Chelant-enhanced phytoextraction is one of the most promising technologies to remove heavy metals from soil. The key of the technology is to choose suitable additives in combination with a suitable plant. In the prese...Chelant-enhanced phytoextraction is one of the most promising technologies to remove heavy metals from soil. The key of the technology is to choose suitable additives in combination with a suitable plant. In the present study, laboratory batch experiment of metal solubilization, cress seeds germination were undertaken to investigate the metal-mobilizing capability and the phytotoxicity of organic additives, including ethylene diamine triacetic acid （EDTA）, citric acid, acetic acid, oxalic acid, glutamine and monosodium glutamate waste liquid （MGWL） from food industry. Experiments in pots were carried out to study the effects of the additives on Zn and Cd phytoextraction. Furthermore, a leaching experiment with lysimeter was performed to evaluate the environmental risks of additive-induced leaching to underground water. The results showed that EDTA had a strong mobilizing ability for Zn and Cd, followed by mixed reagent （MR） and MGWL. MGWL and acetic acid at 5 mmol equivalent per liter resulted in seed germination index less than 2%. Experiments in pots verified the phytotoxicity of acetic acid and MGWL. Addition of the mixed reagent at 6--10 mmol/kg significantly increased Zn phytoextraction by Thlaspi caerulescens. The same for EDTA and the mixed reagent at 10 mmol/kg by Sedum dfredii. But only mixed reagents could significantly increase Cd phytoextraction by the studied hyperaccumulators. This suggested that the strong chelant was not always the good agent to enhance phytoextraction. S. alfredii combined with 2--10 mmol/kg soil MR was preferred for phytoremediation of Cd/Zn contaminated soils in southern China, this could result in high phytoextraction of Cd/Zn and reduce the leaching risk to underground water than EDTA assisted phytoextration.展开更多
The use of lead in ammunition for hunting exposes waterfowl to lead poisoning (plumbism) by accidental consumption of shotgun pellets. To test this hypothesis we sampled 18 liver tissue samples of Snow Goose (Chen cae...The use of lead in ammunition for hunting exposes waterfowl to lead poisoning (plumbism) by accidental consumption of shotgun pellets. To test this hypothesis we sampled 18 liver tissue samples of Snow Goose (Chen caerulescens) collected during the 2012-2013 hunting season in a wetland near the city of Durango, Mexico. We quantified liver lead levels using an atomic absorption spectrophotometer and portions of liver were fixed and stained for their histological study. Average lead concentration (in dry weight) were under the normal range (mean = 0.73 ± 0.2, standard error) which do not represent any risk of poisoning. Liver tissue injuries were not observed in the histopathological analysis, suggesting no reaction to a xenobiotic agent such as lead. Gastrointestinal content analysis showed lead pellet in the gizzard of one individual, but we could not find a relationship between pellet ingestion and lead concentration in the liver. Although the results did not provide evidences of lethal or sublethal effects caused by lead poisoning, they show a possible risk due to the presence of lead pellets in the digestive tract.展开更多
基金The Hi-Tech Research and Development Program (863) of China (No. 2001-AA-640501-3)French-Chinese Programme deRecherche Avancee (No. PRA E-03-02) the National Natural Science Foundation of China (No. 40571141)
文摘Chelant-enhanced phytoextraction is one of the most promising technologies to remove heavy metals from soil. The key of the technology is to choose suitable additives in combination with a suitable plant. In the present study, laboratory batch experiment of metal solubilization, cress seeds germination were undertaken to investigate the metal-mobilizing capability and the phytotoxicity of organic additives, including ethylene diamine triacetic acid （EDTA）, citric acid, acetic acid, oxalic acid, glutamine and monosodium glutamate waste liquid （MGWL） from food industry. Experiments in pots were carried out to study the effects of the additives on Zn and Cd phytoextraction. Furthermore, a leaching experiment with lysimeter was performed to evaluate the environmental risks of additive-induced leaching to underground water. The results showed that EDTA had a strong mobilizing ability for Zn and Cd, followed by mixed reagent （MR） and MGWL. MGWL and acetic acid at 5 mmol equivalent per liter resulted in seed germination index less than 2%. Experiments in pots verified the phytotoxicity of acetic acid and MGWL. Addition of the mixed reagent at 6--10 mmol/kg significantly increased Zn phytoextraction by Thlaspi caerulescens. The same for EDTA and the mixed reagent at 10 mmol/kg by Sedum dfredii. But only mixed reagents could significantly increase Cd phytoextraction by the studied hyperaccumulators. This suggested that the strong chelant was not always the good agent to enhance phytoextraction. S. alfredii combined with 2--10 mmol/kg soil MR was preferred for phytoremediation of Cd/Zn contaminated soils in southern China, this could result in high phytoextraction of Cd/Zn and reduce the leaching risk to underground water than EDTA assisted phytoextration.
文摘The use of lead in ammunition for hunting exposes waterfowl to lead poisoning (plumbism) by accidental consumption of shotgun pellets. To test this hypothesis we sampled 18 liver tissue samples of Snow Goose (Chen caerulescens) collected during the 2012-2013 hunting season in a wetland near the city of Durango, Mexico. We quantified liver lead levels using an atomic absorption spectrophotometer and portions of liver were fixed and stained for their histological study. Average lead concentration (in dry weight) were under the normal range (mean = 0.73 ± 0.2, standard error) which do not represent any risk of poisoning. Liver tissue injuries were not observed in the histopathological analysis, suggesting no reaction to a xenobiotic agent such as lead. Gastrointestinal content analysis showed lead pellet in the gizzard of one individual, but we could not find a relationship between pellet ingestion and lead concentration in the liver. Although the results did not provide evidences of lethal or sublethal effects caused by lead poisoning, they show a possible risk due to the presence of lead pellets in the digestive tract.
