Arsenic Speciation and Localization in Horticultural Produce Grown in a Historically Impacted Mining Region

Abstract

A field and market basket study (~1300 samples) of locally grown fruits and vegetables from historically mined regions of southwest (SW) England (Cornwall and Devon), and as reference, a market basket study of similarly locally grown produce from the northeast (NE) of Scotland (Aberdeenshire) was conducted to determine the concentration of total and inorganic arsenic present in produce from these two geogenically different areas of the U.K. On average 98.5% of the total arsenic found was present in the inorganic form. For both the market basket and the field survey, the highest total arsenic was present in open leaf structure produce (i.e., kale, chard, lettuce, greens, and spinach) being most likely to soil/dust contamination of the open leaf structure. The concentration of total arsenic in potatoes, swedes, and carrots was lower in peeled produce compared to unpeeled produce. For baked potatoes, the concentration of total arsenic in the skin was higher compared to the total arsenic concentration of the potato flesh, this difference in localization being confirmed by laser ablation inductively coupled plasma mass spectroscopy (LA-ICP-MS). For all above ground produce (e.g., apples), peeling did not have a significant effect on the concentration of total arsenic present.

Cadmium and lead in vegetable and fruit produce selected from specific regional areas of the UK

“…Locally produced fruit and vegetables in retail outlets from the SW of Britian and NE Britian, as well as field crops and soil from the SW, were sampled as described in Norton et al (2013). The basket survey selected locally grown produce from a wide range of retailers as described in Norton et al (2013).…”

“…The basket survey selected locally grown produce from a wide range of retailers as described in Norton et al (2013). Samples were prepared by washing the produce to a level normally used in food preparation, in a kitchen sink using local tap water.…”

“…Once dry the samples were diced in a food processor then frozen before further processing. To establish the link between cadmium and lead in the produce and the concentration of cadmium and lead in the soil, both produce (fruit and vegetables in season) and soil in farmers' fields in the SW Britain geographic areas were sampled, with the farmers' permissions, as described in Norton et al (2013). A total of 174 soil samples were analysed along with corresponding crops, as well as 56 alternative preparations for produce eaten either peeled or unpeeled.…”

“…For each potato sample three individual potatoes were baked and samples prepared as described in Norton et al (2013). To compare the concentrations of cadmium and lead in the flesh and the skin a paired t-test was performed on the matching skin and flesh.…”

Perspective: City farming needs monitoring

“…Each potential location should be screened for contaminants and each variety of produce grown must be analysed, because of the differences in the accumulation of contaminants. For example, an extensive survey of fruit and vegetables in a historic mining region of southwest England showed that soil-dust-contaminated leafy vegetables and tuber crops contaminated by direct soil contact were important sources of toxic metals in commercial horticultural produce 3 . Monitoring of this kind is intensive, but the consequences of unsafe produce entering the food chain impel us to implement these measures for crops grown in cities.…”