Microbial toxicity

EFDB has been developed in support of US EPA. It is comprised of DATALOG and BIOLOG, which contain environmental fate, microbial toxicity and biodegradation data. 

Jonioh, V., Obbard, J.P., and Stanforth, R.R., Impact of treatment additives used to reduce lead solubility and microbial toxicity in contaminated soils, in Bioremediation of Metals and Inorganic Compounds, Leeson, A. and Alleman, B.C., Eds, Battelle Press, Columbus, OH, 1999, pp. 7-12. 

Decreasing /1-cyclodextrin to the microbial toxicity of some pesticides and aromatics for wastewater treatment and bioreactor applications [174,302]. 

Van Beelen, P. Doehnann, P. Significance and apphcation of microbial toxicity tests in assessing ecotoxicological risks of contaminants in soil and sediment. Chemosphere 1997, 34, 455-499. 

Dutton, R.J. Bitton, G. Koopman, B. Enzyme biosynthesis versus enzyme activity as a basis for microbial toxicity testing. Toxic. Assess. 1988, 3, 245 -253. 

Chen, C.-Y., Huang, J.-B. and Chen, S.-D. (1997) Assessment of the microbial toxicity test and its application for industrial wastewaters, Water Science and Technology 36 (12), 375-382. 

Trevizo, C. and N. Nirmalakhandan. 1999. Prediction of microbial toxicity of industrial organic chemicals. Water Sci. Technol 39 63-69. 

Hypersensitivity reactions to antimicrobial drugs or their metabolic products frequently occur. For example, the penicillins, despite their almost absolute selective microbial toxicity, can cause serious hypersensitivity problems, ranging from urticaria (hives) to anaphylactic shock. 

Ahtiainen, J., Valo, R., Jarvinen, M. Joutti, A. (2002). Microbial toxicity tests and chemical analysis as monitoring parameters at composting of creosote-contaminated soil. Ecotoxicology and Environmental Safety, 53, 323-9. 

Environmental Eate Data Base (EEDB) (from Syracuse Research Corporation) - data related to chemical environmental fate, microbial toxicity, biodegradation, etc. - http //www.syrres.com... 

A purpose-built software converts the scan to produce numerical output generating a microbial toxic concentration (MTC) for each constituent species and a mean MARA MTC value. 

The microbial toxic concentration (MTC) pattern of the MARA array for the samples tested in the trial showed that a unique toxicity fingerprint was evident for the reference chemicals and the environmental samples as shown in Figures 3.1.9a-d. 

Nirmalakhandan, N., Xu, S., Trevizo, C., Brennan, R., and Peace, J. (1997) Additivity in microbial toxicity of nonuniform mixtures of organic chemicals. Ecotoxicology and Environmental Safety, 37, 97-102. 

The availability of pesticides in soil is a critical factor in the induction or inhibition of enhanced biodegradation. The pesticides, whether toxic to the microbes or serving as a suitable substrate, should be available to the microorganisms to exert their toxicity or provide nutrient value. Thus, availability, low microbial toxicity, and high nutritive value seem to be the properties that could favor enhanced degradation of a pesticide. 

Diazinon. 2-Isopropyl-6-methyl-4-hydroxypyrimidine, the hydrolysis product of diazinon, did not condition the soils for enhanced degradation of diazinon (Table II). Despite the low microbial toxicity and high availability (discussed elsewhere in this chapter), the hydroxypyrimidine metabolite did not predispose soils for rapid degradation of diazinon. Enhanced biodegradation of diazinon in rice soils has been previously reported (1). Evidently, the soil we studied did not contain microbes capable of adapting for diazinon enhanced degradation. 

Isofennhos. Exposure of soils to salicylic acid, the secondary hydrolysis product of isofenphos, resulted in enhanced degradation of isofenphos (Table IV). Nearly two-thirds of the applied isofenphos was converted to soil-bound residues in soil pretreated 3 and 4 times with salicylic acid. Seventy-eight percent of the applied isofenphos was recovered at the end of the 3-week incubation in the control treatment as compared with 34 to 65% in soils pretreated with salicylic acid. The ability of microbes to metabolize structurally similar compounds such as 3,5-dichlorosalicylate, 3,6-dichlorosalicylic acid (24), and 5-chlorosalicylate (25) to their benefit has been reported. The low microbial toxicity, relative availability (as discussed later in this chapter), and nutritive value of salicylic acid may contribute to its potential to condition soils for enhanced degradation of isofenphos. 

The hydroxypyrimidine hydrolysis product of diazinon is more readily available in all soils tested and is mineralized by microbes (33). Our Microtox studies have demonstrated its low toxicity to bacteria. Availability, low microbial toxicity, and susceptibility to microbial metabolism of this hydrolysis product may favor enhanced degradation of its parent compound in soils with populations of degrading microorganisms, but no adaptation was noted in our laboratory studies. 

Chlorpyrifos is immobile in soil and is not available to microbes. However, its pyridinol hydrolysis product is relatively mobile its microbial toxicity and availability in soil may contribute to the increased persistence of chlorpyrifos observed in pyridinol-treated soils. 

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