Drinking Water Health Standards Research Articles

Brackish water pre-treatment method: selection of the study area and water sample testing

Abstract Climate change significantly disrupts the global water cycle, impacting rainfall and social and economic development in countries like Morocco. This has led to the need for alternative solutions like desalinating sea and brackish water. However, the efficiency of water pre-treatment operations depends on the characteristics of the raw water to be treated and affects the overall system's performance in terms of water quality and cost. The final objective of this study is to design a solar-powered brackish pre-treatment technique before desalination for remote rural populations. The primary task is to select the most suitable geographical area in Morocco for sampling and analysis of water characteristics and their compliance with drinking water standards. The results help identify the most appropriate provinces for our case according to certain selection criteria (distance, annual solar radiation, rural population, access to drinking water) and analyse the water's characteristics and compliance with national or international drinking water health standards. This provides a solid foundation for the next stages of desalination method development.

Pollution Characteristics and Health Risk Assessment of Heavy Metals in the Water of Lijiang River Basin

In order to clarify the pollution levels of heavy metals in the drinking water sources of the Lijiang River Basin, surface water samples were collected from 62 sites throughout the Lijiang River during May 2019. Heavy metals, including As, Cd, Cr, Mn, Cu, Zn, Hg, Co, and Sb, in the water samples were analysed. Health risk assessments associated with these nine heavy metals were conducted using the health risk assessment model from the US EPA. The results indicated that the order of the average concentrations of heavy metals in the water samples were Mn > Zn > As > Cr > Cu > Sb > Co > Cd > Hg. No heavy metals exceeded the limit values of the drinking water health standards in China (GB 5749-2006), and the concentrations were lower than the limitations of Grade Ⅰ level in the environmental quality standards for surface water (GB 3838-2002). According to the spatial distribution, the high contents areas of As, Cr, Zn, and Sb were predominantly distributed downstream of the Lijiang River, while the high contents areas of Cd, Cu, Hg, Co, and Mn were mostly distributed in the upper reaches. Multivariate analysis indicated that Cd, Mn, Cu, and Co were primarily from agricultural production; Cr, Zn, and Sb were mainly from tourism transportation; As was predominantly from the weathering of rock parent material and soil erosion; Hg was mainly from the improper disposal of domestic garbage and atmospheric deposition. The results of the health risk assessment indicated that children were more susceptible to the threat of heavy metal pollution than adults, and the average annual risk of carcinogenic heavy metals to human health through drinking water ingestion were higher than those of non-carcinogenic metals. The maximum personal average annual health risk of Cr was higher than the maximum allowance levels recommended by the International Commission on Radiological Protection (5×10-5 a-1). The average annual risk of non-carcinogenic heavy metals (10-14-10-9 a-1) decreased in the order of Co > Cu > Hg > Zn > Sb > Mn, which were far below the maximum allowance levels recommended by the ICRP.

The impact of UV treatment on microbial control and DBPs formation in full-scale drinking water systems in northern China

To manage potential microbial risks and meet increasingly strict drinking water health standards, UV treatment has attracted increasing attention for use in drinking water systems in China. However, the effects of UV treatment on microbial control and disinfection by-products (DBPs) formation in real municipal drinking water systems are poorly understood. Here, we collected water samples from three real drinking water systems in Beijing and Tianjin to investigate the impacts of UV treatment on microbial control and DBP formation. We employed heterotrophic plate count (HPC), flow cytometry (FCM), quantitative PCR analysis, and high-throughput sequencing to measure microorganisms in the samples. Different trends were observed between HPC and total cell count (measured by FCM), indicating that a single indicator could not reflect the real degree of biological re-growth in drinking water distribution systems (DWDSs). A significant increase in the 16S rRNA gene concentration was observed when the UV system was stopped. Besides, the bacterial community composition was similar at the phylum level but differed markedly at the genera level among the three DWDSs. Some chlorine-resistant bacteria, including potential pathogens (e.g., Acinetobacter) showed a high relative abundance when the UV system was turned off. It can be concluded that UV treatment can mitigate microbial re-growth to some extent. Finally, UV treatment had a limited influence on the formation of DBPs, including trihalomethanes, haloacetic acids, and nitrogenated DBPs. The findings of this study may help to understand the performance of UV treatment in real drinking water systems.

Risk Perception and Human Health Risk in Rural Communities Consuming Unregulated Well Water in Saskatchewan, Canada.

Rural communities dependent on unregulated drinking water are potentially at increased health risk from exposure to contaminants. Perception of drinking water safety influences water consumption, exposure, and health risk. A community-based participatory approach and probabilistic Bayesian methods were applied to integrate risk perception in a holistic human health risk assessment. Tap water arsenic concentrations and risk perception data were collected from two Saskatchewan communities. Drinking water health standards were exceeded in 67% (51/76) of households in Rural Municipality #184 (RM184) and 56% (25/45) in Beardy's and Okemasis First Nation (BOFN). There was no association between the presence of a health exceedance and risk perception. Households in RM184 or with an annual income >$50,000 were most likely to have in-house water treatment. The probability of consuming tap water perceived as safe (92%) or not safe (0%) suggested that households in RM184 were unlikely to drink water perceived as not safe. The probability of drinking tap water perceived as safe (77%) or as not safe (11%) suggested households in BOFN contradicted their perception and consumed water perceived as unsafe. Integration of risk perception lowered the adult incremental lifetime cancer risk by 3% to 1.3 × 10-5 (95% CI 8.4 × 10-8 to 9.0 × 10-5 ) for RM184 and by 8.9 × 10-6 (95% CI 2.2 × 10-7 to 5.9 × 10-5 ) for BOFN. Probability of exposure to arsenic concentrations >1:100,000, negligible cancer risk, was 23% for RM184 and 22% for BOFN.

Determination and Health Risk Assessment of Heavy Metals on the Source of Underground Water in Yulin City

The source of the underground water in Yulin city were applied to monitor and evaluate five kinds of heavy metals which are Cr6+, Cd, As, Pb and Hg, and it revealed that the concentration of them were lower than the "drinking water health standards" (GB5749-2006), taking the source of drinking water in Yulin University as an example. A preliminary health risk assessment of the risk caused by drinking water has been done, based on the health risk assessment model recommended by USA Environmental Protection Agency. The datum showed that the health risk of carcinogenic substances (Cr6+, Cd and As) were much larger than that of non-carcinogenic substances (Pb, Hg) , so the priority control sequence should be Cr6+>Cd>As>Pb>Hg. The result showed that, human health of personal annual risk caused by the heavy metal pollutants in drinking water from the campus of Yulin University had exceeded the acceptable health risk level of 5 × 10-5/a which is established by the Radiation Protection Committee. Cr6+ is the main contribution, and should cause the attention of the relevant departments, also is the priority governance indicators.

The Research on Mineralization of Desalinated Water by Dissolving Ore for Entering into Municipal Water Supply Network

Desalination is the main method to solve the lack of freshwater resources in coastal areas. However, the desalinated water needs further treatment to have good chemical stability and meet the drinking water health standards before transporting by municipal pipe network. Considering desalinated seawater in Beijiang Power Plant and current situation of municipal pipe network, the desalinated water was mineralized by dissolving limestone with CO2 in this work. The process results in an enrichment of the water with calcium ions and carbonate. The effect of the limestone particle size, pH, the packed bed height and desalinated water flow rate on result water was investigated, which could offer a principle for the utilization of desalinated.

Study on Production Wastewater in Water Treatment Plants by Submerged Micro-Filtration Membrane

To verify the feasibility of micro-filtration membrane process to treat the water treatment plants production wastewater, a submerged polypropylene membrane module was applied in a test pilot plant. It was found that membrane process had remarkable characteristics of stable operation, high water quality and the membrane module were needed to chemical medicine washing as trans-membrane pressure (TMP) to 36 Kpa after running across 41day. The operation cycle was the best period for 20 minutes (filter 18 minutes, backwash 2 minutes). Membrane filtration water was showed as turbidity of 0.1-0.2NTU, CODMn generally less than 3mg / L, CODMn removal efficiency of 60% -80%.Fe2 +, Mn2 +,Al3 + and THMFP of membrane filtration water were lower than the national drinking water health standards.

Endemic fluorosis in Jilin province: analysis of surveillance data for 2006 - 2010

Objective To identify changes in the occurrence of endemic fluorosis in order to provide scientific basis for making countermeasures. Methods Five villages from 14 counties of mild, moderate and severe fluorosis affected areas were selected by stratified cluster sampling every year in the whole province during 2006 - 2010. Water and urinary fluorine were determined by ion selective electrode method(GB/T 8538-1995); dental fluorosis of children 8-12 years old was diagnosed with Dean method; skeletal fluorosis was diagnosed according to clinical indexing standards of endemic skeletal fluorosis (GB 16396-1996), between 2006 and 2008, and clinical diagnosis standard of endemic skeletal fluorosis(WS 192-2008) between 2009 and 2010. Results A total of 25 diseased villages were surveyed, 14 with water sources changed, covered a resident population of 8005 people, beneficiary population 7154, and accounting for 89.37% of the resident population; not changed villages 11. In accordance with the State drinking water health standards, in the 14 changed villages the fluoride in drinking water was qualified (≤ 1.20 mg/L), there were 3 schools whose water fluorine content exceeded the standard; among the 11 villages that did not change water sources 7 drinking water samples fluorine content exceeded the standard. Of the 8 to 12 years old children in villages with changed water sources, 363 of them were checked and 142 dental fluorosis were found, the detection rate of dental fluorosis was 39.12% (142/363); in villages with water sources not changed, 303 children were checked, the detection rate of dental fluorosis was 43.89%(133/303). Of sixteen and elder adults in water source changed villages, 6424 people were checked and 403 skeletal fluorosis were found, skeletal fluorosis detection rate was 6.27% (403/6424); 3572 people were checked in not changed villages, the detection rate of skeletal fluorosis was 13.89%(496/3572). In water sources changed areas, geometric mean of urinary fluoride was in the normal reference value(WS/T 256-2005, 1.40 mg/L)or less. Conclusions Endemic fluorosis is decreased in water improved areas, but in unimproved areas the disease is still severe, and control of endemic fluorosis is still an arduous task. Key words: Endemic diseases; Fluorosis, dental; Osteofluorosis

Preozonation on Removal of Organic Matter in Water and Biological Stability

The pollution of drinking water source has become a serious problem facing the world, and it is even more severe in China undergoing rapid development. Statistics show that the total annual emissions in China is 35.3 billion m3, CODMnis about 760 million tons, the treatment rate is only 23.6%, a lot of waste water without being treated in many small towns was discharged directly . It polluted seriously the water supply in many cities and industrial and mining water. According to the survey, among China's seven major river systems, 110 Key Sections, 68% of Water Quality is Ⅲ, Ⅳ, Ⅴ Grade. 90% of the national urban water has been polluted, the most prominent problem is the organic pollution. There are low dissolved oxygen, and the density of ammonia nitrogen, COD, BOD, and TOC in the water is high. Some of the polluted water bodies often appear black smelly serious situation. These organic polluted drinking water source, due to the presence of a large number of organic ozone-depleting substances , by conventional coagulation, sedimentation, filtration and disinfection treatment process, is difficult to achieve the requirements of the national mandatory Standard— "drinking water health standards"(GB 5749-2006) , issued and revised by the national standards committee and Ministry of Health, which there is a new comprehensive index of organic matter - the oxygen consumption is to control trace organic matter in water.

Monitoring and analysis of arsenic pollution in Yangzonghai lake and the influence of arsenic to the surrounding drinking water and local food in Chengjiang of Yunnan province in 2008 and 2009

Objective To find out the arsenic pollution in Yangzonghai lake and its influence to the surrounding drinking water source and the local food and to provide a scientific basis for arsenic pollution control,drinking water and food safety. Methods Arsenic monitoring were carried out in 10 points of Yangzonghai lake,45 water sources within 5 km of Yangzonghai lake, and locally produced food. Results From September 2008 to December 2009, the water arsenic concentrations of Yangzonghai lake ranged 0.06 - 0.18 mg/L, the average arsenic concentrations were 0.12 mg/L and 0.10 mg/L for 2008 and 2009, respectively, the value of 2009 was higher, and the difference was statistically significant(t = 3.284, P ＜ 0.05). There were no significant difference in the average of arsenic concentration of Yangzonghai lake between the dry and rainy season in 2009(t = 0.905, P ＞0.05). The arsenic concentrations from the No. 3 spring water ranged from 0.12 - 30.36 mg/L. After a peak value early in October 2008, the No. 3 spring water showed a downward trend month by month. In 2008 the average arsenic concentration was 23.92 mg/L, 2009 was 2.41 mg/L, down 89.92% over the previous year, the difference was statistically significant(t = 9.582, P ＜ 0.05 ). In January and February 2009, the average arsenic concentration (11.96 mg/L) was significantly higher than those of March-December(0.50 mg/L, t = 57.759, P＜ 0.05). In Yangzong town, the arsenic concentration in the drinking water and river met the national drinking water health standards. Among 78 samples monitored of the locally produced food in Yangzong town, 77 passed, with a pass rate of 98.72%. Conclusions Arsenic contamination has been effectively controlled. The drinking water and local food production has not been contaminated by arsenic except aquatic products in Yangzonghai Lake. It is recommended to take effective measures to prevent water contamination. Key words: Arsenic poisoning; Drinking; Food; Data collection

Use of Ground Water Monitoring Data for Pesticide Regulation

Growing public concern for pesticide residues in drinking water has resulted in tighter federal and state regulations to prevent ground-water contamination. There are many uncertainties in estimating human exposure risk, yet standards are being set to protect human health. In the last several years, drinking water health standards have been developed for a number of pesticides, often at levels of a few μg L−1 or less. Ground-water monitoring studies, first required by the U.S. Environmental Protection Agency in 1984, have now become an integral requirement to support registration of pesticides shown to have leaching potential. Regulators are now faced with deciding the extent to which pesticides can still be used while continuing to meet legal requirements to protect the public and preserve ground-water resources. The implications are that pesticide use may be severely limited in regions with ground-water resources considered especially vulnerable to contamination, dramatically affecting the type of agricultural practices and crops grown in these regions.