جستجوی مقالات مرتبط با کلیدواژه « limits » در نشریات گروه « محیط زیست »
تکرار جستجوی کلیدواژه «limits» در نشریات گروه «علوم پایه»-
Pollution, Volume:9 Issue: 4, Autumn 2023, PP 1653 -1665The heavy metal concentrations of water and shrimp (Penaeus monodon) from Isaka Bundu swamp, Niger Delta were evaluated between January and June 2022. The non-carcinogenic health risk assessment was used to assess the water's suitability for recreation and the shrimps for consumption. Five heavy metals (Pb, Cu, Cd, Ni, and Zn) were assessed in both media using standard methods and compared with national and international standards. The Chronic daily intake (CDI) for Cd and Cu (in children) exceeded their respective reference doses while hazard quotients (HQs) for Cd and Cu (in children) and all the hazard indices were greater than 1 in the water. All the target hazard quotients (THQs) and total hazard index (THIs) were lower than 1 in the shrimps. The heavy metal concentrations, CDIs, HQ/THQs and HI/THIs were higher in the more impacted stations 1 and 3. Based on the heavy metal concentrations and health risk assessment, the waters of the Isaka Bundu swamp are unsafe for recreational purposes. However, shrimps are safe for human consumption. The high concentrations of heavy metals in the water influenced the concentrations in the shrimps. Anthropogenic activities in the area contributed to the heavy metal concentrations in the environment. The results also showed that the children were more prone to adverse health impacts.Keywords: limits, Heavy metal, Water quality, Anthropogenic, Shrimp}
-
Pollution, Volume:6 Issue: 4, Autumn 2020, PP 909 -922This study on the heavy metal content of a local drinking water source in South-east Nigeria was carried out in 3 sampling stations between May 2019 and October 2019. Pollution indices and health risk assessment for non-carcinogenic were used to check the water’s suitability for human consumption. The indices were heavy metal pollution index (HPI) and Contamination Index (Cd). Eight metals were evaluated with standard methods and compared with Nigerian and WHO drinking water standards. Some metals like iron, lead and cadmium exceeded the recommended limits. The stations Heavy Metal Pollution Index ranged between 511.4 and 512.4 while the monthly values ranged between 279.8 and 547.6; all exceeding the threshold value of 100. Contamination Index ranged between 3.12 and 3.32 (stations) and -0.80 to 4.80 (month) indicating high contamination potential and low to high contamination potentials respectively. All the hazard indices also exceeded one (1). Stations 1 and 2 were higher in all the indices. All the indices were linked the high values of iron, lead and cadmium, influenced by sand mining activities. The pollution indices and Health Risk Assessment converged to show that the waters of Iyiakwu River are not fit for human consumption. The children are more vulnerable since it the main source of drinking water in the area.Keywords: limits, HPI, Heavy metal, Water quality, indices}
-
زمینه و هدففلوراید یکی از شناخته شده ترین و مفیدترین مواد در مهار پوسیدگی دندان و استخوان می باشد، ولی مصرف مقادیر بالای آن می تواند باعث بروز بیماری فلوئوروزیس دندانی و استخوانی شود. از آنجایی که چای و آب آشامیدنی به عنوان یکی از مواد دارای فلوراید می باشد، بنابراین بررسی مطالعه حاضر با هدف سنجش غلظت فلوراید در آب شرب و چای مصرفی شهر تهران در سال 1392 صورت گرفت.روش بررسیدر این پژوهش توصیفی- تحلیلی، 25 نوع برند تجاری چای ایرانی و خارجی موجود در بازار شهر تهران و 30 نمونه آب شرب مصرفی شهر تهران در 4 تکرار مورد بررسی قرار گرفتند. مقدار فلوراید موجود در نمونه های چای خشک و در دم کرده چای در مدت زمان های 3، 5 و 10 دقیقه و نمونه های آب بعد از هضم اسیدی توسط دستگاه الکترود انتخابی یون فلوراید اندازه گیری شدند. اطلاعات پس از جمع آوری با استفاده از نرم افزار SPSS ورژن 18 تجزیه و تحلیل گردید.یافته هانتایج به دست آمده نشان داد که مقدار فلوراید در انواع برند چای خشک بین 2/22-8/303 میلی گرم بر کیلوگرم، در محلول چای بین 2/0- 37/2 میلی گرم بر لیتر و در آب شرب مصرفی بین 012/0-95/0 میلی گرم بر لیتر قرار دارد. هم چنین نتایج نشان داد که با افزایش مدت زمان دم کردن، میزان فلوراید آزاد شده در چای افزایش خواهد یافت به طوری که در مدت زمان های 3، 5 و 10 دقیقه به ترتیب متوسط درصد آزادسازی یون فلوراید در محلول چای 88/31% ، 34/53 % و 08/78 % بود.بحث و نتیجه گیریدر انتها مشخص شد که مصرف روزانه چای های بررسی شده به اندازه 5 فنجان توسط کودکان و بزرگسالان هیچگونه مشکلاتی را برای سلامتی آن ها ایجاد نخواهد کرد. اما بایستی غیر از مصرف چای به سایر منابع ورود یون فلوراید به بدن نظیر آب آشامیدنی و غیره نیز توجه داشت، تا از بروز بیماری های استخوانی و دندانی جلوگیری کرد.کلید واژگان: چای سیاه, یون فلوراید, جذب روزانه, حد مجاز}Background and ObjectiveFluoride is one of the most well-known and useful substances to inhibit tooth decay and bone caries, but high doses of it can cause dental and skeletal fluorosis. Since tea and water contains fluoride, the present study was performed to measure fluoride concentration in drinking water and tea in Tehran in 2014 year.MethodIn this descriptive-analysis study, 25 types of Iranian and foreign brands of tea available in Tehran's market and 30 samples of drinking water from Tehran city were studied in 4 replications. The amount of fluoride in the tea and brewed tea samples within 3, 5 and 10 m and water samples after digestion were measured by fluoride ion selective electrode. Finally, the obtained data was analyzed by SPSS Ver. 18 software.FindingsThe results indicated that the amounts of fluoride in different brands of tea, tea solution and water were 22.2-303.8 mg/kg, 0.2–2.37 mg/L and 0.95-0.012 mg/L, respectively. Also, the results showed that the amount of released fluoride in tea increases with the increase of brewing time. Therefore, after 3, 5 and 10 m, the average percentages of fluoride released in the tea solution were 31.88%, 53.34% and 78.08% respectively.Discussion and ConclusionFinally, it was found that daily consumption of five cups of the studied tea by children and adults may not lead to health problem. However, other sources of fluoride ions such as drinking water, etc should be taken into consideration to prevent the occurrence of skeletal and dental diseases.Keywords: Black tea, Fluoride, Daily intake, Limits}
نکته
- نتایج بر اساس تاریخ انتشار مرتب شدهاند.
- کلیدواژه مورد نظر شما تنها در فیلد کلیدواژگان مقالات جستجو شدهاست. به منظور حذف نتایج غیر مرتبط، جستجو تنها در مقالات مجلاتی انجام شده که با مجله ماخذ هم موضوع هستند.
- در صورتی که میخواهید جستجو را در همه موضوعات و با شرایط دیگر تکرار کنید به صفحه جستجوی پیشرفته مجلات مراجعه کنید.