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Regulations and control of in-transit fumigated containers as well as of fumigated cargo ships.

INTRODUCTION: According to IMO's international regulations, e.g. "Recommendations on the safe use of pesticides in ships", fumigated containers and ship cargoes must be labeled giving specifications about dates of fumigation and the fumigation gas used. Furthermore, appropriate certificates are necessary and these records have to be forwarded to the Port Health Authorities without their explicitly asking for them. BACKGROUND AND OBJECTIVES: According to IMO (DSC/Circ.8.24.7.2001) a recent inspection of containers unloaded in ports showed that some were under fumigation, but not declared as such and in a few cases these ventilated containers arrive with "Degas Certificates" stating that fumigant has been removed, but still have a high fumigant concentration inside when opened. There are similar reports from The Netherlands, where 21% of the fumigated containers had missing or false declarations and contained measurable amounts of toxic gas. In England 6% were mentioned to be allegedly false. Reports exist of a number of other incidents with containers under fumigation arriving in English ports with no accompanying documents on the ship or at the port of discharge as to the type of cargo. In one case several people were hospitalized after exposure to phosphine gas because the fumigant tablets were not yet totally decomposed before the ship arrived at its destination port. In Bavaria, Germany, a bad accident recently occurred through a non declared fumigated container (see press release). Our sample: a large container ship in the Port of Hamburg where 27 of the cargo's containers were found fumigated with 27 non/incomplete/false declarations. These examples show that missing/false labelling is frequent. CONCLUSIONS AND RECOMMENDATIONS: Clearance of in-transit fumigated containers in ports is complicated and time-consuming for the captain and shipping company. The above mentioned accident and also the results of our spot check prove, as do the experiences in The Netherlands and England, that false declarations of fumigated containers seem commonplace. This coincides with a considerable danger for ship crews, port workers and end users. More stringent controls, including gas analysis, are necessary as well as a systematic study. As a first step in that direction, we included the question "Are fumigated containers on board?", in the form of the Maritime Declaration of Health we demand. A computer controlled information and communication system network between ports and its link with the Waterways and Shipping Directorate would enable comprehensive plausibility monitoring and thus help achieve a better surveillance.

Fumigation↗

Effects of methyl bromide concentration, fumigation time, and fumigation temperature on Mediterranean and oriental fruit fly (Diptera: Tephritidae) egg and larval survival.

The effects of methyl bromide (MB) concentration (16, 32,48, or 64 g/m3), fumigation temperature (15, 20, 25, or 30 degrees C), and fumigation time interactions on the survival of Mediterranean fruit fly, Ceratitis capitata (Wiedemann), and oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), eggs and first and third instars were recorded. Increasing the fumigation temperature from 15 to 20 degrees C or from 20 to 25 degrees C resulted in a significant reduction in fumigation time required for equivalent egg and larval mortalities at all studied MB concentrations; no further reductions in fumigation time resulted from increasing the temperature from 25 to 30 degrees C. Conversely, increasing temperature and time allowed for a reduction in MB concentration to obtain equivalent mortality. Thus, the optimum fumigation temperature for Mediterranean and oriental fruit fly eggs and larvae was 25 degrees C. Reducing MB concentrations required for phytosanitary fumigations would save time and expense, and reduce the amount of MB released into the atmosphere during aeration. Mediterranean fruit fly was as or more tolerant to MB than oriental fruit fly in MB tolerance for eggs and first instars. The egg stage was generally more tolerant to MB regardless of concentration. However, Mediterranean fruit fly eggs showed similar tolerance to first instars at 25 degrees C for the three highest concentrations and to third instars at 25 and 30 degrees C for the highest concentration, with no significant difference between them. Therefore, eggs alone can be used to obtain MB fumigation efficacy and quarantine security data at fumigation temperatures between 15 and 30 degrees C for Mediterranean and oriental fruit fly.

Animals↗

Analysis of fumigants and fumigant residues.

The terms fumigant and fumigant residue are defined. Interrelationships between physically and chemically bound residues, storage environments, nature of the substrate and other influencing factors are outlined. Analytical methods include polarography by DME and RPE, titrimetry, spectrophotometry, and GC with microthermal conductivity, hydrogen flame ionization, electron capture, microcoulometric, thermionic, and flame photometric detector systems, with backup by enzymatic, radiometric, NAA and X-ray flourescence methods. Various aspects are illustrated with different fumigants used commercially. Supplementary methods to extend the power and usefulness of analytical methods in fumigant research are indicated.

Bromides↗

Fumigation toxicity of volatile natural and synthetic cyanohydrins to stored-product pests and activity as soil fumigants.

Insecticidal fumigation toxicity of natural and synthetic cyanohydrins was evaluated with four stored-product pests: the lesser grain borer, Rhyzopertha dominica (F), the red flour beetle, Tribolium castaneum Herbst, the saw-toothed grain beetle Oryzaephilus surinamensis L, the maize weevil, Sitophilus zeamais (Motsch) and the house fly, Musca domestica L. The fumigation LC50 values were calculated by probit analysis. For house flies, all but one of the cyanohydrins tested were more potent than 1,3-dichloropropene (Telone). Three were as efficacious as chloropicrin. For the lesser grain borer, all cyanohydrins tested were more insecticidal than dichloropropene, and all but one were more potent than chloropicrin. Four were as insecticidal as dichlorvos. The acetate of 1-cyano-1-hydroxy-2-propene (CHP-ace) was also tested in soil for antifungal and antibacterial activity, and inhibition of weed seed germination. CHP-ace reduced the total soil bacterial and fungal counts significantly, and was effective in inhibiting the germination of weed seeds in soil, indicating a broad spectrum of activity as a soil fumigant.

Allyl Compounds↗

Fumigation with carbonyl sulfide: a model for the interaction of concentration, time and temperature.

The new fumigant carbonyl sulfide offers an alternative to both methyl bromide and phosphine as a grain fumigant. Separate mathematical models for levels of kill, based on quantitative toxicological studies were developed for adults and eggs of the rice weevil Sitophilus oryzae (L.). These models suggest that fumigation exposure times for carbonyl sulfide will be a compromise between those of methyl bromide (typically 24h) and phosphine (7-10d) to achieve a very high kill of all developmental stages. S. oryzae eggs were more difficult to kill with carbonyl sulfide fumigation than the adults. At 30 degrees C, a 25gm(-3) fumigation killed 99.9% of adults in less than 1d, but took 4d to kill the same percentage of eggs. Models were generated to describe the mortality of adults at 10, 15, 20, 25 and 30 degrees C. From these models it is predicted that fumigation with carbonyl sulfide for 1-2d at 30gm(-3) will kill 99.9% of adults. Furthermore the models illustrate that fumigations with concentrations below 10gm(-3) are unlikely to kill all adult S. oryzae. Significant variation was observed in the response of eggs to the fumigant over the temperature range of 10 to 30 degrees C. Models were generated to describe the mortality of eggs at 10, 15, 20, 25 and 30 degrees C. As the temperature was reduced below 25 degrees C, the time taken to achieve an effective fumigation increased. Extrapolating from the models, a 25gm(-3) fumigation to control 99.9% of S. oryzae eggs will take 95h (4d) at 30 degrees C, 77h (3.2d) at 25 degrees C, 120h (5d) at 20 degrees C, 174h (7.5d) at 15 degrees C and about 290h (11d) at 10 degrees C. The role of temperature in the time taken to kill eggs with carbonyl sulfide cannot be ignored. In order to achieve the desired level of kill of all developmental stages, the fumigation rates need to be set according to the most difficult life stage to kill, in this instance, the egg stage.

Journal Article↗

Incompatibility of metam sodium with halogenated fumigants.

Metam sodium (metam) is a widely used soil fumigant. Combined application of metam and other available fumigants is intended to produce synergic pesticidal effects for a broad spectrum of pest control in soil fumigation. This study aimed to test the compatibility of metam with the halogenated fumigants 1,3-dichloropropene (1,3-D), chloropicrin, methyl bromide, methyl iodide and propargyl bromide. Halogenated fumigants and metam were spiked simultaneously into organic solvents, water and moist soils, and metam-induced degradation of these halogenated chemicals was evaluated. In all three media, the halogenated fumigants were incompatible with metam and degraded via rapid chemical reactions. The degradation rate varied with halogenated fumigant species and increased as the amount of metam present was increased. In moist soil, 15-95% of the halogenated fumigants were decomposed within 72 h by metam at a 1:1 molar ratio. Combined application of Telone C-35 (62.5% 1,3-D + 35% chloropicrin) at 265 mg kg(-1) and Vapam (42% metam) at 567 mg kg(-1) in soil resulted in complete disappearance of the applied chloropicrin and 20-38% of the 1,3-D within 8 h. The results suggest that simultaneous application of halogenated fumigants and metam at the same soil depth will not maximize pest control. In practice, sequential treatment of soil or application at different soil depths is recommended when these two types of fumigants are used in combination.

Allyl Compounds↗

Leaching potential of persistent soil fumigant residues.

Persistent fumigant residues in soil resulting from agricultural pest-control practices may be released into water and leached to groundwater. In this study, the leaching potential of persistent soil fumigant residues was evaluated, and the effect of dissolved organic matter (DOM) and ammonium thiosulfate (ATS) amendment was investigated. A silt loam soil was incubated separately with the fumigants 1,3-dichloropropene (1,3-D), chloropicrin (CP), and methyl isothiocyanate (MITC) at 240-990 mg kg(-1) for 35 d, followed by 48 h of evaporation. The soil was packed into stainless steel columns (1.4 cm x 10 cm) and leached with water, 5 mM ATS, and DOM solution (DOC 250 mg L(-1)) by gravity. Residues of 1,3-D, CP, and MITC in the evaporated soil were 5.61, 11.38, and 1.83 mg kg(-1), respectively. Concentrations of 1,3-D, CP, and MITC in column effluents ranged from 0.05 to 0.73, 0.16 to 0.81, and 0.05 to 0.27 mg L(-1), respectively, when the soil was leached with 10 pore volumes of water. DOM did not promote the leaching of persistent fumigant residues, and ATS remarkably reduced the amount of 1,3-D and CP yet notably increased MITC recovered in the effluents. The results suggest that the leaching of persistent fumigant residues through soil to water is significant, and movement of fumigants in soil is not facilitated by DOM. Amending soil with ATS through irrigation is an effective method to remove persistent residues of halogenated fumigants. To reduce groundwater pollution risks posed by fumigation, persistent soil fumigant residues have to be considered.

Allyl Compounds↗

Effect of application variables on emissions and distribution of fumigants applied via subsurface drip irrigation.

Soil fumigation is useful for controlling soil-borne pests and diseases in high-cash-value crops. Fumigants are highly volatile, and approaches to reduce atmospheric emissions are required to protect human and environmental health. Application of fumigants through drip irrigation has been proposed as a means to decrease fumigant emissions, improve fumigant distribution in soil, and minimize worker exposure. These experiments were conducted to investigate the effect of the configuration of the drip system on the volatilization and distribution of the fumigants 1,3-dichloropropene (1,3-D), propargyl bromide (PrBr), and methyl isothiocyanate (MITC) in bedded systems. Results indicated that changing the drip emitter spacing and using multiple drip lines in each bed had little effect on the emissions and distribution of any fumigant. Increasing the depth of application from 15 to 30 cm reduced volatilization of MITC by approximately 20 to >90%; emissions were reduced due to a decrease in the flux from the bed top, and deeper injection did not change the amount of fumigant volatilized from the bed side slope and furrow. Increasing the application depth resulted in a slight decrease in the rate of fumigant dissipation in soil, indicating the potential for some improvement in pest-control efficacy with deeper application.

Allyl Compounds↗

Dehalogenation of halogenated fumigants by polysulfide salts.

Halogenated fumigants are among the most heavily used pesticides in agriculture. Because of their high mobility and toxicological characteristics, the contamination of air or groundwater by these compounds has been a great environmental concern. In this study, we investigated dehalogenation of several halogenated fumigants by polysulfides. The reaction of polysulfides and methyl iodide (MeI), 1,3-dichloropropene (1,3-D), and chloropicrin (CP) was very rapid. When the initial fumigant and polysulfide concentrations were both 0.2 mM, the observed 50% disappearance time values (DT50) of MeI, cis-1,3-D, and trans-1,3-D were 27.2, 29.6, and 102 h, respectively. When the initial polysulfide concentration was 1.0 mM, the corresponding DT50 values were only 2.2, 1.6, and 3.8 h. Under similar conditions, the reaction with CP was even more rapid than with the other fumigants. In 0.2 mM polysulfide solution, more than 90% of the spiked CP disappeared in 1 h after the initiation of the reaction. The reaction between fumigants and polysulfides also progressed at enhanced rates when the polysulfide solution was initially purged with nitrogen. Analysis of reaction kinetics and initial products suggests that the reaction is SN2 nucleophilic substitution for MeI and 1,3-D but likely reductive dehalogenation for CP. Given the high reactivity of polysulfide salts toward halogenated fumigants, this reaction may be used as a pollution mitigation strategy, such as for disposal of fumigant wastes, treatment of fumigant-containing wastewater, and cleanup of fumigant residues in environmental media.

Allyl Compounds↗

Quantification of the effect of fumigation on short- and long-term nitrogen mineralization and nitrification in different soils.

The effect of soil fumigation on N mineralization and nitrification needs to be better quantified to optimize N fertilizer advice and predict NO(-)(3) concentrations in crops and NO(-)(3) leaching risks. Seven soils representing a range in soil texture and organic matter contents were fumigated with Cyanamid DD 95 (a mixture of 1,3-dichloropropane and 1,3-dichloropropene). After removal of the fumigant, the fumigated soils and unfumigated controls were incubated for 20 wk and N mineralization and nitrification were monitored by destructive sampling. The average short-term N mineralization rates (k(s)) were significantly larger in the fumigated than in the unfumigated soils (P = 0.025), but the differences in k(s) between fumigated and unfumigated soils could not be related to soil properties. The average long-term N mineralization rates (k(l)) were slightly larger in the fumigated soils but the difference with the unfumigated soils was not significant. Again, the differences in k(l) values could not be related to soil properties. Nitrification was inhibited completely for at least 3 wk in all soils, and an effect on nitrification could be observed up to 17 wk in one soil. An S-shaped function was fitted to the nitrification data corrected for N mineralization, and both the rate constant (gamma) and the time at which maximum nitrification was reached (t(max)) were strongly correlated to soil pH. However, since no correlations were found between the effect of fumigation on N mineralization and soil properties, taking into account the effects of fumigation in fertilizer advice and in the prediction of NO(-)(3) leaching risks will need further research.

Allyl Compounds↗

Effect of surface tarp on emissions and distribution of drip-applied fumigants.

Soil fumigants are used to control a wide variety of soil-borne pests in high-cash-value crops. Application of soil fumigants through drip irrigation systems is receiving increasing attention as a method to improve the uniformity of fumigant application. Little information is available on the emissions and soil distribution of fumigants following subsurface drip application, or the effect of plastic tarp on fumigant emissions in these systems. In these experiments, the fumigant compounds 1,3-dichloropropene (1,3-D), Vapam (a methyl isothiocyanate (MITC) precursor), and propargyl bromide (PrBr) were applied to soil beds via drip irrigation at 15 cm depth. Beds were tarped with either standard 1-mil high-density polyethylene (HDPE) or a virtually impermeable film (VIF), leaving the furrows bare. Cumulative emissions of 1,3-D, MITC, and PrBr in these tarped bedded systems was very low, amounting to <10% of the applied mass. These experiments were conducted in the winter months, with average air temperatures of 12-15 degrees C. Cumulative emissions of MITC and 1,3-D from a sandy loam field soil were decreased by > or =80% by tarping the bed with VIF rather than HDPE. A large fraction of the 1,3-D and PrBr flux was from the untarped furrows in VIF-tarped plots, indicating that inhibiting volatilization from the furrow will be important in further reducing emissions in these systems. Monitoring the fumigant distribution in soil indicated that tarping the bed with VIF resulted in a more effective containment of fumigant vapors compared to use of a HDPE tarp.

Air Movements↗

Occupational and environmental hygiene assessment of fumigations with methyl bromide.

Use of methyl bromide for pest control fumigation may result in adverse exposure to three populations: the actual fumigators; other workers not actually involved in the fumigation; and the general public in the vicinity. The risk of exposure of these three target populations in Switzerland was investigated. The methodology was a combination of occupational hygiene surveys, including a preliminary hazard analysis, with a comprehensive assessment of the safety and health systems in use based on the 'Management Oversight and Risk Tree' (MORT) method [Knox and Eicher, MORT User's Manual, Revision 2. DOE 76-45/4 (1983)]. The target populations most concerned depend on the type of fumigation. Fumigators risk severe accidental exposure although they usually wear personal protection devices. In soil and chamber fumigation, workers not involved in the fumigation may undergo high exposure (75-100 pm for 1 h), far greater than the usual time-weighted average and short-term occupational exposure limits (5-20 ppm range). Occupants of premises adjoining the fumigated buildings may also be exposed to significant concentrations (25-50 ppm for 0.1-2 h). Problems originate mainly from a lack of management controls, failure to apply an appropriate code of practice and the use of personnel who are not properly qualified and trained.

Air Pollutants↗

Neurobehavioral evaluation of soil and structural fumigators using methyl bromide and sulfuryl fluoride.

Neurobehavioral functions affected by methyl bromide exposure were evaluated in California structural and soil fumigators using methyl bromide and sulfuryl fluoride. Sampling data revealed that structural fumigators are exposed for up to 1.5 hrs/day to 0-2.2 ppm methyl bromide and/or 10-200 ppm sulfuryl fluoride, and soil fumigators can be exposed to 2.3 ppm methyl bromide over an 8-hr day. Subjects were grouped for statistical analysis on the basis of exposure history: Those exposed primarily (80% or more of the work period with exposure potential) to methyl bromide (N = 32), primarily to sulfuryl fluoride (24), or to a combination of methyl bromide and sulfuryl fluoride (40-60% of each) for a minimum of one year (18), and those not exposed to high concentrations of any chemicals (29 Referents). Fumigators using methyl bromide reported a significantly higher prevalence of 18 symptoms consistent with methyl bromide toxicity than did Referents. Methyl bromide fumigators did not perform as well as Referents on 23 of 27 behavioral tests (chosen to reflect methyl bromide effects), and were significantly lower on one test of finger sensitivity and one of cognitive performance. These consistent differences suggest that even the low levels of methyl bromide found in fumigation today may produce slight neurotoxic effects. found in fumigation today may produce slight neurotoxic effects. The greater number of symptoms and reduced performance on all cognitive tests in sulfuryl fluoride fumigators compared to the Reference Group plus the absence of published research on this compound suggest that the data base for sulfuryl fluoride is inadequate.

Adult↗