The efficiency of heterogeneous photocatalysis using N–F–TiO₂ as photocatalyst to degrade a priority pollutant, pentachlorophenol (PCP), in the presence of oxalates (OA) was investigated in detail. Response surface methodology was used to optimize the effect of three variables (catalyst concentration, OA/PCP ratio, and pH) on the photocatalytic degradation of pentachlorophenol. A quadratic model was established as a functional relationship between three independent variables and the degradation efficiency of PCP. The results of model fitting and statistical analysis demonstrated that the pH played a key role in the degradation of PCP. Within the studied experimental ranges, the optimum conditions for maximum PCP degradation efficiency (97.5 %) were: catalyst concentration 600 mg L⁻¹, OA/PCP ratio 2, and pH 10. The contribution of HO·, O₂ ·⁻, and e⁻ produced during the photocatalytic treatment was investigated with the addition of scavengers. The photocatalytic degradation was essentially proceeded through an oxidative mechanism at both acid and alkaline pH values by HO. and O₂ ·⁻ radicals attack. It was found that O₂ ·⁻ were the major reactive species involved in PCP degradation in pH 4 and HO· in pH 10.

This study aims to compare pregnancy outcomes in four contaminated areas to those observed in a non-contaminated area of similar socioeconomic status. A cross-sectional study was carried out. A structured and pre-tested questionnaire was administered to population-based samples of 788–920 families in each of the five studied areas. The exposure assessment used was an ecological measure. Using logistic regression, odds of several pregnancies outcomes (pregnancy occurrence, miscarriage, stillbirth, prematurity, low birth weight, congenital malformation, and multiple births) were estimated after adjustment for potential confounders such as socioeconomic, demographic, and substance abuse factors. We adopted a statistical significance level of 5 %. In three of the four exposed areas, pregnancy occurrence was reduced in comparison to the control area (Area 2, odds ratio (OR) = 0.68, 95 % CI = 0.54–0.86; Area 3, OR = 0.76, 95 % CI = 0.60–0.97; Area 4, OR = 0.71, 95 % CI = 0.56–0.90). Also, a significantly increased odds of miscarriage for living in Area 3 (OR = 1.83, 95 % CI = 1.07–3.12) was found. The other pregnancy outcomes were not significantly elevated in the exposed areas. In conclusion, this study shows evidence of reduced pregnancy occurrence and increased miscarriage occurrence in some of the contaminated areas, compared to the control area.

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are used in a wide range of products of all day life. Due to their toxicological potential, an emerging focus is directed towards their exposure to humans. This study investigated the PFAS load of consumer products in a broad perspective. Perfluoroalkyl sulfonic acids (C₄, C₆–C₈, C₁₀-PFSA), carboxylic acids (C₄–C₁₄-PFCA) and fluorotelomer alcohols (4:2, 6:2; 8:2 and 10:2 FTOH) were analysed in 115 random samples of consumer products including textiles (outdoor materials), carpets, cleaning and impregnating agents, leather samples, baking and sandwich papers, paper baking forms and ski waxes. PFCA and PFSA were analysed by HPLC-MS/MS, whereas FTOH were detected by GC/CI-MS. Consumer products such as cleaning agents or some baking and sandwich papers show low or negligible PFSA and PFCA contents. On the other hand, high PFAS levels were identified in ski waxes (up to about 2000 μg/kg PFOA), leather samples (up to about 200 μg/kg PFBA and 120 μg/kg PFBS), outdoor textiles (up to 19 μg/m² PFOA) and some other baking papers (up to 15 μg/m² PFOA). Moreover, some test samples like carpet and leather samples and outdoor materials exceeded the EU regulatory threshold value for PFOS (1 μg/m²). A diverse mixture of PFASs can be found in consumer products for all fields of daily use in varying concentrations. This study proves the importance of screening and monitoring of consumer products for PFAS loads and the necessity for an action to regulate the use of PFASs, especially PFOA, in consumer products.

An extensive and year-round survey was conducted to assess metal pollution in vast watershed areas of the Selenga River Basin (2007–2009), which provided baseline heavy metal database for the future management. Sources and environmental hazard and risk indices associated with metal pollution were evidenced across the countries of Mongolia and Russia (Buryatia Republic). In general, the concentrations of heavy metals in river water of Mongolia were greater than those of Russia, expect for the upstream of the Dzhida River in Russia. The spatial distribution generally indicated that metal pollution in the Selenga River was mainly associated with the activities in the Mongolian upstream regions. Similar pollution sources of metals between river water and wastewater associated with surrounding activities were found across the industrial and mining areas. Compositional patterns of metals suggested their sources were independent of each other, with hot spots in certain sites. Our measurements indicated that about 63 % of the locations surveyed (48 of 76) exceeded the critical heavy metal pollution index of 100, identifying possible harmful effects on aquatic ecosystems through metal pollution. Zinc was found to be the chemical of priority concern, as more than half of the locations exceeded the corresponding water quality guideline. Other metals including Mn, Fe, Cr, Cu, and As might be problematic in the Selenga River Basin considering the occurrence and their concentrations. Results of our extensive survey during the period of 3 years indicated that urgent action would be necessary in timely manner to improve water quality and mitigate the impact of heavy metals on aquatic environment of the Selenga River Basin.

The aims of this study were to provide basic data for determining policies on air quality for multi-user facilities, including the legal enrollment of the indoor air quality regulation as designated by the Ministry of Environment, and to establish control plans. To this end, concentrations of ten pollutants (PM₁₀, carbon monoxide (CO), carbon dioxide (CO₂), nitrogen dioxide (NO₂), formaldehyde (HCHO), total volatile organic compounds (TVOCs), radon (Rn), oxone (O₃), total bacteria counts (TBC), and asbestos) in addition to nicotine, a smoking index material used to determine the impact of smoking on the air quality, were investigated in indoor game rooms and lobbies of 64 screen golf courses. The average concentration of none of the ten pollutants in the game rooms and lobbies of screen golf courses was found to exceed the limit set by the law. There were, however, pollutant concentrations exceeding limits in some screen golf courses, in order to establish a control plan for the indoor air quality of screen golf courses, a study on the emission sources of each pollutant was conducted. The major emission sources were found to be facility users’ activities such as smoking and the use of combustion appliances, building materials, and finishing materials.

Persistent organic pollutants (POPs) have been of environmental and health concern for more than half a century and have their own intergovernmental regulation through the Stockholm Convention, from 2001. One major concern is the nursing child’s exposure to POPs, a concern that has led to a very large number of scientific studies on POPs in mothers’ milk. The present review is a report on the assessment on worldwide spatial distributions of POPs and of their temporal trends. The data presented herein is a compilation based on scientific publications between 1995 and 2011. It is evident that the concentrations in mothers’ milk depend on the use of pesticides and industrial chemicals defined as POPs. Polychlorinated biphenyls (PCBs) and “dioxins” are higher in the more industrialized areas, Europe and Northern America, whereas pesticides are higher in Africa and Asia and polybrominated diphenyl ethers (PBDEs) are reported in higher concentrations in the USA. POPs are consequently distributed to women in all parts of the world and are thus delivered to the nursing child. The review points out several major problems in the reporting of data, which are crucial to enable high quality comparisons. Even though the data set is large, the comparability is hampered by differences in reporting. In conclusion, much more detailed instructions are needed for reporting POPs in mothers’ milk. Temporal trend data for POPs in mothers’ milk is scarce and is of interest when studying longer time series. The only two countries with long temporal trend studies are Japan and Sweden. In most cases, the trends show decreasing concentrations of POPs in mothers’ milk. However, hexabromocyclododecane is showing increasing temporal concentration trends in both Japan and Sweden.

In this work, bioavailability and ecotoxicity of arsenite (As(III)) and arsenate (As(V)) species were compared between solution culture and soil system. Firstly, the adsorption of As(III) and As(V) was compared using a number of non-allophanic and allophanic soils. Secondly, the bioavailability and ecotoxicity were examined using germination, phytoavailability, earthworm, and soil microbial activity tests. Both As-spiked soils and As-contaminated sheep dip soils were used to test bioavailability and ecotoxicity. The sheep dip soil which contained predominantly As(V) species was subject to flooding to reduce As(V) to As(III) and then used along with the control treatment soil to compare the bioavailability between As species. Adsorption of As(V) was much higher than that of As(III), and the difference in adsorption between these two species was more pronounced in the allophanic than non-allophanic soils. In the solution culture, there was no significant difference in bioavailability and ecotoxicity, as measured by germination and phytoavailability tests, between these two As species. Whereas in the As-spiked soils, the bioavailability and ecotoxicity were higher for As(III) than As(V), and the difference was more pronounced in the allophanic than non-allophanic soils. Bioavailability of As increased with the flooding of the sheep dip soils which may be attributed to the reduction of As(V) to As(III) species. The results in this study have demonstrated that while in solution, the bioavailability and ecotoxicity do not vary between As(III) and As(V), in soils, the latter species is less bioavailable than the former species because As(V) is more strongly retained than As(III). Since the bioavailability and ecotoxicity of As depend on the nature of As species present in the environment, risk-based remediation approach should aim at controlling the dynamics of As transformation.

The effect on the environment of the operation of sludge treatment in reed beds (STRB) system is seen as quite limited compared to traditional sludge treatment systems such as mechanical dewatering, drying and incineration with their accompanying use of chemicals and energy consumption. There are several STRB systems in Denmark receiving sludge from urban wastewater treatment plants. Stabilization and mineralization of the sludge in the STRB systems occur during a period between 10 and 20 years, where after the basins are emptied and the sludge residue typically is spread on agricultural land. In the present study, the sludge residue quality after treatment periods of 10–20 years from four Danish STRBs is presented. After reduction, dewatering and mineralization of the feed sludge (dry solid content of 0.5–3 %) in the STRB systems, the sludge residue achieved up to 26 % dry solid, depending on the sludge quality and dimensioning of the STRB system. The concentration of heavy metals and hazardous organic compounds in the sludge residue that are listed in the Danish and EU legislation for farmland application of sludge was below the limit values. The nitrogen and phosphorus concentrations as an average in the sludge residue were 28 and 36 g/kg dry solid (DS), respectively. In addition, mineralization on average across the four STRB systems removed up to 27 % of the organic solids in the sludge. The investigation showed that the sludge residue qualities of the four STRBs after a full treatment period all complied with the Danish and European Union legal limits for agricultural land disposal.

Eighty-seven soil samples collected from North China were analyzed for decabromodiphenyl ethane (DBDPE). The concentrations of DBDPE ranged from undetectable to 1612 ng/g, with the highest concentration present in Shandong. Additionally, the mean concentration of DBDPE in Shandong was found to be onefold higher than those found in Hebei and Shanxi, likely due to DBDPE production in Shandong. Relatively high concentrations of DBDPE in soils were also present in the south of Tianjin, where e-waste recycling may provide a source in this region. The fractions of DBDPE [DBDPE/(DBDPE + BDE209)] were lower than 0.5 in most soil samples, in agreement with the fact that deca-BDE is currently the main additive in brominated flame retardants (BFR) used in China. An obvious decreasing trend in DBDPE concentrations from east to west in North China was noted, with relatively higher DBDPE concentrations present in Shandong. A soil ingestion exposure assessment showed that for most sites, soil ingestion EDI was slightly lower than inhalation EDI; exceptions were found in several polluted sites, where soil ingestion was a more significant exposure route.