Association between Pesticides in House Dust and Residential Proximity to Farmland in a Rural Region of Taiwan.

Pesticide drift was reported in many international studies, but rarely studied in Taiwan. We conducted a study in a rural region of Taiwan to examine the associations between pesticides in house dust and nearby agricultural areas using geographic information system (GIS). A questionnaire regarding home characteristics and pesticide use, and indoor and outdoor dust samples were collected from 47 rural homes. Dust samples were analyzed for six pesticides, and agricultural land data for GIS analysis were retrieved from a national website. All but prallethrin were frequently detected from indoor dust samples (>50%), and the maximum concentrations were all below 1000 ng/g. Detection frequencies and concentrations of pesticides in outdoor dust samples were even lower than that in indoor dust samples. Only "work involving pesticides" in the questionnaire was significantly associated with four pesticides in house dust (p < 0.05). Carbofuran and tetramethrin in house dust were significantly correlated with rice cultivation area at certain buffer distances (ρ > 0.33, p < 0.05), and chlorpyrifos was found to be associated with abandoned cultivation area, suggesting the occurrence of pesticide drift. Despite the low levels of pesticides in house dust, residents in the rural region should be cautious of pesticide drift from nearby active or abandoned farmlands.

Associations between phthalic acid esters in house dust and home characteristics/living habits in a rural region of Taiwan.

Phthalic acid esters (PAEs) commonly used as plasticizers are distributed ubiquitously in the living environment. We conducted a field study to examine the associations between PAE residue in dust and home characteristics/living habits in 47 rural homes in Taiwan. A questionnaire regarding home characteristics/living habits and composite sampling of house dust were conducted in each participating home. Five PAEs were selected for analysis on gas chromatography-mass spectrometry with the limits of quantification being 0.5 ng/g or lower. Uni- and multivariate linear regression analyses were performed for examining the associations. The five PAEs were prevalently detected from the samples, and the concentrations were below 1000 ng/g; di(2-ethylhexyl) phthalate (DEHP) was the most frequently detected PAE (85%), whereas di-isobutyl phthalate (DiBP) appeared to the most abundant congener with the maximum concentration of 807.65 ng/g. Floor cleaning frequency and use of detergents for floor cleaning were significantly associated with DEHP in dust (P < 0.05), suggesting additives of plasticizers in detergent products. The factors of plastic wraps in storage and use of disposable cups were both significantly related to DiBP (P < 0.01), which could be extensively used in food packaging products. We confirmed that several home characteristics/living habits were related to certain PAE residue in dust.

Analysis of Leafy Vegetable Nitrate Using a Modified Spectrometric Method.

A quick and cost-effective method to analyze leafy vegetable nitrate on spectrometry was developed and compared with a standard method using high performance liquid chromatography (HPLC). This method was designed to use ion-exchange solid phase extraction (SPE) cartridges in reducing interference from organic matrices to meet the criterion of an existing method for analyzing nitrate in wastewater. Nine vegetables (bok coy, cabbage, celery, Chinese cabbage, Chinese kale, lettuce, mustard green, pak choi, and water spinach) were selected for the method testing with three replicates being conducted for each vegetable. The nitrate contents ranged from 800 to 4,300 µg/g, with bok coy, celery, and pak choi being the highest. Data derived from spectrometry and HPLC were close to each other with most relative errors being within ±10% and were highly correlated with an R square value of 0.969. Stability testing and spike analysis resulted in a mean coefficient of variation lower than 6% and a mean recovery rate of 83.7%, suggesting reliability of the method. In addition, both the cost and time consumption for using this method were lower than the standard method using HPLC or ion chromatography, making this spectrometric method a good alternative for analysis of leafy vegetable nitrate.