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conferenceseries.com
October 24-25, 2016 | Valencia, Spain
International Conference on
Environmental Health & Safety
Volume 4, Issue 5 (Suppl) Occup Med Health
ISSN:2329-6879 OMHA, an open access journal Environmental Health 2016
October 24-25, 2016
Occup Med Health Aff 2016, 4:5 (Suppl)
EXPOSURE PATHWAYS AND HUMAN HEALTH RISK ASSESSMENT FROM ARSENIC
EXPOSURE IN BANGLADESH
Tijo Josepha , Brajesh K Dubeyb and Edward A McBeana
aUniversity of Guelph, Canada
bIIT Kharagpur, India
High arsenic exposures, prevalent through dietary and non-dietary sources in Bangladesh, present a major health risk to the
public. Groundwater, the most important source of water for drinking, cooking, and irrigation in Bangladesh, is a significant
contributor to the daily human intake of arsenic. Other arsenic intake pathways, established as relevant for Bangladeshi adults
through this study, include consumption of contaminated edible plant parts and animal-origin food, inhalation of contaminated
air, soil ingestion, betel quid chewing, and tobacco smoking. A quantitative human health risk assessment is described as a result of
arsenic exposure through food and water intake, tea intake, accidental soil ingestion, and chewing of betel quid, while people meet
their desirable dietary intake requirements throughout their lifetime. This study qualifies and quantifies these arsenic intake pathways
through analysis of the range of arsenic levels observed in different food types, water, soil, and air in Bangladesh, and highlights the
contributions of dietary intake variation and cooking method in influencing arsenic exposures. In evaluating the contribution of
each intake pathway to average daily arsenic intake, the results show that food and water intake combined, make up approximately
98% of the daily arsenic intake with the balance contributed to by intake pathways such as tea consumption, soil ingestion, and quid
consumption. Under an exposure scenario where the arsenic concentration in water is in the WHO guideline (0.01mg/L), food intake
is the major arsenic intake pathway ranging from 67% to 80% of the average daily arsenic intake. However, the contribution from
food drops to a range of 29% to 45% for an exposure scenario where arsenic in water is at the Bangladesh standard (0.05mg/L). The
lifetime excess risk of cancer occurrence from chronic arsenic exposure, considering a population of 160 million people, based on
an exposure scenario with 85 million people on the WHO guideline value and 75 million people at the Bangladesh standard, and
assuming 35 million people associated with a heavy activity level, is estimated as 1.15 million cases. This study also highlights the
potential of desirable dietary patterns and intakes in increasing arsenic exposure which is relevant to Bangladesh where nutritional
deficiencies and lower-than-desirable dietary intakes continue to be a major concern.
PHENOTYPIC VARIABILITY CONFIRMED BY NUCLEAR RIBOSOMAL DNA SUGGESTS A
POSSIBLE NATURALHYBRID ZONE OFTRIATOMABRASILIENSIS SPECIES COMPLEX
Jane Costaa
aInstituto Oswaldo Cruz, Brazil
Triatoma brasiliensis macromelasoma occurs in Pernambuco state, Brazil, which is situated between the distribution areas of
Triatoma brasiliensis brasiliensis (north) and Triatoma juazeirensis (south). T. b. macromelasoma displays greater variations in
its chromatic phenotype than either T. b. brasiliensis or T. juazeirensis and patterns reminiscent of one or the other. Experimental
crosses from each of these members of the T. brasiliensis species complex generated fertile offspring suggesting that viable hybrids
could be present in nature, despite their significant genetic distances. Considering the geographical position of occurrence of the
T. b. macromelasoma (in Pernambuco) it was proposed to be an area capable of supporting natural hybridization between T. b.
brasiliensis and T. juazeirensis. Since phenotypic variability is expected, this study investigated the existence of intermediate chromatic
phenotypes for T. b. macromelasoma in various locations in areas between the T. b. brasiliensis and T. juazeirensis occurrences.
Thirteen different color patterns were for the first time characterized and nine of those displayed intermediate phenotypes. Molecular
analysis performed using ribosomal DNA intergenic region, grouped all within the T. brasiliensis complex.The intermediate chromatic
phenotypes, molecular analysis and experimental crosses all support the distinction of a zone of hybridization that gave rise to the T.
b. macromelasoma through homoploidal evolution.