Abstract Quantitative evaluation of ecological effect of combined pollution of heavy metals in real site soil is considered as a great issue in ecological risk assessment of contaminated sites. In this work, a quantitative ecological assessment approach for combined contaminated soil in field by heavy metals was developed based on “top-down” and “bottom-up” knowledge, which was made up of three steps, namely, “screening of effective biomarkers-identification of dominant pollutants-evaluation of joint effect of different exposure types/contaminants”. Finally, taking an abandoned electronic planting site in Jiangsu Province as a case, the developed approach was verified using soil microcosm of earthworm. Results of the experiment by taking the biomarkers including malondialdehyde (MDA), metallothionein (MT), catalase (CAT), superoxide dismutase (SOD), reduced glutathione (GSH)as effect endpoints, suggested that the bioaccumulation of main heavy metal contaminants including Cd, Cu, Zn, Ni, Pb and Cr by earthworms ranged in an order: Cd>Cu>Zn>Ni>Pb>Cr. Principal component analysis (PCA)revealed that GSH, CAT and MDA were screened as effective biomarkers, and heavy metals Cd and Zn were dominant contaminants. It was found that there was a significant multivariate linear relationship between the change of GSH and concentrations of total Cd and DTPA-Zn in soil. And the change of MDA could be predicted by DTPA-Cd in soil. The change of CAT activity was predictive by the total Zn in soil and the bioaccumulated Zn in earthworm. Evaluation of half effect dose (EC50) based on the site-specific soil properties and heavy metal contamination characteristics revealed that the sensitivity of the 3 screened effective biomarkers ranged in an order: GSH>CAT>MDA. Interactions will occur in between different heavy metals and exposure types (e.g., between soil total Cd and DTPA-Zn corresponding to GSH change), and (or) in between different exposure types of the same heavy metal (e.g., between soil total Zn and bioaccumulated Zn corresponding to the change of CAT activity).

Abstract The weathering of mining wastes with a high content of metallic sulfides is involved in the release and mobility of heavy metals, being one of the main risk factors for the environment and public health. In this work, two types of manure were used to evaluate their effect on the mobile or bioavailable chemical fractions of Cu in a soil contaminated with mining waste. An experiment was conducted using a soil artificially contaminated with 25% mining waste from Zimapán, to which increasing doses of composted cow and pig manure (0, 3, 6, 12 and 24%) were added. The pseudo-total Cu concentration was determined by atomic absorption spectrophotometry after acid digestion, while the Cu chemical fractions were determined from sequential extractions. The results obtained showed a high pseudo-total Cu concentration in the mining residues and low in the soil and in both types of manure. In the treatments with greater application of pig manure, there was a decrease in the concentration of soluble-interchangeable Cu and an increase in the concentration of Cu strongly bound to the organic fraction. While with cow manure there were higher concentrations of soluble-interchangeable Cu and an increase in the fraction of Cu weakly bound to the organic fraction.

Abstract The middle reaches of Xiaonan River, a tributary of Puhe River, was selected as the research object, the river water, river bottom mud, riverbank soil and surrounding vegetation at six monitoring points was collected as samples, and the content of heavy metals was detected by ICP-OES. The experimental results showed that:the main heavy metals in the Xiaona River are Cd, Cr, Cu, Ni, Pb and Zn, and the content of Cr and Zn is high, the content of Cr exceeds the third-level standard limit, and the pollution is most serious. Using the potential ecological risk index method to analyze, the damage coefficient of Cd was very strong, and overlying water and the riparian soil were seriously harmed. The migration characteristics of Cr and Zn with larger contents were different in the water, the content of Cr in the riparian soil was high, and the content of Zn in the river bottom mud was high. The absorption and transfer capacity of surrounding plants to Cd is the least, while that of Ni is the largest. The possible sources of pollution are analyzed by judging the contents of each heavy metal and using ecological risk index, so as to provide a basis for solving pollution from the source and protecting the ecological environment of the Puhe River Basin.

Abstract To investigate terminal equipment direct drinking water quality and sanitation status that sampled from community, school and home, and to provide evidence for the setting of standard, department supervision and consumer consumption. 232 samples were randomly sampled from community, school and home during June to November of 2019. The aerobic plate count, coliforms and Pseudomonas aeruginosa were detected in accordance with standard operating procedure provided by manual of China national food contamination and harmful factors risk monitoring 2019. The positive detection rates of aerobic plate count. Coliforms and Pseudomonas aeruginosa in 232 samples were 84.05%, 3.02% and 7.33%, respectively, the aerobic plate count was main contamination factor of fine drinking water, while Pseudomonas aeruginosa was the main pathogenic bacteria. The overall exceeded the standard rate of terminal equipment fine drinking water was 9.48%. The exceeded the standard rate ranked in order of high was the family, schools and community, compared the sampling link, which was 12.68% ､ 8.97% and 7.23%, respectively, and was not statistically significant between the groups ( χ 2 =1.36 , P>0.05). There was not seasonal variation regularity of the detection rate to the aerobic plate count, coliforms and Pseudomonas aeruginosa. The was different of exceeded the standard rate for every months, which was November > June > September > October > August > July, in order from higher to low, the exceeded the standard rate was 15.00%, 13.89%, 11.76%, 6.25%, 5.88% and 5.00%, respectively. There was not statistically significant between the groups( χ 2 =4.47, P>0.05). There were multiple contaminations of the aerobic plate count, coliforms and Pseudomonas aeruginosa in a single sample. The terminalequipment fine drinking water was commonly contaminated by aerobic plate count, coliforms and Pseudomonas aeruginosa, the aerobic plate count was the main pollution factor.

Abstract Science curricula emphasize the need to involve students in civil society issues related to science, highlighting the primacy of learning about the science-technology-society-environment relationship. The objective of this work is to know the students' learning when they get involved in the attempt to solve the problem related to the pollution of the stream near their school. The research methodology is qualitative, interpretative and based on participant observation. Twenty-one students from two 8th grade classes[1] with an alternative curriculum, living in a rural environment in southwestern Portugal, participated in the study. Data were collected through the teacher's diary, written documents and interviews with the students (conducted at the final of the study). The results reveal that the positive experiences provided by the radio club gave them confidence and encouraged them to engage in community activism related to the pollution of the local stream. This activism takes the form of a puppet show about sewage treatment. Also, the results show us that activism leads students to the identification of the science and technology issues that are at the root of the pollution of the creek, expanding their knowledge about the problem and discussing different perspectives for its solution. In addition, young people recognize that knowledge enables them to inform other members of the community and realize that they have the right to become involved in socio-scientific issues that affect their quality of life.