RESUMO
BACKGROUND: Previous biomonitoring studies have shown that people in the rural population of Coquimbo, the major agricultural area in northern Chile are being occupationally and environmentally exposed to organophosphate/carbamate (OP/CB) pesticides. Given their harmful effects, this study had two aims; first, to evaluate the effect of cumulative or chronic exposure to OP/CB pesticides on the neurobehavioral performance of agricultural workers and rural inhabitants; second, to determine if changes in the neurobehavioral performance are associated to changes in blood biomarkers of OP/CB pesticides during the spray season, when exposure is higher. METHODS: For the first aim, a cross sectional study of neurobehavioral performance in adult volunteers (men and women, 18-50 years-old, right-handed) was carried out in the pre-spray season. Sampling was done by convenience and a questionnaire was used to categorize participants depending on their level of chronic exposure, as either: occupationally exposed (OE, n = 87), environmentally exposed (EE, n = 81), or non-exposed controls or reference group (RG, n = 100). A neurobehavioral test battery consisting of 21 tests to measure cognitive, motor and emotional state was applied. For the second aim, neurobehavioral measures were taken a second time from EE and OE groups during the spray season, and their exposure corroborated by blood-based biomarker inhibition. RESULTS: Lower neurobehavioral performance was observed in the pre-spray evaluation of EE and OE groups compared to the non-exposed, OE being the worst performing group. Seasonal exposure impaired performance in both exposure groups on all tests except those on attention and mood. Data modeling of the basal (pre-spray) measurements showed that the level of exposure was the best predictor of performance. During spraying, inhibition of BChE activity in the EE group was the best predictor of low performance in tests measuring logical, auditory and visual memory, inhibitory control of cognitive interference, constructional and planning abilities, executive functions, and motor speed and coordination. CONCLUSION: Long-term occupational or environmental exposure to pesticides caused impairment in neurobehavioral functioning, which worsened during the spraying season, mainly in EE. BChE inhibition was the best predictor for seasonal neurobehavioral changes in EE.
Assuntos
Doenças dos Trabalhadores Agrícolas/induzido quimicamente , Exposição Ambiental/efeitos adversos , Fazendeiros/estatística & dados numéricos , Doenças do Sistema Nervoso/induzido quimicamente , Praguicidas/efeitos adversos , População Rural/estatística & dados numéricos , Adulto , Biomarcadores/sangue , Carbamatos/efeitos adversos , Chile , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos , Exposição Ocupacional/efeitos adversos , Organofosfatos/efeitos adversos , Adulto JovemRESUMO
BACKGROUND: In Chile organophosphate pesticides are widely used in the production of fruits. Pesticides use is regulated for professional practice but there is no regulation regarding exposure to the general population. OBJECTIVE: To relate exposure to cholinesterase's inhibitor pesticides during the spray season with neuropsychological impairment in occupationally exposed (OE) and environmentally exposed (EE) groups of people. METHODS: Exposure was assessed through inhibition of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activity and neuropsychological outcomes were evaluated through a large battery of tests covering general mental status, language, memory, attention, executive function, praxis and psychomotricity. Evaluations were carried out firstly in a period of no/low organophosphate pesticide use and subsequently during the spray season. All parameters were calculated as the relative change from baseline to spray season. RESULTS: For this study in total 156 participants were recruited divided equally over participants with environmental exposures (EE) and participants with occupational exposure (OE). In the EE, BChE's enzyme activity inhibition ≥30% showed significant association with 10% or more decreased performance in several tests evaluating six of the eight cognitive areas (excepting psychomotricity and mood status); besides, for AChE inhibition in EE, the association was significant in three tests evaluating attention and one of executive function. Whereas, in OE, the inhibition of the BChE ≥30% was associated with a low performance of one attention test and for AChE the exceedance of the standard was associated with diminished performance in one test of memory and attention, respectively. The association between biomarkers of biological effect and cognitive impairment persisted among the EE group after removing confounders. No association was found between biomarkers of biological acute effect and decreased cognitive performance in the OE group. CONCLUSIONS: Increased exposure to pesticides was confirmed by increased inhibition of cholinesterase's in both exposure groups; which was associated with a diminished neuropsychological performance, mainly in the environmentally exposed study group. [310 words].
Assuntos
Disfunção Cognitiva , Exposição Ocupacional , Praguicidas , Carbamatos , Chile , Humanos , Exposição Ocupacional/análise , Organofosfatos/toxicidade , Praguicidas/toxicidadeRESUMO
In Chile, agriculture is a relevant economic activity and is concomitant with the use of pesticides to improve the yields. Acute intoxications of agricultural workers occur with some frequency and they must be reported to the surveillance system of the Ministry of Health. However the impacts of chronic and environmental pesticide exposure have been less studied. Among pesticides frequently used in Chile for insects control are organophosphates (OP) and carbamates (CB). They are inhibitors of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). In this study we determined the pattern of both biomarkers activity in three populations with different type of chronic exposure to OP/CB: environmentally exposed (EE), occupationally exposed (OE) and a reference group (RG) without exposure. Besides this, we also measured the activity of acylpeptide hydrolase (APEH), an enzyme involved in relevant functions in the central synapses that is also expressed in erythrocytes and previously reported to be highly inhibited by some OP. A baseline measurement was done in both exposure groups and then a second measurement was done during the spraying season. The RG was measured only once at any time of the year. Our results indicate that people under chronic OP/CB exposure showed an adaptive response through an increase of basal BChE activity. During the spray season only BChE activity was decreased in the EE and OE groups (p<0.05 and p<0.01, respectively) and the higher magnitude of BChE inhibition was observed in the EE group. The analysis of the frequencies of inhibition above 30% (biological tolerance limit declared by Chilean legislation) indicated that BChE was most frequently inhibited in the EE group (53% of the individuals displayed inhibition) and AChE in the OE group (55% of the individuals displayed AChE inhibition). APEH activity showed the highest frequency of inhibition in the EE group independent of its magnitude (64%). Our results demonstrate that the rural population living nearby agricultural settings displays high levels of environmental exposure. APEH activity seems to be a sensitive biomarker for acute low-level exposure and its usefulness as a routine biomarker must to be explored in future studies. Systematic biomonitoring and health outcomes studies are necessary as well as obtaining the baseline for BChE and AChE activity levels with the aim to improve environmental and occupational health policies in Chile.
Assuntos
Butirilcolinesterase/sangue , Exposição Ambiental/efeitos adversos , Exposição Ambiental/análise , Monitoramento Ambiental , Peptídeo Hidrolases/sangue , Praguicidas/toxicidade , População Rural/estatística & dados numéricos , Adolescente , Adulto , Biomarcadores/sangue , Biomarcadores/metabolismo , Butirilcolinesterase/metabolismo , Chile , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Peptídeo Hidrolases/metabolismo , Adulto JovemRESUMO
BACKGROUND: Health effects of pesticides are easily diagnosed when acute poisonings occurs, nevertheless, consequences from chronic exposure can only be observed when neuropsychiatric, neurodegenerative or oncologic pathologies appear. Therefore, early monitoring of this type of exposure is especially relevant to avoid the consequences of pathologies previously described; especially concerning workers exposed to pesticides on the job. For acute organophosphate pesticides (OPP) exposure, two biomarkers have been validated: plasma cholinesterase (ChE) and acetylcholinesterase (AChE) from erythrocytes. These enzymes become inhibited when people are exposed to high doses of organophosphate pesticides, along with clear signs and symptoms of acute poisoning; therefore, they do not serve to identify risk from chronic exposure. This study aims to assess a novel biomarker that could reflect neuropsychological deterioration associated with long-term exposure to organophosphate pesticides via the enzyme acylpeptide-hydrolase (ACPH), which has been recently identified as a direct target of action for some organophosphate compounds. METHODS/DESIGN: Three population groups were recruited during three years (2011-2013): Group I having no exposure to pesticides, which included people living in Chilean coastal areas far from farms (external control); Group II included those individuals living within the rural and farming area (internal control) but not occupationally exposed to pesticides; and Group III living in rural areas, employed in agricultural labour and having had direct contact with pesticides for more than five years. Blood samples to assess biomarkers were taken and neuropsychological evaluations carried out seasonally; in three time frames for the occupationally exposed group (before, during and after fumigation period); in two time frames for internal control group (before and during fumigation), and only once for the external controls. Neuropsychological evaluations considered cognitive functions, affectivity and psychomotor activity. The biomarkers measured included ChE, AChE and ACPH. Statistical analysis and mathematical modelling used both laboratory results and neuropsychological testing outcomes in order to assess whether ACPH would be acceptable as biomarker for chronic exposure to OPP. DISCUSSION: This study protocol has been implemented successfully during the time frames mentioned above for seasons 2011, 2012 and 2013-2014.
Assuntos
Exposição Ambiental/análise , Doenças do Sistema Nervoso/etiologia , Compostos Organofosforados/toxicidade , Peptídeo Hidrolases/sangue , Praguicidas/intoxicação , População Rural , Acetilcolinesterase/sangue , Agricultura , Biomarcadores , Chile/epidemiologia , Colinesterases/sangue , Transtornos Cognitivos/sangue , Transtornos Cognitivos/etiologia , Humanos , Masculino , Doenças do Sistema Nervoso/sangue , Exposição Ocupacional/análise , Transtornos Psicomotores/sangue , Transtornos Psicomotores/etiologia , Projetos de Pesquisa , Fatores de RiscoRESUMO
BACKGROUND: The Pilcomayo River is polluted by tailings and effluents from upstream mining activities, which contain high levels of metals. The Weenhayek live along this river and are likely to have elevated exposure. OBJECTIVES: To assess whether the Weenhayek have increased risk of reproductive and developmental disorders related to elevated metal exposure in comparison with a reference population. METHODS: We assessed reproductive and developmental outcomes, i.e. fertility, fetal loss, congenital anomalies, and walking onset by means of structured interviews. We sampled hair, water and fish to assess the relative exposure of the Weenhayek. Samples were analyzed for Pb and Cd with ICP-MS techniques. RESULTS: The Weenhayek communities studied had a higher prevalence of small families (OR 2.7, 95% CI 1.3-6.0) and delayed walking onset (OR 2.7, 95% CI 1.4-5.1) than the reference population. Median Pb levels in Weenhayek hair were 2-5 times higher than in the reference population, while Cd levels were not elevated. In water and fish, both Pb and Cd levels were increased in the Weenhayek area. CONCLUSIONS: We found indications for increased risks of small families and delayed walking onset among the Weenhayek living along the Pilcomayo River. Lactants form a high risk group for lead exposure.