Scattered literature is harnessed to critically review the possible sources, chemistry, potential biohazards and best available remedial strategies for a number of heavy metals (lead, chromium, arsenic, zinc, cadmium, copper, mercury and nickel) commonly found in contaminated soils. The principles, advantages and disadvantages of immobilization, soil washing and phytoremediation techniques which are frequently listed among the best demonstrated available technologies for cleaning up heavy metal contaminated sites are presented. Remediation of heavy metal contaminated soils is necessary to reduce the associated risks, make the land resource available for agricultural production, enhance food security and scale down land tenure problems arising from changes in the land use pattern.

/pdf/heavy-metals-in-contaminated-soils-a-review-of-sources-2f0ps3ifym.pdf

Heavy Metals in Contaminated Soils: A Review of Sources, Chemistry, Risks and Best Available Strategies for Remediation

Heavy metal removal from water/wastewater by nanosized metal oxides: a review.

http://www.eedu.org.cn/Article/UploadFiles/200906/2009061916001277.pdf

Health risk from heavy metals via consumption of food crops in the vicinity of Dabaoshan mine, South China.

https://repository.hanyang.ac.kr/bitstream/20.500.11754/110830/1/Heavy%20metals%20in%20food%20crops%20Health%20risks%2c%20fate%2c%20mechanisms%2c%20and%20management.pdf

Heavy metals in food crops: Health risks, fate, mechanisms, and management

http://www.jlakes.org/config/hpkx/news_category/2016-03-24/1-s2.0-S0160412015000021-main.pdf

Impacts of soil and water pollution on food safety and health risks in China

Health risks of heavy metals in contaminated soils and food crops irrigated with wastewater in Beijing, China

Ex situ conservation efforts are the last resort for many critically endangered species, and captive breeding centers are thought to provide a safe environment for producing individuals for eventual re-introduction to the wild. The giant panda (Ailuropoda melanoleuca) is one of the world's most endangered animals and is a widely recognized symbol for conservation. Here, we report that captive pandas in China experience environmental and dietary exposures to high concentrations of persistent organic pollutants (polychlorinated dibenzo-p-dioxins, dibenzofurans, and biphenyls) and heavy metals (arsenic, cadmium, chromium, and lead). In the short term, those animals exhibiting elevated levels of such toxins should be relocated to breeding centers in less contaminated areas. Ensuring the long-term survival of both captive and wild pandas depends in part on reducing atmospheric emissions of toxic pollutants throughout China.

/pdf/captive-pandas-are-at-risk-from-environmental-toxins-3j1dntkngt.pdf

Captive pandas are at risk from environmental toxins

The Qinling panda subspecies (Ailuropoda melanoleuca qinlingensis) is highly endangered with fewer than 350 individuals inhabiting the Qinling Mountains. Previous studies have indicated that giant pandas are exposed to heavy metals, and a possible source is vehicle emission. The concentrations of Cu, Zn, Mn, Pb, Cr, Ni, Cd, Hg, and As in soil samples collected from sites along a major highway bisecting the panda's habitat were analyzed to investigate whether the highway was an important source of metal contamination. There were 11 sites along a 30-km stretch of the 108th National Highway, and at each site, soil samples were taken at four distances from the highway (0, 50, 100, and 300 m) and at three soil depths (0, 5, 10 cm). Concentrations of all metals except As exceeded background levels, and concentrations of Cu, Zn, Mn, Pb, and Cd decreased significantly with increasing distance from the highway. Geo-accumulation index indicated that topsoil next to the highway was moderately contaminated with Pb and Zn, whereas topsoil up to 300 m away from the highway was extremely contaminated with Cd. The potential ecological risk index demonstrated that this area was in a high degree of ecological hazards, which were also due to serious Cd contamination. And, the hazard quotient indicated that Cd, Pb, and Mn especially Cd could pose the health risk to giant pandas. Multivariate analyses demonstrated that the highway was the main source of Cd, Pb, and Zn and also put some influence on Mn. The study has confirmed that traffic does contaminate roadside soils and poses a potential threat to the health of pandas. This should not be ignored when the conservation and management of pandas is considered.

/pdf/highway-increases-concentrations-of-toxic-metals-in-giant-5ftgqguqu2.pdf

Ying-juan Zheng

Papers

Health risks of heavy metals in contaminated soils and food crops irrigated with wastewater in Beijing, China

Captive pandas are at risk from environmental toxins

Highway increases concentrations of toxic metals in giant panda habitat

PBDEs (polybrominated diphenyl ethers) pose a risk to captive giant pandas.

Trace elements exposure of endangered crested ibis (Nipponia nippon) under in situ and ex situ conservations.