
Dioxin Emission Factors for the Incineration of Different Medical Waste Types
Previous research works showed that to protect public health, hospital incinerators should be provided with equipment to reduce atmospheric emissions. Most hospital incinerators do not possess such equipment, so efficient methodologies should be developed to evaluate the safety of incineration procedures. Emission factors can be used for an easy estimation of the parameters defined in legislation. Nevertheless, the actual knowledge is very scarce, mainly because previously published emission factors do not include enough information about the incinerated waste types and the respective proportion in incinerated mixture. The existence of different waste classifications also reduces the usefulness of previously published results. This study reports the first dioxin emission factors estimated for the incineration of medical waste, segregated in different types according to the classification of the Portuguese legislation. The main purpose was to evaluate the influence of waste type on emission factors, assessing how useful they are if not associated to the composition of the incinerated mixture. The study also allowed analyzing the correspondence between different waste classifications that are being used, comparing the estimated emission factors with the sole results previously published for specific waste types but segregated according to a different classification. The influence of the incinerated waste type and segregation practices on the concentration and amount of emitted dioxin was assessed, as well as the influence of segregation practices on the amount of wastes that must be incinerated. To estimate eventual hazards for human health, dioxin concentrations in combustion gas flow were compared with the respective legal limits.
Solid medical waste: a cross sectional study of household disposal practices and reported harm in Southern Ghana
BackgroundSolid medical waste (SMW) in households is perceived to pose minimal risks to the public compared to SMW generated from healthcare facilities. While waste from healthcare facilities is subject to recommended safety measures to minimize risks to human health and the environment, similar waste in households is often untreated and co-mingled with household waste which ends up in landfills and open dumps in many African countries. In Ghana, the management of this potentially hazardous waste stream at household and community level has not been widely reported. The objective of this study was to investigate household disposal practices and harm resulting from SMW generated in households and the community.MethodsA cross-sectional questionnaire survey of 600 households was undertaken in Ga South Municipal Assembly in Accra, Ghana from mid-April to June, 2014. Factors investigated included socio-demographic characteristics, medication related practices, the belief that one is at risk of diseases associated with SMW, SMW disposal practices and reported harm associated with SMW at home and in the community.ResultsEighty percent and 89% of respondents discarded unwanted medicines and sharps in household refuse bins respectively. A corresponding 23% and 35% of respondents discarded these items without a container. Harm from SMW in the household and in the community was reported by 5% and 3% of respondents respectively. Persons who believed they were at risk of diseases associated with SMW were nearly three times more likely to report harm in the household (OR 2.75, 95%CI 1.15–6.54).ConclusionThe belief that one can be harmed by diseases associated with SMW influenced reporting rates in the study area. Disposal practices suggest the presence of unwanted medicines and sharps in the household waste stream conferring on it hazardous properties. Given the low rates of harm reported, elimination of preventable harm might justify community intervention.
Geographic And Environmental Influence On Maya Settlement Patterns Of The Northwest Yucatan: An Explanation For The Sparsely Settled Western Cenote Zone
Most settlement pattern research and GIS analysis of the ancient Maya of the Northern Yucatan have focused on water availability in a dry landscape where cenotes are often the only water source. While water is of paramount importance, permanent settlement secondarily requires farmable soil, a resource often as precious as water in many parts of the Yucatan. The dynamics between these resources reveal areas of ideal settlement and more challenging landscapes for which the Maya developed strategies to overcome environmental conditions. A region of the southwest "Cenote Zone", however, appears to have presented the ancient Maya with insurmountably poor environmental conditions despite abundant water resources. The lack of dense population and stone architecture in this area emphasizes the lack of a simple correlation between cenotes and settlement. This thesis uses GIS analysis to identify and explore such problematic settlement areas to better understand the factors and complexities involved in the more successful settlements of neighboring regions. iv This work is dedicated to my late father, who first introduced me to the Mundo Maya through a visit to the ruins of Tikal at the age of nine, and who instilled in me strength, curiosity, and a love for exploring the world. v ACKLOWLEDGEMENTS I'd like to acknowledge Dr. Arlen Chase and Dr. Diane Chase for providing such outstanding opportunities and instruction, and for leading by example both in the field and in the classroom. Dr. John Walker for his eye-opening perspectives, GIS instruction, inspiring hard-working attitude, and patience in the field. Dr. Clifford Brown and Dr. Walter Witschey for their invaluable correspondence and for their contributions to mapping and GIS data of Maya sites.