Richard K. Shaw

Trace Metal Contamination in New York City Garden Soils

Abstract Urban gardening, urban agriculture, and urban farming provide healthy food and promote environmental, social, cultural, and educational benefits. However, urban soil is a natural sink for contaminants derived mainly from historical anthropogenic activities. This article reports a summary of trace metal concentrations (Cr, Co, Ni, Cu, Zn, As, Cd, and Pb) of 1,652 garden soil samples from 904 gardens in New York City. Based on the Soil Cleanup Objective (SCO) criteria developed by New York State Department of Environmental Conservation (6 NYCRR Part 375). Many of the soils analyzed exceeded the limits for Pb, Cr, As, and Cd levels. Higher percentages of home gardens are contaminated than community gardens. When accounting for Pb and As levels, about 21% of the community garden samples and 71% of the home garden samples exceed respective SCO limits. Among all home and community garden samples, less than 3% meet the criteria for unrestricted use when all trace metals are considered. There are controversies on the appropriateness of SCO criteria for urban gardening situations. Consistent soil trace metal guidelines pertaining to gardening need to be developed. Expanded soil screening, greater public awareness, and education are urgently needed to ensure safe and successful urban agriculture.

Background concentrations of PAHs and metals in surface and subsurface soils collected throughout Manhattan, New York

ABSTRACT This article summarizes the results from a survey of polycyclic aromatic hydrocarbon (PAH) and metal concentrations measured in surface and subsurface soil samples that were collected from background locations throughout Manhattan, New York, between August 2005 and May 2006. The 95th percentile total 16 US EPA Priority Pollutant PAH concentrations in surface and subsurface soils were 24.8 and 53.1 mg/kg, respectively. Diagnostic PAH source ratios for surface and subsurface soils are presented, which provide plausible bounds for where these ratios would and would not be able to confidently differentiate background soils from soil samples that are impacted by PAH contamination. The 95th percentile concentrations for lead in surface and subsurface soils were 891 and 2,540 mg/kg, respectively, and the 95th percentile concentrations for mercury in surface and subsurface soils were 1.9 and 2.7 mg/kg, respectively. A not-unexpected finding of the study was that most surface soils and all subsurface soils contained a relatively high fraction of anthropogenic carbon, in addition to the presence of historic fill materials such as glass, brick, coal, and slag from more than 400 years of human activity on Manhattan Island. The concentration ranges for PAHs and metals measured in these background soil samples, coupled with the visual observations of historic fill materials in nearly all soil samples, emphasize that soils in Manhattan are altogether different from rural soils and thus warrant a different framework for site management decisions than rural soils.

Characterizing urban soils in New York City: profile properties and bacterial communities

PurposeThe influence of human activities on the development and functioning of urban soils and their profile characteristics is still inadequately understood. Microbial communities can change due to anthropogenic disturbances and it is unclear how they exist along urban soil profiles. This study investigates the dynamic soil properties (DSPs) and the bacterial communities along the profiles of urban soils in New York City (NYC) with varying degree of human disturbances.Materials and methodsEleven pedons were investigated across NYC as well as one control soil in a nearby non-urban area. Six soils are formed in naturally deposited materials (ND) and five in human-altered and human-transported materials (HAHT). For each soil, the profile was described and each horizon was sampled to assess DSPs and the bacterial community composition and diversity.Results and discussionThe development and the DSPs of NYC soils are influenced by the incorporation of HAHT materials and atmospheric deposits. The most abundant bacterial taxa observed in the NYC soils are also present in most natural and urban soils worldwide. The bacterial diversity was lower in some soils formed in ND materials, in which the contribution of low-abundance taxa was more restricted. Some differences in bacterial community composition separated the soils formed in ND materials and in dredged sediments from the soils formed in high artifact fill and serpentinite till. Changes in bacterial community composition between soil horizons were more noticeable in urban soils formed in ND materials than in those formed in HAHT materials which display less differentiated profiles and in the non-urban highly weathered soil.ConclusionsThe bacterial diversity is not linked to the degree of disturbance of the urban soils but the variations in community composition between pedons and along soil profiles could be the result of changes in soil development and properties related to human activities and should be consistently characterized in urban soils.

Soils in Urban Areas: Characterization, Management, Challenges

T he International Union of Soil Sciences (IUSS) Working Group on urban soils, SUITMA (Soils in Urban, Industrial, Traffic, Mining and Military Areas), was launched at the 16th IUSS World Congress in Montpellier in 1998. The group held its first conference in Essen, Germany, in 2001, with approximately 200 participants from 36 countries in attendance. It has met biennially since then, most recently this year in Mexico City. This special issue of Soil Science was planned to coincide with the eighth SUITMA conference and to collect some international perspectives on aspects of soils in urban areas. In light of increasing worldwide urbanization, the articles here examine some of the more important characteristics and applications of urban soils. The human factor in soil formation has been the subject of some classic articles in Soil Science: Bidwell and Hole, 1965, Yaalon and Yaron, 1966, and Amundson and Jenny, 1991. However, given the extent of global environmental change resulting from human activities, emphasized by the proposed term “Anthropocene” to describe the geologic epoch in which we live (Crutzen, 2002), there is a new urgency in the study of anthropogenic soil attributes and effects. Soil scientists need to characterize, classify, and map human-altered soils and to understand their properties and genesis in order to manage these soils to enhance sustainable delivery of ecosystem services. But to a degree, all soils will be affected by anthropogenically induced global change. Technogenic materials, or artifacts, are ubiquitous in urban soils, and their content is used as a differentiating criterion in several soil classification systems. Useful information on artifact identification in soils by chemical and geophysical surveying methods is provided by Howard and Orlicki; Abel et al. examine sulfate release dynamics from building rubble; and Huot et al. review pedogenesis in technogenic parent materials.

IUSS SUITMA 6 International Symposium 2011

Soils in urban, industrial, traffic, mining and military areas (SUITMA) is a working group of the International Union of Soil Sciences created in 1998 to increase and promote soil science in strongly anthropized areas (Morel and Heinrich 2008). Originally dedicated to basic soil science aimed at the description, analysis, classification, and mapping of soils developed in humantransformed environments, i.e., the SUITMAs, which exhibit contrasting features in comparison with natural soils, the SUITMA group interest has shifted towards the study of soil functions, their status and restoration, and their role in the functioning and evolution of urban ecosystems. Every 2 years, the SUITMA group organizes a conference (i.e., Essen, Nancy, Cairo, Nanjing, New York City, Marrakech) which gathers 100–150 scientists and professionals whose activities are centered in urban and peri-urban environments. The 2011 conference (SUITMA 6) was held in Marrakech, Morocco. It was co-organized by the Faculte des Sciences et Techniques of Marrakech and the GISFI (http://www.gisfi.fr). One hundred participants attended the conference and a total of 45 communications and 48 posters were presented in four sessions: session 1: SUITMA properties and diversity, contamination, and remediation; session 2: role of SUITMAs in global change and water quality; session 3: biodiversity in SUITMAs; and session 4: SUITMAs as buffer for human health and social stability. Eleven peer-reviewed papers are being published in this special issue of the Journal of Soils and Sediments, which focus on the properties, processes, evolution, and management of soils in urban and human-altered environments. Targets of study include soils with technic materials (Abakumov et al. 2013; El Khalil et al. 2013; Houben et al. 2013; Huot et al. 2013; Nehls et al. 2013; Schonsky et al. 2013), those with elevated metal contents (Aboudrar et al. 2013; Jean-Soro et al. 2013), soils in storm water infiltration basins (Coulon et al. 2013; El-Mufleh et al. 2013), and soils with landmines (Preetz et al. 2013). The conference was completed with a 2-day field trip in Marrakech and its vicinity to study the impacts of mining activities on soils, the consumption of agricultural soils by urbanization (e.g., the Palmeraie of Marrakech), the management of water in arid zones, and the creation of urban parks. During the meeting, Torun, Poland, was selected for the next conference (SUITMA 7, September 16–22, 2013; http://www.suitma7.umk.pl). SUITMA will also be present in 2014 at the 20th World Congress of Soil Science in Jeju, South Korea, with a symposium entitled “Urban soils—properties, functions, and evolution.” We look forward to welcoming new members and old friends at both events. N. Dickinson Department of Ecology, Lincoln University, PO Box 84, Lincoln, Canterbury 7647, New Zealand

Accumulation of arsenic and lead in garden-grown vegetables: Factors and mitigation strategies

Pesticides containing lead and arsenic were widely used in the US through the 20th century. Legacy contamination from this use poses a health risk as interest in cultivation of abandoned agricultural lands has grown in recent years. We addressed these risks by quantifying Pb and As in soils and produce from a suburban farm in New Jersey, USA and examining the ability of phosphate-bearing amendments (bone meal, triple super phosphate, manure compost and raised bed soil) in combination with Fe and/or Mn amendments to stabilize these metals and prevent their movement into vegetables. Common produce (tomato, carrot, lettuce, and radish) was grown in soils with 133-307 mg Pb kg-1 and 19-73 mg As kg-1. Our results suggest that vegetables produced on these soils can have Pb and As at levels above health and safety standards, especially root and leafy green vegetables. Phosphate-bearing amendments can reduce extractable Pb but can increase extractable As in soils, and can have similar effects on vegetables. Iron amendment increased both extractable Pb and As, likely due to the presence of elemental sulfur in the Fe amendment, which lowered soil pH, while Mn amendment had the opposite effect. Most of the Pb and As in vegetables appear to be associated with soil particles adhered to the vegetables, and the contribution from uptake was relatively small except for plots treated with Fe-amendments and for carrots. Thus, proper crop selection, rigorous cleaning, and dust and dirt control are critical to reduce the risk of contaminant exposure through the consumption of garden produce.

Estimation of soil organic carbon stocks of two cities, New York City and Paris

In cities, the strong heterogeneity of soils, added to the lack of standardized assessment methods, serves as a barrier to the estimation of their soil organic carbon content (SOC), soil organic carbon stocks (SOCS; kgC m-2) and soil organic carbon citywide totals (SOCCT; kgC). Are urban soils, even the subsoils and sealed soils, contributing to the global stock of C? To address this question, the SOCS and SOCCT of two cities, New York City (NYC) and Paris, were compared. In NYC, soil samples were collected with a pedological standardized method to 1 m depth. The bulk density (Db) was measured; SOC and SOCS were calculated for 0-30 cm and 30-100 cm depths in open (unsealed) soils and sealed soils. In Paris, the samples were collected for 0-30 cm depth in open soils and sealed soils by different sampling methods. If SOC was measured, Db had to be estimated using pedotransfer functions (PTFs) refitted from the literature on NYC data; hence, SOCS was estimated. Globally, SOCS for open soils were not significantly different between both cities (11.3 ± 11.5 kgC m-2 in NYC; 9.9 ± 3.9 kgC m-2 in Paris). Nevertheless, SOCS was lower in sealed soils (2.9 ± 2.6 kgC m-2 in NYC and 3.4 ± 1.2 kgC m-2 in Paris). The SOCCT was similar between both cities for 0-30 cm (3.8 TgC in NYC and 3.5 TgC in Paris) and was also significant for the 30-100 cm layer in NYC (5.8 TgC). A comparison with estimated SOCCT in agricultural and forest soils demonstrated that the citys open soils represent important pools of organic carbon (respectively 110.4% and 44.5% more C in NYC and Paris than in agricultural soils, for 0-30 cm depth). That was mainly observable for the 1 m depth (146.6% more C in NYC than in agricultural soils). The methodology to assess urban SOCS was also discussed.

Removal of Heavy Metals and Metalloids in an Industrial Stormwater Treatment System

This study examines the efficiency and process of metals and metalloids removal from the runoff by an innovative stormwater capture and treatment system at the SIMS Metal recycling site in New York City. This system is one of the very early pilots of stormwater management systems in New York City, and uses a combination of natural and engineering approaches (e.g., filtration capacity of soils and patented engineering designs). The runoff, with particulate and dissolved metals, metalloids and hydrocarbons, were directed into a vegetated field with engineered soil and mulch. The spatial distribution of metals and metalloids within the soil (soil surface and soil columns) and groundwater quality (water in the StormChambers and pumped to the surface) were evaluated. Even with less than 30 cm of topsoil, the system removes metal and metalloid contaminants efficiently.

Lead in New York City Soils

Urban soil is a sink for anthropogenic lead (Pb) and the latter is a persistent threat to human health, especially to children and the gardening population. In the past decade, several organizations have tested soil samples for Pb in New York City. Here we summarize the available soil Pb data for New York City and create a spatial distribution map. The highest Pb levels were present in the oldest parts of the city, and mostly industrial and high traffic areas. There is overlap between high Pb areas with areas of high population density and high poverty rates. The analyses help delineate parts of the city that are most affected, possible sources of Pb, and where to prioritize resources for mitigation and remediation.