-dried and ground to <2 mm before chemical analysis. Soil pH and electrical conductivity (EC) were measured in water at a soil/water ratio of 1:1 (Mclean, 1982) using a pH/ion/conductivity meter (Accumet Model 50, Fisher Scientific, Norcross, GA). We used 1:1 ratio of soil/water for pH measurement because the studied soils were sandy soils with very low buffer capacity. The pH value measured with higher soil/water ratio may not reflect real pH of the soils. Total C was determined using a CN-Analyzer (Vario MAX CN Macro Elemental Analyzer, Elemental Analysensystem GmbH, Hanau, Germany). Particle-size composition of each soil sample was determined using the micropipette method (Miller and Miller, 1987).

Five different extraction methods were used to extract soil labile heavy metals: (i) 0.01 M CaCl₂ [1:10 ratio of soil/0.01 M CaCl₂; 60-min reaction time (Kuo, 1996)], extracting water-soluble and readily exchangeable metals; (ii) Mehlich-1 [1:4 ratio of soil/0.05 M HCl + 0.0125 M H₂SO₄; 5-min reaction time (Reed and Martens, 1996)], including water soluble, exchangeable, and partially CaCO₃–associated metals; (iii) DTPA-TEA (pH 7.3) [1:2 ratio of soil/DTPA-TEA extraction solution; 120-min reaction time (Reed and Martens, 1996)], including water soluble, exchangeable, and partially organic associated metals; (iv) 1 M ammonium acetate (NH₄OAc) [1:4 ratio of soil/1 M NH₄OAc extraction solution; 60-min reaction time (Reed and Martens, 1996)], including water soluble and exchangeable metals; and (v) Mehlich-3 [1:10 ratio of soil/Mehlich-3 extraction solution (0.2 M CH₃COOH + 0.25 M NH₄NO₃ + 0.015 M NH₄F + 0.013 M HNO₃ + 0.001 M EDTA, pH 2.0); 5-min reaction time (Mehlich, 1984)], including water soluble, exchangeable, partially CaCO₃ and organic associated metals. After each extraction, the suspension was centrifuged at 7500 x g relative centrifuge force for 30 min and then the supernatant was passed through a Whatman #42 filter paper. The metal concentrations in the supernatant after centrifugation were determined by the ICP-AES. Statistical analyses (t test, correlation, mean) were performed using SAS procedures (SAS Institute, 1998). Annual mean concentrations of metals in runoff water among different sites were compared with ANOVA followed by the Duncan's multiple range test. A significance level of p < 0.05 was selected for determination of statistical significance. Correlation analyses between concentrations of metals in the runoff and extractable metals in the soils were conducted using SAS generalized linear model procedure.

	RESULTS AND DISCUSSION

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS NOTES RESULTS AND DISCUSSION DISCUSSION CONCLUSIONS REFERENCES

 
Extractable Metals in Soils
Surface soil pH varied greatly across the 11 sites and ranged from 4.4 to 8.1. Clay content of the soil samples ranged from 19 to 81 g kg^–1. Extractable-soil Cd, Co, Cr, Fe, Pb, Ni, Mn, Zn, and Mo concentrations varied greatly with soils and extractants (Table 2). Extracted Cu, Zn, Fe, Pb, and Mn concentrations with five extractants decreased in the order of Mehlich-1 > Mehlich-3 > DTPA-TEA > 1 M NH₄OAc > 0.01 M CaCl₂. The highest extracted Cu, Zn, Fe, and Mn concentrations occurred at Site 11 whereas the lowest extracted metal concentrations occurred at Site 7 for 0.01 M CaCl₂–extractable, and Site 10 for 1 M NH₄OAc, Mehlich-3, DTPA-TEA, and Mehlich-1 extractable (data not shown). Extractable Cd, Co, Cr, Ni, and Mo were lower than Cu, Zn (Table 2). Extractable Cu, Zn, Mn, Fe, Co, and Cr in the soil of this study were significantly higher than those in forest soils (nonagricultural soils) (Zhang et al., 2003b).

The concentrations of metals in surface runoff samples that were collected randomly from forestland in South Florida (nonagricultural soils) in the year 2001–2002 were presented in Table 3 for comparison purpose (He, Z. L. and Y. C. Li, unpublished data, 2002). The mean concentrations of Cu, Zn, Fe, Mo, and Cd in surface runoff from agricultural soils in the 11 sites were significantly higher than those in the runoff water from nonagricultural land, approximately three times higher for Cu, eight times higher for Zn, and two times higher for Fe, Mo, and Cd. The increased concentrations of these elements in surface runoff water from agricultural field likely resulted from their input in fertilizers and fungicides in the agricultural production systems. There were no significant differences in concentrations of Co, Ni, and Mn in runoff water between the agricultural and nonagricultural land. However, the mean concentrations of Cr and Pb in runoff water from the agricultural field were lower than those measured in runoff samples from the forestland (Table 3). This difference might be caused by some point sources of these elements, such as Pb-containing dusts from highway that might be more readily caught by trees in the forestland than crops in the agricultural field. All these results suggested that agricultural practices such as fertilization and use of fungicides tended to increase the concentrations of Cu, Zn, Fe, and Cd in surface runoff.

There were significant correlations among the concentrations of dissolved metals in the runoff water (Table 4). Significant correlations (r > 0.45, n = 1127) were found among Cr, Cu, Zn, Mn, and Fe, probably due to similar accumulation extent for these metals in the soils. In addition, there were high correlations between Cd, Co, and Pb that had low concentrations in the runoff water.

View larger version (40K): [in this window] [in a new window]   Fig. 1. Variation of monthly mean concentrations of dissolved Cu, Fe, Zn, and Mn in the runoff samples from Sites 2, 3, and 7. Error bars represent one standard deviation.

Dissolved Metal Loads in Runoff
Annual rainfall for the 11 sites ranged from 1203 to 1572 mm for 2001, and from 1002 to 1362 mm for 2002. The rainfall in 2001 was higher than 2002. Rainfall varied seasonally, and most of the rainfall occurred from May to October (Fig. 2a) . The differences in annual rainfall among the 11 sites were minimal, but either monthly (Fig. 2b) or annual runoff discharge at each site varied greatly. The annual runoff discharge ranged from 47 to 5268 m³ ha^–1 (Fig. 2). The discharge was generally higher in 2001 than 2002 with exception of Sites 1 and 5. In 2001, the highest discharge (Site 10) was 10 times more than the lowest (Site 5). In 2002, the highest discharge (Site 1) was 48 times more than the lowest (Site 8).

View larger version (35K): [in this window] [in a new window]   Fig. 2. Mean (a) monthly rainfall and (b) discharge of the 11 tested field sites. Error bars represent one standard deviation.

	DISCUSSION

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS NOTES RESULTS AND DISCUSSION DISCUSSION CONCLUSIONS REFERENCES

The relatively high concentrations of Cu, Zn, and Fe detected in runoff water from the citrus groves and vegetable fields, as compared with those measured in runoff water samples from the nonagricultural land, are likely related to the input of these elements in fertilizers and Cu- and Zn-containing pesticides and/or fungicides (Simonne and Hochmuth, 2001). In Florida, significant accumulation of Cu in soils occurred in some old citrus groves because of repeated use of Cu- and Zn-containing pesticides and fungicides such as Cu hydroxides (Alva, 1993). The higher Cu or Zn concentration in runoff from citrus or vegetable fields mainly resulted from accumulated Cu and Zn in the soils, as runoff Cu and Zn were positively correlated with extractable Cu and Zn in the soils. Due to differences in cropping history, Cu and Zn application rate and frequency, and management practices, Cu and Zn concentrations in soils varied greatly from location to location (Zhang et al., 2003a). Consequently, Cu and Zn concentrations in surface runoff differed from field to field, higher with old citrus groves (Sites 9 of 42 yr and Site 11 of 25 yr) than young citrus groves or vegetable fields (Site 8 of 2 yr) (Table 5). The Cu and Zn loads in runoff depend on both concentrations of these elements and discharge of runoff. The highest runoff loads of Cu and Zn corresponded with the old citrus groves (Sites 9 and 11) and the lowest with either a young vegetable field (Sites 8) or the least discharge rate (Site 5 of 2 yr) (Table 6).

The transport of metals from soils to runoff is a complex process, which involved in many chemical reactions. The transport of metals in the soils may occur in dissolved and colloidal forms (Gasser et al., 1994; Keller and Domergue, 1996). Physicochemical properties of soils and environmental conditions affect metal movement (Denaix et al., 2001). Basically, the process consisted of two steps (Li, 1995). The first step is movement of metals from solid to soil solution, and second is the transport of the metals from soil solution to runoff. Mobility of metals from solid to solution in the soils is mainly controlled by sorption–desorption, chelating, precipitation–dissolution, and oxidation–reduction processes of the metals in the soils (Sedlak et al., 1997; Basta and McGowen, 2004). The sorption–desorption is more important for acidic soils, chelating process for soils with high organic matter, and precipitation–dissolution process for the high pH soils. Decreased sorption and increased solubility and chelating can increase metal transport and redistribution in contaminated soils. Low pH and high accumulation of metals in soils can increase the movement of the metals from solid to solution. Because leaching is the opposite process to retention, high metal loss is often related to low metal-retention soils. The sandy soils in this study contained minimal amounts of clay and Fe and Al oxides, and therefore, have a very small holding capacity for Cu, Zn, and other metals. However, for high pH (7–8) soils such as Sites 1 and 10 in this study, Cu and Zn losses into the surface runoff were much smaller than low pH soils with similar cropping history (Sites 9 and 11). Obviously, this is due to reduced solubility of Cu and Zn in high pH soils. The transport of metals from solution to runoff occurs simultaneously with water movement in soils. Many factors, including rainfall intensity, water discharge, water storage capacity of soils, and agricultural practices, can affect metal transport in runoff (Basta and McGowen, 2004; Denaix et al., 2001; Xue et al., 2000; Xue et al., 2003). The variation of dissolved metal concentration at the same site was probably affected by the seasonal difference in rainfall and soil moisture status in Florida. Xue et al. (2000) found that dissolved Cu concentration in runoff generally decrease with increasing discharge. Denaix et al. (2001) reported that soil moisture could affect the metal concentrations in the soil solution and thus influence metal concentrations in runoff.

The extractable soil Cu and Zn by either 1 mol L^–1 NH₄OAc or Mehlich-3 reagent are often used as indexes of Cu and Zn availability to plants because of the close relationship of the extractable amount with plant uptake of the metals (Reed and Martens, 1996). A variable portion of the exchangeable Cu and Zn that are tightly bound to the organic and inorganic colloids become available to plants mainly through root activity (Marschner, 1995). This part of soil Cu and Zn are extractable to the 1 mol L^–1 NH₄OAc or Mehlich-3 reagent but may not be subjected to leaching or runoff loss. On the other hand, the CaCl₂–extractable Cu and Zn involve mainly water soluble form and part of the exchangeable form that is loosely bound to the soil colloids and thus are readily subjected to runoff loss. This may explain why the CaCl₂–extractable Cu and Zn are better correlated with runoff Cu and Zn than either 1 mol L^–1 NH₄OAc or Mehlich-3 extractable Cu and Zn.

Although concentrations of metals including Cu and Zn in the runoff were mostly below USEPA critical levels for drinking water, runoff metals may become nonpoint sources of contaminants to surface waters. In the Indian River Area where this study was conducted, accumulation of Cu and Zn in the sediments of St. Lucie Estuary and Indian River Lagoon has been recently accelerated due to agricultural development (He et al., 2003). In some area of those water bodies, sediment concentrations of Cu and/or Zn up to 300 mg kg^–1 were detected (Haunert, 1988; He et al., 2003) and were suspected to affect water quality and ecosystem biodiversity (Trocine and Trefry, 1993). Therefore, transport of Cu and Zn from agriculture to surrounding surface waters merits further attention due to their potential impact on ecological health of surface water systems.

	CONCLUSIONS

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS NOTES RESULTS AND DISCUSSION DISCUSSION CONCLUSIONS REFERENCES

 
The results from this study provide evidence of a positive correlation between amounts of soil extractable metals and dissolved metal concentrations in runoff from sandy agricultural soils. Low concentrations and loads of Cd, Co, Ni, Pb, and Mo in runoff corresponded to very low extractable Cd, Co, Ni, Pb, and Mo in the soils. The concentrations and loads of Cu, Fe, Zn, and Mn in the runoff were correlated with the amounts of 0.01 M CaCl₂–extractable Cu, Fe, Zn, and Mn in the soils. The metal losses in surface runoff in the study areas varied greatly among the field locations, and were probably affected by many factors, such as extent of metal accumulation in the soils, rainfall intensity, volumes of runoff, soil properties, agricultural practices (spraying or fertilization), and seasonal variation (dry season or rainy season). The concentrations of metals including Cu and Zn in the runoff from agricultural fields were mostly below USEPA critical levels for drinking water. However, transport of Cu and Zn from agriculture to surrounding surface waters merits further attention due to their potential impact on ecological health of surface water systems.

	ACKNOWLEDGMENTS

 
This study was, in part, supported by a section 319 Nonpoint Source Management Program grant (DEP contract # WM746) from the U.S. Environmental protection Agency (USEPA) through a contract with the Nonpoint Source Management/Water Quality Standard Section of the Florida Department of Environmental Protection (FDEP) and by grants (DEP contract # SP566 and DEP contract # G0018) from the FDEP and a grant (2002CB410804) from the Science and Technology Ministry of China. Florida Agricultural Experiment Station Journal Series No. R-09484.

	NOTES

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS NOTES RESULTS AND DISCUSSION DISCUSSION CONCLUSIONS REFERENCES

 
¹ Mention of particular companies or commercial products does not imply recommendations or endorsement by the Zhejiang University, Hangzhou, China or the University of Florida, Gainesville, FL USA over other companies or products not mentioned.

Received for publication June 19, 2003.

	REFERENCES

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS NOTES RESULTS AND DISCUSSION DISCUSSION CONCLUSIONS REFERENCES

 

• Alloway, B.J. (ed.) 1995. Heavy metals in soils. Blackie Academic & Professional, London.
• Alva, A.K. 1993. Copper contamination of sandy soils and effects on young Hamlin orange trees. Bull. Environ. Contam. Toxicol. 51:857–864.[Medline]
• Basta, N.T., and S.L. McGowen. 2004. Evaluation of chemical immobilization treatments for reducing heavy metal transport in a smelter-contaminated soil. Environ. Pollut. 127:73–82.[Medline]
• Denaix, L., R.M. Semlali, and F. Douay. 2001. Dissolved and colloidal transport of Cd, Pb and Zn in a silt loam soil affected by atmospheric industrial deposition. Environ. Pollut. 113:29–38.
• Dowdy, R.H., and V.V. Volk. 1983. Movement of heavy metals in soils. p. 229–240. In D.W. Nelsen et al. (ed.) Chemical mobility and reactivity in soil systems. SSSA Spec. Publ. 11. SSSA, Madison, WI.
• Gasser, U.G., S.J. Juchler, and H. Sticher. 1994. Chemistry and speciation of soil water from serpentinic soils: Importance of colloids in the transport of Cr, Fe, Mg, and Ni. Soil Sci. 158:314–322.
• Han, F.X., W.L. Kingery, H.M. Selim, and P.D. Derard. 2000. Accumulation of heavy metals in a long-term poultry waste-amended soil. Soil Sci. 165:260–268.
• Haunert, D.E. 1988. Muck characteristics and toxic substances in the St. Lucie Estuary, Florida. South Florida Water Management District Tech. Pub. 88–10, South Florida Water Management District, West Palm Beach, FL.
• He, Z.L., P.J. Stoffella, D.V. Calvert, M.K. Zhang, and X.E. Yang. 2003. Characterization of organic and inorganic colloidal fractions in the St. Lucie marine muck sediments. Project Final Rep. South Florida Water Management District, West Palm Beach, FL.
• Iyengar, S.S., D.C. Martens, and W.P. Miller. 1981. Distribution and plant availability of soil zinc fractions. Soil Sci. Soc. Am. J. 45:735–739.[Abstract/Free Full Text]
• Kabala, C., and B.R. Singh. 2001. Fractionation and mobility of copper, lead, and zinc in soil profiles in the vicinity of a copper smelter. J. Environ. Qual. 30:485–492.[Abstract/Free Full Text]
• Keller, C., and F.L. Domergue. 1996. Soluble and particular transfer of Cu, Cd, Al, Fe and some major elements in gravitational water of a podzol. Geoderma. 71:263–274.
• Kingery, W.L., C.W. Wood, D.P. Delaney, J.C. Williams, and G.L. Mullins. 1994. Impact of long-term application of broiler litter on environmentally related soil properties. J. Environ. Qual. 23:139–147.
• Kuo, K. 1996. Phosphorus. p. 869–919. In D.L. Sparks (ed.) Methods of soil analysis. Part 3. SSSA Book Series No 5, SSSA and ASA. Madison, WI.
• Li, M., N.V. Hue, and S.K.G. Hussain. 1997. Changes of metal forms by organic amendments to Hawaii soils. Commun. Soil Sci. Plant Anal. 28:381–394.
• Li, T.J. 1995. Heavy metal pollution in soil and its prevention. p. 105–111. In Soil and environmental science. Chine Education Press, Bejing.
• Maskall, J., K. Whitehead, and I. Thornton. 1995. Heavy metal migration in soils and rocks at historical smelting sites. Environ. Geochem. Health 17:127–138.
• Manahan, S.E. (ed.) 1991. Environmental chemistry. 5th ed. Lewis Publisher, Chelsea, MI.
• Marschner, H. (ed.) 1995. Mineral nutrition of higher plants. 2nd ed. Academic Press. London.
• McLean, E.O. 1982. Soil pH and lime requirement. p. 199–224. In A.L. Page et al. (ed.) Methods of soil analysis. Part 2. Agron. Monogr. No. 9. SSSA and ASA. Madison, WI.
• Mehlich, A. 1984. Mehlich No. 3 soil test extractant: A modification of Mehlich No. 2 extractant. Commun. Soil Sci. Plant Anal. 15:1409–1416.
• Miller, W.P., and D.M. Miller. 1987. A micro-pipette method for soil mechanical analysis. Commun. Soil Sci. Plant Anal. 18:1–15.
• Moore, P.A., Jr., T.C. Daniel, J.T. Gilmour, B.R. Shreve, D.R. Edwards, and B.H. Wood. 1998. Decreasing metal runoff from poultry litter with aluminum sulfate. J. Environ. Qual. 27:92–99.
• Payne, G.G., D.C. Martens, C. Winarko, and N.F. Perera. 1988. Availability and form of copper in three soils following eight annual applications of copper-enriched swine manure. J. Environ. Qual. 17:740–746.[Abstract/Free Full Text]
• Purves, D. 1985. Trace element contamination of the environment. Elsevier, New York.
• Reed, S.T., and D.C. Martens. 1996. Copper and zinc. p. 703–722. In D.L. Sparks (ed.) Methods of soil analysis. Part 3. SSSA Book Series No 5. SSSA and ASA. Madison, WI.
• Sedlak, D.L., J.T. Phinney, and W.W. Bedsworth. 1997. Strongly complexed Cu and Ni in wastewater effluents and surface runoff. Environ. Sci. Technol. 31:3010–3016.
• SAS Institute. 1998. SAS user's guide. SAS Inst., Cary NC.
• Sawhney, B.L., G.J. Bugbee, and D.E. Stilwell. 1995. Heavy metals leachability as affected by pH of compost-amended growth medium used in container-grown rhododendrons. Compost Sci. Util. 3:64–73.
• Scokart, P.O., K. Meeus-verdinne, and R. Deborger. 1983. Mobility of heavy metals in polluted soils near Zn smelters. Water Air Soil Pollut. 20:451–463.
• Senesi, G.S., G. Baldassarre, N. Senesi, and B. Radina. 1999. Trace element inputs into soils by anthropogenic activities and implications for human health. Chemosphere 39:343–377.[Medline]
• Simonne, E.H., and G.J. Hochmuth. 2001. Soil and fertilizer management for vegetable production in Florida. p. 3–14. In D.N. Maynard and S.M. Olsen (ed.) Vegetable production guide for Florida. Univ. of Florida Coop. Extension Service. Univ. of Florida, Gainesville.
• Sims, J.T., and J.S. Kline. 1991. Chemical fractionation and plant uptake of heavy metals in soils amended with co-composed sewage sludge. J. Environ. Qual. 20:387–395.[Abstract/Free Full Text]
• Sims, J.T., and D.C. Wolf. 1994. Poultry manure management: Agricultural and environmental issues. Adv. Agron. 52:1–83.
• Stewart, J.C., A.T. Lemley, S.I. Hogan, R.A. Weismiller, and A.G. Hornsby. 2001. Drinking water standards. Florida Coop. Ext. Service, Institute of Food and Agricultural Sciences, Univ. of Florida. Available online at http://edis.ifas.ufl.edu/SS297 (verified 5 Apr. 2004).
• Trocine, R.P., and J.H. Trefry. 1993. Toxic substances survey for the Indian River Lagoon system. Vol. 1: Trace metals in the Indian River Lagoon. Final Project Report. South Florida Water Management District, West Palm Beach.
• U.S. Public Health Service. 1962. Public health service drinking water standards. Public Health Service, Washington, DC.
• Xue, H., P.H. Nhat, R. Gachter, and P.S. Hooda. 2003. The transport of Cu and Zn from agricultural soils to surface water in a small catchment. Adv. Environ. Res. 8:69–76.
• Xue, H., L. Sigg, and R. Gachter. 2000. Transport of Cu, Zn and Cd in a small agricultural catchment. Water Res. 34:2558–2568.
• van der Watt, H.V.H., M.E. Sumner, and M.L. Cabrera. 1994. Bioavailability of copper, manganese, and zinc in poultry litter. J. Environ. Qual. 23:43–49.
• Zhang, M.K., Z.L. He, D.V. Calvert, P.J. Stoffella, and X.E. Yang. 2003a. Surface runoff losses of copper and zinc in sandy soils. J. Environ. Qual. 32:909–915.[Abstract/Free Full Text]
• Zhang, M.K., Z.L. He, D.V. Calvert, P.J. Stoffella, X.E. Yang, and E.M. Lamb. 2003b. Accumulation and partitioning of phosphorus and heavy metals in a sandy soil under long-term vegetable crop production. J. Environ. Sci. Health A. 38:1981–1995.

This article has been cited by other articles:

				Z. L. He, M. Zhang, X. E. Yang, and P. J. Stoffella Release Behavior of Copper and Zinc from Sandy Soils Soil Sci. Soc. Am. J., August 22, 2006; 70(5): 1699 - 1707. [Abstract] [Full Text] [PDF]

This Article Abstract Figures Only Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in ISI Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (12) Citing Articles via Google Scholar Google Scholar Articles by He, Z. L. Articles by Yu, S. Search for Related Content PubMed Articles by He, Z. L. Articles by Yu, S. GeoRef GeoRef Citation Agricola Articles by He, Z. L. Articles by Yu, S. Related Collections Surface Water Quality Toxic Trace Metals Soil Chemistry