The rapid development of modern industries is accompanied with the aggravating water heavy metal pollution, which poses a potential threat to the aquatic environment and the health of local populations. As an efficient and economical adsorbent, biochar demonstrates the adsorption capacity for heavy metal ions and its adsorption capacity is significantly enhanced after modification. Therefore, biochar can effectively mitigate environmental pollution. By reviewing the existing studies, we summarize the modification methods of biochar, compare the advantages and disadvantages of physical, biological, and chemical modification methods, analyze the effects of modification on the adsorption capacity of biochar for heavy metal ions, and expound the modification mechanism of biochar. On this basis, this article puts forward the future research directions of the application of biochar in treating coexisting pollutants, aiming to provide a reference for the application of biochar in the purification of heavy metal-containing wastewater.
Charcoal/chemistry* ; Metals, Heavy ; Adsorption ; Wastewater/chemistry* ; Water Pollutants, Chemical/chemistry* ; Water Purification/methods* ; Heavy Ions ; Waste Disposal, Fluid/methods*

Objective To understand the status of field feces in Jingzhou City, so as to provide the evidence for improving the control measures to interrupt the transmission routes of schistosomiasis. Methods The distribution of field feces was investigated in 27 schistosomiasis endemic villages in Gong’an,Jianli,Jiangling,Honghu and Shishou counties(cities)from 2010 to 2012. The schistosome positive status of the field feces was surveyed with the hatching method. Results There were 1 366 field feces and the average density was 0.089 2 feces per 100 square meters in this survey. The cattle feces,human feces,dog feces and elk feces respectively accounted for 99.71%,0.07%,0.15% and 0.07% in the survey. The infection rates of the field feces were 1.46%and 2.42%in the channels and bottomlands,respectively(P>0.05). The average rate of infected field feces was 3.21%in 2010,0.36%in 2011,and 1.60%in 2012,and the difference between 2010 and 2012 was not statistically significant(P>0.05). Conclusions The main field feces come from cattle,and the main distribution of infected field feces is in channels and bottom-lands. Therefore,the management of cattle and treatment of field feces should be strengthened.

Objective To understand the key risk factors of schistosomiasis transmission in Jingzhou City,so as to provide the evidence for improving the treatment of these risk factors. Methods Each village of six counties was investigated and 3 envi-ronments were surveyed each village for the distribution of Oncomelania snails and animal stools in the field. The results were ana-lyzed and the risk factors of schistosomiasis transmission were assessed. Results The density of living snails was 0.43 snails per 0.1 m2,the frequency of the frames with snails was 9.12%,and no schistosome infected snails were found. All of the animal stools collected from the field were from bovines. The schistosome positive rate of animal stools was 37.50%(3/8)among the environ-ments,and the schistosome infection rate of stools was 8.11%(3/37). The schistosome infection rate of animal stools was 0 near the residence living sites,and the positive rates were 12.50%and 8.33%in the ditches and slopes,respectively(χ2=0.07,P>0.05). Conclusions Bovine is still the main infectious source of schistosomiasis,i.e. the main risk factor of the disease transmis-sion. Therefore,the strategy of controlling bovine should be strengthened.

Objective To evaluate the detection rate and the efficiency of the modified crushing-cercariae escaping method.Methods The detection rates of the modified crushing-cercariae escaping method and the crushing methods were compared by using a double-blind control experiment with the latter as a gold standard.meanwhile the number of the cercariae was quantified.The efficiency of the two methods aforementioned and the cereariae escaping method were compared in field.Results The detection rate of the modified crushing-cercariae escaping method was 100%.the average number of cercariae in each infected snail was (4 778±1 157);and the number in certain volume of water sample was positively correlated with the number of infected snails.The efficiency of the modified menthed Was 18.2 times and 17.3 times as high as those of the crushing method and cereariae escaping method,respectively.Conclusions The modified crushing-cercariae escaping method Can detect the infected snails quicky and Can quantify the number of infected snails and cercariae,and is suitable for the detection of infected snails in large number.

According to the National Scheme of Shistosomiasis Surveillance,the endemic situation in 8 national surveillance sites in Jingzhou City were monitored and analyzed.The results showed that the average human infection rate in 8 sites was 0.93%,and the rates in residents above 40 years old were high.People with positive results in fecal examination were all farmers,with an infection rate of 1.16%.The average infection rate of cattle was 6.26%.The total snail area was 1 511.50 hm~2,among which an area of 0.98 hm~2 was newly discovered and the area with infected snails was 1.17 hm~2.It concludes that the endemie situation in surveillance sites decreases year by year.However,the infection rate of earle still remains high and the snail status is still severe,which suggests that the control should be strengthened further.

A survey on schistosomiasis conducted in sampled 453 out of 1971 villages in Jingzhou City in the year of 2006. Miracidia hatching test demonstrated that the prevalence in human population was 3.9% (12 006/310 232), with sporadic cases of acute schistosomiasis, and the prevalence in cattle was 10.2%(270/2 651). The mean density of living snails was 0.67/0.11 m2(1 988/1 054 597) with a density of infected snails of 0.001 9/0.11 m2(1 988/713 486). In comparison to those of 2004, prevalence in humans decreased by 40.0%, prevalence in cattle increased by 22.3%; the snail-ridden area increased by 4.0%, but the mean density of living snails increased by 68.5% and the infected snail density increased by 18.8% with a decrease of 36.4% in snail infection rate. Consequently, there is an urgent need in controlling schistosome infection in cattle.