Natural Background and Anthropogenic Arsenic Enrichment in Florida Soils, Surface Water, and Groundwater: A Review with a Discussion on Public Health Risk

Florida geologic units and soils contain a wide range in concentrations of naturally-occurring arsenic. The average range of bulk rock concentrations is 1 to 13.1 mg/kg with concentrations in accessary minerals being over 1000 mg/kg. Florida soils contain natural arsenic concentrations which can exceed 10 mg/kg in some circumstances, with organic-rich soils often having the highest concentrations. Anthropogenic sources of arsenic have added about 610,000 metric tons of arsenic into the Florida environment since 1970, thereby increasing background concentrations in soils. The anthropogenic sources of arsenic in soils include: pesticides (used in Florida beginning in the 1890’s), fertilizers, chromated copper arsenate (CCA)-treated wood, soil amendments, cattle-dipping vats, chicken litter, sludges from water treatment plants, and others. The default Soil Cleanup Target Level (SCTL) in Florida for arsenic in residential soils is 2.1 mg/kg which is below some naturally-occurring background concentrations in soils and anthropogenic concentrations in agricultural soils. A review of risk considerations shows that adverse health impacts associated with exposure to arsenic is dependent on many factors and that the Florida cleanup levels are very conservative. Exposure to arsenic in soils at concentrations that exceed the Florida default cleanup level set specifically for residential environments does not necessarily pose a meaningful a priori public health risk, given important considerations such as the form of arsenic present, the route(s) of exposure, and the actual circumstances of exposure (e.g., frequency, duration, and magnitude).

Soil Contamination by a Lead Smelter in Brazil in the View of the Local Residents

A primary lead smelter operated in Santo Amaro City in Brazil from 1960 to 1993, leaving approximately 500,000 tons of industrial dross containing 2–3% of lead and other toxic elements that contaminated the industry grounds and the urban environment. This study aimed to present the local residents’ perception towards soil contamination by the smelter. In a cross-sectional study, 208 residents from randomly selected households were interviewed about dross hazards and proposals for its management. A city map depicts the distribution and concentration of lead, cadmium, arsenic, zinc, nickel, and antimony, measured in the soil of the 39 households with visible smelter dross. Only one site complies with the soil quality reference values; 27 (69.2%) call for preventive measures, and 11 (28.2%) require intervention. The smelter dross continues widely spread over the city. Thirty (76.9%) out of the 39 residents were able to recognize the smelter dross on household surroundings. However, this ability was not associated with the concentrations of toxic elements in the soil of their residences and surroundings. The smelter and the local Prefecture were most frequently held liable for taking soil cleanup actions. The most frequently (38.0%) cited solution for managing the dross found in the households was “to provide the residents with information about health risks related to the dross”.

Natural Background and Anthropogenic Arsenic Enrichment in Florida Soils, Surface Water, and Groundwater: A Review with a Discussion on Public Health Risk

Florida geologic units and soils contain a wide range in concentrations of naturally-occurring arsenic. The average range of bulk rock concentrations is 1 to 13.1 mg/kg with concentrations in accessary minerals being over 1,000 mg/kg. Soils contain natural arsenic concentrations of between 0.18 and 2.06 mg/kg with organic-rich soils having the highest concentrations. Anthropogenic sources of arsenic have added about 610,000 metric tons of arsenic into the Florida environment since 1970, thereby increasing background concentrations in soils. The anthropogenic sources of arsenic in soils include: pesticides (used in Florida beginning in the 1890’s), fertilizers, chromated copper arsenate (CCA)-treated wood, soil amendments, cattle-dipping vats, chicken litter, sludges from water treatment plants, and others. The default Soil Cleanup Target Level (SCTL) in Florida for arsenic in residential soils is 2.1 mg/kg which is below some naturally-occurring background concentrations in soils and anthropogenic concentrations in agricultural soils. A review of risk considerations shows that adverse health impacts associated with exposure to arsenic is dependent on many factors and that the Florida cleanup levels are very conservative. Exposure to arsenic in soils at concentrations that exceed the Florida residential cleanup level in residential environments does not necessarily pose a meaningful public health risk.

Assessing the Risk of Phthalate Ester (PAE) Contamination in Soils and Crops Irrigated with Treated Sewage Effluent

Waste/reclaimed irrigation water has been promoted due to water shortages in arid and semi-arid areas. However, this process may be one of the sources of phthalate esters (PAEs) in agricultural soils, and the potential risks of PAEs for soil ecosystems and human health have attracted considerable attention. A two-year (from October 2014 to October 2016) field experiment was conducted to assess the contamination risk of PAEs from reclaimed irrigation water in winter wheat (Triticum aestivum L.) and summer maize (Zea mays L.) fields on the North China Plain. Three types of irrigation water quality were arranged for each variety, including reclaimed water, groundwater, and a mixture of reclaimed water and groundwater (1:1, v/v). The results indicate that the concentrations of the 6 PAEs in topsoil ranged from 2.79 to 5.34 mg/kg at the time of crop harvest. There was no significant effect of reclaimed irrigation water on the concentrations of PAEs in the soil. Di-n-butyl phthalate (DnBP) and di (2-ethylhexyl) phthalate (DEHP) were the most abundant contaminants in all soil samples, accounting for 43.2%~68.7% and 27.1%~48.6%, respectively, of the 6 PAEs. The levels of dimethyl phthalate (DMP) and DnBP in all soil samples exceeded the allowable soil concentrations, but the levels were far below the recommended soil cleanup objectives. The grain yields of winter wheat and summer maize ranged from 4.35 to 7.1 t/ha and 1.03 to 6.46 t/ha, respectively. There were no significant effects of reclaimed water on the growth characteristics and grain yield of winter wheat (p > 0.05); however, the effect of reclaimed irrigation water on summer maize was influenced by climate. The concentrations of the 6 PAEs in wheat grain and maize grain ranged from 1.03 to 4.05 mg/kg and from 0.37 to 3.29 mg/kg, respectively. For the same variety, there was no significant difference in the concentrations of the 6 PAEs in cereal grains among different treatments (p > 0.05). DEHP and DnBP were the most abundant components in most crop samples, accounting for 31.6%~77.9% and 21.1%~64.7%, respectively, of the 6 PAEs. The concentrations of the PAEs, DnBP and DEHP in cereal grains were lower than those in the reference doses. The BCFs of the 6 PAEs and of each PAE in cereal grains were 0.43~1.25 and 0.33~35.75, respectively. The BCFs of butyl benzyl phthalate (BBP) were the highest (1.41~35.75), followed by DMP and DEHP. There were almost no significant differences in the BCFs of each PAE among the three treatments. The total carcinogenic risks of PAEs were 2.82 × 10−5 for adults and 1.81 × 10−5 for children. The total non-carcinogenic risks of PAEs were 3.37 × 10−1 for adults and 7.98 × 10−1 for children. DHEP was the dominant contributor to both risks, and the intake of cereals was the main exposure pathway for the two risks. In conclusion, there were no significant effects of reclaimed irrigation water on the concentrations of PAEs in soil and cereal grains compared with groundwater irrigation, and the human health risks were within the acceptable range. Long-term studies are needed to evaluate the long-term effects of reclaimed irrigation water on the contamination risk posed by PAEs.

Soil pollution and site remediation policies in China: A review

It was not until the 1980s that China’s policy makers became aware of the detrimental impacts on urban health from soil pollution as a result of industrial waste emissions. For the past three decades, the Chinese government has strived to prevent and control industrial pollution. Setting appropriate environmental policies is the key to mitigating the legacy of industrial waste emissions accumulated for three decades. In this paper, we review the development process by outlining the evolution of the policies and the resulting legal infrastructure in terms of acts, regulations, ordinances, and standards. Deficiencies of the existing policies are identified. In the early stages, environmental policies were fragmented, consisting of single-purpose laws that are narrowly focused. With time, these policies gradually evolved to become better integrated and comprehensive management plans. However, the laws emphasize contaminated site restoration instead of preventing soil pollution. The legal framework shows that the policies that are in place often lack clear mandates because the authorizations are piggybacked on environmental acts and regulations that do not directly address issues of soil pollution. Furthermore, implementation plans are impractical due to outdated soil quality standards, unclear soil cleanup goals, unenforceable liability and supervision mechanisms, limited funding, lack of transparency and public outreach, and the unreliable financial and technical capabilities of the remediation industries.