Pesticide residues, bioavailability

Petty JD, Huckins JN, Martin DB. 1995. Use of semipermeable membrane devices (SPMDS) to determine bioavailable organochlorine pesticide residues in streams receiving irrigation drainwater. Chemosphere 30(10) 1891-1903. 

Petty, J.D. Huckins, J.N. Orazio, C.E, Lebo, J.A. Poulton, B.C. Gale, R.W. Charbonneau, C.S. Kaiser, E.M. 1995b, Determination of bioavailable organochlorine pesticide residues in the Lower Missouri River. Environ. Sci. Technol. 29 2561-2566. 

As with the FFDCA, the FIFRA requires pesticide firms to conduct batteries of extensive testing to identify and characterize a candidate pesticide s bioavailability, distribution, metabolites, routes of excretion in experimental animals, and any adverse or toxic effects that the substance may cause, so that the safety of the pesticide can be assessed. In addition, in cases of pesticides intended to have food uses, extensive field trials must be conducted to characterize residues of the pesticide or metabolites thereof remaining on or in raw agricultural commodities. 

Kloskowski, R., Ftihr, F., and Mittelstaedt, W. (1986a). Formation of bound residues of [benzene ring-U-14C]- anilazine and [triazine-U-14C]-anilazine inparabraunerde (Alfisol soil) and their availibility to maize. In Quantification, Nature, and Bioavailability of Bound 14C-Pesticide Residues in Soil, Plants, and Food. Int. Atomic Energy Agency, Vienna, 65-70. 

Andreux F., Scheunert I., Adrian P., and Schiavon M. (1993) The binding of pesticide residues to natural organic matter, their movement and their bioavailability. In Fate and Prediction of Environmental Chemicals in Soils, Plants, and Aquatic Systems (ed. M. Mansour). Lewis Publishers, Boca Raton, FL, pp. 133-149. 

Xenobiotics are frequently metabolized in plants by mechanisms that lead to the incorporation or inclusion of the xenobiotic into biological polymers or tissue residues that are not soluble in commonly used nonreactive solvents. These residues are frequently refered to as bound, insoluble, or nonextractable residues (2 ). Bound residues in plants have most commonly been detected in plant tissues treated with radloactlvely-labeled pesticides. These residues were an important topic of a symposium held in Vail, Colo, in 1975 (17) they have been discussed in mauiy more recent papers (11,154-1577"and they were discussed at a symposium at the l88th ACS National Meeting, 1984 "Non-extractable Pesticide Residues Characteristics, Bioavailability and Toxicological Significance". 

Gevao B, Mordaunt C, Semple KT, Piearce TG, Jones KC (2001) Bioavailability of nonextractable (bound) pesticide residues to earthworms. Environ Sci... 

Limited bio availability may lead to unexpected persistence of transformation products in soil and sediment, and longer persistence could lead to accumulation of residues. Whether bound pesticide residues in soils are occluded or may remain bioavailable in the long term in the environment is still an ongoing debate [33]. Generally, soil-bound chemicals are not considered bioavailable prior to desorption [41]. However, some evidence suggests that bound residues can be bioavailable or at least that desorption is not a requisite for biodegradation. Bioavailability is considerably lower from bound residues than from freshly treated soil. It has been suggested that the uptake ratio of chemicals and their transformation products from bound residues compared to those from freshly treated soils was about 1 5 [42]. 

Y. Li, J. J. Keenan, H. Vega, R. I. Krieger, Human Exposure to Surface Pesticide Residues Dislodgeable Foliar Residues and Pilot Studies to Predict Bioavailability, Abstract, American Chemical Society Meeting, San Francisco, CA., 2006. 

Pesticide Metabolism, Conjugate, Bound Residue, Bioavailability... 

When significant quantities of residues remain at the skin site, the conventional approach is to include these residues in the percentage of absorbed dose. Eor instance, as part of the North American Free Trade Agreement (NAFTA) Technical Working Group on Pesticides, there was agreement that bound skin residues are considered absorbed when the bioavailability of residues cannot be determined (NAFTA, 2000). This approach is considered conservative as it is unlikely that all... 

While the conjugates are safely trapped to the cell wall as the plant is alive, the soluble conjugates in the vacuole may become liberated quickly after the plant is dead. Research showed that polymerization of xenobiotics into lignin did not prevent the bioavailability. Sandermann demonstrated that dichloroanilin in wheat straw was liberated when feeding animals. Research about the availability of residues is mainly focused on pesticides, insecticides, and drugs. A similar research on ordinary contaminants will shed light on the study of phytoremediation. 

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