Environmental equity and pesticide exposure

Liquid Bioformulation: A Trending Approach Towards Achieving Sustainable Agriculture

The human population is expanding at an exponential rate, and has created a great surge in the demand for food production. To intensify the rate of crop production, there is a tremendous usage of chemical pesticides and fertilizers. The practice of using these chemicals to enhance crop productivity has resulted in the degradation of soil fertility, leading to the depletion of native soil microflora. The constant application of these hazardous chemicals in the soil possesses major threat to humans and animals thereby impacting the agroecosystem severely. Hence, it is very important to hunt for certain new alternatives for enhancing crop productivity in an eco-friendly manner by using the microbial bioformulations. Microbial bioformulations can be mainly divided into two types: solid and liquid. There is a lot of information available on the subject of solid bioformulation, but the concept of liquid bioformulation is largely ignored. This article focuses on the diverse spectrum of liquid bioformulation pertaining to the market capture, its different types, potency of the product, mode of usage, and the limitations encountered. Also the authors have tried to include all the strategies required for sensitizing and making liquid bioformulation approach cost effective and as a greener strategy to succeed in developing countries.

Urinary Glyphosate, 2,4-D and DEET Biomarkers in Relation to Neurobehavioral Performance in Ecuadorian Adolescents in the ESPINA Cohort

BACKGROUND

Herbicides are the most used class of pesticides worldwide, and insect repellents are widely used globally. Yet, there is a dearth of studies characterizing the associations between these chemical groups and human neurobehavior. Experimental studies suggest that glyphosate and 2,4-dichlorophenoxyacetic acid (2,4-D) herbicides can affect neurobehavior and the cholinergic and glutamatergic pathways in the brain. We aim to assess whether herbicides and insect repellents are associated with neurobehavioral performance in adolescents.

METHODS

We assessed 519 participants (11-17 years of age) living in agricultural communities in Ecuador. We quantified urinary concentrations of glyphosate, 2,4-D, and two N,N-diethyl-meta-toluamide (DEET) insect repellent metabolites [3-(diethylcarbamoyl)benzoic acid (DCBA) and 3-(ethylcarbamoyl)benzoic acid (ECBA)] using isotope-dilution mass spectrometry. We assessed neurobehavioral performance using 9 subtests across 5 domains (attention/inhibitory control, memory/learning, language, visuospatial processing, and social perception). We characterized the associations using generalized estimating equations and multiple imputation for metabolites below detection limits. Models were adjusted for demographic and anthropometric characteristics, urinary creatinine, and sexual maturation. Mediation by salivary cortisol, dehydroepiandrosterone, 17 β -estradiol , and testosterone was assessed using structural equation modeling.

RESULTS

The mean of each neurobehavioral domain score was between 7.0 and 8.7 [standard deviation (SD) range: 2.0-2.3]. Glyphosate was detected in 98.3% of participants, 2,4-D in 66.2%, DCBA in 63.3%, and ECBA in 33.4%. 2,4-D was negatively associated with all neurobehavioral domains, but statistically significant associations were observed with attention/inhibition [score difference per 50% higher metabolite concentration ( β ) = - 0.19 95% confidence interval (CI): - 0.31 , - 0.07 ], language [β = - 0.12 (95% CI: - 0.23 , - 0.01 )], and memory/learning [β = - 0.11 (95% CI: - 0.22 , 0.01)]. Glyphosate had a statistically significant negative association only with social perception [β = - 0.08 (95% CI: - 0.14 , - 0.01 )]. DEET metabolites were not associated with neurobehavioral performance. Mediation by gender and adrenal hormones was not observed.

CONCLUSION

This study describes worse neurobehavioral performance associated with herbicide exposures in adolescents, particularly with 2,4-D. Replication of these findings among other pediatric and adult populations is needed. https://doi.org/10.1289/EHP11383.

Why We Will Continue to Lose Our Battle with Cancers If We Do Not Stop Their Triggers from Environmental Pollution

Besides our current health concerns due to COVID-19, cancer is a longer-lasting and even more dramatic pandemic that affects almost a third of the human population worldwide. Most of the emphasis on its causes has been posed on genetic predisposition, chance, and wrong lifestyles (mainly, obesity and smoking). Moreover, our medical weapons against cancers have not improved too much during the last century, although research is in progress. Once diagnosed with a malignant tumour, we still rely on surgery, radiotherapy, and chemotherapy. The main problem is that we have focused on fighting a difficult battle instead of preventing it by controlling its triggers. Quite the opposite, our knowledge of the links between environmental pollution and cancer has surged from the 1980s. Carcinogens in water, air, and soil have continued to accumulate disproportionally and grow in number and dose, bringing us to today's carnage. Here, a synthesis and critical review of the state of the knowledge of the links between cancer and environmental pollution in the three environmental compartments is provided, research gaps are briefly discussed, and some future directions are indicated. New evidence suggests that it is relevant to take into account not only the dose but also the time when we are exposed to carcinogens. The review ends by stressing that more dedication should be put into studying the environmental causes of cancers to prevent and avoid curing them, that the precautionary approach towards environmental pollutants must be much more reactionary, and that there is an urgent need to leave behind the outdated petrochemical-based industry and goods production.

Long Term Comparison of Talc- and Peat-Based Phytobeneficial Pseudomonas fluorescens and Pseudomonas synxantha Bioformulations for Promoting Plant Growth

Use of plant growth promoting rhizobacteria (PGPR) is an important strategy in sustainable agriculture. Among PGPR, many Pseudomonas strains are of great interest due to their abilities to colonize and thrive in the rhizosphere, in addition to displaying mechanisms in plant growth promotion and biocontrol activities. However, as Pseudomonas strains are non-spore forming micro-organisms, their development into stable bioformulations for commercial applications can be difficult. This study examined over a long term period the effect of two different carriers, peat and talc, to prepare bioformulations using phytobeneficial Pseudomonas strains belonging to two taxonomical groups of interest: P. fluorescens and P. synxantha. Each strain has previously demonstrated plant growth promotion activity when inoculated in the rhizosphere. Each bioformulation was stored at ambient temperature and their viability was measured up to 180 days. In parallel, every 30 days (up to 180 days) each bioformulation was also applied in the rhizosphere of plantlets to validate their plant growth promotion activity, and their establishment in the rhizosphere was quantified by using strain-specific quantitative polymerase chain reaction assays. The viability of both Pseudomonas strains in the bioformulations was found to decrease after the first 15 days and remained relatively stable for up to 180 days. When applying the bioformulations to Buglossoides arvensis plantlets, the expected plant growth promotion was observed when using up to 180 day-old formulations of P. fluorescens and up to 120 day-old formulations of P. synxantha, with similar results for both carriers. Establishment of both Pseudomonas strains in the rhizosphere inoculated with the peat-based carrier bioformulations stored for up to 180 days was found to be stable. While a lower establishment of P. fluorecens in the rhizosphere was observed when talc-based bioformulations were stored for 90 days or more, rhizosphere colonization by P. synxantha talc-based bioformulations remained stable for up to 180 days. In conclusion, both peat and talc appear to be suitable carriers for Pseudomonas bioformulations, however strain-specific variability exists and therefore the viability of each Pseudomonas strain and its capacity to maintain its plant growth promotion activity should be validated in different substrates before determining which formulation to use.

Degradation of chlorpyrifos in soil using laccase immobilized iron oxide nanoparticles and their competent role in deterring the mobility of chlorpyrifos

Covalent-immobilization of the laccase enzyme onto the iron oxide nanoparticles was achieved using N-(3-Dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride (EDAC) as cross-linkers. The presence of sulphur moeity in the laccase immobilized nanoparticles (LNPs) observed through Scanning Electron Microscopy- Energy dispersive X-ray spectroscopy (SEM-EDS) spectra confirmed the immobilization of laccase enzyme. The TEM analysis of iron oxide nanoparticles (FNPs), chitosan coated iron nanoparticles (CNPs) and laccase immobilized nanoparticles (LNPs) confirmed their sizes around 12, 15 and 20 nm, respectively. The effect of LNPs in degrading chlorpyrifos under field conditions was studied by simulating the conditions in a column. Column A, which was used as control showed more leaching of chlorpyrifos as compared to column B containing LNPs. The sorption coefficient (K_d) value obtained for control (column A) and LNPs containing column B were 21.6 and 112.3 L/kg, respectively. LNPs altered the K_d values of soil thereby showing lesser leaching potential. Higher the K_d value, lesser will be the leaching potential in the ground water. Copper in laccase enzyme resulted in hydrolysis of chlorpyrifos. Chitosan used for coating on FNPs and soil organic matter resulted in the adsoption of chlorpyrifos. Current results will allow a better assessment of the role of LNPs as a competent deterrent in chlorpyrifos mobility and degradation.

Evaluation in situ of genotoxic and cytotoxic response in the diploid/polyploid complex Odontophrynus (Anura: Odontophrynidae) inhabiting agroecosystems

Polyploidization has been documented across a wide range of vertebrates. Gene duplication could promote better adaptation to environmental changes and to chronic injury or stress. We investigated if genotoxic and cytotoxic responses to agricultural impact are affected by ploidy. We evaluate syntopic populations of the cryptic diploid/polyploid complex Odontophrynus cordobae/O. americanus breeding in an agroecosystem from Central Argentina. The blood of 72 adult anurans was analysed. We used erythrometry to distinguish Odontophrynus individuals with different ploidy levels. We calculated micronucleus frequencies (Mn) and erythrocytic nuclear abnormalities (ENAs) as genotoxic effects and enucleated, mitotic, pyknotic and immature erythrocytes as cytotoxic endpoints (CYT). Mn, ENAs and CYT frequencies were significantly different between diploid and polyploid organisms. The higher frequencies of Mn and CYT were recorded in polyploid organisms, and the higher frequency of ENAs was recorded in diploids. These results indicate that stress response, as indicated by most genotoxic and cytotoxic endpoints, was higher in polyploids respect to diploids. Polyploidy could provide greater genetic flexibility increasing buffering against exogenous DNA-damaging agents and thus confer an advantage over diploids under certain environmental conditions.

Disseminating Pesticide Exposure Results to Farmworker and Nonfarmworker Families in an Agricultural Community: A Community-Based Participatory Research Approach

OBJECTIVE

The aim of this study was to examine the impact of a dissemination process to provide individual pesticide results to study participants.

METHODS

After working with community members to disseminate data, 37 participants were recontacted via an interview survey to assess the effectiveness of the dissemination process.

RESULTS

Almost all participants (97.3%) recalled a home visit from a health promoter; 29 (78.4%) correctly recalled that the health promoter used a thermometer or graphic to explain the results; 26 (70.3%) correctly interpreted graphics showing high and low exposure levels in adults and 75.7% correctly interpreted results for children.

CONCLUSIONS

The study results support the use of a community-based participatory research approach to decide how to best depict and disseminate study results, especially among participants who are often left out of the dissemination process.

Interaction of Beauveria bassiana and Metarhizium anisopliae with chlorpyrifos ethyl and spinosad in Spodoptera frugiperda larvae

BACKGROUND

The high natural resistance of the fall armyworm (FAW) to entomopathogenic fungi and the speed at which it develops resistance to chemical insecticides make it difficult to control in several crops where it is a key pest. The aim of the study was to improve mortality by combining a 50% lethal concentration of chlorpyrifos ethyl or spinosad with the entomopathogenic fungus Beauveria bassiana (Bb88) or Metarhizium anisopliae (ETL).

RESULTS

Three main results were obtained. (i) Both insecticides improved the performance of the fungus when the insecticide and fungus were applied simultaneously and when spinosad preceded fungi. In control larvae treated with fungi, <1% of larvae showed fungal sporulation, but under simultaneous application of the fungus with chlorpyrifos or spinosad, 31 and 47% did so, with 68 and 93% of cadavers showing sporulation, respectively. (ii) Synergistic mortality was observed when Bb88 and spinosad were applied simultaneously, which resulted in 34% more dead larvae than the spinosad control (44%). Finally, (iii) antagonism occurred when Bb88 was applied before chlorpyrifos, when Bb88 and chlorpyrifos were applied simultaneously, and when ETL was applied before chlorpyrifos, which reduced larval mortality by 27, 31 and 19%, respectively.

CONCLUSION

The synergistic mortality and improved fungal performance observed here support the hypothesis that combinations of low insecticide doses and entomopathogenic fungi can enhance integrated pest management programs and reduce the environmental impact of insecticides. Antagonism shows that some particular combinations and application sequences may produce disadvantages in pest control. © 2018 Society of Chemical Industry.

Long term exposure to low dose neurotoxic pesticides affects hatching, viability and cholinesterase activity of Artemia sp

The brine shrimp Artemia was used as a model organism to test toxicity of several neuroactive pesticides (chlorpyrifos (CLP), chlorpyrifos oxon (CLP ox), diazinon (DZN), carbaryl (CBR)) following exposure to far below than lethal doses. Cysts were exposed to the pesticides in order to test a scenario similar to actual coastal environment contamination, by analyzing different responses. Cysts were rehydrated in water containing the pesticides at concentrations ranging from 10^-11 to 10^-5 M, for 72, 96 and 192 h, respectively. For these exposure times, morpho-functional and biochemical parameters, such as hatching speed and viability were investigated in the larvae together with cholinesterase (ChE) activity quantification and histochemical localization. Finally, ChE inhibition was also compared with conventional selective ChE inhibitors. Results showed that CLP ox and CBR caused a significant dose-dependent decrease in hatching speed, followed by high percentages of larval death, while CLP and DZN were responsible for irregular hatching patterns. In addition, the pesticides mostly caused larval death some days post-hatching, whereas this effect was negligible for the specific ChE inhibitors, suggesting that part of pesticide toxicity may be due to molecules other than the primary target. ChE activity was observed in the protocerebrum lobes, linked to the development of pair eyes. Such activity was inhibited in larvae exposed to all pesticides. When compared to conventional selective inhibitors of ChE activities, this inhibition demonstrated that the selected pesticides mainly affect acetylcholinesterase and, to a lesser extent, pseudocholinesterases. In conclusion, the brine shrimp is a good model to test the environmental toxicity of long term exposure to cholinergic pesticides, since changes in hatching speed, viability and ChE activity were observed.

Imidacloprid application changes microbial dynamics and enzymes in rice soil

Extensive use of imidacloprid in rice ecosystem may alter dynamics of microorganisms and can change soil biochemical properties. The objective of this study was to assess the effect of imidacloprid on growth and activities of microbes in tropical rice soil ecosystem. Four treatments, namely, recommended dose (at 25g a.i. ha^-1, RD), double the recommended dose (at 50g a.i. ha^-1, 2RD), five times the recommended dose (at 125g a.i. ha^-1, 5RD) & ten times the recommended dose (at 250g a.i. ha^-1, 10RD) along with control were imposed under controlled condition. Dissipation half lives of imidacloprid in soil were 19.25, 20.38, 21.65 and 33.00 days for RD, 2RD, 5RD and 10RD, respectively. In general bacteria, actinomycetes, fungi and phosphate solubilising bacteria population were disturbed due to imidacloprid application. Changes in diversity indices within bacterial community confirmed that imidacloprid application significantly affected distribution of bacteria. Total soil microbial biomass carbon content was reduced on imidacloprid application. Except dehydrogenase and alkaline phosphatase activities, all other soil enzymes namely, β-glycosidase, fluorescien diacetate hydrolase, acid phosphatase and urease responded negatively to imidacloprid application. The extent of negative effect of imidacloprid depends on dose and exposure time. This study concludes imidacloprid application had transient negative effects on soil microbes.

Malathion increases apoptotic cell death by inducing lysosomal membrane permeabilization in N2a neuroblastoma cells: a model for neurodegeneration in Alzheimer's disease

Malathion is an organophosphate with severe neurotoxic effects. Upon acute exposure, malathion initially enhances cholinergic activity by inhibition of acetylcholinesterase, which is its major pathological mechanism. Malathion also induces non-cholinergic neuronal cell death in neurodegenerative conditions; the associated molecular mechanism is not well-characterized. To investigate the molecular mechanism of malathion-induced cell death, N2a mouse neuroblastoma cells were exposed to malathion and cell death-related parameters were examined. Malathion reduced cell viability mainly by apoptosis through mitochondrial dysfunction in N2a cells, as judged by an increase in the level of the pro-apoptotic protein Bax and decrease in the levels of the anti-apoptotic proteins p-Akt and Bcl2, resulting in cytochrome c release and caspase-dependent DNA fragmentation and condensation. Malathion treatment also induced autophagy and lysosomal membrane permeabilization (LMP) in N2a cells. LMP caused a lessening of autophagic flux via inhibition of lysosomal fusion with the autophagosome. LMP-induced cathepsin B release and its proteolytic effect may intensify apoptotic insults. Moreover, malathion-exposed N2a cells showed a marked reduction in the levels of the neuronal marker proteins vascular endothelial growth factor and heart fatty acid binding protein 3, along with diminished neuritogenesis in N2a cells and nerve growth factor secretion in C6 glioma cells. Our data suggest that the non-cholinergic effect of malathion may be mediated by apoptotic cell death via LMP induction in N2a cells. Malathion-treated N2a cells can be utilized as an in vitro model system to screen natural and new chemical drug candidates for neurodegenerative diseases such as Alzheimer’s disease.

Ground-Truthing Validation to Assess the Effect of Facility Locational Error on Cumulative Impacts Screening Tools

Researchers and government regulators have developed numerous tools to screen areas and populations for cumulative impacts and vulnerability to environmental hazards and risk. These tools all rely on secondary data maintained by government agencies as part of the regulatory and permitting process. Stakeholders interested in cumulative impacts screening results have consistently questioned the accuracy and completeness of some of these datasets. In this study, three cumulative impacts screening tools used in California were compared, and ground-truth validation was used to determine the effect database inaccuracy. Ground-truthing showed substantial locational inaccuracy and error in hazardous facility databases and statewide air toxics emission inventories of up to 10 kilometers. These errors resulted in significant differences in cumulative impact screening scores generated by one screening tool, the Environmental Justice Screening Method.

Influence of short-time imidacloprid and acetamiprid application on soil microbial metabolic activity and enzymatic activity

The influence of two neonicotinoids, i.e., imidacloprid (IMI) and acetamiprid (ACE), on soil microbial activities was investigated in a short period of time using a combination of the microcalorimetric approach and enzyme tests. Thermodynamic parameters such as Q T (J g(-1) soil), ∆H met (kJ mol(-1)), J Q/S (J g(-1) h(-1)), k (h(-1)), and soil enzymatic activities, dehydrogenase, phosphomonoesterase, arginine deaminase, and urease, were used to evaluate whole metabolic activity changes and acute toxicity following IMI and ACE treatment. Various profiles of thermogenic curves reflect different soil microbial activities. The microbial growth rate constant k, total heat evolution Q T (expect for IMI), and inhibitory ratio I show linear relationship with the doses of IMI and ACE. Q T for IMI increases at 0.0-20 μg g(-1) and then decreases at 20-80 μg g(-1), possibly attributing to the presence of tolerant microorganisms. The 50 % inhibitory ratios (IC50) of IMI and ACE are 95.7 and 77.2 μg g(-1), respectively. ACE displays slightly higher toxicity than IMI. Plots of k and Q T against microbial biomass-C indicate that the k and Q T are growth yield-dependent. IMI and ACE show 29.6; 40.4 and 23.0; and 23.3, 21.7, and 30.5 % inhibition of dehydrogenase, phosphomonoesterase, and urease activity, respectively. By contrast, the arginine deaminase activity is enhanced by 15.2 and 13.2 % with IMI and ACE, respectively. The parametric indices selected give a quantitative dose-response relationship of both insecticides and indicate that ACE is more toxic than IMI due to their difference in molecular structures.

Triazophos induced oxidative stress and histomorphological changes in liver and kidney of female albino rats

Organophosphate (OP) pesticides toxic manifestations have been associated with enhanced generation of reactive oxygen species (ROS) which culminates into oxidative stress (OS). Triazophos (TZ), a broad spectrum OP, was used in the present study to investigate toxic effects on liver and kidney of female albino rats at three sub-chronic dose levels of 1/10th, 1/20th and 1/40th of LD50 for 30 days. Activity levels of different OS parameters viz: catalase (CAT), superoxide dismutase (SOD), glutathione-S-transferase (GST), glutathione reductase (GR), glutathione peroxidase (GPx) and lipid peroxidation (LPO) were differentially altered in liver and kidney of TZ treated rats as compared to control rats. Histomorphological studies further revealed number of abnormalities as infiltration, vacuolization, enlarged sinusoids and necrosis in liver of TZ treated rats, while renal histoarchitecture of 1/10th and 1/20th of LD50 TZ treated rats showed high degeneration of glomeruli. Enhanced apoptosis was also observed in hepatocytes at dose levels of 1/10th and 1/20th of LD50 TZ treated female rats. The results infer that exposure of female albino rats to TZ leads to number of pathophysiological conditions in the liver and kidney at dose dependent manner.

Levels of selected persistent organic pollutants in blood from delivering women in seven selected areas of São Paulo State, Brazil

Persistent organic pollutants (POPs) present in the living environment are thought to have detrimental health effects on the population, with pregnant women and the developing foetus being at highest risk. We report on the levels of selected POPs in maternal blood of 155 delivering women residing in seven regions within the São Paulo State, Brazil. The following selected POPs were measured in the maternal whole blood: 12 polychlorinated biphenyls (PCBs) congeners (IUPAC Nos. 99, 101, 118, 138, 153, 156, 163, 170, 180, 183, 187, 194); dichlordiphenyltrichloroethane p,p'-DDT, diphenyldichloroethylene p,p'-DDE and other pesticides such as hexachlorocyclohexanes (α-HCH, β-HCH, γ-HCH), hexachlorobenzene (HCB), chlordane derivatives cis-chlordane, trans-chlordane, oxy-chlordane, cis-nonachlor and trans-nonachlor. Statistical comparisons between regions were performed only on compounds having concentrations above LOD in 70% of the samples. PCB118 congener was found to be highest in the industrial site (mean 4.97 ng/g lipids); PCB138 congener concentration was highest in the Urban 3 site (mean 4.27 ng/g lipids) and congener PCB153 was highest in the industrial and Urban 3 sites with mean concentration of 7.2 ng/g lipids and 5.89ng/g lipids respectively. Large differences in levels of p,p'-DDE between regions were observed with the Urban 3 and industrial sites having the highest concentrations of 645 ng/g lipids and 417 ng/g lipids, respectively; β-HCH was found to be highest in the Rural 1 site; the γ-HCH in Rural 1 and industrial; the HCB in the Rural 1 and industrial sites and oxy-chlordane and t-NC in the Rural 2 sites. An association between levels of some contaminants and maternal age and parity was also found.

Pesticide poisoning in a preschool child: a case study examining neurocognitive and neurobehavioral effects

Exposure to environmental toxins, such as pesticides, has been shown to have adverse effects in humans, particularly neurological effects. Cases of acute pesticide poisoning occur less frequently and are less well documented; specific deficits (e.g., in processing speed, working memory) have not consistently been discussed. This is a case study of a preschooler who underwent a neuropsychological assessment due to a pesticide poisoning. His parents reported attention, speech, social, and gross and fine motor concerns after the poisoning. A number of methods and measures were used, including observational data, neuropsychological, and behavioral and social-emotional measures. Consistent with past research, results from the assessment demonstrated the subtle and not-so-subtle effects of acute pesticide poisoning. Implications of the findings are discussed.

Comparative toxicity of chlorpyrifos and its oxon derivatives to soil microbial activity by combined methods

The inhibitory effects of the pesticide Chlorpyrifos (CPF) and its oxon derivative (CPO) on soil microbial activity were evaluated through the measurement of metabolic parameters and the microbial urease enzyme. The thermodynamic parameters related to microbial activity were measured and recorded as power-time curves. Microbial growth rate constant k, total heat evolution Q(T), metabolic enthalpy DeltaH(met), mass specific heat rate J(Q/S), microbial biomass C and inhibitory ratio I were calculated. They showed the linear relationship with doses of CPF and CPO. Thereinto, the linear correlations, k versus biomass C and DeltaH(met) versus biomass C, elucidated that k and DeltaH(met) were growth yield dependent. In this work, 20% inhibitory ratio IC(20) was obtained with 9.8 microg g(-1) for CPF and 0.37 microg g(-1) CPO, meaning that the acute toxicity of CPO was 26 times that of CPF, since the CPO had more potent toxicity to living organism due to its active functional group. Comparing the change tendency of DeltaH(met) and other parameter, the values almost kept constant when exposure to CPF (<5.0 microg g(-1)). It illustrates that individual reacted to stress resulted from environment change by shifting resources from other biological activities (such as reproduction or growth) toward survival to some extent. Urease activity responses in relation to the CPF and CPO exposure were observed and consistent with above thermodynamic parameters.

Genotoxicity of the herbicide formulation Roundup (glyphosate) in broad-snouted caiman (Caiman latirostris) evidenced by the Comet assay and the Micronucleus test

The genotoxicity of pesticides is an issue of worldwide concern. The present study was undertaken to evaluate the genotoxic potential of a widely used herbicide formulation, Roundup (glyphosate), in erythrocytes of broad-snouted caiman (Caiman latirostris) after in ovo exposure. Caiman embryos were exposed at early embryonic stage to different sub-lethal concentrations of Roundup (50, 100, 200, 300, 400, 500, 750, 1000, 1250 and 1750microg/egg). At time of hatching, blood samples were obtained from each animal and two short-term tests, the Comet assay and the Micronucleus (MN) test, were performed on erythrocytes to assess DNA damage. A significant increase in DNA damage was observed at a concentration of 500microg/egg or higher, compared to untreated control animals (p<0.05). Results from both the Comet assay and the MN test revealed a concentration-dependent effect. This study demonstrated adverse effects of Roundup on DNA of C. latirostris and confirmed that the Comet assay and the MN test applied on caiman erythrocytes are useful tools in determining potential genotoxicity of pesticides. The identification of sentinel species as well as sensitive biomarkers among the natural biota is imperative to thoroughly evaluate genetic damage, which has significant consequences for short- and long-term survival of the natural species.

Phytotoxicity of four herbicides on Ceratophyllum demersum, Vallisneria natans and Elodea nuttallii

The physiological effects of 4 herbicides (butachlor, quinclorac, bensulfuron-methyl and atrazine) on 3 submerged macrophytes (Ceratophyllum demersum, Vallisneria natans and Elodea nuttallii) were tested in laboratory. The variables of the relative growth rate and the photosynthetic pigment content showed that all of the tested herbicides affected the growth of the plants obviously, even at the lowest concentration (0.0001 mg/L). Except for the C. demersum treated with quinclorac at 0.005 and 0.01 mg/L, the relative growth rates of the plants were inhibited significantly (p < 0.01). Statistical analysis of chlorophyll a (Chl-a) contents was carried out with both the t-test and one-way ANOVA to determine the difference between the treatment and control. The results showed that Chl-a contents of the plants in all treatment groups were affected by herbicides significantly, except for the C. demersum treated with bensulfuron-methyl at 0.0005 mg/L. The decrease in Chl-a content was positively correlated to the dosage of the herbicides in most treatment groups. It was suggested that herbicides in water bodies might potentially affect the growth of aquatic macrophytes. Since the Chl-a content of submerged macrophytes responded to the stress of herbicides sensitively and directly, it could be used as a biomaker in environmental monitoring or in the ecological risk assessment of herbicide contamination.

Environmental impact of pesticides in Egypt

The first use of petroleum-derived pesticides in Egyptian agriculture was initiated in 1950. Early applications consisted of distributing insecticidal dusts containing DDT/BHC/S onto cotton fields. This practice was followed by use of toxaphene until 1961. Carbamates, organophosphates, and synthetic pyrethroids were subsequently used, mainly for applications to cotton. In addition to the use of about 1 million metric tons (t) of pesticides in the agricultural sector over a 50-yr period, specific health and environmental problems are documented in this review. Major problems represented and discussed in this review are human poisoning, incidental toxicity to farm animals, insect pest resistance, destruction of beneficial parasites and predators, contamination of food by pesticide residues, and pollution of environmental ecosystems. Several reports reveal that chlorinated hydrocarbon pesticide residues are still detectable in several environmental compartments; however, these residues are in decline. Since 1990, there is a growing movement toward reduced consumption of traditional pesticides and a tendency to expand use of biopesticides, including "Bt," and plant incorporated protectants (PIPs). On the other hand, DDT and lindane were used for indoor and hygienic purposes as early as 1952. Presently, indoor use of pesticides for pest control is widespread in Egypt. Accurate information concerning the types and amounts of Egyptian household pesticide use, or numbers of poisoning or contamination incidents, is unavailable. Generally, use of indoor pesticides is inadequately managed. The results of a survey of Egyptian farmers' attitudes toward pesticides and their behavior in using them garnered new insights as to how pesticides should be better controlled and regulated in Egypt.

Toxicity of organophosphates on morphology and locomotor behavior in brine shrimp, Artemia salina

The acute toxicity and hatching success of four organophosphorus insecticides--acephate (ACEP), chlorpyrifos (CPP), monocrotophos (MCP), and profenofos (PF)--was studied in a short-term bioassay using brine shrimp, Artemia salina. Fifty percent hatchability inhibition concentration and median lethal concentration (LC(50)) values were calculated after probit transformation of the resulting data. Among the insecticides tested, CPP is found to be the most toxic and also to inhibit hatching success of A. salina cysts in a concentration-dependent manner. In addition, the effect of these pesticides on locomotor behavior (swimming speed) and morphologic differences were studied in LC(50)-exposed nauplii after 24 hours. The in vivo effect of these insecticides on acetylcholinesterase (Enzyme commission number (EC 3.1.1.7) activity was also determined in LC(50)-exposed nauplii after 24 hours. Maximum percent decrease in their swimming speed and significant morphologic alterations were noticed in CPP-exposed brine shrimps. The order of toxicity was CPP > PF > MCP > ACEP in all the parameters studied.

Vulnerability as a function of individual and group resources in cumulative risk assessment

BACKGROUND

The field of risk assessment has focused on protecting the health of individual people or populations of wildlife from single risks, mostly from chemical exposure. The U.S. Environmental Protection Agency recently began to address multiple risks to communities in the "Framework for Cumulative Risk Assessment" [EPA/630/P02/001F. Washington DC:Risk Assessment Forum, U.S. Environmental Protection Agency (2003)]. Simultaneously, several reports concluded that some individuals and groups are more vulnerable to environmental risks than the general population. However, vulnerability has received little specific attention in the risk assessment literature.

OBJECTIVE

Our objective is to examine the issue of vulnerability in cumulative risk assessment and present a conceptual framework rather than a comprehensive review of the literature. In this article we consider similarities between ecologic and human communities and the factors that make communities vulnerable to environmental risks.

DISCUSSION

The literature provides substantial evidence on single environmental factors and simple conditions that increase vulnerability or reduce resilience for humans and ecologic systems. This observation is especially true for individual people and populations of wildlife. Little research directly addresses the topic of vulnerability in cumulative risk situations, especially at the community level. The community level of organization has not been adequately considered as an end point in either human or ecologic risk assessment. Furthermore, current information on human risk does not completely explain the level of response in cumulative risk conditions. Ecologic risk situations are similarly more complex and unpredictable for cases of cumulative risk.

CONCLUSIONS

Psychosocial conditions and responses are the principal missing element for humans. We propose a model for including psychologic and social factors as an integral component of cumulative risk assessment.

Preventing occupational exposure to pesticides: using participatory research with latino farmworkers to develop an intervention

Pesticide exposure is an occupational health hazard for migrant farmworkers. The US-EPA Worker Protection Standard (WPS) mandates training programs to prevent or reduce exposure. WPS implementation in a local context requires understanding individual, workplace, and community environmental factors that lead to exposure and influence intervention effectiveness. Participatory research within the PRECEDE-PROCEED planning framework was used to design a WPS training program for Mexican farmworkers in North Carolina cucumber and tobacco production. Research with farmworkers, farmers, health care providers, and Cooperative Extension agents identified modifiable behaviors and environmental factors, as well as structural and regulatory barriers requiring intervention. Data were gathered and analyzed through individual and group interviews, community forums, an advisory board, and a partnership between academic researchers and a community-based organization. The intervention's dominant features are (a) focus on key health behaviors, (b) relevance to local conditions, and (c) attention to issues of control in the workplace. Participatory research is effective for designing a health intervention where diverse social, cultural, political, and regulatory issues affect farmworkers' risk of exposure.

Un lugar seguro para sus ninos: development and evaluation of a pesticide education video

The need exists for culturally appropriate and effective educational interventions to reduce pesticide exposure in migrant and seasonal farm-worker (MSFW) communities. The development of one such intervention was part of a community-based research project which partnered the Oregon Health Sciences University and the Oregon Child Development Coalition (Migrant Head Start). The process involved identifying an optimal educational method and content, evaluating existing educational materials on pesticides, developing the selected educational tool (a video), and assessing the effectiveness of the video as an intervention. Focus groups were conducted with MSFWs to elicit their perceived need for education and desired content, method, and delivery. Four currently used educational tools were evaluated for satisfaction, preference, recall ability and knowledge change. Based on these findings, a pesticide exposure video directed at the protection of children was produced. To determine the effectiveness of the video, knowledge, satisfaction and self-reported behaviors were assessed with MSFWs. A sizeable increase in overall pesticide knowledge was measured after seeing the video (p < 0.0001). MSFWs overall were satisfied with the video and reported increased protective behaviors after seeing the video.

Use of Daphnia spp. for the ecotoxicological assessment of water quality in an agricultural watershed in South-Central Chile

Because of the importance of surface waters from the Chillán River watershed (Chile) for recreation, agricultural irrigation, and the production of drinking water, local concern about river water quality has increased considerably during the last decade. Agricultural and forestry activities in the watershed, characterized by an intensive use of pesticides, are thought to play an important role in the generation of non-point-source pollution, whereas the discharge of urban wastewater from the city of Chillán constitutes a major point source of pollution. In the present investigation, acute and chronic laboratory bioassays using Daphnia spp. were conducted on surface water samples from 17 river stations located throughout the watershed. Sampling occurred on 6 occasions during a 16-month period (2000 to 2001) and included both high and low flow conditions. Almost all toxic effects observed in summer were directly related to the discharge of urban wastewater, whereas toxicity in rural areas was mainly detected during the winter period when rainfall and river flow are high. Toxicity test results were compared with measured physicochemical water-quality data. Mortality and alterations in reproductive success of Daphnia spp. were not consistently reflected in detected chemical pollution. With only one exception (atrazine), detected pesticide concentrations were below known toxicity levels. However, additive and synergistic effects of the presence of a mixture of pesticides could not be excluded as a possible cause of observed toxicity. At several stations, filtering of the water sample led to a strong decrease in toxicity, which suggests the presence of xenobiotics attached to the smaller sediment fraction. Inclusion of sediment chemical analysis and sediment toxicity testing in future work should therefore be encouraged. The presented approach provided information about the adverse effects of human activities on surface water quality in the watershed, not easily obtained from classical monitoring schemes. In specific cases, the approach may represent an economically attractive alternative to physicochemical analyses. Modifications to the proposed methodology should be introduced if the effects of intrastorm and interstorm variability of water quality are to be analyzed.

Environmental health disparities: a framework integrating psychosocial and environmental concepts

Although it is often acknowledged that social and environmental factors interact to produce racial and ethnic environmental health disparities, it is still unclear how this occurs. Despite continued controversy, the environmental justice movement has provided some insight by suggesting that disadvantaged communities face greater likelihood of exposure to ambient hazards. The exposure-disease paradigm has long suggested that differential "vulnerability" may modify the effects of toxicants on biological systems. However, relatively little work has been done to specify whether racial and ethnic minorities may have greater vulnerability than do majority populations and, further, what these vulnerabilities may be. We suggest that psychosocial stress may be the vulnerability factor that links social conditions with environmental hazards. Psychosocial stress can lead to acute and chronic changes in the functioning of body systems (e.g., immune) and also lead directly to illness. In this article we present a multidisciplinary framework integrating these ideas. We also argue that residential segregation leads to differential experiences of community stress, exposure to pollutants, and access to community resources. When not counterbalanced by resources, stressors may lead to heightened vulnerability to environmental hazards.

Prostate cancer among pesticide applicators: a meta-analysis

OBJECTIVES

To analyse data from peer-reviewed, case-referent and cohort studies, studying the occurrence of prostate cancer in pesticide applicators and in some other, related, occupational categories, in order to determine a possible relationship of cancer of the prostate with pesticide exposure; to calculate a meta-rate ratio and to compare it with the meta-rate ratios obtained in a previous meta-analysis performed over a shorter time (1995-2001) in a broader exposure category, including many pesticide-related agricultural and non-agricultural occupations.

METHODS

Medline was searched for the years between 1966 and 2003, and relevant studies were identified from 1986 on. We conducted a meta-analysis of 22 studies complying with the inclusion criteria in order to pool their relative risk (RR) estimates. Studies were summarised and assessed for homogeneity and publication bias.

RESULTS

The meta-rate ratio, based on 22 estimates of RR, is 1.24 [95% confidence interval (95% CI) 1.06-1.45]. This pooled risk estimate for the occupational categories selected is higher than the one previously calculated for farmers in general over a shorter period of publication. Substantial heterogeneity of rate ratios exists between the different studies. The major source of heterogeneity identified is geographic location. Increased meta-rate ratios are observed for studies derived from North America as well as from Europe, the meta-rate ratios from Europe being lower than those from North America. There is no obvious indication of publication bias.

CONCLUSION

The increased meta-rate ratio for prostate cancer in agricultural pesticide applications provides additional evidence for a possible relationship between pesticide exposure and prostate cancer. The homogeneity observed between the individual rate ratios, after we had regrouped the data according to geographic location, tends to increase the consistency of the association. However, the data available from the individual studies do not provide sufficient exposure information for firm conclusions to be drawn about pesticide exposure as the cause of prostate cancer, independently from other factors.

Association of pesticide exposure with neurologic dysfunction and disease

Poisoning by acute high-level exposure to certain pesticides has well-known neurotoxic effects, but whether chronic exposure to moderate levels of pesticides is also neurotoxic is more controversial. Most studies of moderate pesticide exposure have found increased prevalence of neurologic symptoms and changes in neurobehavioral performance, reflecting cognitive and psychomotor dysfunction. There is less evidence that moderate exposure is related to deficits in sensory or motor function or peripheral nerve conduction, but fewer studies have considered these outcomes. It is possible that the most sensitive manifestation of pesticide neurotoxicity is a general malaise lacking in specificity and related to mild cognitive dysfunction, similar to that described for Gulf War syndrome. Most studies have focused on organophosphate insecticides, but some found neurotoxic effects from other pesticides, including fungicides, fumigants, and organochlorine and carbamate insecticides. Pesticide exposure may also be associated with increased risk of Parkinson disease; several classes of pesticides, including insecticides, herbicides, and fungicides, have been implicated. Studies of other neurodegenerative diseases are limited and inconclusive. Future studies will need to improve assessment of pesticide exposure in individuals and consider the role of genetic susceptibility. More studies of pesticides other than organophosphates are needed. Major unresolved issues include the relative importance of acute and chronic exposure, the effect of moderate exposure in the absence of poisoning, and the relationship of pesticide-related neurotoxicity to neurodegenerative disease.

Pesticide exposure--Egyptian scene

Pesticides have contributed to dramatic increases in crop yields and in the quantity and variety of the diet. Also, they have helped to limit the spread of certain diseases. But pesticides have harmful effects; they can cause injury to human health as well as to the environment. The range of these adverse health effects includes acute and persistent injury to the nervous system, lung damage, injury to the reproductive organs, dysfunction of the immune and endocrine systems, birth defects, and cancer. Problems associated with pesticide hazards to man and the environment are not confined to the developing countries. Developed nations have already suffered these problems, and still facing some problems in certain locations. For many reasons, the severity of pesticide hazards is much pronounced in Third World Countries. A number of long persistent organochlorines and highly toxic organophosphates, which have been banned or severely restricted, are still marketed and used in many developing countries. The misuse of pesticides by concerned individuals, in addition to lack of or weak national controlling plans are behind the outbreak of adverse effects in developing countries. Since about 25 years, the use of DDT and many other organochlorine pesticides in Egyptian agriculture has been banned. However, these long persistent compounds are still detectable in many different types of environmental samples (e.g., water, fish, sediment, vegetables, fruits, milk, foodstuffs, etc.). Large number of compounds known as "extremely hazardous", "highly hazardous", "probable human carcinogenic", and "possible human carcinogenic", are listed among the pesticides registered and recommended for use in Egypt during the season of 2001/2002. The present article deals with: trends and patterns of pesticide use, impact of pesticides on human health, factors contributing to pesticide risks, environmental impacts of pesticides, and bioaccumulation of pesticide residues in food; giving special concern to the situation in Egypt.

The environment of childhood poverty

Poor children confront widespread environmental inequities. Compared with their economically advantaged counterparts, they are exposed to more family turmoil, violence, separation from their families, instability, and chaotic households. Poor children experience less social support, and their parents are less responsive and more authoritarian. Low-income children are read to relatively infrequently, watch more TV, and have less access to books and computers. Low-income parents are less involved in their children's school activities. The air and water poor children consume are more polluted. Their homes are more crowded, noisier, and of lower quality. Low-income neighborhoods are more dangerous, offer poorer municipal services, and suffer greater physical deterioration. Predominantly low-income schools and day care are inferior. The accumulation of multiple environmental risks rather than singular risk exposure may be an especially pathogenic aspect of childhood poverty.

Pesticide take-home pathway among children of agricultural workers: study design, methods, and baseline findings

Farmworkers are exposed to pesticides and may take home pesticide residues to their families. In this paper, self-reported pesticide exposure and home practices to reduce the amount of pesticide residues taken home were examined among 571 farmworkers. Urine samples from a subsample of farmworkers and children and dust samples from households and vehicles also assessed pesticide exposure. Overall, 96% of respondents reported exposure to pesticides at work. Many employers did not provide resources for hand washing. Farmworkers' protective practices to keep pesticide residues out of the home were at a low level. In a subset of respondents, pesticide levels above the limit of quantitation were seen in the urine of children and adults and in house and vehicle dust. The results support the take-home pathway of pesticide exposure. Ways must be found to reduce this pesticide exposure among children of farmworkers.

Socioeconomic status and health: the potential role of environmental risk exposure

Among several viable explanations for the ubiquitous SES-health gradient is differential exposure to environmental risk. We document evidence of inverse relations between income and other indices of SES with environmental risk factors including hazardous wastes and other toxins, ambient and indoor air pollutants, water quality, ambient noise, residential crowding, housing quality, educational facilities, work environments, and neighborhood conditions. We then briefly overview evidence that such exposures are inimical to health and well-being. We conclude with a discussion of the research and policy implications of environmental justice, arguing that a particularly salient feature of poverty for health consequences is exposure to multiple environmental risk factors.

Discrimination and the Political Economy of Environmental Inequality

Over the last decade there has been a surge in academic and scientific inquiry into disparities in environmental hazards among diverse communities. Much of the evidence points to a general pattern of disproportionate exposures to toxics among communities of color and the poor, with racial differences often persisting across economic strata. Although results have implications for the politics of environmental decisionmaking, most of these analyses are limited to illustrating how inequities in exposures and health risks are spread across the landscape, while shedding little light on their origins or the reasons for their persistence. Previous attempts to theorize the causes of environmental inequality have focused on procedural justice in the regulatory arena, emphasizing civil rights jurisprudence and social theories on individual and institutional discrimination. Although these approaches offer insights into the epistemology of environmental inequality, they fail adequately to account for the political economy of discrimination relating to industrial location behavior and racialized labor markets. By integrating relevant social and legal theories with a spatialized economic critique, this paper formulates a more supple theory of environmental discrimination. How the political economy of place shapes distributions of people and pollution and ultimately gives rise to environmental inequality are revealed by exploring the following factors: historical patterns of industrial development and racialized labor markets; suburbanization and segregation; and economic restructuring. This multidisciplinary approach to theorizing the dynamic of environmental discrimination provides a new framework for future policymaking and community organizing to address environmental and economic justice. Implications of this broader framework for policy and politics are discussed in the conclusion.

Determining the probability of pesticide exposures among migrant farmworkers: results from a feasibility study

BACKGROUND

Migrant and seasonal farmworkers are exposed to pesticides through their work with crops and livestock. Because workers are usually unaware of the pesticides applied, specific pesticide exposures cannot be determined by interviews. We conducted a study to determine the feasibility of identifying probable pesticide exposures based on work histories.

METHODS

The study included 162 farm workers in seven states. Interviewers obtained a lifetime work history including the crops, tasks, months, and locations worked. We investigated the availability of survey data on pesticide use for crops and livestock in the seven pilot states. Probabilities of use for pesticide types (herbicides, insecticides, fungicides, etc.) and specific chemicals were calculated from the available data for two farm workers. The work histories were chosen to illustrate how the quality of the pesticide use information varied across crops, states, and years.

RESULTS

For most vegetable and fruit crops there were regional pesticide use data in the late 1970s, no data in the 1980s, and state-specific data every other year in the 1990s. Annual use surveys for cotton and potatoes began in the late 1980s. For a few crops, including asparagus, broccoli, lettuce, strawberries, plums, and Christmas trees, there were no federal data or data from the seven states before the 1990s.

CONCLUSIONS

We conclude that identifying probable pesticide exposures is feasible in some locations. However, the lack of pesticide use data before the 1990s for many crops will limit the quality of historic exposure assessment for most workers.

Prenatal exposure to pesticides: a feasibility study among migrant and seasonal farmworkers

BACKGROUND

Migrant and seasonal farmworkers have a high potential for pesticide exposures, yet are rarely included in epidemiologic studies. This study examined the feasibility of assessing prenatal exposures to pesticides and other compounds in pregnant Hispanic farmworkers.

METHODS

Nine women completed a survey about work experiences during pregnancy. Maternal urine, cord blood, and placenta samples were obtained at delivery for analysis of 51 analytes, including 6 phenoxy acid or triazine herbicides, 21 organochlorine insecticides, 10 PCBs, and 14 volatile organic compounds.

RESULTS

Seven of 51 analytes were found in the biological samples. DDE, DDT, dichlorbenzene, toluene, trimethylbenzene, and endosulfan sulfate were detected in cord blood samples, and 2,4-D in urine from one or more women.

CONCLUSIONS

We documented the feasibility of following farmworkers to assess in utero exposure to pesticides and other contaminants, and demonstrated exposure to these compounds. Difficulties in measuring pesticides with short half lives were noted.

Development of a neurobehavioral battery for children exposed to neurotoxic chemicals

In recent years there has been heightened concern over the potential impact of environmental exposures on neurological function in children. Children are thought to be especially vulnerable to neurotoxic effects due to a number offactors including play behavior, differences in metabolism, and the development state of the brain. Performance tests from the computerized Behavioral Assessment and Research System (BARS) and other non-computerized tests have been combined to develop a brief battery that assesses multiple neurobehavioral functions in preschool children aged 4-6. Tests were selected to assess a variety of cognitive functions including attention, memory, motor speed and coordination and other executive functions. The battery has also been translated into Spanish and developed for use with Latino populations. Four to six-year-old children are particularly challenging because of the shorter attention span and lower motivation to complete an extended test session. When testing this group it is important to maintain the motivation of the child throughout the entire session in order to obtain accurate performance measures. A series of sequential pilot studies were used to select and develop appropriate methods and parameters for the tests in the battery. Although English-speaking children were able to complete the initial battery with minimal difficulties, several difficulties were encountered when the tests were administered to a Latino population. Cultural differences made some material inappropriate for testing due to unfamiliarity with the material, and in some cases items in a test had more than one correct translation which made administration difficult.

Olfaction and symptoms in the multiple chemical sensitivities syndrome

Whereas most idiosyncratic environmental sensitivity complaints do not fit known diagnoses, the multiple chemical sensitivities syndrome (MCS) is an extreme presentation that has defined diagnostic criteria. MCS symptomatics claim that they acquired a sensitized state as the result of a chemical exposure, usually to a solvent or pesticide, but not to a fragrance. Before this exposure, they did not experience symptoms. Following sensitization, symptoms increasing in number and severity with time are attributed by the MCS symptomatic to various exposures that are innocuous to most individuals. Although phenomenological studies have provided no evidence that particular odors elicit MCS symptoms, low levels of fragrances and perfumes are frequently associated with the reporting of MCS symptoms. This evaluation examines proposed mechanisms by which odorants and fragrances might cause either sensitization or elicitation of MCS symptoms, including altered odor sensitivity, primary irritancy or irritancy-induced upper airway reactivity, neurogenic switching of trigeminal irritancy signals, time-dependent sensitization and limbic kindling, CNS toxicity, and various psychiatric conditions. In no case was there persuasive evidence that any olfactory mechanism involving fragrance underlies either induction of a sensitized state or the triggering of MCS symptoms. Fragrances and other odorants could, however, be associated with symptoms as claimed by MCS symptomatics, because they are recognizable stimuli, but fragrance has not been demonstrated to be causal in the usual sense.

Cancer incidence in a cohort of licensed pesticide applicators in Florida

This study is a standardized incidence ratio (SIR) analysis of cancer incidence of licensed pesticide applicators in Florida, compared with that of Florida's general population. Through extensive data linkages, 33,658 applicators were assembled who had 1266 incident cancers and 279,397 person-years from January 1, 1975, to December 31, 1993. Disease risk from ethanol and tobacco use were significantly decreased. Among males, prostate cancer (SIR = 1.91; 95% confidence interval [CI], 1.72-2.13) and testicular cancer (SIR = 2.48; 95% CI, 1.57-3.72) were significantly elevated. No confirmed cases of soft tissue sarcoma (STS) were found, and the incidence of non-Hodgkin's lymphoma was not increased. There were few female applicators; nevertheless, cervical cancer incidence (SIR = 3.69; 95% CI, 1.84-6.61) was significantly increased, while the incidence of breast cancer was significantly decreased. Cancers that have been associated with estrogen disrupters were found in male, but not female, pesticide applicators. The lack of soft tissue sarcoma is at odds with prior literature associated with the use of phenoxy herbicides.

Biomarkers of exposure to organophosphorous insecticides among farmers' families in rural El Salvador: factors associated with exposure

Most studies of the health effects of pesticides have concentrated on occupational exposure. Little is known about community environmental exposure to agricultural pesticides. The purpose of this study was to investigate nonoccupational pesticide exposure among farmers' families in rural El Salvador, a country known for intensive use of extremely toxic compounds. The study population included all residents 8 years and older living in five agricultural communities in El Salvador. Current exposure to organophosphate insecticides (OPs) was established through analysis of urine samples for alkyl phosphate metabolites of OPs. Nearly half of 358 analyzed samples had detectable levels of OP metabolities. Of subjects not performing agricultural fieldwork, 30% nonetheless excreted detectable levels of metabolities. Similar rates held for children and adults. The best independent predictors for an individual's excretion of OP metabolites were (a) performing fieldwork during the past 2 weeks, (b) the head household farmer's application of OPs during the past 2 years, and (c) the household mother reporting use of OPs in the home or yard. The latter factors were significantly associated with metabolite excretion regardless of whether the individual had done fieldwork. The results of this study support the hypothesis that a large proportion of rural Salvadorans, including children, is exposed to pesticides through environmental as well as occupational routes.

Acute health effects associated with nonoccupational pesticide exposure in rural El Salvador

Little is known about the health effects of nonoccupational pesticide exposure in agricultural communities of poor countries. Therefore, this study investigated acute symptoms associated with nonoccupational exposure to organophosphate insecticides (OPs) in rural El Salvador, a region known for intensive pesticide use. In the five communities studied, 2-week prevalences of several acute symptoms were associated with living with a farmer who had recently applied methyl parathion. These included cramps in limbs (odds ratio 2.1, 95% confidence interval 1.2-3.7), chest pressure (OR 2.3, 95% CI 1.3-4.0), change in defecation (OR 2.3, 95% CI 1.3-4.1), feeling dazed (OR 2.4, 95% CI 1.3-4.4), and eyes tearing (OR 2.5, 95% CI 1. 4-4.5). Associations were found regardless of whether the individuals reporting the symptoms had themselves performed field labor. These results suggest that living in areas where pesticides are used on crops may represent an environmental health concern, especially for children.

Pesticide exposures and fetal death: a review of the epidemiologic literature

Despite considerable concern regarding the effects on reproductive outcome of exposures to pesticides, convincing evidence for the developmental toxicity of occupational and environmental pesticide exposure in humans is lacking. In this comprehensive review of the English language epidemiologic literature, we summarize studies that have examined potential associations between fetal deaths (both spontaneous abortions and stillbirths) and specific pesticides, as well as maternal and paternal employment in occupations with potential for exposure. While many of the epidemiologic studies to date suffer from methodologic problems, the data are suggestive of increased risks of fetal deaths associated with pesticides in general and maternal employment in the agricultural industry. There is a clear need for epidemiologic research that focuses on specific pesticide products or chemical families, with improved exposure assessment. The potential role of solvents in developmental toxicity associated with pesticide use by both males and females should also be considered.

Applied epidemiology and environmental health: emerging controversies

This review article assesses the state of the science in environmental epidemiology, not by summarizing current scientific findings but rather by examining conceptual controversies in the study of how environmental factors influence human health. This approach seems necessary because environmental epidemiology presently stands at a crossroads-in fact, at a number of overlapping crossroads. The field teems with epistemologic debates concerning appropriate paradigms for framing research questions, interpreting data, and applying research findings to policy. The present review focuses on emerging controversies related to three questions: What is considered "environmental"? What counts as credible research in environmental epidemiology? And what does "applied epidemiology" mean in the context of environmental health? The goal is to organize the presently fragmented critical literature on these issues and to promote productive dialogue by identifying central themes in current conceptual debates.

Educational and informational strategies to reduce pesticide risks. Council on Scientific Affairs

BACKGROUND

In 1993, the American Medical Association (AMA) requested its Council on Scientific Affairs to investigate issues and concerns related to (1) improving public notification of pesticide applications and (2) improving educational programs for commercial and farm pesticide applicators and increasing enforcement of licensing examination requirements. This report was presented at the 1994 Interim Meeting of the AMA House of Delegates as Report 4 of the Council on Scientific Affairs.

METHODS

Information for the report was derived from published literature and from personal communications with state and federal regulatory officials, physicians, and representatives of pest control, lawn care, and farm organizations. Some information about state certification and training programs was obtained from telephone conversations with pesticide applicator training program coordinators from California, Florida, Illinois, Iowa, Michigan, Missouri, Nebraska, New Jersey, New York, Texas, Washington, and Wisconsin. These states were selected because they contain large agricultural or urban populations that are likely to require the services of trained professional pesticide applicators.

RESULTS

Current surveillance systems are inadequate to characterize potential exposure problems related either to pesticide usage or to pesticide related illnesses. The effectiveness of applicator certification and training programs and public notification programs could not be determined because of a lack of federal and state survey data for making useful assessments.

CONCLUSIONS

Considering current data gaps, it is prudent for homeowners, farmers, and workers to limit pesticide exposures to themselves and others.

Agricultural and horticultural chemical poisonings: mortality and morbidity in the United States

STUDY OBJECTIVE

To provide a comprehensive analysis of morbidity and mortality from poisoning by agricultural and horticultural chemicals in the United States.

METHODS

Descriptive analysis of national mortality data, National Hospital Discharge Survey data, and American Association of Poison Control Centers national data for 1985 through 1990.

RESULTS

There were 341 fatalities from agricultural and horticultural chemicals over the 6-year period, of which 64% were suicides, 28% were unintentional, and 8% were of undetermined intent. There were 25,418 hospitalizations; 78% were reported to be unintentional. Both deaths and hospitalizations occurred more frequently in males, and rates were higher in nonwhites than in whites. There were 338,170 poison exposures reported to poison centers for fungicides, herbicides, pesticides/insecticides, and rodenticides. Life-threatening manifestations or long-term sequelae occurred in 782 cases, and 97 deaths were reported. Pesticides and insecticides accounted for 72% of the poison center cases and 63% of the fatalities. Although they accounted for only 8% of poison exposures, herbicide deaths were disproportionately high (25%).

CONCLUSION

Poisonings with agricultural and horticultural chemicals are an important public health problem. Prevention efforts need to incorporate the fact that many serious cases, such as paraquat poisonings, are suicidal in nature.