Verification on the Developmental Toxicity of Short-term Exposure to Phenol in Rats

Objective To verify the health advisory for short-term exposure to phenol.Methods The method of this validation experiment was the same as the US Environmental Protection Agency(EPA)methodology for toxicology experiments used to determine phenol drinking water equivalent level(DWEL).Pregnant female Sprague-Dawley rats were administered phenol in distilled water by gavage at daily doses of 15,30,60,120,and 240 mg/kg body weight(b.w.)from implantation(the 6 th day post-mating)to the day prior to the scheduled caesarean section(the 20th day of pregnancy).The following information was recorded:general behavior;body weight;number of corpus luteum,live birth,fetus,stillbirth,and implantation;fetal gender;body weight;body length;tail length;and abnormalities and pathomorphological changes in the dams.Results In the 60 mg/kg b.w.dose group,the mortality of pregnant rats increased with increasing doses,suggesting maternal toxicity.Fetal and placental weights decreased as phenol dose increased from30 mg/kg b.w.,and were significantly different compared those in the vehicle control group,which suggested developmental toxicity in the fetuses.However,the phenol-exposed groups showed no significant change in other parameters compared with the vehicle control group(P>0.05).Conclusion Despite using the same method as the US EPA,a different NOEAL of 15 mg/(kg·d)was obtained in this study.

Hydrogeochemical and Multivariate Statistical Techniques to Trace the Sources of Ground Water Contaminants and Affecting Factors of Groundwater Pollution in an Oil and Gas Producing Wetland in Rivers State, Nigeria

Background: Groundwater is an important source of drinking water for the indigenous communities of Ebocha-Obrikom. Access to safe drinking water, in particular, is critical to one’s health and, by extension, one’s income and well-being. Underground wells are the primary supply of drinking water in the Niger Delta, and the groundwater is not always treated before consumption. As a result, water continues to be a vital environmental component that affects both humans and other life forms. Objectives: The aims of the research are to trace the sources and affecting factors of groundwater pollution via statistical and multivariate statistical techniques. Method: The investigation made use of standard analytical procedures. All sampling, conservation, transportation and analysis followed standard procedures described in APHA (2012). To prevent degradation of the organic substances, all obtained samples were transferred to the laboratory, while kept in an icebox. Results: The study reveals that the greater the number of principal components extracted the greater variation in geochemical composition of the ground waters. It indicated that 34 parameters were distributed into six (6) and nine (9) principal components (PCs) extracted for groundwater samples for both rainy and dry seasons, potentially suggesting the input of different pollutants from different sources. Gas flaring, mineral dissolution/precipitation and anthropogenic input are the main sources of the physicochemical indices and trace elements in the groundwater. Groundwater chemistry is predominantly regulated by natural processes such as dissolution of carbonates, silicates, and evaporates and soil leaching, followed by human activities. Climatic factors and land use types are also important in affecting groundwater chemistry. Conclusion: Greater efforts should be made to safeguard groundwater, which is hampered by geogenic and anthropogenic activities, in order to achieve sustainable groundwater development. As a result, communities are recommended to maintain a groundwater management policy to ensure long-term sustainability. The study is useful for understanding groundwater trace sources in Rivers State’s Ebocha-Obrikom districts. Such understanding would enable informed mitigation or eradication of the possible detri-mental health consequences of this groundwater, whether through its use as drinking water or indirectly through consumption of groundwater-irrigated crops. As a result, determining its primary probable source of pollution (MPSP) is critical since it provides a clearer and more immediate interpretation. Furthermore, the research findings can be used as a reference for groundwater pollution prevention and water resource protection in the Niger Delta region of Nigeria.

Consumption of rice and fish in an electronic waste recycling area contributes significantly to total daily intake of mercury

Mercury is a global pollutant due to its widespread use,emission,and long-range transport（Blum,2013;Pacyna et al.,2010）.It is considered a priority pollutant due to its neurological toxicity,persistence,and bioaccumulation（Pacyna et al.,2010;Sharma et al.,2015）.Mercury pollution can occur when products that contain mercury are improperly disposed of and mercury is released into the air,water,and soil（Zhang and Wong,2007）.An estimated 22%of the annual world usage of mercury is in electrical equipment such as batteries,thermometers,and discharge lamps,and electronic devices such as monitors and