Potential Pathways Of Exposure Research Articles

Potential Pathways of Exposure for DDE and Mirex and Reported Health Problems in Mexican-American Migrant and Seasonal Farmworker Children Residing in Texas

A pilot study was conducted to measure past organochlorine pesticide (OCP) exposure in 36 children/adolescents (14 males, 22 females) of migrant and seasonal farmworkers (MSFs). We administered a questionnaire to the mothers that provided sociodemographic, medical information, and a set of questions regarding possible pathways of exposure (in utero, through breast-feeding, going to the fields with parents, working in the fields). Each participant donated a blood sample. Two OCPs, Mirex [1.7 parts per billion (ppb) and 1,1-dichloro-2, 2-bis(chlorophenyl)ethylene (DDE) 1.6 ppb] were detected in our study, although these chemicals had been banned in the U.S. since the 1970s (USEPA 1992]. The detected Mirex levels in our study were far higher than the average population standard provided by the referent laboratory [< 0.03 nanograms per milliliter (ng/ml) or ppb; non-detectable). Age, body mass index, country of origin, breast-feeding, fieldwork, and frequency of illness were associated with OCP exposure. Thes...

Radiological Conditions of the Western Kara Sea: assessment of the radiological impact of the dumping of radioactive waste in the Arctic Seas

This report is a product of the International Arctic Seas Assessment Project (IASAP), instituted in 1993 by the IAEA and endorsed by the Consulting Parties of the London Convention. IASAP was set up following the 1992 revelations of radioactive waste dumping in the Kara and Barents Seas by the Former Soviet Union. These were later detailed in Yablokov's famous `White Book'. IASAP was constituted as a Coordinated Research Programme, with additional contacts and consultancies, coordinated with the Norwegian-Russian Expert Group investigating contamination in northern areas. Its objectives were to assess the risks to human health and, at the request of the LD's Contracting Parties, to consider possible remedial actions and their justification. The present report contains only some of the results of the study. An earlier IASAP report provided predictions of release rates from dumped marine reactors (IAEA TECDOC-938, 1997) and two further TECDOCS are in preparation on: `Anthropogenic radionuclides in the Arctic Seas' and `Modelling of the radiological impact ... '. The report opens with a 7-page Executive Summary, providing a condensed and reassuring assessment of the current and future radiological situation and the feasibilty, cost and justification for remediation. It concludes that leakage from dumped wastes has been small, with negligible doses when compared with those from natural sources. Future doses to `typical' local human population groups are predicted to be low. Doses to marine organisms are predicted to be orders of magnitude below levels at which detrimental effects at a population level would be expected. Remediation is not justified on radiological grounds although controls on beach occupancy and the utilisation of marine resources will have to be maintained. The remainder of the report provides more detail on the methodology, assumptions and databases which were used to support the conclusions. It is divided into 8 main chapters with the following content: (1) Introduction; (2) Radiological protection and decision making; (3) The Arctic environment; (4) The radioactive source term; (5) Environmental modelling for radiological impact assessment; (6) Possible remedial action; (7) Analysis of the need for remdial action; (8) Conclusions and recommendations. The bibliography contains 120 references (up to 1997) and there is a list of contributors to the drafting and review. Each chapter is further subdivided to three levels of hierarchy, allowing the reader to navigate quite effectively. Overall the text is easy to follow and there are useful illustrations provided of data sets and technical information. For example, the food web and potential food sources for humans in the Kara Sea are well presented graphically. However, those interested in a more critical examination of some of the data, or some of the modelling assumptions made, will have to consult the primary sources cited in the text. A minor irritation was the presentation of much of the geographic information, such as distributions of radionuclides in seawater, on a rectangular grid, where some form of polar projection would have been more appropriate. The report provides an excellent summary of an important international collaborative project. It is presented in a style which should encourage a wide readership, amongst students, scientists, NGOs and decision makers. It demonstrates, in a logical sequence, how a complex radiological assessment is undertaken, taking into account the environmental setting, the nature of the waste, potential pathways of human exposure and how conclusions and recommendations are arrived at.

Risk-based priorities for pesticide management initiatives

Agricultural pesticide applications in tropical countries may not be subject to the same types of regulations as in the United States. To guide environmental protection efforts for multinational agribusiness firms operating in such countries, a risk-based Pesticide Priority System has been developed. Using simple equations that combine information on use, chemical and physical properties, transport and fate, human and ecosystem exposure conditions, and toxicity, the system computes indexes for several potential pathways of exposure. The indexes can be used to suggest where further environmental protection efforts are justified. Example results are presented for a fungicide and a nematicide.

Issues in risk assessment of compost from municipal solid waste: occupational health and safety, public health, and environmental concerns

Risks posed by composting of municipal solid waste (MSW) depend on the assessment approach used. Occupational risks at present are not overtly serious— only nausea, eye irritation, etc. are reported from inhalation, the chief exposure pathway—but details are lacking on outcomes of pathogenic, chemical and physical threats, including potential secondary problems with organisms developed in compost, their endotoxins, and metabolic products such as aflatoxin. Potential risk pathways of public exposure to MSW compost are dominated by children's lead ingestion, but “dioxins” and other persistent organic carcinogens are also of dietary concern. Risks to the “most exposed individual” (MET) may differ substantially from those based on the Alternative Pollutant Limit (APL) approach. Neither deals adequately with uncertainty or multiple pathway/chemical threats to public and environmental health. Additional issues include (a) incremental vs. total risk, (b) required nutrient intake vs. proscribed toxicant exposure (for the same element) and (c) long-term matters of “no net degradation,” and composting in recycling.

Evaluation of Environmental and Human Risk From Crude-Oil Contamination

Summary The presence of petroleum compounds in soils, water, or petroleum compoundsin soils, water, or air does not necessarily result in a risk to populations. This paper presents a method of quantitative risk assessment (QRA) usedsuccessfully to assess, describe, and understand the environmental- andhuman-heath risks found in the oilfield environment. Introduction Soil contamination from petroleum hydrocarbons has become an important humanand environmental-health issue in the U.S. over the last decade. Yet, thiscontamination has probably occurred since the use of petroleum becamewidespread during the petroleum became widespread during the early part of thiscentury. The potential exists for humans to be exposed to petroleumconstituents in soils through various pathways. Potential pathways of exposureto pathways. Potential pathways of exposure to petroleum hydrocarbons in soilat a site depend petroleum hydrocarbons in soil at a site depend on the type ofsoil, petroleum, and petroleum constituents present. petroleum constituentspresent. Potential human exposures to petroleum in soils can be evaluatedthrough the use of formal QRA. This method incorporates information about thetoxicity of the petroleum and its constituents. the environmental behavior ofthese agents. and the estimated exposure to these agents to evaluate thepossible health risks to humans exposed to possible health risks to humansexposed to petroleum in soil. petroleum in soil. Crude oil is the naturallyoccurring liquid phase of petroleum. Natural crude-oil seeps are common inregions of petroleumbearing formations. This natural petroleumbearingformations. This natural contamination may result in human exposures to crudeoil and subsequent associated health risks. Risks from natural contaminationsources are often referred to as background risks. Health risks associated withexposures resulting from accidental releases of chemicals into the environmentare referred to as additional or incremental risks. QRA's are used to evaluateincremental health risks from accidental releases of petroleum products intothe environment. For example, if products into the environment. For example, ifa QRA concludes that the presence of crude oil in soil results in exposuresthat may cause adverse effects, then the concentration of the crude in soil mayneed to be reduced to an acceptable level. Use of Risk Assessment. Companies use formal health-based risk assessmentfor a variety of reasons, including the need to understand risks and toprioritize the remediation and prevention of risk. Internally, companies wantto understand the potential risks at a given site for decision-making reasonsand for comparison with other sites. The QRA provides information that cananswer a variety of internal questions. For example, how can one company withmultiple sites contaminated with a variety of chemicals prioritize remediationalternatives? How can a company develop a structured enviroinmental program toremediate each of those sites when the given fiscal reality does not permitremediation of all sites in a given year? Companies can use QRA's to prioritizethe sites and clean up the most risky sites first. This equates to a program ofrisk prevention in which the greatest amount of prevention in which thegreatest amount of risk reduction is achieved for every remediation dollarspent. QRA's can also be used to prioritize the remediation within a givensite. The chemical with the highest concentration may not be the chemical withthe highest risk. Use of QRA's within a site allows, first, for the remediationof chemical contaminants that pose the highest risk to the exposed population, with subsequent remediation of the remaining chemical contaminants having lowerrisk. Externally, QRA's are used in a variety of situations, includingregulatory responses and dealings with the public and media. QRA's can providealternative contamination levels or remediation goals at a given site and canbe used to convey the conditions at the site to the public and media. QRA's arescientifically defensible documents, based on the best and most currentunderstanding of the toxicity and exposure data base, that provide a logical, documented transition from site-specific exposure and toxicity data to theestimated risk. As legal documents, QRA's are used in liability cases and inthe defense of product liability suits. QRA's provide a structure to theremediation process and address an endpoint; they can be used to provide analternative remediation goal to one being proposed by regulators-i.e., arisk-driven rather than technology-driven remediation endpoint. QRA Components. The principle of risk assessment can be summed up as hazardtimes exposure equals risk. JPT P. 14