**6. Mitigation and control of dioxins and furans**

Various techniques are available for the controlled emission of dioxins and furans depending upon the type of feed stocks. Some popular and effective methods are: using sulfur compounds namely (NH<sup>4</sup> )2 SO<sup>4</sup> , pyrite (FeS2 ), changing the operating conditions of incinerations. Present chapter discuss methods to minimize effect of dioxins and benzofurans and their formation in different types of incineration systems. Municipal solid waste incineration system, hazardous solid waste incineration system and bio medical waste incineration system. Formation mechanism and the various sources including the precursors of PCDD/Fs formation need to be controlled during the combustion. It is also evident through literature that risk management strategies to reduce polychlorinated dibenzo-dioxins (PCDDs) and dibenzofurans (PCDFs) exposure, consideration may be given to the potential impact of changes to food and nutrition policies, particularly those related to public health and food.

female and disrupt the sperm production in male progeny. Many diseases like hypospadias, ectopic testes, vaginal pouches, agenesis of the ventral prostate, and nipple retention were notice [43]. Exposure to TCDD leads to prevalence and complication endometriosis [44]. Dioxin and furans are well declared endocrine disrupters thus lessened the production of thyroid hormones [45–47]. Exposure of wildlife to dioxins cause many reproductive variations such as cryptorchidism in the Florida panther, small baculum in young male otters,

TCDD/PCDFs are recommended highly damaging to immune system and thus decreasing host resistance to infectious diseases and lowered immune responses. Dioxins also disturb production of inflammatory cytokines such as interleukin and necrosis factor [48]. TCDD/ PCDFs significantly affect the neuron populations of vertebrate brain; however their damage to brain function is still not clear and need more research to reveal the truth. It is noticed that TCDD/PCDFs affect the gonadal and thyroid hormones and slow down the neural transmis-

Chloracne is a skin damaging condition with both hyper keratotic and hyper proliferative responses of the epidermis is caused by the exposure of TCDD/Fs. Many animals such as cows, horses and rabbits also revealed this disease notice [50]. In addition to these, loss of sebaceous gland and atrophy of hair follicle also noticed due the severe exposure of TCCD/ PCDFs [51]. With the exposure to TCDD/PCDFs excessive keratinization may also occur in

Some biochemical changes also seen with exposure to congeners of TCDD/Fs [53]. It was noticed that insulin level goes down after TCDD/PCDFs massive accumulation. It is also observed TCCD/PCDFs exposure effect the body growth, deplete the energy stores and thus organism has to lower insulin level to sustain blood glucose levels. On the other side tryptophan concentrations of brain increase, due to increase free fatty acids in blood circulation. These changes allow tryptophan to compete with binding site of albumin and help its transport to central nervous system [54]. Similarly, oxidative processes have been considered

necessary for metabolic (e.g., porphyria) and morphological damage of the liver [55].

10 mg TCDD/kg for a 16 week period resulted in ovarian atrophy in mice [58] .

**6. Mitigation and control of dioxins and furans**

, pyrite (FeS2

)2 SO<sup>4</sup>

Another study reports that TCCD/PCDFs have effects on female Rhesus monkeys when exposed to 0, 5, or 25 ng/L in their diet for 4 years and then protected for 10 additional years. It was noticed that these monkeys caught with severity of endometriosis [56]. On the other hand, endometriosis cyst growth in both rats and mice has also been enhanced by exposure to TCDD/PCDFs at very low doses where no ovarian toxicity occurred [57]. However, a dose of

Various techniques are available for the controlled emission of dioxins and furans depending upon the type of feed stocks. Some popular and effective methods are: using sulfur com-

), changing the operating conditions of incinerations.

small penises in alligators, sex reversal in fish, and altered social behavior in bird [45].

118 Air Pollution - Monitoring, Quantification and Removal of Gases and Particles

sion network [49].

dermal epithelium [52].

pounds namely (NH<sup>4</sup>

There are number of technologies practiced around the globe to control combustion practice coupled with end of pipe treatment. Most preferably these are selective catalytic reduction, addition of suitable inhibitors for dioxins and furans eradication in the flue gas of waste incinerators. A brief background with pictorial images of the present technologies has been presented in this chapter (**Figure 2**) three different technologies used for the control of dioxins and furans have been discussed. Selective catalytic oxidation or reduction (SCR) using NH3-SCR catalysts (commercial V2 O5 -WO3 /TiO2 ) could effectively promote the decomposition of PCDD/PCDFs without hampering the normal operating conditions of the incineration studied by [60]. Vermeulen et al. added urea for the purpose of decomposition of dioxins reducing it upto 90% under the same operating conditions as of ammonia [59]. In the process of adding compounds of sulfur to control the formation different congeners of PCDD/PCDFs (**Figure 3**) the feedstock is firstly prepared, homogenized with crushing and adding into the rotary kiln. The emission of dioxin compounds were controlled by a series of operations that includes quenching tower, acid neutralizing tower, wet scrubber, bag filter and activated

**Figure 2.** Inhibition of PCDD/PCDFs by the aid of V2 O5 -WO3 /TiO2 catalysts [59].

ambient air. The concentrations of PCDD/PCDFs in the environment are not well controlled due to many reasons like temperature variations and seasonal pattern. Although a large no of research studies have been conducted to investigate and control PCDD/PCDFs but even then information is limited to get about these compounds therefore it is difficult to get rid of them. Further investigations should be conducted to establish a comprehensive approach to investigate the recent profiles of PCDD/PCDFs found in various parts of the world especially in developing countries. This chapter will help the stake holders in decision making process to establish a sustainable waste management system in future. New and better innovative

Dioxins and Furans: Emerging Contaminants of Air http://dx.doi.org/10.5772/intechopen.80680 121

research plans are necessary for addressing the problems related to pollution.

Department of Chemistry, Faculty of Science, University of Gujrat, Pakistan

Environmental Science and Pollution Research. 2010;**17**(1):49-63

Health Risks. Springer Science & Business Media; 2012

Environment. 2014;**466**:586-597

[1] Colbeck I, Nasir ZA, Ali Z. The state of ambient air quality in Pakistan—A review.

[2] Zhang Q, Jiang X, Tong D, Davis SJ, Zhao H, Geng G, et al. Transboundary health impacts of transported global air pollution and international trade. Nature. 2017;**543**(7647):705

[3] Kumar JM, Deepika D, Srinithya B, Kalaichelvan P. Polychlorinated dibenzo P dioxins and furans—A review. International Journal of Current Research and Review.

[4] Boffetta P, Gouas DA, da Costa AN, Abedi-Ardekani B, Hainaut P. Cancers of the Intestine, Liver, and Biliary Tract. Occupational Cancers. Springer; 2014. pp. 127-137 [5] Safe S, Hutzinger O, Hill TA. Polychlorinated Dibenzo-p-Dioxins and-Furans (PCDDs/ PCDFs): Sources and Environmental Impact, Epidemiology, Mechanisms of Action,

[6] Hoogenboom RL, ten Dam G, van Bruggen M, Jeurissen SM, van Leeuwen SP, Theelen RM, et al. Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and biphe-

[7] Urban JD, Wikoff DS, Bunch AT, Harris MA, Haws LC. A review of background dioxin concentrations in urban/suburban and rural soils across the United States: Implications for site assessments and the establishment of soil cleanup levels. Science of the Total

nyls (PCBs) in home-produced eggs. Chemosphere. 2016;**150**:311-319

\*Address all correspondence to: muhammad.zubair@uog.edu.pk

**Author details**

**References**

2013;**5**(3):14

Muhammad Zubair\* and Amina Adrees

**Figure 3.** Flow diagram of sulfur dioxide circulation system [61].

**Figure 4.** Flow diagram of the waste incinerator that uses thiourea (1: feeder; 2: furnace; 3: cyclone separator; 4: SNCR; 5: secondary combustion chamber; 6: boiler; 7: semi-dry spray neutralizer; 8: AC injector; 9: bag house filter; 10: stack; 11: dissolving tank) [60].

carbon dosing [61]. One important criterion to optimize the minimization of PCDD/PCDFs is the proper selection of sulfur compounds. In third technology, compounds of nitrogen such as ethanolamine, mono-ethanolamine (MEA), urea, ammonia, tri-ethanolamine, di-methylamine were added to control the formation of dioxins and furans. It was studied that thiourea is a suitable dioxin inhibitor with high S and N-content **Figure 4** [61].

#### **7. Conclusions**

The concentration of PCDD/PCDFs in environment has been increased up to the range of toxicity so these compounds may affect the biological systems. There are various means of production of PCDD/PCDFs which has significant impact on rise of levels of these compounds in ambient air. The concentrations of PCDD/PCDFs in the environment are not well controlled due to many reasons like temperature variations and seasonal pattern. Although a large no of research studies have been conducted to investigate and control PCDD/PCDFs but even then information is limited to get about these compounds therefore it is difficult to get rid of them. Further investigations should be conducted to establish a comprehensive approach to investigate the recent profiles of PCDD/PCDFs found in various parts of the world especially in developing countries. This chapter will help the stake holders in decision making process to establish a sustainable waste management system in future. New and better innovative research plans are necessary for addressing the problems related to pollution.
