Pollution Characteristic And Distribution Of PAHs And PCBs In Tissues Of Goats

Polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) are listed in the primary group pollutants in "Stockholm Convention on Persistent Organic Pollutants" for their persistence, bioaccumulation and high toxicity. Persistent organic pollutants (POPs) have taken more attention from governments, academia and the public. PAHs and PCBs can accumulate along the food chain, via herbivores feeding into the ecosystem and then cause serious harm to senior consumers, including humans. Therefore, the study of the distribution and accumulation of PAHs and PCBs in vivo of herbivores can enrich the basic theory in terms of bio-accumulation, providing a theoretical basis for environmental management and food safety supervision, contributing to scientific assessment of potential environmental risks of PAHs and PCBs, and protecting human health and ecological safety.Supported by the Shandong Provincial Natural Science Foundation of China " The research on environmental background and bioavailability of persistent organic pollutants (POPs) in the province " and the Plan of Shandong Provincial Environmental Protection Science and Technology " POPs pollution characteristics and bioavailability of Shandong Province", etc., this study worked up a firstly and accurately method of PAHs and PCBs in tissues of goats in different ages, examined the concentrations of PAHs and PCBs in tissues of goats, indicating the level of contamination in vivo goats, component characteristics, distribution, accumulation and toxicity characteristics, exploring the difference and the mother-child transmission of PAHs and PCBs between parent and offspring, and identifying the main sources of PAHs and PCBs in vivo of the goats.1. Research on the analysis method of trace PAHs and PCBs in goatsThe analysis of PAHs and PCBs in animals are difficult to pre-treatment and purify for their trace concentration, complex components of tissues, etc. In this study, we developed a rapid and accurate analysis method by study of pretreatment technology and experimental parameters improvement basing on accelerated solvent extraction (ASE)+saponification-Gel Permeation Chromatography (GPC)+column chromatography combined purification+GC/MS-ECD chromatographic analysis of qualitative and quantitative analysis.(1) The parameters of ASE was studied, the results are as follows:mixed ratio of solvents hexane/acetone (1:1, V/V) were used to extract tissues samples, temperature was100℃and static extraction time was5min.(2) The matrix of saponification, GPC and silicone/florisil column was used to purify the extracts. The parameters of saponification:150mL NaOH (1.0mol/L), temperature60℃; The optimization parameters of GPC was to collect extracts from1000s to1800s. The extraction was then concentrated and treated with silicone or florisil column. The spiked recovery of16PAHs was from70.5%to113.6%. The spiked recovery of PCBs was from79.2%to109.0%, illustrating the effective separation and purification.(3) The parameters of GC-MS/ECD, using Dual-column system, were studied, and found an effectively method to analyze PAHs and PCBs in animal samples. The results found the spiked recovery of PAHs was in the range of79.8%-122.6%, the spiked recovery of PCBs was in the range of69.8%-90.6%. The relative standard deviation (RSD) of repeated plant samples was in the range of3.6%-18.5%, meeting the US EPA standard of recoveries (70%-140%) and RSD of repeated samples (<20%).2. The concentration and distribution of PAHs in tissues of goats(1) The concentration and compositional characteristics of PAHs in goats①The concentration of PAHs. The total concentrations of16PAHs in48-month goats were in the range of349.1-14818.7μg/kg wet weight (wet wt), in30-month goats were262.1-16405.2μg/kg wet wt, in18-month goats were189.7-18263.0μg/kg wet wt, and in2-month goats were273.3-16724.7μg/kg wet wt. The concentration levels were two times higher than some light pollution districts.①The compositional characteristics of PAHs. The main compositions were low molecular weight PAHs (LMW). The proportion of LMW PAHs was in the range of85.2%-99.0%. The high molecular weight PAHs (HMW) were not been detected in muscle, liver, heart and lung, consistently with other researches.(2) The distribution of PAHs in goats①The distribution among tissues in goats. The ascending order of16PAHs in2-month and18-month goats were muscle, lung, liver, heart, kidney, brain, adipose. The ascending order in30-month and48-month goats were muscle, liver, heart, lung, kidney, brain, adipose. The concentrations in muscle were always lower than other six tissues, and adipose always had the highest concentrations. The LMW PAHs were the main composition in all tissues.②Impact of the lipid content in tissues on the distribution of PAHs. The correlation analysis between lipid content and the concentration in the same tissues illustrated a significant correlation by the Pearson coefficient, p<0.05. It can explain that PAHs can easily accumulate in lipid.③Impact of age on the distribution of PAHs in goat. The concentrations of different age goats were similar to each other. There was a light increase of PAHs concentrations along with the increase of ages.④Mother-child transmission of PAHs. Between baby and lactating goats, correlation analysis shows significant positive correlation of16PAHs in tissues, which indicates mother-child transmission has occurred.(3) The toxic equivalent (TEQ) of PAHs. Benzo(a)pyrene (BaP) was studied as a risk marker for the total PAH exposure, to estimate the TEQ. The TEQs were1.8-196.3μg/kg wet wt,0.6-107.5μg/kg wet wt,1.1-246.6μg/kg wet wt and1.9-172.9μ/kg wet wt in48,30,18,2-month goats. The indicator carcinogenic PAHs in goats were Anthracene (AnT) and BaP.The values in tissues, other than muscle, were higher than the value of0.67ng/g wet wt recommended by USEPA for human health, indicating the harm of PAHs in goats.3. The concentration and distribution of PCBs in tissues of goats(1) The concentration and compositional characteristics of PCBs in goats①Concentration of PCBs. The total concentrations of7PCBs in48-month goats were in the range of100.6-2828.4ng/kg wet wt, in30-month goats were171.4-4102.1 ng/kg wet wt, in18-month goats were203.2-4167.5ng/kg wet wt, and in2-month goats were217.8-4026.6ng/kg wet wt. The total concentrations of12DL-PCBs in48-month goats were in the range of91.9-1392.2ng/kg wet wt, in30-month goats were89.6-2020.4ng/kg wet wt, in18-month goats were79.3-1453.5ng/kg wet wt, and in2-month goats were74.7-1360.6ng/kg wet wt. The concentration levels of7PCBs were lower than other animal. The concentrations of12DL-PCBs were2-5times higher than some animal in Dalian Bay.②Compositional characteristics of PCBs. The main compositions of7PCBs were PCB52(11.9%-88.2%), followed by PCB138,101, and28. The main compositions of12PCBs were PCB126(10.6%-54.2%), followed by PCB77,81,118,169.(2) The distribution of PCBs in goats①Distribution of PCBs among tissues in goats. The lowest concentrations of7PCBs presented in muscle (100.6-217.8ng/kg wet wt), and the highest concentrations presented in adipose (2215.2-4102.1ng/kg wet wt), or brain (2470.0-4167.5ng/kg wet wt). The lowest concentrations of12DL-PCBs presented in muscle (74.7-91.9ng/kg wet wt), and the highest concentrations presented in adipose (986.2-2020.4ng/kg wet wt), or brain (711.2-1453.5ng/kg wet wt). The main composition of PCBs were PCB52,126, followed by PCB101,138,77,81and169.②Impact of age on the distribution of PCBs. There was a light increase of PCBs concentrations along with the increase of ages. The main PCBs in low age goat were low chlorine PCBs, and the main PCBs in high age goat were high chlorine PCBs③Impact of the lipid content in tissues on the distribution of PCBs. The correlation analysis between lipid content and the concentration of PCBs in the same tissues indicated a significant correlation, the Pearson coefficient was p<0.05. It can explain that PCBs can easily accumulate in lipid.④Mother-child transmission of PCBs. Correlation analysis shows significant positive correlation of PCBs in tissues between baby and lactating goats, indicating the happen of mother-child transmission.(3) The toxic equivalent (WHO-TEQ) of PCBs. The TEQs were2.5-53.8ng/kg wet wt,2.6-69.7ng/kg wet wt,2.1-50.5ng/kg wet wt and2.0-69.7ng/kg wet wt in48,30,18,2-month goats. The indicator carcinogenic PCBs in goats were PCB126.4. Sources of PAHs and PCBs in goats(1) Sources of PAHs in goats①Correlation of PAHs between soil and goats. PAHs in liver presented highly significant correlation with soil (p<0.01). PAHs in lung, heart and kidney presented significant correlation with soil (p<0.05).②Correlation of PAHs between atmosphere and goats. PAHs in muscle, heart and liver presented significant correlation with atmosphere in heating seasons (p<0.05). PAHs in all tissues presented weak correlation with atmosphere in non-heating season.③Correlation of PAHs among grass, corn, wheat, water and goats. In48-month goats, PAHs in lung presented highly significant correlation with wheat (p<0.01), PAHs in muscle and heart presented significant correlation with wheat (p<0.05), these results showed that PAHs in48-month goats presented weak correlation with other food sources. In30-month goats, PAHs in muscle and liver presented highly significant correlation with grass in withering period (p<0.01), PAHs in liver and brain presented significant correlation with wheat (p<0.05), and PAHs in brain also presented significant correlation with water (p<0.05). In18-month goats, PAHs in liver and heart presented highly significant correlation with wheat (p<0.01), PAHs in liver presented significant correlation with grass in withering period (p<0.05), PAHs in lung presented significant correlation with wheat (p<0.05). In2-month goats, PAHs in muscle presented highly significant correlation with wheat (p<0.01), PAHs in heart and kidney presented significant correlation with wheat (p<0.05), PAHs in brain presented significant correlation with water (p<0.05).In summary, the main source of PAHs in goats were soil, atmosphere in heating season, grass in withering period, corn, wheat and water.(2) Sources of PCBs in goats①Correlation of PCBs between soil and goats. PCBs in muscle, liver, brain, adipose and kidney presented significant correlation with soil (p<0.05). ②Correlation of PCBs between atmosphere and goats. PCBs in muscle, heart, lung, brain, adipose and kidney presented highly significant correlation with atmosphere in heating seasons (p<0.01). PCBs in liver presented significant correlation with atmosphere in heating seasons (p<0.05). PCBs in all tissues presented weak correlation with atmosphere in non-heating season.③Correlation of PCBs among grass, corn, wheat, water and goats. In48-month goats, PCBs in liver presented significant correlation with water (p<0.05). In18-month goats, PCBs in liver presented significant correlation with corn (p<0.05). In2-month goats, PCBs in liver presented significant correlation with water (p<0.05).In summary, the main sources of PCBs in goats were soil, atmosphere in heating season and water, followed by corn.5. Photocatalytic degradation of POPsPOPs have been causing serious environmental problems. Photocatalytic degradation of these pollutants using solar energy is an attractive solution to the global problem. Accordingly, some scientific researches are now devoted to prepare these materials with high photocatalytic efficiency especially working under visible light. Carbon nitride materials are considered as novel types of non-metallic materials, which could be widely used in the field of pollution control owing to their remarkable large surface area and strong adsorption capacity. Herein, we report the synthesis of porous m-Fe-C3N4photocatalysts by using SiO2nanoparticles as template and dicyandiamide as precursor, and the physicochemical properties of synthesized m-Fe-C3N4and g-Fe-C3N4were characterized by X-ray diffractometer (XRD), transmission electron microscopy (TEM), UV-visible spectrophotometer (UV-vis), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) spectra and N2adsorption-desorption measurement. Moreover, their performance for photodegradation of Rhodamine B (RhB) was evaluated.