Distribution of pesticide residues within homes in central New York State

Airborne Pesticides-Deep Diving into Sampling and Analysis

The escalating utilization of pesticides has led to pronounced environmental contamination, posing a significant threat to agroecosystems. The extensive and persistent global application of these chemicals has been linked to a spectrum of acute and chronic human health concerns. This review paper focuses on the concentrations of airborne pesticides in both indoor and outdoor environments. The collection of diverse pesticide compounds from the atmosphere is examined, with a particular emphasis on active and passive air sampling techniques. Furthermore, a critical evaluation is conducted on the methodologies employed for the extraction and subsequent quantification of airborne pesticides. This analysis takes into consideration the complexities involved in ensuring accurate measurements, highlighting the advancements and limitations of current practices. By synthesizing these aspects, this review aims to foster a more comprehensive and informed comprehension of the intricate dynamics related to the presence and measurement of airborne pesticides. This, in turn, is poised to significantly contribute to the refinement of environmental monitoring strategies and the augmentation of precise risk assessments.

Maternal and Paternal Household Pesticide Exposure During Pregnancy and Risk of Childhood Acute Lymphoblastic Leukemia

OBJECTIVE

The aim of this study was to investigate whether risk estimates for childhood acute lymphoblastic leukemia change when restricting model comparison groups to "nonpesticide exposure" (NPE10) households.

METHODS

Cases ( n = 1810) 15 years or younger were identified through Children's Cancer Group institutions between 1989 and 1993 and age-/sex-matched to controls ( n = 1951). Household pesticide use during pregnancy/month prior was collected via telephone. NPE10 comparison group reporting no parental exposure to 10 pesticide classes was identified.

RESULTS

Adjusted odds ratios increased from 15% to 49% when limiting the comparison to NPE10. Maternal termite insecticide exposure was associated with greatest risk (adjusted odds ratio, 4.21; 95% confidence interval, 2.00-8.88). There was minimal evidence of interaction by child sex or occupational pesticide exposure, and no monotonic dose-response pattern with frequency of use (times per year).

CONCLUSIONS

Elevated risks are consistent with published pooled-/meta-analyses and DNA damage. The consistency and magnitude of these associations warrant product labeling, exposure reduction interventions, or both.

Iodine-Modified Ag NPs for Highly Sensitive SERS Detection of Deltamethrin Residues on Surfaces

It is essential to estimate the indoor pesticides/insecticides exposure risk since reports show that 80% of human exposure to pesticides occurs indoors. As one of the three major contamination sources, surface collected pesticides contributed significantly to this risk. Here, a highly sensitive liquid freestanding membrane (FSM) SERS method based on iodide modified silver nanoparticles (Ag NPs) was developed for quantitative detection of insecticide deltamethrin (DM) residues in solution phase samples and on surfaces with good accuracy and high sensitivity. The DM SERS spectrum from 500 to 2500 cm-1 resembled the normal Raman counterpart of solid DM. Similar bands at 563, 1000, 1165, 1207, 1735, and 2253 cm-1 were observed as in the literature. For the quantitative analysis, the strongest peak at 1000 cm-1 that was assigned to the stretching mode of the benzene ring and the deformation mode of C-C was selected. The peak intensity at 1000 cm-1 and the concentration of DM showed excellent linearity from 39 to 5000 ppb with a regression equation I = 649.428 + 1.327 C (correlation coefficient R2 = 0.991). The limit of detection (LOD) of the DM was found to be as low as 11 ppb. Statistical comparison between the proposed and the HPLC methods for the analysis of insecticide deltamethrin (DM) residues in solution phase samples showed no significant difference. DM residue analysis on the surface was mimicked by dropping DM pesticide on the glass surface. It is found that DM exhibited high residue levels up to one week after exposure. This proposed SERS method could find application in the household pesticide residues analysis.

Contributions of nearby agricultural insecticide applications to indoor residential exposures

BACKGROUND

Pesticide exposure has been associated with adverse health effects. We evaluated relationships between proximity to agricultural insecticide applications and insecticides in household dust, accounting for land use and wind direction.

METHODS

We measured concentrations (ng/g) of nine insecticides in carpet-dust samples collected from 598 California homes. Using a geographic information system (GIS), we integrated the California Pesticide Use Reporting (CPUR) database to estimate agricultural use within residential buffers with radii of 0.5 to 4 km. We calculated the density of use (kg/km2) during 30-, 60-, 180-, and 365-day periods prior to dust collection and evaluated relationships between three density metrics (CPUR unit-based, agricultural land area adjusted, and average daily wind direction adjusted) and dust concentrations. We modeled natural-log transformed concentrations using Tobit regression for carbaryl, chlorpyrifos, cypermethrin, diazinon, and permethrin. Odds of detection were modeled with logistic regression for azinphos-methyl, cyfluthrin, malathion, and phosmet. We adjusted for season, year, occupation, and home/garden uses.

RESULTS

Chlorpyrifos use within 1-4 km was associated with 1 to 2-times higher dust concentrations in both the 60- and 365-day periods. Carbaryl applications within 2-4 km of homes 60-days prior to dust collection were associated with 3 to 7-times higher concentrations and the 4 km trend was strongest using the wind-adjusted metric (p-trend = 0.04). For diazinon, there were 2-times higher concentrations for the 60-day metrics in the 2 km buffer and for the CPUR and wind-adjusted metrics within 4 km. Cyfluthrin, phosmet, and azinphos-methyl applications within 4 km in the prior 365-days were associated with 2-, 6-, and 3-fold higher odds of detection, respectively.

CONCLUSIONS

Agricultural use of six of the nine insecticides within 4 km is an important determinant of indoor contamination. Our findings demonstrated that GIS-based metrics for quantifying potential exposure to fugitive emissions from agriculture should incorporate tailored distances and time periods and support wind-adjustment for some, but not all insecticides.

Pesticides in doormat and floor dust from homes close to treated fields: Spatio-temporal variance and determinants of occurrence and concentrations

Indoor dust has been postulated as an important matrix for residential pesticide exposure. However, there is a lack of information on presence, concentrations and determinants of multiple pesticides in dust in residential homes close to treated fields. Our objective was to characterize the spatial and temporal variance of pesticides in house dust, study the use of doormats and floors as proxies for pesticides in indoor dust and identify determinants of occurrence and concentrations. Homes within 250 m from selected bulb fields were invited to participate. Homes within 20 km from these fields but not having agricultural fields within 500 m were selected as controls. House dust was vacuumed in all homes from floors (VFD) and from newly placed clean doormats (DDM). Sampling was done during two periods, when pesticides are used and not-used. For determination of 46 prioritized pesticides, a multi-residue extraction method was used. Most statistical analyses are focused on the 12 and 14 pesticides that were detected in >40% of DDM and VFD samples, respectively. Mixed models were used to evaluate relationships between possible determinants and pesticides occurrence and concentrations in DDM and VFD. 17 pesticides were detected in more than 50% of the homes in both matrixes. Concentrations differed by about a factor five between use and non-use periods among homes within 250 m of fields and between these homes and controls. For 7 pesticides there was a moderate to strong correlation (Spearman rho 0.30-0.75) between concentrations in DDM and VFD. Distance to agricultural fields and air concentrations were among the most relevant predictors for occurrence and levels of a given pesticide in DDM. Concentrations in dust are overall higher during application periods and closer to fields (<250 m) than further away. The omnipresence of pesticides in dust lead to residents being exposed all year round.

Cytogenetic markers and their spatial distribution in a population living in proximity to areas sprayed with pesticides

Human populations are in contact with potentially toxic substances in varying amounts, if the exposure is work-related or direct, generally the amount of toxin is usually greater than if the exposure is environmental through the drifts that occur. It was proposed to determine the existence of genotoxic damage evaluated through Chromosomal Aberrations and Micronuclei assays and their spatial distribution pattern, as well as the possible relationship between that damage and the values found in biochemical biomarkers, in groups of individuals environmental exposure (respiratory exposure) to mixtures of pesticides, in the province of Córdoba-Argentina. Biochemical and hematological determinations were made in each samples. The results reveal that the monitoring of human populations through the analysis of cytogenetic markers enabled the detection of direct damage in man caused by polluting substances and the results were obtained rapidly. The disadvantage of this type of study is the inability to estimate the degree of exposure.

A randomized, controlled field study to assess the efficacy and safety of lotilaner flavored chewable tablets (Credelio™ CAT) in eliminating fleas in client-owned cats in the USA

BACKGROUND

Studies show that the novel isoxazoline, lotilaner (Credelio™ CAT; Elanco Animal Health), which is administered orally to cats, provides rapid and sustained flea kill for least 1 month following administration with a wide safety margin. A clinical trial was undertaken to confirm its efficacy, impact on flea allergy dermatitis (FAD) and safety under field conditions.

METHODS

A total of 343 cats were enrolled in the study at 11 veterinary clinics in the USA. Upon inclusion, cat households were randomized at a ratio of 2:1 to receive lotilaner tablets at the recommended dose (minimum 6 mg/kg) or a topical formulation containing fipronil + S-methoprene (Frontline® Plus for cats; Boehringer Ingelheim), administered per label. Owners were dispensed treatments for administration on days 0, 30 and 60; all household cats were administered the same treatment. Flea counts were made on primary cats (1 cat per household) on days 0 (pre-treatment), 30, 60 and 90. Flea allergy dermatitis was assessed on days 30, 60 and 90 for all cats with signs of FAD on day 0. Lotilaner-treated cats were also assessed for their acceptance of oral tablet administration by the pet owner, and safety was assessed for all cats in both groups.

RESULTS

Lotilaner efficacy was 98.3, 99.9 and 99.9% on days 30, 60 and 90, respectively, while the efficacy of fipronil + S-methoprene was 61.6, 75.4 and 84.7%, respectively (P < 0.0001, within both groups and all days). Flea counts were significantly lower in the lotilaner group than in the fipronil + S-methoprene group (P < 0.0001) on each assessment day. On day 90, 98.3% of lotilaner-treated cats and 28.8% of fipronil + S-methoprene-treated cats were free of fleas. Owners successfully administered 99.5% of tablets to their cats. Total FAD score was reduced significantly following treatment in both groups by day 30 (lotilaner: P < 0.0001; fipronil + S-methoprene: P = 0.0041) and continued to decrease following multiple treatments. Total FAD scores were also significantly lower in the lotilaner group than in the fipronil + S-methoprene group on day 90 (P = 0.0006 for FAD total score). Pruritus scores were significantly lower in the lotilaner group on all assessment days.

CONCLUSION

A single lotilaner treatment, administered by the pet owner, was > 98% efficacious in reducing flea counts within 30 days. Three consecutive monthly lotilaner treatments resulted in nearly 100% reduction in flea infestation. In the evaluations of flea counts, number of cats free from fleas and pruritus FAD score, lotilaner was shown to be superior to fipronil + S-methoprene at all time points. Lotilaner was more efficacious than fipronil + S-methoprene and was associated with greater reduction in FAD signs. Lotilaner flavored tablets were well accepted by cats. Adverse reactions were mild and infrequent, confirming the safety of lotilaner tablets in client-owned cats.

Passive monitoring techniques to evaluate environmental pesticide exposure: Results from the Infant's Environmental Health study (ISA)

BACKGROUND

Pesticides used in agriculture may expose populations living nearby. Costa Rica is a major banana-exporting country, its production depends on extensive pesticide use.

OBJECTIVES

To evaluate environmental pesticide exposure, we measured levels of current-use pesticides in air and dust from 12 schools in Matina County, Costa Rica, with passive sampling methods.

METHODS

We selected ten proximal and two non-proximal schools and placed polyurethane foam passive air samplers outdoors at each school, during four consecutive periods. At three of these schools, we also placed an active air sampler during the first 24 h of each sampling period. We collected passive dust samples by placing a glass Petri Dish at the inside of each school. We subsequently performed a chemical analysis of 18 pesticides, using gas chromatography with mass detector.

RESULTS

With passive air samplers we detected ten different pesticides: two insecticides, two nematicides, and six fungicides, of which nine reported to be used on banana plantations. More than half of the samples contained at least five pesticides. Chlorpyrifos was detected most-frequently, in 98% of samples, followed by the nematicides etoprophos and the fungicide pyrimethanil that were both detected in 81% of samples. Chlorpyrifos concentrations were five times higher in proximal as compared to non-proximal schools: mean = 18.2 ng/m3 (range = 6.1-36.1) and mean = 3.5 ng/m3 (range= <0.5-11.4) and varied more between schools than in time (intra-class correlation coefficient = 0.80). In general, results from passive and active samplers showed similar exposure patterns; yet median concentrations tended to be higher in passive samplers. In dust samples, mostly fungicides were detected; chlorothalonil was detected most frequently, in 50% of samples.

DISCUSSION

Passive air sampling is a promising technique to characterize environmental exposure to current-use pesticides; more studies are needed to characterize the sampling rates, reproducibility and optimum sampling times for passive samplers. School environments near banana plantations are contaminated with multiple pesticides that include insecticides, nematicides, and fungicides, which is of concern.

Electronics, interior decoration and cleaning patterns affect flame retardant levels in the dust from Dutch residences

Consumer products such as furniture foam and electronic device casings are treated with flame retardant chemicals (FRs) to prevent the spread of fire. Many FRs are able to leach out of a product and end up in house dust. FRs in house dust can be taken up by humans through inhalation, ingestion or dermal adsorption. This study aims to identify factors in the home environment that are associated with FR levels in house dust. House dust and a wide range of data on characteristics of electronics, including age and use, interior decoration, domestic house and cleaning patterns, were collected from 50 households in the Netherlands. Decabromodiphenyl ether (BDE209) and several organophosphate flame retardants were measured in dust at detection percentages ranging from 58 to 94%, with median concentrations ranging from 32 ng/g (resorcinol-bis(diphenyl)phosphate (PBDPP)) to 825 ng/g (tris(chloropropyl)phosphate (TCIPP)). For the first time, age, hours of operation and use of the standby function of electronic devices were found to affect FR levels in dust. We found that if the total number of electronic devices purchased before 2008 increased by 1 device, BDE209 levels in house dust significantly increased by 66%. In addition, house dust from homes with carpeted floors was significantly associated with a 70-80% lower concentration of several FRs compared to homes with smooth floors (e.g., laminate). Less frequent vacuum cleaning and dusting were significantly associated with 41 to 88% higher concentrations of several FRs in dust. These associations suggest that actions such as frequent vacuum cleaning and dusting as well as different FR regulations for electronic devices affect indoor exposure levels.

Pesticides in indoor and outdoor residential dust: a pilot study in a rural county of Taiwan

We conducted a pilot study to examine pesticides in dust of homes in a rural county of Taiwan. A total of 56 homes of pregnant women were included in the study. Indoor and outdoor dust was collected by a vacuum sampler and a dustpan/brush set, respectively. Nine pesticides were selected for analysis on gas chromatography-mass spectrometry with the detection limits being 0.088 ng/g or lower. The most detected pesticides were cypermethrin and chlorpyrifos, which appeared in 82.7 and 78.8% of indoor samples and 48.2 and 39.3% of outdoor samples, respectively. The detection of pesticides from indoor and outdoor dust, however, was not consistent, indicating different sources of pesticides. In addition to those two most detected, permethrin, prallethrin, and tetramethrin, which were common ingredients of insecticide products for indoor use, were also frequently found in indoor dust, suggesting that indoor use of such pesticide products may have been a major source. Fewer pesticides were found in outdoor dust, but the outdoor detection of chlorpyrifos was significantly associated with farms present inside the circles with radii of 50 and 100 m surrounding the homes (P = 0.021, 0.016). It is suggested that pesticide drift from agricultural areas to residential environments may have occurred. No seasonal effect on distribution of pesticides in dust was found, indicating that pesticides could be routinely used in Taiwan regardless of season. Compared with other international studies, this study shows relatively high levels of chlorpyrifos but low levels of pyrethroids (i.e., cypermethrin), reflecting a different pattern of pesticide use in Taiwan. Further studies need to be warranted for a better understanding of exposure to pesticides and the associated health effects.

Pyrethroid pesticide residues in the global environment: An overview

Pyrethroids are synthetic organic insecticides with low mammalian toxicity that are widely used in both rural and urban areas worldwide. After entering the natural environment, pyrethroids circulate among the three phases of solid, liquid, and gas and enter organisms through food chains, resulting in substantial health risks. This review summarized the available studies on pyrethroid residues since 1986 in different media at the global scale and indicated that pyrethroids have been widely detected in a range of environments (including soils, water, sediments, and indoors) and in organisms. The concentrations and detection rates of agricultural pyrethroids, which always contain α-cyanogroup (α-CN), such as cypermethrin and fenvalerate, decline in the order of crops > sediments > soils > water. Urban pyrethroids (not contain α-CN), such as permethrin, have been detected at high levels in the indoor environment, and 3-phenoxybenzoic acid, a common pyrethroid metabolite in human urine, is frequently detected in the human body. Pyrethroid pesticides accumulate in sediments, which are a source of pyrethroid residues in aquatic products.

A randomized, controlled field study to assess the efficacy and safety of lotilaner flavored chewable tablets (Credelio™) in eliminating fleas in client-owned dogs in the USA

BACKGROUND

Preclinical studies have shown that the novel isoxazoline, lotilaner (Credelio™, Elanco) administered orally to dogs, produces rapid flea and tick knockdown and sustained speed of kill for at least a month post-treatment with a wide safety margin. A field study was undertaken to validate pre-clinical results.

METHODS

Dogs were enrolled at 10 veterinary clinics across the United States. Qualifying households containing up to three dogs and one primary dog with at least 10 fleas were randomized 2:1 to receive lotilaner (Credelio™, Elanco) at the recommended minimum dose of 20 mg/kg, or afoxolaner (Nexgard®, Merial), administered per label, to give a minimum dose of 2.5 mg/kg. Treatments were dispensed on Days 0, 30 and 60 for administration by owners; all household dogs received the same treatment as the primary dog. Post-enrollment flea and tick counts were made on primary dogs on Days 30, 60 and 90, and all dogs were assessed for tablet palatability and safety.

RESULTS

For efficacy assessments, data were used from 111 lotilaner-treated dogs and 50 afoxolaner-treated dogs; for safety, 197 and 86 dogs, respectively. Percent reductions from baseline in geometric mean flea counts for the lotilaner group were 99.3, 99.9 and 100% on Days 30, 60 and 90, respectively, and for afoxolaner 98.3, 99.8 and 99.8% (P < 0.001, both groups, all days). On Day 90, 100% of lotilaner-treated dogs and 93% of afoxolaner-treated dogs were flea-free. Too few ticks were present to allow assessment. There were no differences in palatability between products (P = 0.2132), with, respectively, 94% and 96% of lotilaner and afoxolaner treatments accepted when offered by hand, in an empty food bowl or with food. Both treatments were well tolerated, alleviating clinical signs of flea allergy dermatitis (FAD) in dogs affected at enrollment.

CONCLUSION

A single owner-administered lotilaner treatment was greater than 99% effective in reducing mean flea counts within 30 days. Three consecutive monthly lotilaner treatments resulted in a 100% reduction in flea infestations, and a substantial reduction in signs of FAD. Lotilaner flavored tablets were readily accepted under field conditions. The absence of treatment-related adverse events confirms the safety of lotilaner in dogs.

Laboratory evaluations of the immediate and sustained efficacy of lotilaner (Credelio™) against four common species of ticks affecting dogs in North America

BACKGROUND

Effective control of tick infestations on dogs is important to reduce the risk of transmission of bacterial, viral, and protozoal pathogens. Laboratory studies were initiated to determine the efficacy of lotilaner against common ticks infesting dogs in the United States.

METHODS

Eight studies investigated the efficacy of lotilaner against ticks. In two studies dogs were infested with both Dermacentor variabilis and Rhipicephalus sanguineus: one additional study was completed for each of these species. Two studies assessed infestations with Amblyomma americanum and two with Ixodes scapularis. In all studies, dogs were ranked and blocked by counts from pre-treatment infestations and randomly allocated, at least eight per group, to be treated orally with lotilaner (minimum dose rate 20 mg/kg), or to be untreated controls. Treatments were administered on Day 0, within 30 min after dogs were fed. In all studies, infestations were performed with 50 adult ticks on Days -2, 7, 14, 21 and 28, and also on Day 35 for R. sanguineus, D. variabilis and I. scapularis. Tick counts were completed 48 h after treatment or after each subsequent challenge. An adequate infestation was defined as at least 25% of the infestation dose recovered from each of at least six control animals at each evaluation. Efficacy calculations for the primary objective were based on geometric means.

RESULTS

In all studies, lotilaner was 100% effective against existing infestations. For post-treatment assessments, on only two occasions did efficacy fall below 99%: in one D. variabilis study efficacy was 98.0% on Day 35 and in one I. scapularis study efficacy on Day 16 was 98.4%. Only mild and transient adverse events were observed, and none were considered to be related to treatment.

CONCLUSION

Lotilaner was completely effective against existing infestations with four common species of ticks, D. variabilis, R. sanguineus, A. americanum and I. scapularis, that affect dogs in North America, with at least 4 weeks efficacy of 98.0% or more against subsequent challenge infestations. These results show that lotilaner is a highly effective isoxazoline that offers sustained efficacy against ticks through and beyond the one-month end-of-dose treatment interval.

Reducing chemical exposures at home: opportunities for action

Indoor environments can influence human environmental chemical exposures and, ultimately, public health. Furniture, electronics, personal care and cleaning products, floor coverings and other consumer products contain chemicals that can end up in the indoor air and settled dust. Consumer product chemicals such as phthalates, phenols, flame retardants and per- and polyfluorinated alkyl substances are widely detected in the US general population, including vulnerable populations, and are associated with adverse health effects such as reproductive and endocrine toxicity. We discuss the implications of our recent meta-analysis describing the patterns of chemical exposures and the ubiquity of multiple chemicals in indoor environments. To reduce the likelihood of exposures to these toxic chemicals, we then discuss approaches for exposure mitigation: targeting individual behaviour change, household maintenance and purchasing decisions, consumer advocacy and corporate responsibility in consumer markets, and regulatory action via state/federal policies. There is a need to further develop evidence-based strategies for chemical exposure reduction in each of these areas, given the multi-factorial nature of the problem. Further identifying those at greatest risk; understanding the individual, household and community factors that influence indoor chemical exposures; and developing options for mitigation may substantially improve individuals' exposures and health.

Adaptive response of rat pancreatic β-cells to insulin resistance induced by monocrotophos: Biochemical evidence

Our previous findings clearly suggested the role of duration of exposure to monocrotophos (MCP) in the development of insulin resistance. Rats exposed chronically to MCP developed insulin resistance with hyperinsulinemia without overt diabetes. In continuation of this vital observation, we sought to delineate the biochemical mechanisms that mediate heightened pancreatic β-cell response in the wake of MCP-induced insulin resistance in rats. Adult rats were orally administered (0.9 and 1.8mg/kgb.w/d) MCP for 180days. Terminally, MCP-treated rats exhibited glucose intolerance, hyperinsulinemia, and potentiation of glucose-induced insulin secretion along with elevated levels of circulating IGF1, free fatty acids, corticosterone, and paraoxonase activity. Biochemical analysis of islet extracts revealed increased levels of insulin, malate, pyruvate and ATP with a concomitant increase in activities of cytosolic and mitochondrial enzymes that are known to facilitate insulin secretion and enhanced shuttle activities. Interestingly, islets from MCP-treated rats exhibited increased insulin secretory potential ex vivo compared to those isolated from control rats. Further, MCP-induced islet hypertrophy was associated with increased insulin-positive cells. Our study demonstrates the impact of the biological interaction between MCP and components of metabolic homeostasis on pancreatic beta cell function/s. We speculate that the heightened pancreatic beta cell function evidenced may be mediated by increased IGF1 and paraoxonase activity, which effectively counters insulin resistance induced by chronic exposure to MCP. Our findings emphasize the need for focused research to understand the confounding environmental risk factors which may modulate heightened beta cell functions in the case of organophosphorus insecticide-induced insulin resistance. Such an approach may help us to explain the sharp increase in the prevalence of type II diabetes worldwide.

Efficiency of wipe sampling on hard surfaces for pesticides and PCB residues in dust

Pesticides and polychlorinated biphenyls (PCBs) are commonly found in house dust and have been described as a valuable matrix to assess indoor pesticide and PCB contamination. The aim of this study was to assess the efficiency and precision of cellulose wipe for collecting 48 pesticides, eight PCBs, and one synergist at environmental concentrations. First, the efficiency and repeatability of wipe collection were determined for pesticide and PCB residues that were directly spiked onto three types of household floors (tile, laminate, and hardwood). Second, synthetic dust was used to assess the capacity of the wipe to collect dust. Third, we assessed the efficiency and repeatability of wipe collection of pesticides and PCB residues that was spiked onto synthetic dust and then applied to tile. In the first experiment, the overall collection efficiency was highest on tile (38%) and laminate (40%) compared to hardwood (34%), p<0.001. The second experiment confirmed that cellulose wipes can efficiently collect dust (82% collection efficiency). The third experiment showed that the overall collection efficiency was higher in the presence of dust (72% vs. 38% without dust, p<0.001). Furthermore, the mean repeatability also improved when compounds were spiked onto dust (<30% for the majority of compounds). To our knowledge, this is the first study to assess the efficiency of wipes as a sampling method using a large number of compounds at environmental concentrations and synthetic dust. Cellulose wipes appear to be efficient to sample the pesticides and PCBs that adsorb onto dust on smooth and hard surfaces.

Household organophosphorus pesticide use and Parkinson's disease

BACKGROUND

Household pesticide use is widespread in the USA. Since the 1970s, organophosphorus chemicals (OPs) have been common active ingredients in these products. Parkinson's disease (PD) has been linked to pesticide exposures but little is known about the contributions of chronic exposures to household pesticides. Here we investigate whether long-term use of household pesticides, especially those containing OPs, increases the odds of PD.

METHODS

In a population-based case-control study, we assessed frequency of household pesticide use for 357 cases and 807 controls, relying on the California Department of Pesticide Regulation product label database to identify ingredients in reported household pesticide products and the Pesticide Action Network pesticide database of chemical ingredients. Using logistic regression we estimated the effects of household pesticide use.

RESULTS

Frequent use of any household pesticide increased the odds of PD by 47% [odds ratio (OR)=1.47, (95% confidence interval (CI): 1.13, 1.92)]; frequent use of products containing OPs increased the odds of PD more strongly by 71% [OR=1.71, (95% CI: 1.21, 2.41)] and frequent organothiophosphate use almost doubled the odds of PD. Sensitivity analyses showed that estimated effects were independent of other pesticide exposures (ambient and occupational) and the largest odds ratios were estimated for frequent OP users who were carriers of the 192QQ paraoxonase genetic variant related to slower detoxification of OPs.

CONCLUSIONS

We provide evidence that household use of OP pesticides is associated with an increased risk of developing PD.

Indoor environment and children's health: recent developments in chemical, biological, physical and social aspects

Much research is being carried out into indoor exposure to harmful agents. This review focused on the impact on children's health, taking a broad approach to the indoor environment and including chemical, microbial, physical and social aspects. Papers published from 2006 onwards were reviewed, with regards to scientific context. Most of publications dealt with chemical exposure. Apart from the ongoing issue of combustion by-products, most of these papers concerned semi volatile organic compounds (such as phthalates). These may be associated with neurotoxic, reprotoxic or respiratory effects and may, therefore, be of particular interest so far as children are concerned. In a lesser extent, volatile organic compounds (such as aldehydes) that have mainly respiratory effects are still studied. Assessing exposure to metals is still of concern, with increasing interest in bioaccessibility. Most of the papers on microbial exposure focused on respiratory tract infections, especially asthma linked to allergens and bio-aerosols. Physical exposure includes noise and electromagnetic fields, and articles dealt with the auditory and non auditory effects of noise. Articles on radiofrequency electromagnetic fields mainly concerned questions about non-thermal effects and papers on extremely low-frequency magnetic fields focused on the characterization of exposure. The impact of the indoor environment on children's health cannot be assessed merely by considering the effect of these different types of exposure: this review highlights new findings and also discusses the interactions between agents in indoor environments and also with social aspects.

Organic contamination of settled house dust, a review for exposure assessment purposes

People spend a considerable amount of time indoors. As a result, exposure to indoor contaminants is of great concern, notably via settled dust ingestion in particular for infants and toddlers. This paper proposes a critical review on the organic contamination of settled house dust and human exposure over the past 10 years and focused on sources, contaminations and measurement methods (sampling, pretreatment, storage and analysis). As many compounds were identified, arises the question of which ones to consider. Sensitive and selective analytical methods for simultaneous determination of targeted substances should be developed and evaluated. Various methods were described for sampling and sample preparation. Harmonization and standardization are needed to enable comparison of results from similar studies. Finally, an integrated multipollutant and multicompartment (settled dust, suspended particles and air) approach appears essential in order to determine the extent of the threat to public health posed by indoor contaminants.

Determinants of agricultural pesticide concentrations in carpet dust

BACKGROUND

Residential proximity to agricultural pesticide applications has been used as a surrogate for exposure in epidemiologic studies, although little is known about the relationship with levels of pesticides in homes.

OBJECTIVE

We identified determinants of concentrations of agricultural pesticides in dust.

METHODS

We collected samples of carpet dust and mapped crops within 1,250 m of 89 residences in California. We measured concentrations of seven pesticides used extensively in agriculture (carbaryl, chlorpyrifos, chlorthal-dimethyl, diazinon, iprodione, phosmet, and simazine). We estimated use of agricultural pesticides near residences from a statewide database alone and by linking the database with crop maps. We calculated the density of pesticide use within 500 and 1,250 m of residences for 180, 365, and 730 days before collection of dust and evaluated relationships between agricultural pesticide use estimates and pesticide concentrations in carpet dust.

RESULTS

For five of the seven pesticides evaluated, residences with use of agricultural pesticides within 1,250 m during the previous 365 days had significantly higher concentrations of pesticides than did residences with no nearby use. The highest correlation with concentrations of pesticides was generally for use reported within 1,250 m of the residence and 730 days before sample collection. Regression models that also accounted for occupational and home use of pesticides explained only a modest amount of the variability in pesticide concentrations (4-28%).

CONCLUSIONS

Agricultural pesticide use near residences was a significant determinant of concentrations of pesticides in carpet dust for five of seven pesticides evaluated.

Where's the dust? Characterizing locations of azinphos-methyl residues in house and vehicle dust among farmworkers with young children

Organophosphate pesticides are commonly used in the United States, and farmworkers are at risk for chronic exposure. Using data from a community randomized trial to interrupt the take-home pathway of pesticide exposure, we examined the association between floor surface type (smooth floor, thin carpet, and thick carpet) and rooms in which dust samples were collected (living room vs. non-living room) and concentrations of azinphos-methyl residues in home environments. We also examined the association between vehicle type (truck, auto, or other) and footwell floor surfaces (carpeted, smooth surface, or no mat) and concentrations of azinphos-methyl in vehicle dust samples. Dust samples were collected from 203 and 179 households and vehicles, respectively. All households had at least one child aged 2-6. Vehicle dust samples were collected from footwells of the vehicle used for commuting to and from work. A total of 183 samples were collected from living rooms, and 20 were collected from other rooms in the home. Forty-two samples were collected from thick carpets, 130 from thin carpets, and 27 from smooth floor surfaces. Thick and thin carpets had a significantly greater dust mass than smooth floor surfaces (6.0 g/m(2) for thick carpets, 7.8 g/m(2) for thin carpets, and 1.5 g/m(2) for smooth surfaces). Of the 179 vehicle samples, 113 were from cars, 34 from trucks, and 32 from other vehicles. Vehicles with no mats had a significantly higher mass of dust (21.3 g) than those with hard mats (9.3 g) but did not differ from vehicles with plush mats (12.0 g). Further research is needed to characterize the environment in which children may be exposed to pesticides.

Residential proximity to agricultural pesticide applications and childhood acute lymphoblastic leukemia

Ambient exposure from residential proximity to applications of agricultural pesticides may contribute to the risk of childhood acute lymphoblastic leukemia (ALL). Using residential histories collected from the families of 213 ALL cases and 268 matched controls enrolled in the Northern California Childhood Leukemia Study, the authors assessed residential proximity within a half-mile (804.5m) of pesticide applications by linking address histories with reports of agricultural pesticide use. Proximity was ascertained during different time windows of exposure, including the first year of life and the child's lifetime through the date of diagnosis for cases or reference for controls. Agricultural pesticides were categorized a priori into groups based on similarities in toxicological effects, physicochemical properties, and target pests or uses. The effects of moderate and high exposure for each group of pesticides were estimated using conditional logistic regression. Elevated ALL risk was associated with lifetime moderate exposure, but not high exposure, to certain physicochemical categories of pesticides, including organophosphates, chlorinated phenols, and triazines, and with pesticides classified as insecticides or fumigants. A similar pattern was also observed for several toxicological groups of pesticides. These findings suggest future directions for the identification of specific pesticides that may play a role in the etiology of childhood leukemia.

American Healthy Homes Survey: a national study of residential pesticides measured from floor wipes

The U.S. Department of Housing and Urban Development in collaboration with the United States Environmental Protection Agency conducted a survey measuring lead, allergens, and insecticides in a randomly selected nationally representative sample of residential homes. Multistage sampling with clustering was used to select the 1131 homes of which a subset of 500 randomly selected homes included the collection of hard surface floor wipes. Samples were collected by trained field technicians between June 2005 and March 2006 using isopropanol wetted wipes. Samples were analyzed for a suite of 24 compounds which included insecticides in the organochlorine, organophosphate, pyrethroid and phenylpyrazole classes, and the insecticide synergist piperonyl butoxide. The most commonly detected were permethrin (89%), chlorpyrifos (78%), chlordane (64%), piperonyl butoxide (52%), cypermethrin (46%), and fipronil (40%). Mean and geometric mean (GM) concentrations varied widely among compounds, but were highest for trans-permethrin (mean 2.22 ng/cm2 and GM 0.14 ng/ cm2) and cypermethrin (mean 2.9 ng/cm2 and GM 0.03 ng/ cm2). Results show that most floors in occupied homes in the U.S. have measurable levels of insecticides that may serve as sources of exposure to occupants.

Evaluation of physiological measures for correcting variation in urinary output: Implications for assessing environmental chemical exposure in children

Urinary contaminant concentrations are commonly adjusted by creatinine to account for the variability in urinary output. This approach may not be optimal among children due to developmental growth of muscle mass and the associated increase in creatinine formation. An alternative approach is to measure the specific gravity of the urine sample, which reflects the solute concentration of the urine. We compare the appropriateness of urinary creatinine and urinary-specific gravity as factors for correcting morning and evening spot urine samples collected from 23 children (3-11 years) for a total of 41 days in four different seasons. Two linear mixed-effects models were fit using age, sex, season, and sample collection time (morning/evening) as predictors with specific gravity and creatinine as dependent variables. Specific gravity was significantly associated with the sample collection time (P<0.001) with morning samples higher than evening samples. Creatinine was significantly associated with season (P<0.05), sample collection time (P<0.0001), and age (P<0.0001). Creatinine levels were higher during the summer compared to the other seasons, higher in the morning compared to the evening, and higher with increases in children's age. Normalizing the children's spot urine samples using creatinine would introduce bias to the data analysis. Whereas using specific gravity to correct for variable urinary output would be more robust. In addition, measuring specific gravity is relatively easy, does not require the use of chemicals, and the results are available instantaneously.

Determination of organophosphorus insecticides (malathion and diazinon) residue in the drinking water

In this study, the amount and origin of the pollution of Karaj river and Amir-Kabir dam, which is the most important supply of Tehrans (capital of Iran) drinking water with malathion and diazinon, have been assessed by High Performance Thin Layer Chromatography (HPTLC) technique. This is a descriptive and cross-sectional study. After initial assessments, four stations were selected for water sampling. In all stations, sampling was done in one day, one week, two weeks, one month, two months and three months after insecticide spraying. Extraction and separating of organophosphorus insecticides from water samples was done by acetone and methylen chloride solvents, using decanter. Then, the residue of malathion and diazinon insecticides was determined using HPTLC technique. The residue of malathion and diazinon in water decreases with increasing the distance and time of spraying. The residues of malathion and diazinon insecticides at station 1 and 2, which were close to spraying places, 1-2 months after spraying was more than allowed limits. But at the ending stations (3 and 4), malathion and diazinon were detectable just in the 1 day and 1 month after spraying, respectively. It is unlikely that Tehran's drinking water be polluted with these two insecticides and the most adverse effect can be seen in the area of spraying. Therefore not only the environment, but also the people in area of Karaj river are at risk of chronic toxicity with malathion and diazinon through consuming polluted water and agriculture products.

Soil-skin adherence from carpet: use of a mechanical chamber to control contact parameters

A computer-controlled mechanical chamber was used to control the contact between carpet samples laden with soil, and human cadaver skin and cotton sheet samples for the measurement of mass soil transfer. Mass soil transfers were converted to adherence factors (mg/cm2) for use in models that estimate dermal exposure to contaminants found in soil media. The contact parameters of pressure (10 to 50 kPa) and time (10 to 50 sec) were varied for 369 experiments of mass soil transfer, where two soil types (play sand and lawn soil) and two soil sizes (< 139.7 microm and > or = 139.7 < 381) were used. Chamber probes were used to record temperature and humidity. Log transformation of the sand/soil transfers was performed to normalize the distribution. Estimated adjusted means for experimental conditions were exponentiated in order to express them in the original units. Mean soil mass transfer to cadaver skin (0.74 mg/cm2) was higher than to cotton sheets (0.21 mg/cm2). Higher pressure (p < 0.0001), and larger particle size (p < 0.0001) were also all associated with larger amounts of soil transfer. The original model was simplified into two by adherence material type (i.e., cadaver skin and cotton sheets) in order to investigate the differential effects of pressure, time, soil size, and soil type on transfer. This research can be used to improve estimates of dermal exposure to contaminants found in home carpets.

Residential exposures to pesticides and childhood leukaemia

Like many chemicals, carcinogenicity of pesticides is poorly characterised in humans, especially in children, so that the present knowledge about childhood leukaemia risk derives primarily from epidemiological studies. Overall, case-control studies published in the last decade have reported positive associations with home use of insecticides, mostly before the child's birth, while findings for herbicides are mixed. Previous studies relied solely on self-reports, therefore lacking information on active ingredients and effects of potential recall bias. Few series to date have examined the influence of children's genetic susceptibility related to transport and metabolism of pesticides. To overcome these limitations, investigators of the Northern California Childhood Leukaemia Study (NCCLS) have undertaken, in collaboration with a multidisciplinary team, a comprehensive assessment of residential pesticide exposure, including: (1) quality control of self-reports; (2) home pesticide inventory and linkage to the Environmental Protection Agency to obtain data on active ingredients; (3) collection and laboratory analyses of approximately 600 home dust samples for over 60 pesticides and (4) geographic information studies using California environmental databases to assess exposure to agricultural pesticides. The NCCLS is also conducting large-scale genotyping to evaluate the role of genes in xenobiotic pathways relevant to the transport and metabolism of pesticides. A better quantification of children's exposures to pesticides at home is critical to the evaluation of childhood leukaemia risk, especially for future gene-environment interaction studies.