Integration of biological monitoring, environmental monitoring and computational modelling into the interpretation of pesticide exposure data: introduction to a proposed approach.

Open field, variability of climatic and working conditions, and the use of complex mixtures of pesticides makes biological and environmental monitoring in agriculture, and therefore risk assessment and management, very complicated. A need of pointing out alternative risk assessment approaches, not necessarily based on measures, but simple, user-friendly and reliable, feasible also in the less advanced situations and in particular in small size enterprises, arises. This aim can be reached through a combination of environmental monitoring, biological monitoring and computational modelling. We have used this combination of methods for the creation of "exposure and risk profiles" to be applied in specific exposure scenarios, and we have tested this approach on a sample of Italian rice and maize herbicide applicators. We have given specific "toxicity scores" to the different products used and we have identified, for each of the major working phases, that is mixing and loading, spraying, maintenance and cleaning of equipment, the main variables affecting exposure and inserted them into a simple algorithm, able to produce "exposure indices". Based on the combination of toxicity indices and exposure indices it is possible to obtain semiquantitative estimates of the risk levels experienced by the workers in the exposure scenarios considered. Results of operator exposure data collected under real-life conditions can be used to validate and refine the algorithms; moreover, the AOEL derived from pre-marketing studies can be combined to estimate tentative biological exposure limits for pesticides, useful to perform individual risk assessment based on technical surveys and on simple biological monitoring. A proof of principle example of this approach is the subject of this article.

Evaluation of immune parameters in propanil-exposed farm families.

The rice herbicide propanil induces alterations in the mouse immune system, causing significant decreases in T cell-dependent and T cell-independent antibody responses. This postemergent herbicide is used extensively in rice production in the Mississippi River delta region of the southern United States. The aerial application and airborne drift of propanil may pose health concerns to exposed farm families living adjacent to sprayed rice fields. To determine if aerial spraying of propanil increases risks of altered immune responses in families bordering rice fields, immune parameters were assessed during a 2-year study. Families living within 100 yards of rice fields were compared in a case control study to farm families whose homes exceeded 1 mile from any rice field. Blood was analyzed in adults (n = 56) and children (n = 52) at three time intervals: (1) preseason, prior to propanil application; (2) 5-7 days after aerial application of propanil to rice fields; and (3) postseason, following harvest. Exposed adults and children were compared with controls for a number of immune parameters. Total cell count and the percentage of various lymphocytes (T cells, B cells, CD4+ helper cells, and CD8+ suppressor cells) and natural killer (NK) cells, mitogen-induced cell proliferation, cytokine (IL-2+) production, and NK cell function were assessed. A comparison of immune function between exposed and nonexposed farm families showed no significant differences, possibly related to propanil exposure. However, some immune test parameters changed as a function of season rather than propanil exposure. The data indicate that individuals living next to rice fields are not at increased risk of altered immune function due to propanil exposure.

Determination of dichloroanilines in human urine by GC-MS, GC-MS-MS, and GC-ECD as markers of low-level pesticide exposure.

Methods for the determination of 3,4-dichloroaniline (3,4-DCA) and 3,5-dichloroaniline (3,5-DCA) as common markers of eight non-persistent pesticides in human urine are presented. 3,5-DCA is a marker for the exposure to the fungicides vinclozolin, procymidone, iprodione, and chlozolinate. Furthermore the herbicides diuron, linuron, neburon, and propanil are covered using their common marker 3,4-DCA. The urine samples were treated by basic hydrolysis to degrade all pesticides, metabolites, and their conjugates containing the intact moieties completely to the corresponding dichloroanilines. After addition of the internal standard 4-chloro-2-methylaniline, simultaneous steam distillation extraction (SDE) followed by liquid-liquid extraction (LLE) was carried out to produce, concentrate and purify the dichloroaniline moieties. Gas chromatography (GC) with mass spectrometric (MS) and tandem mass spectrometric (MS-MS) detection and also detection with an electron-capture detector (ECD) after derivatisation with heptafluorobutyric anhydride (HFBA) were employed for separation, detection, and identification. Limit of detection of the GC-MS-MS and the GC-ECD methods was 0.03 and 0.05 microg/l, respectively. Absolute recoveries obtained from a urine sample spiked with the internal standard, 3,5-, and 3,4-DCA, ranged from 93 to 103% with 9-18% coefficient of variation. The three detection techniques were compared concerning their performance, expenditure and suitability for their application in human biomonitoring studies. The described procedure has been successfully applied for the determination of 3,4- and 3,5-DCA in the urine of nonoccupationally exposed volunteers. The 3,4-DCA levels in these urine samples ranged between 0.13 and 0.34 microg/g creatinine or 0.11 and 0.56 microg/l, while those for 3,5-DCA were between 0.39 and 3.33 microg/g creatinine or 0.17 and 1.17 microg/l.