Insecticides

A growing number of well-designed epidemiological and molecular studies provide substantial evidence that the pesticides used in agricultural, commercial, and home and garden applications are associated with excess cancer risk. This risk is associated both with those applying the pesticide and, under some conditions, those who are simply bystanders to the application. In this article, the epidemiological, molecular biology, and toxicological evidence emerging from recent literature assessing the link between specific pesticides and several cancers including prostate cancer, non-Hodgkin lymphoma, leukemia, multiple myeloma, and breast cancer are integrated. Although the review is not exhaustive in its scope or depth, the literature does strongly suggest that the public health problem is real. If we are to avoid the introduction of harmful chemicals into the environment in the future, the integrated efforts of molecular biology, pesticide toxicology, and epidemiology are needed to help identify the human carcinogens and thereby improve our understanding of human carcinogenicity and reduce cancer risk.

Because pesticides may operate through different mechanisms, the authors studied the risk of prostate cancer associated with specific pesticides in the Agricultural Health Study (1993–2007). With 1,962 incident cases, including 919 aggressive prostate cancers among 54,412 applicators, this is the largest study to date. Rate ratios and 95% confidence intervals were calculated by using Poisson regression to evaluate lifetime use of 48 pesticides and prostate cancer incidence. Three organophosphate insecticides were significantly associated with aggressive prostate cancer: fonofos (rate ratio (RR) for the highest quartile of exposure (Q4) vs. nonexposed = 1.63, 95% confidence interval (CI): 1.22, 2.17; Ptrend < 0.001); malathion (RR for Q4 vs. nonexposed = 1.43, 95% CI: 1.08, 1.88; Ptrend = 0.04); and terbufos (RR for Q4 vs. nonexposed = 1.29, 95% CI: 1.02, 1.64; Ptrend = 0.03). The organochlorine insecticide aldrin was also associated with increased risk of aggressive prostate cancer (RR for Q4 vs. nonexposed = 1.49, 95% CI: 1.03, 2.18; Ptrend = 0.02). This analysis has overcome several limitations of previous studies with the inclusion of a large number of cases with relevant exposure and detailed information on use of specific pesticides at 2 points in time. Furthermore, this is the first time specific pesticides are implicated as risk factors for aggressive prostate cancer.

De bestrijdingsmiddelenfabriek van het Amerikaanse bedrijf Union Carbide was in 1969 in de stad Bhopal gebouwd en was zo'n tien jaar later uitgebreid voor de productie van het insecticide carbaryl. Methyl-isocyanaat (MIC) is een halffabricaat voor de productie van carbaryl. In de nacht van 3 december kwam door onbekende omstandigheden water in de opslagtanks met MIC terecht. Hierdoor ontstond een chemische reactie waarbij de druk enorm opliep. De veiligheidskleppen van de opslagtanks gingen normaal open, waardoor een grote hoeveelheid zeer giftig gas vrijkwam. Normaliter zou dat zijn opgevangen door zogenaamde gaswassers, een filter waarbij door middel van een vloeistof giftige stoffen uit (industriële) lucht- of afgasstroom wordt geneutraliseerd, maar vanwege reparaties waren deze niet in werking. Het bleek slechts één van de veiligheidsprocedures die niet waren gevolgd. Zo ontbraken afsluitplaten, waardoor er water in de opslagtanks terechtkwam, werkte de koelinstallatie niet en ontbrak eveneens de fakkelinstallatie waarmee het vrijkomende gas verbrand had kunnen worden. Kort na middernacht constateerde een medewerker een plotselinge stijging van de temperatuur en druk in één van de opslagtanks. De man dacht echter dat de wrakke apparatuur weer eens nukken had en ging eerst een kopje thee drinken. Zo'n twee uur later gingen de interne alarmen af.

A butterfly at risk from pesticides and a plant potentially targeted by collectors are B.C.'s newest endangered species, according to an annual assessment by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC). The Oregon branded skipper (Hesperia colorado oregonia) inhabits sparsely vegetated at-risk Garry Oak and coastal sandspit ecosystems and is found in only four of 16 fragmented sites totalling less than 16 square kilometres. It is threatened by the application of Btk pesticide used to control the invasive gypsy moth and by the encroachment of vegetation in open habitats. Also endangered is Tweedy's Lewisia, a showy perennial plant that exists in two small sub-populations and has undergone a decline of up to 30 per cent in recent years.

Monsanto, een van de belangrijkste producenten van genetisch gemodificeerde zaden (ggo-zaden) ter wereld, bouwt een fabriek in Malvinas Argentinas, een stadje van 15.000 inwoners in de provincie Córdoba. Het moet een van de grootste Monsanto-fabrieken voor maïszaaigoed worden. De fabriek zou in maart volgend jaar operationeel moeten worden maar de werken werden in oktober stilgelegd. De inwoners van het stadje protesteren fel tegen de komst van Monsanto, sinds 18 september houden ze de bouwplaats bezet door middel van vijf kampen. Bij het gerecht dienden ze verschillende klachten in. Vorige donderdag probeerde de constructeur de blokkade te breken en meerdere vrachtwagens naar binnen te loodsen. Daarbij vielen meer dan twintig gewonden. Zaterdag kwamen er militairen aan te pas om de vrachtwagens opnieuw naar buiten te krijgen.

Imidacloprid was applied as Confidor® 200 SC at the recommended field dose of 100 g a.i./ha to a Portuguese rice plot. Subsequently, fate of the test compound in water and potential effects of water samples on a battery of test species were determined. As compared to the first-tier predicted environmental concentrations (PECs) calculated using MED-Rice (around 30 µg/L depending on the scenario used) and US-EPA (78 µg/L) simulations, the actual peak concentration measured in the paddy water (52 µg/L) was higher and lower, respectively. As was anticipated based on 50% effect concentrations (EC50 values) for Daphnia magna published in the open literature and that calculated in the present study (48 h-EC50 immobility=84 mg/L), no effects were observed of field water samples on daphnids. The sediment-dwelling ostracod Heterocypris incongruens, however, appeared relatively sensitive towards imidacloprid (6 d-EC50 growth inhibition=0.01–0.015 mg/L) and a slight effect was indeed noted in field samples taken the first week after application. Species sensitivity distributions based on published EC50 and NOEC values also revealed that other species are likely to be affected at the peak and time-weighted average imidacloprid concentrations, respectively. By applying the relative tolerance approach (i.e. by dividing the EC50 value of a certain species with that of Daphnia magna), ostracods appear to contain the most sensitive taxa to imidacloprid, followed by EPT (Ephemeroptera, Plecoptera and Trichoptera) taxa.

Many of the arguments deployed in opposition to these restrictions were misleading, and based upon flawed research, much of it funded by neonicotinoid manufacturers themselves. The two principal arguments against restricting neonicotinoids were that yields would suffer, and that farmers would resort to older, even more harmful chemicals. However, evidence from Italy, where neonicotinoids have been banned from use on maize since 2008, suggests the opposite. Moreover, the EU precautionary approach on neonicotinoids represents a potential turning point for acting more widely to replace highly hazardous chemical pesticides with effective and sustainable alternatives. To achieve this, collaborative effort is needed on the part of governments, industry, civil society organisations, retailers and others. The PAN UK welcomes the EU temporary suspension of three neonicotinoid pesticides as a step in the right direction in protecting bees. We believe that this presents a unique opportunity to introduce safer, ecologically informed methods of pest management. The experience in Italy has shown that is not an unrealistic aspiration. Moreover, the EU restrictions also present the possibility of a turning point more generally on the use of highly hazardous toxic pesticides, in favour of non-chemical and IPM pest control methods. What is needed now is the political will of governments around the world to take action to promote these alternatives.

Persistence of imidacloprid was studied under laboratory conditions in four types of soil viz.sandy loam, clay, red and black soils following treatment at 1.0, 2.0 and 4.0 μg/g fortification levels. The imidacloprid residue in the soil samples were measured by validated analytical method. The dissipation of imidacloprid was found to be faster in black soil followed by sandy loam, clay and red soil with half life value of 50.10, 42.74 and 45.69 days, respectively.

The persistence and metabolism of imidacloprid in sugarcane leaves and juice were studied following application of imidacloprid @ 20 and 80 g a.i. ha−1. Samples of sugarcane leaves were collected at various time intervals (7, 15, 30, 45, 60 and 90 days after treatment), whereas those of juice were collected at the time of harvest. The residues of imidacloprid and its metabolites (6-chloronicotinic acid, nitrosimine, imidacloprid-NTG, olefin, urea and 5-hydroxy) were quantified by high-performance liquid chromatograph. In leaves, the total imidacloprid residues were mainly constituted by the parent compound followed by 6-chloronicotinic acid metabolite. Total residues of imidacloprid and its metabolites were found to be 4.97 and 12.99 mg kg−1 in sugarcane leaves collected 7 days after the application of imidacloprid @ 20 and 80 g a.i. ha−1 respectively. At both the doses, these residues declined to below the detectable limit in the leaves after 90 days of application with the half-life values of 9.68 and 8.14 days of imidacloprid @ 20 and 80 g a.i. ha−1 respectively. The total toxic residues of imidacloprid in sugarcane leaves were 0.90 and 6.29 mg kg−1 at 7 days after treatment of imidacloprid @ 20 and 80 g a.i. ha−1 respectively. The bioconcentration factor in sugarcane leaves was 0.35 and 1.03 in the lower and higher dose respectively at 7 days after treatment. The total residues followed the pseudo first order kinetics with R2 of 0.9243 and 0.944 for recommended dose and four times the recommended dose, respectively. The residues of imidacloprid and its metabolites were not detected in samples of sugarcane juice.