Massive PCDD/F contamination at the Khimprom organochlorine plant in Ufa--a review and recommendations for future management

Geographical distribution of dioxins, cadmium, and mercury concentrations in reindeer liver, kidneys, and muscle in the Russian Far North

Reindeer herding is a vitally important agricultural sector in the Russian Far North. It is believed that Northern ecosystems readily accumulate persistent pollutants because of trophic chains and climate features peculiar to the region. Reindeers graze on vast areas, and their seasonal migrations to distances of up to hundreds of kilometers in the North-South direction increase the likelihood of crossing a locally polluted area. Here, we present the results of a large-scale nationwide study of reindeer liver, kidneys, and muscle pollution by dioxins, cadmium, and mercury. Samples were taken in 2015-2020 from 41 locations in 8 reindeer-herding regions of Russia. Dioxins were determined in 383 samples of liver and 13 of muscle, and cadmium and mercury-in 505 samples of liver, 315 of kidneys, and 22 of muscle. Dioxin pollution has shown a clear geographical trend, i.e., liver concentrations of dioxins steadily decrease from the Western to the Eastern parts on the Russian Far North, with the highest concentration of 76.5 pg/g of fat WHO-TEQ. The discovered trend may be explained by the pattern of chemical plants' localization and by the density of reindeer population (as known from the literature sources). The highest concentrations of metals were found in kidneys (7.3 mg/kg of cadmium and 1.1 mg/kg of mercury). The contribution of local sources to cadmium and mercury pollution was found to be less than expected. We also suggest that reindeer liver may serve as a good additional indicator of environmental pollution by dioxins and heavy metals.

Insights into the Formation and Profile of Chlorinated Polycyclic Aromatic Hydrocarbons during Chlorobenzene and Chloroethylene Manufacturing Processes

Chlorinated polycyclic aromatic hydrocarbons including chlorinated naphthalenes and congeners with three to five rings are ubiquitous atmospheric pollutants. Congener profiles and formation mechanisms from typical chemical manufacturing have not been researched extensively. We measured the concentrations of 75 chlorinated naphthalenes and 18 chlorinated polycyclic aromatic hydrocarbons in raw materials, intermediates, products, and bottom residues from chemical plants producing monochlorobenzene and chloroethylene by different techniques. The findings confirmed that these chemical manufacturing processes are newly identified sources of atmospheric emissions of these compounds. More-chlorinated naphthalenes were formed from chloroethylene production than from monochlorobenzene production, which could be explained by the higher temperatures in the former process. Successive chlorination appeared to be an important formation pathway of polychlorinated naphthalenes according to their congener profiles and was supported by quantum chemical calculations of electrophilic chlorination on various positions of naphthalene. Chlorinated polycyclic aromatic hydrocarbons were more likely to be formed during the production of monochlorobenzene than chloroethylene. Moreover, we suggested that ring rearrangement and ring coupling are important transformation reactions between polychlorinated naphthalenes and chlorinated polycyclic aromatic hydrocarbons.

Assessment and review of organochlorine pesticide pollution in Kyrgyzstan

The current study describes the preliminary assessment and securing activities of the largest and most hazardous POPs-contaminated sites in Kyrgyzstan. In 2010, cattle died and population were found with high pesticide levels in blood, human milk, and placenta. In the first phase of the study, a historic assessment of the pesticide dumping at the landfill/dump sites have been conducted. In the second phase, soil analysis for organochlorine pesticides in the areas of the pesticide disposal sites, the former pesticides storehouses, agro-air strips, and the cotton-growing fields were conducted. By this assessment, a first overview of the types and sources of pollution and of the scale of the problem is compiled including information gaps. From major pesticides used, DDT, DDE, and HCH were measured in the highest concentrations. With the limited analytical capacity present, a reasonable risk assessment could be performed. This paper also reports on practical risk reduction measures that have been carried out recently at the two major pesticide disposal sites with support of a Dutch environmental engineering company, an international NGO (Green Cross Switzerland) and local authorities from the Suzak region within an UN project. Local population living near the sites of the former pesticide storehouses and agro-airstrips are advised not to cultivate vegetables and melons or to raise cattle on these areas. Instead, it is recommended to grow technical crops or plant trees. Further recommendations on monitoring and assessment is given including the suggestion to consider the findings in the National Implementation Plan of Kyrgyzstan.

Organochlorine pesticides in placenta in Kyrgyzstan and the effect on pregnancy, childbirth, and newborn health

Organochlorine pesticides (OCPs) were determined by gas chromatography in 241 placentas from cotton-growing regions, 121 placentas from an urban area (city of Osh), and 146 placentas from unpolluted mountain regions of Kyrgyzstan. Manifestations of disease were recorded in the mothers during pregnancy and parturition and in their newborns during the first 6 days of life. OCPs were detected in 240 out of 508 placentas (47.2%), with increased incidence in the two polluted regions (65%), particularly in placentas from women living near former pesticide storehouses and agro air-strips (99%), but only in 2.7% of placentas from the unpolluted region. α-, β-, and γ-hexachlorocyclohexane (HCH); DDT; DDE; aldrin; and heptachlor were detected. The sum of concentrations of all OCPs (total OCPs) was calculated for each of the 240 placentas with detectable OCPs (median 9.5 μg/kg placenta, mean 88.3 μg/kg, range 0.1-3070 μg/kg). The incidence of health problems in four subgroups of this data set, with increasing levels of total OCPs, was compared with the incidence of health problems in the group of 268 placentas, where OCPs were undetectable. Relative risk of health problems in both, mothers and newborns, increased significantly, in a concentration-dependent manner, with increasing levels of total OCPs (p < 0.0001). Health complications with increased incidence in OCP-exposed newborns included, i.a., low birth weight, congenital malformations, infections, and stillbirths, in OCP-exposed mothers preterm delivery, (pre-)eclampsia/gestosis, and frequency of hospitalizations after delivery (infections). Women living near former pesticide storehouses and agro airstrips should be considered as being at risk. Reduction of exposure is urgently needed.

Catalytic decomposition of dioxins and other unintentional POPs in flue gas from a municipal waste incinerator (MWI) in China: a pilot testing

Unintentionally produced persistent organic pollutants (UPOPs) include polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), dioxin-like polychlorinated biphenyls (dl-PCBs), pentachlorobenzene (PeCBz), and hexachlorobenzene (HxCBz). With the booming of municipal waste incinerators (MWIs) in China, the emission of UPOPs has generated great concern. As an alternative technology of dioxin control, catalytic decomposition has not been used in China, mainly due to the absence of national demonstration projects. Also, the simultaneous removal of various UPOPs has not been well investigated.In this study, a pilot-scale selective catalytic oxidative (SCO) system using a self-developed honeycomb catalyst was built and tested in a typical municipal waste incinerator (MWI) of China. The original concentration of PCDD/Fs in flue gas after the treatment of activated carbon injection (ACI) still exceeded the national emission standard (0.1 ng I-TEQ/Nm³), while the concentrations of PeCBz and HxCBz were one order of magnitude higher than that of PCDD/Fs. For the testing temperature varying from 300 to 200 °C, the removal efficiency of PCDD/Fs range from 39 to 95 %, followed by dl-PCBs with the range of 56-89 %. PeCBz and HxCBz were also removed, though their removal efficiencies were lower than those of PCDD/Fs and dl-PCBs. Both temperature and degree of chlorination influence the removal efficiencies.

Microbial communities in pesticide-contaminated soils in Kyrgyzstan and bioremediation possibilities

In Kyrgyzstan, many former storehouses and dump sites for obsolete pesticides exist. In 2009/2010, an inventory and assessment of these sites including risks of environmental hazard has been conducted by FAO and the World Bank. Monitoring revealed high concentration of pesticides listed as persistent organic pollutants (POPs). The purpose of this research was to study the microbial structural complexes of the pesticide-contaminated soils in these dumping zones, and to search for and select microorganism's destructors with cytochrome P450 genes for pesticide degradation. Culture-dependent and culture-independent approaches were used to determine the taxonomic composition of these bacterial communities. The universal primer set for the 16S ribosomal RNA (rRNA) gene and the specific primer set P450R were used to amplify the cytochrome P450 hydroxylase gene. In soils from Suzak A and B and soils from Balykchy dumping sites, the bacteria from the Actinobacteria phylum (Micrococcus genus) were dominant. These bacteria made up 32-47% of the indigenous local microflora; bacteria species from the Pseudomonas genus (Gammaproteobacteria phylum) made up 23% in Suzak, 12% in Balykchy soils. Bacillus species from the Firmicutes phylum were found only in Suzak soils. The 16S rRNA analyses and the specific primer set P450R have revealed bacteria with cytochrome genes which are directly involved in the degradation process of organic carbon compounds. Experiments were carried out to help select active degraders from the bacterial populations isolated and used to degrade Aldrin in laboratory. Active bacterial strains from the Pseudomonas fluorescens and Bacillus polymyxa population were selected which demonstrated high rates of degradation activity on Aldrin.

Dioxins and furans legacy of lindane manufacture in Sabiñánigo (Spain). The Bailín landfill site case study

Lindane (γ-hexachlorocyclohexane) manufacture in Spain generated nearly 200,000tonnes of HCH wastes; near 160,000tonnes were originated by the Inquinosa factory located in Sabiñánigo (northern Spain) and were deposited in unlined landfill sites. This study reports for the first time the content of polychlorinated dibenzo-p-dioxin/dibenzofuran (PCDD/Fs) in non-recycled HCH wastes that had been disposed in the Bailín landfill site in Sabiñánigo. Samples from solid HCH powder residues (white HCH and δ-paste wastes) and the dense non-aqueous phase liquids (DNAPLs), as well as landfill leachates, soil and sediments have been characterized. White HCH wastes exhibited a toxicity of 1488ngWHO-TEQ₂₀₀₅·kg^-1 (Σ₁₇ PCDD/Fs), while δ-paste wastes presented a noticeable higher toxicity (12,094ngWHO-TEQ₂₀₀₅·kg^-1). Nevertheless, the maximum toxicity value was found for DNAPLs (37,353ngWHO-TEQ₂₀₀₅·L^-1). Dioxins were predominant in the DNAPL waste whereas furans predominated in the landfill leachates, soil and sediments. However, in solid HCH wastes, PCDD and PCDFs contributed in a similar proportion. The PCDD/Fs congener profiles in landfill leachates, soil and sediments do not resemble the PCDD/Fs profiles found for the HCH wastes. These preliminary results will be of paramount importance in order to estimate the total quantities of PCDD/Fs disposed to the landfill site and to assess the potential mobility of PCDD/Fs, especially to groundwater and landfill leachates. Besides, this information is of great value to design periodical monitoring plans to evaluate the presence of PCDD/Fs in the impacted groundwater and leachates and finally, to evaluate the risk of PCDD/Fs for the environment and human health.

Genetic Bioaugmentation of Activated Sludge with Dioxin-Catabolic Plasmids Harbored by Rhodococcus sp. Strain p52

Horizontal transfer of catabolic plasmids is used in genetic bioaugmentation for environmental pollutant remediation. In this study, we examined the effectiveness of genetic bioaugmentation with dioxin-catabolic plasmids harbored by Rhodococcus sp. strain p52 in laboratory-scale sequencing batch reactors (SBRs). During 100 days of operation, bioaugmentation decreased the dibenzofuran content (120 mg L^-1) in the synthetic wastewater by 32.6%-100% of that in the nonbioaugmented SBR. Additionally, dibenzofuran was removed to undetectable levels in the bioaugmented SBR, in contrast, 46.8 ± 4.1% of that in the influent remained in the nonbioaugmented SBR after 96 days. Moreover, transconjugants harboring pDF01 and pDF02 were isolated from the bioaugmented SBR after 2 days, and their abilities to degrade dibenzofuran were confirmed. After 80 days, the copy numbers of strain p52 decreased by 3 orders of magnitude and accounted for 0.05 ± 0.01% of the total bacteria, while transconjugants were present at around 10⁶ copies mL^-1 sludge and accounted for 8.2 ± 0.3% of the total bacteria. Evaluation of the bacterial community profile of sludge by high-throughput 16S rRNA gene sequencing revealed that genetic bioaugmentation led to a bacterial community with an even distribution of genera in the SBR. This study demonstrates the promise of genetic bioaugmentation with catabolic plasmids for dioxins remediation.

Threats to water resources from hexachlorobenzene waste at Kalush City (Ukraine)--a review of the risks and the remediation options

The production of chlorinated solvents such as tetrachloroethylene and tetrachloromethane has resulted in large stockpiles of unintentionally produced persistent organic pollutants (POPs) including high content of hexachlorobenzene (HCB waste). HCB waste of 15,000 t arising from the production of chlorinated solvents at the Kalush factory in Ukraine was landfilled. In 2008, it was discovered that HCB and other pollutants were escaping from the landfill into local environment including the Sapogi-Limnytsia Rivers, tributaries of the Dniester River. This showed that the HCB waste was not appropriately contained and represented a threat to the Dniester River basin. A Presidential Decree of Ukraine was therefore issued requiring remediation of the site and excavation of the waste. Between 2010 and 2013, approximately 29,445 t of HCB waste and associated contaminated soil was excavated and exported to various EU countries for incineration. This excavation revealed that these wastes can corrode through their drums within a few decades with release of pollutants. Other sites at which chlorinated solvents were produced should therefore be assessed for possible similar pollution. Despite the remediation efforts and the excavation of the landfill, the Kalush area remains a POP-contaminated site requiring further assessment. A part of the waste was exported to Poland and is stored close to the Baltic Sea and is treated in an incinerator with small capacity over a time frame of years. This case and recent similar cases reveal that the control of POP waste for destruction even in EU countries needs to be improved.