Disposal Of Pesticides Research Articles

Problem of disposal of unwanted pesticides deposited in concrete tombs

The contents of a selected dual-chamber tomb containing pesticide wastes were investigated. Organochlorine pesticides constituted 30% of the buried waste and DDT constituted 50% of the chlorinated hydrocarbons. The investigated tomb also contained about 8.2 kg of mercury in organic and inorganic compounds and 600 kg of explosive nitrophenols. Because the bituminous coatings on the concrete walls of the tomb may be destroyed by oil-water emulsions and/or organic solvents from solvent-based preparations deposited in the tomb, it is possible that the unprotected concrete walls will be corroded and that toxic chemicals may subsequently migrate to the surrounding area. The exact composition of each tomb chamber is unknown, therefore the processing technology needs to be flexible enough to cope with the different properties and concentrations of the deposited chemicals.

Review of Separation Technologies for Treating Pesticide-Contaminated Soil

ABSTRACT Pesticide contamination results from manufacturing, improper storage, handling, or disposal of pesticides, and from agricultural processes. Since most pesticides are mixtures of different compounds, selecting a remedy for pesticide-contaminated soils can be a complicated process. The various available treatment options for remediation fall into three broad categories: containment-immobilization, separation-concentration, and destruction. This paper categorizes pesticides into waste groups based on available treatment options and provides a review of separation treatment options that have been demonstrated to—or show potential to— treat pesticide-contaminated soil. Technologies include radio frequency heating, soil washing, thermal desorp-tion, and solvent extraction.

Parathion degradation by a Pseudomonas sp. and a Xanthomonas sp. and by their crude enzyme extracts as affected by some cations

A Pseudomonas sp. and a Xanthomonas sp. were isolated from a pesticide disposal site in northern Israel. Both degraded parathion in two stages. In the first stage, p-nitrophenol (PNP) was released by a parathion hydrolase, while in the second stage PNP was degraded. The effect of Cu 2+, Fe 2+, Ca 2+, Mn 2+, Al 3+, Zn 2+ and NaEDTA on parathion hydrolysis to PNP by growing cultures and by crude enzyme extracts of the isolates was studied. Parathion hydrolysis by both either living cells or crude enzyme extracts of the Pseudomonas sp. was inhibited by Cu 2+ even at a concentration of 20 μmoll −1, as opposed to this cation's stimulatory effect on the degradation of parathion by the Xanthomonas sp. Other cations investigated had a smaller effect on the rate of degradation by either bacterium. NaEDTA strongly inhibited parathion hydrolysis in the living cells, but not in the crude enzyme extracts of the Pseudomonas sp. In contrast, NaEDTA inhibited parathion hydrolysis in either living cells or crude enzyme extracts of the Xanthomonas sp.

Problems of safe disposal of petroleum products, detergents, heavy metals and pesticides to protect aquatic life

Heavy metals such as zinc, copper, iron and lead, when discharged in mixtures into water, produce an entirely different lethal impact on aquatic life than when they are discharged separately. The toxicity of these metals in mixtures to zooplankton ( Diaptomus forbesi) was increased by 39.2% in the presence of the detergent parnol-J. The presence of a petroleum product, chlorinated and organophosphorus pesticides and nitrogen and phosphorus fertilizers increased the toxicity of metal mixtures to planktons by about 80%. When the petroleum product n-hexane was mixed with the metals, the lethality to worms ( Branchiura sowerbyi) was decreased by 80%, but when the detergent parnol-J was drained with the metals, the lethality was decreased by 42%. Different combinations of metals such as Zn-Cu-Fe, Zn-Cu-Pb, Zn-Fe-Pb, Cu-Fe-Pb, and Zn-Cu-Fe-Pb showed synergism in the receiving water. The synergistic action of different pollutant mixtures proves that the conventional safe disposal method (based on one-third to one-sixth of LC 50 levels of individual pollutants) is no longer safe for aquatic life. Therefore the concept of safe disposal should be based on the non-lethal doses of specific mixtures of toxicants.

The pattern of poisoning in urban Zimbabwe.

A 10-year (1980 to 1989 inclusively) retrospective analysis of poisoning admissions to the six major referral hospitals in Zimbabwe revealed 6018 cases. The majority of the patients were aged 0-5 years (35%) and 21-30 years (22.6%). The main agents associated with acute poisoning were traditional medicines (22.9% of the total), household chemicals (18.8%, 13.2% of which was due to paraffin), snake and insect envenomation (17.1%), orthodox medicines (16.7%) and insecticides (14.8%, 10% of which is accounted for by organophosphates). Mortality was 15% and the main agents associated with fatality were pesticides, traditional medicines and orthodox medicines, in descending order. The prevention and treatment of intoxication caused by traditional and orthodox medicines, the proper storage and disposal of pesticides and legislation regulating their sale and distribution are of high priority in the fight to reduce poisoning caused by these agents.

READ THE LABEL, A PESTICIDE SAFETY VIDEO TAPE

The general public is in need of education regarding the responsible use of pesticides in home gardens. A 1990 California survey indicated that many individuals never read product labels and do not follow safety precautions when applying pesticides. A 1991 EPA study found that the most frequently detected pesticide in well water was a breakdown product of DCPA, a commonly used herbicide on home lawns. A 1988-89 National Gardening Survey found that 39% of US households purchased pesticide products. Excerpts of a video tape titled “Read the Label”, which specifically targets the home gardening audience, will be presented. Because the subject of pesticide safety may be of little intrinsic interest to gardeners, actors were hired to lend a bit of light humor. Highlights feature Gordon Guardian, the Gardening Angel, who comes to Earth to guide Beth Homeowner through the proper selection, use. hazards, storage, and disposal of pesticides. Production methods, funding and budgeting of the video will also be discussed.

Propachlor degradation by a soil bacterial community

Soil from a pesticide disposal site was used to enrich for microorganisms that degraded the acylanilide herbicide propachlor (2-chloro-N-isopropylacetanilide). After seven transfers of the enrichment, the culture contained about six strains. The highest yield of microbial biomass occurred if just two of these isolates, strains DAK3 and MAB2, were inoculated into a mineral salts medium containing propachlor. When only strain DAK3 was grown on propachlor, a metabolite (2-chloro-N-isopropylacetamide) was released into the medium. Strain MAB2 could grow on this metabolite. The results of morphological and physiological tests suggest that strains DAK3 and MAB2 most closely resemble species belonging to the genera Moraxella and Xanthobacter, respectively. Strain DAK3 can respire and grow on N-substituted acylanilides containing methyl, ethyl, or isopropyl substitutions, but is incapable of respiration or growth on acetanilide, aniline, or the acylanilide herbicides alachlor and metolachlor. Strain DAK3 appears to use the aromatic C atoms of propachlor for growth, as suggested by the growth yield on propachlor and the induction of catechol 2,3-oxygenase activity in acylanilide-grown cells.

Fish-based biomonitoring to determine toxic characteristics of complex chemical mixtures: documentation of bioremediation at a pesticide disposal site

Medaka ( Oryzias latipes) embryo and larval short-term bioassays were used to rapidly demonstrate changes in toxicity of aqueous soil extracts at a pesticide disposal site before and after bioremediation. By chemical analysis, concentrations of most pesticides (particularly endosulfans) decreased after the 63-day bioremediation. In static larval assays of extracts before bioremediation, concentrations from 2.2 to 2.9% produced 50% larval mortality after 72 h exposure, whereas extract concentrations of 18 to 34% were required after remediation. Extract concentrations required to inhibit normal embryo development increased from 10% before bioremediation to 20% afterwards. Aqueous extracts from untreated soil were nonmutagenic (Ames bioassay) and, nine months after a 72-h exposure, were associated with no histopath-ologic alterations. Advantages inherent with medaka embryo and larval bioassay indicate that fish-based biomonitoring might significantly improve efforts to characterize hazardous waste sites.

Microbial degradative activity in pesticide pretreated soil

Abstract A pesticide disposal site was identified which had been exposed to various pesticides for several years. The degradative activity of this soil was assessed using several herbicides and a marker compound, 4‐chlorophenol. The phenol was converted to CO2 and other polar products within 157 days in culture. Propanil (3,4‐dichloropropionanilide) was converted to 3,4‐dichloroaniline. Diuron [N'‐(3,4‐dichlorophenyl)‐N,N‐dimethylurea] and Trifluralin [2,6‐dinitro‐N,N‐dipropyl‐4‐(trifluoromethyl) benzenamine] were not degraded over the time period studied. In liquid cultures with a soil inoculum, propanil was completely degraded in 155 hours. These studies showed that the soil from the disposal site was active in degrading several different types of chemicals and may serve as a source for the isolation of degraders.

State Departments of Agriculture

Federal and state regulatory programs that govern pesticide use, storage, and disposal have been asked to deal with increasingly complex and technical issues in the past decade. The public's understanding of these programs forms the basis for either a positive or negative perception of the regulator and the regulated community. Public perception and opinion does have a major effect on these existing pesticide programs. As an example, the involvement among regulatory agencies, government, pesticide industries, and the public in Louisiana is depicted in fig. 1. A pesticide program that does not relate to the concerns of the public often is required to refocus its policy to reflect these local or national issues (i.e., pesticide residues in food and groundwater contamination).

A benchtop system for evaluation of pesticide disposal by composting

A procedure for examining the feasibility of composting certain pesticides as a means for their disposal has been developed using a benchtop model compost system. This system is designed such that samples as small as 10 g can be studied, and, by using radiolabelled materials, compound transformation in compost media can be determined. Transformation of radiolabelled diazinon and chlordane has been examined using this procedure. After 3 weeks incubation under aerobic composting conditions (maximum temperature 65 °C), 21.6% of the diazinon radiolabel was recovered from the volatile organics trap. Of this, 15.1% was solvent extractable and was identified by TLC as diazinon and the hydrolysis product 2-isopropyl-7-methyl-6-hydroxypyrimidine (IMHP). This hydrolysis product was the only radiolabelled form present in solvent extracts of the compost media. Radiolabelled chlordane was recovered as the unconverted alpha and gamma forms with 49.6% volatilized and 47.8% remaining in the compost media.

Glyphosate utilization byPseudomonas sp. andAlcaligenes sp. isolated from environmental sources

A total of 21 bacterial cultures were isolated that could utilize glyphosate (N-phosphonomethyl glycine) as a sole source of phosphorus in a mineral salts medium. Sources of inocula for enrichment cultures included aerobic digester liquid, raw sewage, trickling filter effluent, pesticide disposal pit liquid, and soil. Eleven cultures were identified asPseudomonas sp., one asPseudomonas stutzeri, and nine asAlcaligenes sp. Aminomethylphosphonic acid, the major metabolic intermediate of glyphosate degradation in soil, could also serve as a sole phosphorus source for all 21 isolates. Neither glyphosate nor aminomethylphosphonic acid could serve as carbon sources in mineral salts media. Experiments withPseudomonas sp. SG-1 (isolated from aerobic digester liquid) suggested that enzymatic activity responsible for glyphosate degradation was intracellular, inducible, and required the cofactors pyruvate and pyridoxal phosphate. The degradation pathway for glyphosate in this culture may be similar to that previously reported for aminoethylphosphonic acid.

Bacterial degradation of three dithioate pesticides

The bacterial metabolism of three dithioate pesticides; malathion, gusathion and dimethoate was examined in an effort to obtain cell-free enzyme systems for possible use in pesticide disposal and detoxification processes. Several bacterial strains from soil, sewage and sludge samples were isolated which utilized malathion and gusathion as their sole carbon sources whereas dimethoate was used only as a phosphorus source. Rapid metabolism of malathion and gusathion required strong agitation and aeration. In co-metabolite studies, pesticides disappeared more rapidly when methanol, ethanol, anthranilic acid, yeast extract or glucose were provided. Crude cell-free enzyme extracts obtained from these cultures hydrolyzed the three dithioate insecticides in the absence of co-factors. The enzymes appeared to be constitutive since the presence of dithioate compounds in the grown medium had no influence on the specific activity of the crude enzyme extracts.

Solids Removal from Cattle Dip Pesticide Solution with Sedimentation Tanks

ABSTRACT SEDIMENTATION tanks were installed at dipping vats at two cattle feedlots. The tanks removed 2 to 93 g of solids per head dipped, depending upon flowrate, duration and other factors. Pesticide disposal volume was reduced 50% or more. The number of cattle dipped per vat recharge was doubled. Sedimentation tanks were cost effective.

Bacterial metabolism under conditions representing pesticide disposal pits.

Bacterial cultures were incubated with pesticides at concentrations ranging from 1 to 5,000 ppm. The species selected are important in one or more of the following biogeochemical processes: nitrogen fixation, nitrification, denitrification, sulfur oxidation, sulfate reduction, carbon dioxide fixation, and respiratory carbon dioxide evolution. The pesticides used were atrazine, alachlor, carbaryl, parathion, trifluralin, and 2,4-D. Bacterial cultures were exposed to commercial formulations of these pesticides and to pesticide samples from active disposal pits.

Microbiology of a pesticide disposal pit.

Microbiology of a pesticide disposal pit.

Disposal and Decontamination of Pesticides

Disposal and Decontamination of Pesticides

Static Screening of Feedlot Dipping Vat Solution

ABSTRACT USE of a Hydrasieve screen for suspended solids removal doubles the useful life of coumaphos feedlot cattle dip solution and reduces pesticide disposal requirements by 50 percent. The system produced a 13.5 cent/head savings to feedlot management and paid for itself in 7 months. The op-timum screening duration was 1 h per 1,000 head dip-ped, and the optimum screen slot size was 0.51 mm. Dry solids removal from the pesticide solution was 0.036 kg per head dipped.

Enzymatic hydrolysis of organophosphate insecticides, a possible pesticide disposal method

A crude cell extract from a mixed bacterial culture growing on parathion, an organophosphate insecticide, hydrolyzed parathion (21 C) at a rate of 416 nmol/min per mg of protein. This rate of enzymatic hydrolysis, when compared with chemical hydrolysis by 0.1 N sodium hydroxide at 40 C, was 2, 450 times faster. Eight of 12 commonly used organophosphate insecticides were enzymatically hydrolyzed with this enzyme preparation at rates ranging from 12 to 1,360 nmol/min per mg of protein. Seven pesticides were hydrolyzed at rates significantly higher (40 to 1,005 times faster) than chemical hydrolysis. The pH optimum for enzymatic hydrolysis of the eight pesticides ranged from 8.5 to 9.5, with less than 50% of maximal activity expressed at pH 7.0. Maximal enzyme activity occurred at 35 C. The crude extract lost its activity at the rate of only 0.75%/day when stored at 6 C. Eight organic solvents, ranging from methanol to hexane, at low concentrations stimulated enzymatic hydrolysis by 3 to 20%, whereas at higher concentrations (1,000 mg/liter) they inhibited the reaction (9 to 50%). Parathion metabolites p-nitrophenol, hydroquinone, and diethylthiophosphoric acid, at up to 100-mg/liter concentrations, did not significantly influence enzyme activity.

Federal and state pesticide regulations and legislation.

The combined research, education, and regulatory efforts of federal and state governments have made possible an impressive record of abundant production while imposing minimal harm to human health and the environment. Considering that approximately one billion pounds of pesticides are being applied in the United States annually to control about 2000 pest species, the safety record is remarkable. The increased public concern about environmental values and long-term health effects is constructive and is resulting in some of the regulatory changes discussed in this article. The Federal Environmental Pesticide Control Act can result in an improved and expanded joint effort by federal and state governments to limit the misuse of pesticides while permitting their use to facilitate increased production of food, feed, and fiber; provide protection from spoilage; improve health; and control nuisance insects and unwanted plants. Implementation of current regulations, plus those in the process of being enacted under authority of the new federal act, will be complex and costly. Regulations will control the registration, labeling, distribution, storage, use and application, and disposal of pesticides. A small segment of our society would like to have the use of all chemicals banned. A few individuals oppose all government controls. However, the vast majority of agricultural producer groups, representatives of industry, and the public support the need for pesticide regulations. Only through continued legal controls over pesticides may we hope to retain their use. Our society has gained tremendous benefits from the use of pesticides to prevent disease and to increase the production of food and fiber. Our need to use pesticides will continue to increase for the foreseeable future. Government agencies responsible for protecting human health and the environment must make sound judgments on an individual basis in evaluating the evidence concerning both the benefits and risks of using pesticides.