Trace and nontrace element contents of broiler litter^*

Abstract

Poultry production is rapidly growing in the United States. In 1999, Alabama, the third largest poultry producer in the United States, produced 971.2 million birds and generated about 1.5 million Mg of broiler litter that was mainly applied to agricultural lands as an organic fertilizer. To increase disease resistance of poultry birds, trace elements are often added to poultry diets. However, some of the trace elements are toxic to living systems when present in sufficient concentrations. There is growing concern about accumulation of trace elements in broiler litter added as a soil amendment to agricultural lands and its effects on the soil, groundwater, and the food chain. When added to soils, these elements may compromise safe food and feed production. Broiler litter contains also nontrace elements that normally do not adversely affect directly plant health and soil biological system, but still need to be monitored because of possible effects on soil physicochemical properties. This study investigated the concentrations of thirteen trace [silver (Ag), arsenic (As), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo), nickel (Ni), lead (Pb), selenium (Se), zinc (Zn)] and six nontrace [aluminum (Al), barium (Ba), calcium (Ca), magnesium (Mg), potassium (K), and sodium (Na)] elements in 33 broiler litter samples collected from 12 Alabama counties. A 0.5-g sample was digested by the EPA 3052 method using a Microwave Assisted Reaction System. Results showed a wide variability of element concentrations in the samples. None of the samples tested contained measurable amounts of Ag or Pb at detection limits of 0.2 mg L⁻¹ and 2.0 mg L⁻¹, respectively. Expressed in mg kg⁻¹, the range and median values for the other eleven trace elements were: As (<2.0–70.4, 18.8), Cd (<0.2–1.7, <0.2), Co (<0.2–2.3, <0.2), Cr (<0.2–17.6, 3.2), Cu (211–789, 410), Fe (718–6691, 1596), Mn (254–720, 356), Mo (<0.2–4.9, <0.2), Ni (<0.2–25.1, 1.0), Se (<2.0–24.3, <2.0), and Zn (224–706, 371). Corresponding values expressed in g kg⁻¹ for the nontrace elements were: Al (0.6–8.4, 1.4), Ba (0.014–0.036, 0.025), Ca (18.9–40.2, 27.3), Mg (4.8–10.0, 6.1), K (18.1–36.5, 25.9), and Na (3.6–9.2, 7.1). Substantial amounts of As in the samples and the presence of Cd, Co, and Cr in measurable amounts in some samples are of an environmental concern.

^*Journal Paper No. 319 of the George Washington Carver Agricultural Experiment Station, Tuskegee, AL 36088. This work was supported by the USDA/Capacity Building Program. The authors thank Bennie Moore, USDA/NRCS, Laverne AL 36049 and USDA offices in Alabama counties for selecting participating farmers.

Acknowledgments

Notes

^*Journal Paper No. 319 of the George Washington Carver Agricultural Experiment Station, Tuskegee, AL 36088. This work was supported by the USDA/Capacity Building Program. The authors thank Bennie Moore, USDA/NRCS, Laverne AL 36049 and USDA offices in Alabama counties for selecting participating farmers.