Contamination In China Research Articles

Aging of solidified/stabilized electrolytic manganese solid waste with accelerated carbonation and aging inhibition.

High concentrations of soluble Mn in electrolytic manganese solid waste (EMSW) in soil cause the severe contamination in China. Calcium oxide and magnesium oxide-dominated stabilizers are suitable for the solidification/stabilization (s/s) of EMSW. However, the long-term performance of s/s using those two types of stabilizer is problematic. The aim of this study was to develop an accelerated aging method to simulate the long-term natural carbonation of solidified/stabilized EMSW. The joint use of accelerated carbonation, leaching test, mineralogical analysis, and microstructural observation was applied to assess the long-term performance of the s/s EMSW system. On an accelerated carbonation test for solidified/stabilized EMSW, an increase in Mn leaching from 13.6 to 408mg/kg and a 1.5-2.3 decrease in pH was achieved by using CaO-dominated stabilizers, while an increase in manganese (Mn) from 30 to 266mg/kg and a decrease in pH of 0.17-0.68 was seen using MgO-dominated stabilizers. CaO+Na3PO4 and CaO+CaCO3 were exceptions in that the leaching value of soluble Mn was lower after carbonation. Mineralogical analysis showed that rhodochrosite in the carbonated s/s system was generated not only from the reduction of hausmannite but also from the reversible reaction between Mn(OH)2 and MnCO3. Carbonation destroyed the tight particle structure resulting in a porous and loose structure. As for s/s EMSW treated by MgO-dominated stabilizers, carbonation affected the agglomerating structure and mineralogical composition by increasing magnesium (Mg) migration, thereby forming hydromagnesite that had weak binding ability and a nested porous shape. Therefore, carbonation by itself does not cause deterioration to s/s products of the soluble Mn but does have significant effects on the microstructure and mineralogical composition. It is recommended to add Na3PO4 or CaCO3 into a single CaO stabilized EMSW system to prevent aging of the system, allow formation of Mn phosphate precipitates, and improve the absorption and oxidation of soluble Mn(II).

A predictive risk model of groundwater arsenic contamination in China applied to the Huai River Basin, with a focus on the region’s cluster of elevated cancer mortalities

Recently, a statistical risk model that classifies safe and unsafe areas with respect to geogenic groundwater arsenic contamination in China has been developed. Modeling results indicate that most areas in the Huai River Basin (HRB) are associated with a considerable probability of human exposure to elevated levels of arsenic (>10 μg/L) in groundwater. The high mortality and incidence rates of cancer in the HRB have been widely reported. The predicted high probability of arsenic hazards in this region might suggest a new hypothesis that groundwater arsenic contamination contributes to this cancer cluster. Therefore, we analyzed an arsenic concentration dataset, including 69,702 groundwater samples from 2357 villages in 70 counties, in the HRB to determine whether the region was affected by arsenic. Our findings indicate that groundwater consumed in 408 (17%) villages and 41 (59%) counties contains high levels of arsenic (>10 μg/L). Coincidentally, in some counties with severe groundwater contamination people have been found to exhibit high cancer mortality rates. Furthermore, the model correctly classified 57% of the villages as high- and low-risk areas (0.4 probability cut-off threshold). The model sensitivity (ability to correctly classify villages with arsenic concentrations of >10 μg/L) and specificity (ability to correctly classify villages with arsenic concentrations of ≤10 μg/L) at the village-level were 61% and 56%, respectively. Collectively, our findings confirmed that the HRB was affected by arsenic and suggested, at least to a certain extent, that groundwater arsenic contamination is likely associated with the HRB cancer cluster. Additionally, the data indicated that the model was well-suited to predicting high-risk arsenic exposure areas at the village-level and can thus be used as a tool to prioritize sampling in villages showing high risk.

Brominated flame retardants (BFRs): A review on environmental contamination in China

Brominated flame retardants (BFRs) which were detected extensively in environmental and biota samples worldwide, have raised significant concerns during past decades for their persistence, bioaccumulation and potential toxicity to ecological environment and human health. In this paper, we have compiled and reviewed existing literature on the contamination status of BFRs in abiotic and biotic environments in China, including polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane, tetrabromobisphenol A and new BFRs. Temporal trends were also summarized and evaluated. Based on this review, it has been concluded that (1) high concentrations of PBDEs were generally related to the e-waste disposal processing, while the spatial distribution pattern of other BFRs was not necessarily in accordance with this; (2) extremely high concentrations of BFRs in indoor dust emphasized the importance of indoor contamination to human body burdens, while more work need to be done to confirm its contribution; (3) PBDEs in electronics dismantling workers were higher compared to the general population, indicating the occupational exposure should be of particular concern; (4) more data are now becoming available for BFRs in aquatic and terrestrial organisms not previously studied, while studies that consider the occurrence of BFRs in organisms of different trophic levels are still of urgent need for evaluating the fate of BFRs in the food web; and (5) limited data showed a decreasing trend for PBDEs, while more data on time trends of BFR contamination in various matrices and locations are still needed before the impact of regulation of BFRs can be assessed.

High Prevalence and Widespread Distribution of Zoonotic Enterocytozoon bieneusi Genotypes in Swine in Northeast China: Implications for Public Health.

This study analyzed 563 fecal specimens of asymptomatic pigs from five cities of northeast China for the prevalence and genetic characteristics of Enterocytozoon bieneusi. The parasite was detected in 267 of 563 (47.4%) pigs by nested PCR of the ribosomal internal transcribed spacer (ITS). The differences in prevalence between preweaned (58.0%, 94/162) and growing pigs (39.6%, 114/288) and between weaned (52.2%, 59/113) and growing pigs are significant (p < 0.05). Genotypic typing and phylogenetic analysis facilitated identification of six human-pathogenic genotypes EbpC, O, CS-4, EbpA, Henan-IV, and PigEBITS5 and six potentially zoonotic genotypes EbpB, CC-1, CS-1, CS-3, CHN7, and CS-10. Genotypes CS-4 (32/35) and EbpC (3/35) from Harbin and Henan-IV (5/64) from Qiqihar determined in pigs herein represented the main causative agents of human microsporidiosis in Harbin. The most dominant genotype EbpC found in pigs from Daqing (35/65) and Qiqihar (a close neighbor to Daqing) (47/64) contributed significantly to human infections in Daqing. Genotype EbpC was also a leading E. bieneusi pathogen in humans, drinking water, and wastewater in central China. This study provided robust evidence that pigs could be an outstanding source of human microsporidiosis and water contamination in China.

A review of soil cadmium contamination in China including a health risk assessment.

Cadmium (Cd) is one of the most serious soil contaminants in China, and it poses an increasing risk to human health as large amounts of Cd are emitted into the environment. However, knowledge about soil Cd concentrations and the human health risks of these concentrations at a national scale is limited. In this study, we conducted a review of 190 articles about soil Cd concentrations during 2001 to 2010. The study involved 146 cities in China, and we quantified the risks to human health according to different regions. The results showed that elevated Cd levels were present compared to the background value of soil in 1990, and the soil Cd concentrations in the Guangxi province exceeded even the class III Soil Environmental Quality standard, which is the limit for the normal growth of plants. The Chinese soil Cd concentrations ranged from 0.003 mg kg(-1) to 9.57 mg kg(-1). The soil Cd concentrations had the following trend: northwest > southwest > south central > east > northeast > north. The sources of soil Cd are mainly from smelting, mining, waste disposal, fertilizer and pesticide application, and vehicle exhaust, etc. but differentiated in various regions. The soil Cd contamination in urban areas was more serious than contamination in the agricultural areas. Currently, there is no significant non-carcinogenic risk in any of the provinces. Regarding the different exposure pathways, the dermal pathway is the primary source of soil Cd exposure, and the risk associated with this pathway is generally hundreds of times higher than the risk for an ingestion pathway. For most of the provinces, the health risk to the urban population was higher than the risk to the rural population. For each population, the carcinogenic risk was less than 10(-6) in most of the provinces, except for the urban population in the Hunan province. If the other exposure pathways are fully considered, then the people in these areas may have a higher carcinogenic risk. This review provides a comprehensive assessment of soil Cd pollution in China, and it identifies policy recommendations for pollution mitigation and environmental management in the relevant regions.

Immobilization of arsenic in aqueous solution by waterworks alum sludge: prospects in China

In this study, groups of batch experiments were designed to identify the characteristics of alum sludge for arsenic (As) adsorption. Air-dried alum sludge (moisture content 13.9%) collected from a water treatment works in Xi’an, China, was subjected to artificial As-rich wastewater adsorption tests using As2O3 as a model As source. Adsorption behaviours were investigated and the results have shown that the Langmuir adsorption isotherm well fits the experimental data (R2 = 0.94957–0.99365). The maximum adsorption capacities range from 0.61 to 0.96 mg-As/g when the pH of the As solution was varied from 9.0 to 4.0. The prospects in China for the outcome of this study are discussed. This promising low-cost technique can eradicate As contamination in China.

Prevalence and genetic characteristics of Cryptosporidium, Enterocytozoon bieneusi and Giardia duodenalis in cats and dogs in Heilongjiang province, China

This study investigated 319 fecal specimens of cats (n=52) and dogs (n=267) from Heilongjiang province, China for the prevalence and genetic characteristics of Cryptosporidium, Enterocytozoon bieneusi, and Giardia duodenalis. PCR and DNA sequence analysis of the small subunit rRNA gene identified C. felis and C. parvum in one cat each (3.8%) and C. canis and C. ubiquitum in 6 dogs (2.2%). Polymorphisms in the ribosomal internal transcribed spacer and phylogenetic analysis characterized zoonotic E. bieneusi genotypes D, EbpC, NED1, and NED2 and host-adapted ones NED3, NED4, and PtEb IX in 18 dogs (6.7%) and human-pathogenic genotypes D and IV in 3 cats (5.8%). Genotyping based on the hypermutation of G. duodenalis triosephosphate isomerase gene (TPI) facilitated identification of assemblage F in a cat (1.9%) and assemblages C and E in 12 dogs (4.5%). Subtypes of G. duodenalis isolates were determined by measuring the diversity of both TPI nucleotide and amino acid sequences. C. canis, C. felis, C. parvum, E. bieneusi genotypes D, EbpC, and IV, and G. duodenalis assemblage C identified herein have been documented in human infections in China. C. canis, C. parvum, C. ubiquitum, and E. bieneusi genotypes D, EbpC, and IV carried by cats or dogs also existed in wastewater in China. The finding suggested pet animals could be reservoirs for human cryptosporidiosis, microsporidiosis, and giardiasis and potential sources of water contamination in China.

Ochratoxin A and ochratoxin-producing fungi on cereal grain in China: a review

The mycotoxin ochratoxin A (OTA) is known to be the main contaminant of cereal grain and has become increasingly important in recent years. Therefore, a survey of ochratoxigenic fungi and OTA contamination in China is a special challenge. This paper summarises data on cereals and moulds (Aspergillus niger, Penicillium verrucosum, Aspergillus ochraceus, for example) and on grain and OTA from 1973 by searching Chinese information databases (NCKI, VIP, DuXiu etc.), calculating the OTA-producing mould detection rate, referring to sampling locations, latitude and temperature, and also combining six grain-producing areas of ochratoxigenic fungi and OTA positive rate through a comprehensive analysis. It is concluded that in China rice (excluding shell rice) has less OTA contamination than wheat or maize. The contamination of cereal grains with Aspergillus section Nigri (formerly of the A. niger group) is a serious problem in China, and these fungi may be the main ochratoxigenic fungi on cereals.

Fumonisins in China: update on occurrence, epidemiology, exposure and regulation

Fumonisins (FBs) are one of the most frequently occurring mycotoxins in China. FBs have attracted worldwide attention because of the significant economic losses they cause as well as their impact on human health and animal productivity. FBs have been associated with high incidences of oesophageal and liver cancer in several areas in China. However, the extrapolation of the effects of FBs on humans has always been inaccurate, which can be explained by the lack of adequate food consumption data, lack of knowledge about related health risks associated with specifically proposed limits, and the possibility of synergism with other mycotoxins present in the same food commodities. Domestic legislation is necessary to control contamination by FBs. The assessment of fumonisin exposure and development of preventative strategies in China depend not only on the determination of fumonisin levels in food contributors but also on the distinct dietary patterns of a specific population. Although limited data is available, this review aims to critically evaluate the extent of fumonisin contamination in China as well as epidemiologic studies and human exposure estimates. This review also aims to establish perspectives to aid future research and legislation.

Mycotoxins in Asia: is China in danger?

Mycotoxins such as aflatoxins, ochratoxins, fumonisins, deoxynivalenol and zearalenone are considered to be of particular concern in relation to human and animal health. Contamination of agricultural products by mycotoxins has become an important issue worldwide over the last three decades. Asia contributes a very large part of the globe with most developing countries in the tropical and subtropical regions favouring the growth of fungal species. There is a high potential of mycotoxin occurrence and a number of important mycotoxin outbreaks in Asia. In recent years, increasing number of survey in Asia with regard to prevalence of mycotoxins has evidenced the seriousness of mycotoxins problem in this continent. Among Asian countries, China is the most populous nation with a population of over 1.3 billion. Due to extensive and complex topography, diverse climate zones in China have provided various optimal environments for the growth of mycotoxins-producing fungi. It is evident that people in China have been exposed to various mycotoxins simultaneously in a frequent and chronic manner. Effort on investigation and monitoring with regard to mycotoxins contamination and exposure is necessitated for the sake of public health in this populous country. This review presents several mycotoxins exhibiting strong ecological link with human food supply in Asia. Human mycotoxicoses relating to these mycotoxins, especially in Asia, are highlighted and their contaminations of human foodstuffs in the 21st century in Asian countries are summarized. In particular, the current situation and control measures with regard to mycotoxin contamination in China are discussed.

Soil contamination in China: current status and mitigation strategies.

China faces great challenges in protecting its soil from contamination caused by rapid industrialization and urbanization over the last three decades. Recent nationwide surveys show that 16% of the soil samples, 19% for the agricultural soils, are contaminated based on China’s soil environmental quality limits, mainly with heavy metals and metalloids. Comparisons with other regions of the world show that the current status of soil contamination, based on the total contaminant concentrations, is not worse in China. However, the concentrations of some heavy metals in Chinese soils appear to be increasing at much greater rates. Exceedance of the contaminant limits in food crops is widespread in some areas, especially southern China, due to elevated inputs of contaminants, acidic nature of the soil and crop species or cultivars prone to heavy metal accumulation. Minimizing the transfer of contaminants from soil to the food chain is a top priority. A number of options are proposed, including identification of the sources of contaminants to agricultural systems, minimization of contaminant inputs, reduction of heavy metal phytoavailability in soil with liming or other immobilizing materials, selection and breeding of low accumulating crop cultivars, adoption of appropriate water and fertilizer management, bioremediation, and change of land use to grow nonfood crops. Implementation of these strategies requires not only technological advances, but also social-economic evaluation and effective enforcement of environmental protection law.

Vaccines and diagnostics for zoonotic schistosomiasis japonica.

Schistosomiasis is one of the most prevalent, insidious and serious of the tropical parasitic diseases. Although the effective anthelmintic drug, praziquantel, is widely available and cheap, it does not protect against re-infection, drug-resistant schistosome may evolve and mass drug administration programmes based around praziquantel are probably unsustainable long term. Whereas protective anti-schistosome vaccines are not yet available, the zoonotic nature of Schistosoma japonicum provides a novel approach for developing a transmission-blocking veterinary vaccine in domestic animals, especially bovines, which are major reservoir hosts, being responsible for up to 90% of environmental egg contamination in China and the Philippines. However, a greater knowledge of schistosome immunology is required to understand the processes associated with anti-schistosome protective immunity and to reinforce the rationale for vaccine development against schistosomiasis japonica. Importantly as well, improved diagnostic tests, with high specificity and sensitivity, which are simple, rapid and able to diagnose light S. japonicum infections, are required to determine the extent of transmission interruption and the complete elimination of schistosomiasis following control efforts. This article discusses aspects of the host immune response in schistosomiasis, the current status of vaccine development against S. japonicum and reviews approaches for diagnosing and detecting schistosome infections in mammalian hosts.

Properties of self-consolidating concrete with recycled clay-brick-powder replacing cementitious material

Clay brick is becoming a major demolition waste and causing environmental contamination in China. Recycling of wasted clay brick could conserve natural resources and preserve land from waste filling. In this research, recycled clay-brick-powder (CBP) was used to partially replace Portland cement (PC) and fly ash (FA) in self-consolidating concrete (SCC) mix. The effects of dosage of CBP on the workability, strength, and shrinkage of SCC were investigated. Test results show that partially replacing cementitious material with CBP can reduce the workability of SCC. Compared with the reference concrete, specimens with CBP had higher 28-day and 56-day strength. The specimens containing 1% CBP had the highest compressive strength. Meanwhile, the replacement of CBP to PC and FA could also reduce the shrinkage of the SCC due to the internal curing effect. Based on scanning electron microscope investigation, specimen with CBP had less pores than the specimen without CBP and improved the microstructure of concrete. Hence, CBP had positive effects on the mechanical and physical properties of SCC.

Polychlorinated biphenyls removal from contaminated soils using a transportable indirect thermal dryer unit: Implications for emissions

An assessment in China of the application of a transportable indirect thermal dryer unit for the remediation of soils contaminated with polychlorinated biphenyls (PCBs) demonstrated that it is well suited to remove PCBs from soils. A remarkable reduction of total PCBs in soils from 163–770μgg−1 to 0.08–0.15μgg−1 was achieved. This represented removal efficiencies of greater than 99.9% and an approximate 100% removal of the toxic equivalent of the PCBs. Furthermore, the emissions to the atmosphere from the unit were in compliance with current PCBs regulations. In conclusion, remediation of PCBs-contaminated soils based on a transportable indirect thermal dryer unit appears to be a highly efficient and environmentally sound treatment technology that has huge implications for cleaning thousands of regionally dispersed sites of PCBs contamination in China.

Long-term follow-up of nephrotoxicity in rats administered both melamine and cyanuric acid

BackgroundMelamine was recently identified as a risk factor for renal calculi following the milk powder contamination in China. However, the long-term natural history of melamine exposure and its renal effects remain unknown. We evaluated renal function and other adverse health effects using a rat model administered melamine and cyanuric aid, considering age and sex.MethodsTwelve male F334/N rats each of ages 6, 10, and 26 weeks (N = 36) were equally assigned to Group M + C or controls. Group M + C rats were administered 12 mg · kg-1 · day-1 of melamine and cyanuric acid for 28 days. Serum and urine samples and kidney sections were evaluated on day 28. Six-week-old male and female F344/N rats were administered 12 mg of melamine and cyanuric acid for 28 days. Body weights were measured weekly; on days 0, 28, 90, and 180 after the 28-day period of melamine and cyanuric acid administration, serum samples and kidney sections were obtained.ResultsAlthough the control group had no crystals, 6-week-old Group M + C rats had more crystals compared to the 10- and 26-week old Group M + C rats. Male rats also had significantly more crystals than females of the same age. Male rats were affected to a greater extent than females.ConclusionYounger rats experienced more severe renal failure and greater renal crystal deposition following melamine and cyanuric acid administration. However, after melamine and cyanuric acid administration cessation, crystal deposition and renal failure improved and did not cause growth arrest. Therefore, early diagnosis of melamine-associated calculi is critical.

High diversity of human-pathogenic Enterocytozoon bieneusi genotypes in swine in northeast China

Despite the advances in defining Enterocytozoon bieneusi genotypes worldwide, rare genotypic surveys have been documented on this ubiquitous pathogenic protozoan in mammals in China, especially the role of pigs in zoonotic transmission of microsporidiosis remains unclear. In this study, the distribution of E. bieneusi genotypes in 113 duodenal mucosal specimens of pigs with acute diarrhea from 15 cities in northeast China was determined by PCR and DNA sequence analysis of the ribosomal internal transcribed spacer. The organism was detected in 51 (45.1%) pigs from 12 cities, with infection rates of the nursery pigs (21/33, 63.6%) significantly higher than the preweaned (25/61, 41.0%; P < 0.05) and the growing (5/19, 26.3%; P < 0.01) ones. E. bieneusi belongs to nine known human-pathogenic genotypes (D, EbpA, EbpC, EbpD, H, Henan-I, Henan-III, Henan-IV, and O) and eight new genotypes (CS-1 to CS-8). Genotypes D, EbpA, EbpC, EbpD, Henan-I, Henan-III, and Henan-IV have been found in human infections and D, EbpA, EbpC, and EbpD in wastewater in central China. The new genotypes were genetically clustered into a group of existing E. bieneusi genotypes with zoonotic potential. Considering the discovery of a high prevalence and wide genetic diversity of E. bieneusi zoonotic strains in pigs in northeast China and the co-occurrence of seven known genotypes in pigs and humans and four in pigs and wastewater, pigs probably served as a reservoir for human microsporidiosis and an important source of water contamination in China.

An Arsenic Forecast for China

A map of possible arsenic contamination in China's aquifers may guide mitigation efforts. [Also see Report by Rodríguez-Lado et al. ]

Measurement of &lt;sup&gt;15&lt;/sup&gt;N and &lt;sup&gt;18&lt;/sup&gt;O Isotope Abundance of Nitrate Using Denitrifier Method on Tracegas-Isotope Ratio Mass Spectrometry

A modified denitrifier method on Tracegas-isotope ratio mass spectrometry (IRMS) was developed to determine the nitrogen and oxygen isotopic compositions of nitrate (NO3-) in water samples. The protocol presented in our previous publication was modified in several aspects. Then, the incubation time, amount of NO3-sample, and effect of trapping time in the Tracegas system were analyzed using the standard reference USGS34. Both δ15N and δ18O values demonstrated accurate and reproducible at incubation times exceeding 12 h or overnight as well as added 0.2 μg to 0.4 μg NO3--N samples. Our data also showed that 100 s for trapping time in Tracegas system was adequate to achieve accurate and reproducible results. Finally, the δ15N and δ18O values of nitrate in animal wastewater were measured using this method. The results indicate that the denitrifier method can be used widely for tracing nitrate sources and controlling nitrate contamination in China.

Nitrate in groundwater of China: Sources and driving forces

Identifying the sources of reactive nitrogen (N) and quantifying their contributions to groundwater nitrate concentrations are critical to understanding the dynamics of groundwater nitrate contamination. Here we assessed groundwater nitrate contamination in China using literature analysis and N balance calculation in coupled human and natural systems. The source appointment via N balance was well validated by field data via literature analysis. Nitrate was detected in 96% of groundwater samples based on a common detection threshold of 0.2mgNL−1, and 28% of groundwater samples exceeded WHO's maximum contaminant level (10mgNL−1). Groundwater nitrate concentrations were the highest beneath industrial land (median: 34.6mgNL−1), followed by urban land (10.2mgNL−1), cropland (4.8mgNL−1), and rural human settlement (4.0mgNL−1), with the lowest found beneath natural land (0.8mgNL−1). During the period 1980–2008, total reactive N leakage to groundwater increased about 1.5 times, from 2.0 to 5.0TgNyear−1, in China. Despite that the contribution of cropland to the total amount of reactive N leakage to groundwater was reduced from 50 to 40% during the past three decades, cropland still was the single largest source, while the contribution from landfill rapidly increased from 10 to 34%. High reactive N leakage mainly occurred in relatively developed agricultural or urbanized regions with a large population. The amount of reactive N leakage to groundwater was mainly driven by anthropogenic factors (population, gross domestic product, urbanization rate and land use type). We constructed a high resolution map of reactive N source appointment and this could be the basis for future modeling of groundwater nitrate dynamics and for policy development on mitigation of groundwater contamination.

Occurrence and potential health risk of Cryptosporidium and Giardia in the Three Gorges Reservoir, China

The Three Gorges Reservoir (TGR) is the biggest lake in the world and a major water source in China. There is no information about occurrence and impact of Cryptosporidium and Giardia on the aquatic ecosystem. 61 surface water samples from 23 monitoring sites and 5 treated effluent samples were collected and analyzed. Cryptosporidium oocysts and Giardia cysts were found, respectively, in 86.4% and 65.2% of a total of 66 water samples, with high concentrations in treated effluent. The mean percent recovery was 29.14% for oocysts and 34.86% for cysts. A seasonal pattern was observed, with positive samples for Cryptosporidium more frequent in flood period and positive samples for Giardia more frequent in impounding period. Counts of enterococci, fecal coliforms and total coliforms, and turbidity were significantly associated with Cryptosporidium concentration in backwater (water in a main river which is backed up by the Three Gorges Dam) areas of tributaries but not Giardia. High associations were also found between oocyst and cyst in backwater areas of tributaries and cities. The risks of infection and illness due to water consumption in four different exposure routes were estimated. The results showed that swimming in the TGR has the highest infection risk with 1.39 × 10−3 per time (95% confidence interval (CI): 0.05–600.3 × 10−5) for Cryptosporidium and 2.08 × 10−4 per time (95% CI: 0.05–878.87 × 10−6) for Giardia, while directly drinking unboiled tap water treated with the conventional process has the highest morbidity with 524.98 per 100,000 population per year (95% CI: 10.35–2040.26) for Cryptosporidium and 5.89 per 100,000 population per year (95% CI: 0.08–22.67) for Giardia. This study provides new useful information for drinking water plants, health care workers and managers to improve the safety of tap water and deduce the risk of surface water contamination in China.