Burton C. Kross

Municipal drinking water nitrate level and cancer risk in older women: the Iowa Women's Health Study.

Nitrate contamination of drinking water may increase cancer risk, because nitrate is endogenously reduced to nitrite and subsequent nitrosation reactions give rise to N-nitroso compounds; these compounds are highly carcinogenic and can act systemically. We analyzed cancer incidence in a cohort of 21,977 Iowa women who were 55–69 years of age at baseline in 1986 and had used the same water supply more than 10 years (87% >20 years); 16,541 of these women were on a municipal supply, and the remainder used a private well. We assessed nitrate exposure from 1955 through 1988 using public databases for municipal water supplies in Iowa (quartile cutpoints: 0.36, 1.01, and 2.46 mg per liter nitrate-nitrogen). As no individual water consumption data were available, we assigned each woman an average level of exposure calculated on a community basis; no nitrate data were available for women using private wells. Cancer incidence (N = 3,150 cases) from 1986 through 1998 was determined by linkage to the Iowa Cancer Registry. For all cancers, there was no association with increasing nitrate in drinking water, nor were there clear and consistent associations for non-Hodgkin lymphoma; leukemia; melanoma; or cancers of the colon, breast, lung, pancreas, or kidney. There were positive associations for bladder cancer [relative risks (RRs) across nitrate quartiles = 1, 1.69, 1.10, and 2.83] and ovarian cancer (RR = 1, 1.52, 1.81, and 1.84), and inverse associations for uterine cancer (RR = 1, 0.86, 0.86, and 0.55) and rectal cancer (RR = 1, 0.72, 0.95, and 0.47) after adjustment for a variety of cancer risk/protective factors, agents that affect nitrosation (smoking, vitamin C, and vitamin E intake), dietary nitrate, and water source. Similar results were obtained when analyses were restricted to nitrate level in drinking water from 1955 through 1964. The positive association for bladder cancer is consistent with some previous data; the associations for ovarian, uterine, and rectal cancer were unexpected.

Toxicity assessment of atrazine, alachlor, and carbofuran and their respective environmental metabolites using microtox

Using the Microtox method of toxicity assessment designed by Microbics Corporation, the relative toxicities of alachlor, atrazine, and carbofuran, three pesticides commonly used in agricultural production, were determined. Generally, carbofuran was found to be most acutely toxic, followed closely by atrazine. Alachlor was least toxic of the three pesticides tested. Selected environmental metabolites of these three agri-chemicals were also tested using the same method. Hydroxyalachlor, deethylatrazine, deisopropylatrazine, 3-hydroxycarbofuran, and 3-ketocarbofuran were selected for analysis because previous studies determined their presence in surface and ground-water supplies along with their parents. Results showed that often the metabolites were at least as acutely toxic as their parents, particularly in the case of 3-ketocarbofuran and hydroxyalachlor, which demonstrated toxicities higher or not significantly different than their parents. Hydroxycarbofuran was assessed as the least toxic of all substances tested. The atrazine environmental metabolites were less toxic than their parent.

Proportionate mortality study of golf course superintendents

A proportionate mortality study of a cohort of golf course superintendents was conducted using death certificates for 686 deceased members of the Golf Course Superintendents Association of America who died from 1970 to 1992. White males were included in the study population from all 50 states. The study objective was to compare mortality from this cohort to the general U.S. white male population. The proportionate mortality ratio (PMR) for all types of cancer was 136 (CI: 121, 152). Significant excess mortality from smoking-related diseases was observed. The PMR for arteriosclerotic heart disease was 140, which was significantly elevated (CI: 127, 155). In addition, the PMR for all respiratory diseases was 176 (CI: 135,230), while the PMR for emphysema was 186 (CI: 101,342). The PMR for lung cancer was 117 (CI: 93, 148). Mortality for four cancer types--brain, lymphoma (non-Hodgkins lymphoma, NHL), prostate, and large intestine--occurred at elevated levels within this cohort: brain cancer PMR = 234 (CI: 121,454), non-Hodgkins lymphoma (NHL) PMR = 237 (CI: 137,410), prostate cancer PMR = 293 (CI: 187,460), and large intestine cancer PMR = 175 (CI: 125,245). The PMR for diseases of the nervous system was 202 (CI: 123,333). A similar pattern of elevated NHL, brain, and prostate cancer mortality along with excess deaths from diseases of the nervous system has been noted among other occupational cohorts exposed to pesticides.

METHODS DEVELOPMENT STUDY FOR MEASURING PESTICIDE EXPOSURE TO GOLF COURSE WORKERS USING VIDEO IMAGING TECHNIQUES

Abstract The primary objective of this study was to determine the feasibility of using video imaging methods to assist with the design of improved spray application systems that would reduce golf course worker exposure. Method development studies were performed using design engineers as subjects. No pesticide active ingredient was used during the studies. Results are reported as amounts of fluorescent tracer observed on each worker. Exposures for the two spray applicator drivers were relatively low, with the lowest exposure recorded for the driver of the vehicle with a cab. The most striking result was the large amount of exposure received by the mixing/loading worker, nearly three orders of magnitude greater than for the drivers. Tracer dye amounts were greatest on the hands (about 98% of total), with the balance of the exposure occurring on the face and torso. No dye was observed on the air filters used to estimate breathing zone and ambient air exposure levels. Dye amounts measured on the patches locat...

Pesticide contamination of private well water, a growing rural health concern

The Iowa Statewide Rural Well Water Survey (SWRL) was conducted between April 1988 and June 1989. SWRL was designed to provide a statistically valid assessment of the proportion of private rural wells and rural Iowa residents affected by various environmental contaminants. The survey was a systematic sample, stratified by rural population density. Approximately 14% of wells had detections of pesticides: 16 pesticide compounds (mostly herbicides) were detected, including 11 parent compounds and 5 environmental metabolites; 16 pesticides (mostly insecticides) were not detected. Atrazine and its metabolites were found in 8% of wells. Multiple residues were detected in all regions of the state. The mean concentrations were generally <1 μg/L. Lifetime Health Advisory Levels (HALs) were exceeded in 1.2% of private, rural wells in Iowa. Detailed evaluations of these sites indicate 25% are caused by point source contamination (spill and back-siphoning), while the majority, 62.5%, appear to be nonpoint sources related to normal agricultural practices. Statistical analyses show significant associations between many water quality parameters tested during SWRL, but the associations are not strong predictors based on state-wide data. By far the most significant factor explaining water quality variations is well depth.

Exposure Received from Application of Animal Insecticides

Part of an investigation of data collection methods in epidemiologic studies of farmers evaluated exposures received by farmers from the application of insecticides to animals. Twenty farmers were monitored during a normal application using a fluorescent dye surrogate for the active ingredient (AI). Two exposure measures were estimated, AI concentration and the time-weighted average for the application period (TWAa). Four application methods were used: high- (n = 5) and low-pressure (n = 3) spraying, backpack (n = 2) and pour-on (n = 10). The two farmers using a backpack sprayer had nondetectable levels of dye. Only two of the farmers using the pour-on method had detectable dye levels, but these levels were high. All of the low- and high-pressure sprayers had detectable amounts of dye. Multiple layers of clothing, gloves, and boots (n = 10) were associated with a low mean AI concentration for the exposed farmers (18 micrograms) and more than two-thirds of the farmers wearing this amount of clothing had nondetectable exposures. In contrast, clothing providing little or no protection was associated with a significantly higher (p < 0.01) average AI concentration (4420 micrograms), and less than a third of the farmers with this degree of protection had nondetectable exposures. Poor work practices (leaking equipment, contact with wet animals or fences, and back splash) were associated with statistically higher exposure levels (p < 0.01) than the absence of such practices. There was a moderate statistically significant association between AI concentration and TWAa with total volume of the AI/dye/water mixture using the Spearman coefficient. Time was significantly inversely proportional to the two exposure measures. The association between the two exposure measures and AI volume was not significant.

EIA AND LONG-TERM EVALUATION IN THE LICENSING PROCESS FOR RADIOACTIVE WASTE DISPOSAL IN SLOVENIA

The discussion is about the validity of long-term environmental impact assessment (EIA) and its role in the licensing process for radioactive waste disposal in Slovenia. Owing to uncertainties associated with long-term evaluations an alternative approach is suggested for site selection for the repository. The idea behind the new approach is to integrate environmental planning with the optimisation of land-use as a basis for identifying the best site for the repository. This approach is to complement or, eventually, substitute the existing strictly regulatory concept relying upon criteria compliance tied with the performance assessment of the disposal system. It is expected that the new approach will more effectively build confidence among professionals and the public toward siting of radioactive waste disposal. The new approach suggests not to use dose and risk as individual numerical indicators for deciding about acceptability of the proposed disposal system, since they may vary greatly given the large uncertainties connected to future societal characteristics and human exposures. Instead, a concept of reasonable assurance together with the evaluation of interests and potentials for future land-use in the particular environment is suggested.

a study of the temporal variability of atrazine in private well water. part ii: analysis of data

In 1988, the Iowa Department of Natural Resources, along withthe University of Iowa, conducted the Statewide Rural WellWater Survey, commonly known as SWRL. A total of 686private rural drinking water wells was selected by use of aprobability sample and tested for pesticides and nitrate. A subsetof these wells, the 10% repeat wells, were additionally sampledin October, 1990 and June, 1991. Starting in November, 1991,the University of Iowa, with sponsorship from the United StatesEnvironmental Protection Agency, revisited the 10% repeat wellsto begin a study of the temporal variability of atrazine and nitratein wells. Other wells, which had originally tested positive foratrazine in SWRL but were not in the 10% population, wereadded to the study population. Temporal sampling for a year-long period began in February of 1992 and concluded in Januaryof 1993. All wells were sampled monthly, a subset was sampledweekly, and a second subset was sampled for 14 day consecutiveperiods. Of the 67 wells in the 10% population tested monthly,7 (10.4%) tested positive for atrazine at least once during theyear, and 3 (4%) were positive each of the 12 months. Theaverage concentration in the 7 wells was 0.10 µg/L. Fornitrate, 15 (22%) wells in the 10% repeat population monthlysampling were above the Maximum Contaminant Level of 10 mg/L at least once. This paper, the second of two papers on thisstudy, describes the analysis of data from the survey. The firstpaper (Lorber et al., 1997) reviews the study design, theanalytical methodologies, and development of the data base.

a study of the temporal variability of atrazine in private well water. part i: study design, implementation, and database development

In 1988, the Iowa Department of Natural Resources, along withthe University of Iowa conducted the Statewide Rural WellWater Survey, commonly known as SWRL. A total of 686private rural drinking water wells was selected by use of aprobability sample and tested for pesticides and nitrates. Sixty-eight of these wells, the ’10% repeat‘ wells, were additionallysampled in October, 1990 and June, 1991. Starting inNovember, 1991, the University of Iowa, with sponsorshipfrom the United States Environmental Protection Agency,revisited these wells to begin a study of the temporalvariability of atrazine and nitrates in wells. Other wells, whichhad originally tested positive for atrazine in SWRL but werenot in the 10% repeat population, were added to the studypopulation. Temporal sampling for a year-long period beganin February of 1992 and concluded in January of 1993. Allwells were sampled monthly, one subset was sampled weekly,and a second subset was sampled for 14-day consecutiveperiods. Two unique aspects of this study were the use of animmunoassay technique to screen for triazines before gaschromatography/mass spectrometry (GC/MS) analysis andquantification of atrazine, and the use of well owners to samplethe wells. A total of 1771 samples from 83 wells are in thefinal data base for this study. This paper reviews the studydesign, the analytical methodologies, and development of thedata base. A companion paper (Pinsky et al., 1997) discussesthe analysis of the data from this survey.

RESEARCH ARTICLE: Recent Understanding of and Attitudes toward the Environment in the Koper Region, Slovenia

Reported herein are the results of two surveys designed to determine the predominant social paradigm, together with opinions on and attitudes toward the environment and environmental issues, within the Slovene coastal zone. The research is a cross-sectional study of selected populations in time. Opinions of different social groups with regard to their priority values, trust in technological development, moral responsibility toward their environment, and readiness to participate in environmental protection are analyzed. The study finds that a stable economy is the primary societal goal in the Slovene coastal zone; this must be realized before people begin to concern themselves with environmental protection. Also, the coastal community is prepared to participate in environmentally protective actions such as separate waste collection, but they are not in favor of making major lifestyle changes, although they are aware of that need.