Study on the effect of grain storage and processing on deltamethrin residues in post-harvest treated wheat with regard to baby-food safety requirements

The effects of storage intervals and of milling procedures on dissipation of deltamethrin residues in post-harvest treated wheat grain were studied with the aim to obtain scientific data on compliance of the processed products with the safety requirements concerning baby foods. The insecticide formulation was applied on stored wheat at a recommended rate of active ingredient of 0.5 mg kg^-1 and at a higher rate of 4 mg kg^-1, performing the highest protective effect. The dissipation of residues and their distribution in different fractions of the milled grain were studied after various storage intervals, from 7 to 270 days after treatment. Eight fractions—bran, semolina, three types of groats, and three types of flour—were collected after milling of grain and analysed for determination of pesticide residues. The residues were determined by gas chromatography characterized by the limit of determination of 0.005 mg kg^-1, low enough for enforcement of the maximum residue level of 0.01 mg kg^-1 established by the European Commission Directive for any pesticide in cereal-based foods. Deltamethrin applied post-harvest on wheat as grain protectant was distinguished by low rate of degradation on the grain under practical storage conditions. One hundred and eighty days after treatment at an application rate of 0.5 mg kg^-1, the residues were between 0.03 and 0.2 mg kg^-1 in the various types of flour. Two hundred and seventy days after treatment at a rate of 4 mg kg^-1, the residues in the flour were in the range of 0.4-1.5 mg kg^-1.     

Residues of DDT and HCH in wheat samples collected from different states of India and their dietary exposure: A multicentre study

Under a multicentre study conducted by the Indian Council of Medical Research, 1712 samples of wheat grain/flour were collected from urban and rural areas in 11 states representing different geographical regions of India. These samples were analysed for residues of DDT (2,2-bis (p-chlorophenyl)-1,1,1-trichloro ethane) and different isomers of HCH (1,2,3,4,5,6-hexachloro cyclohexane, a mixture of isomers) by gas-liquid chromatography. Residues of DDT were detected in 59.4% of 1080 samples of wheat grain and in 78.2% of 632 samples of wheat flour. Different isomers of HCH were present in about 45-80% of the samples of wheat grain/flour. Medians of DDT and total HCH, respectively, for pooled samples of wheat grain were 0.013 and 0.035 mg kg^-1, while those for wheat flour were 0.01 and 0.02 mg kg^-1. Estimated daily intakes of DDT and different isomers of HCH through the consumption of wheat contaminated at their median and 90th percentiles constituted a small proportion of their acceptable daily intakes. Amongst the pesticide residues analysed, statutory maximum residue limits have been fixed only for γ-HCH in wheat in India, as 0.1 mg kg^-1 in wheat grain and zero in wheat flour. Residue levels of γ-HCH exceeded these maximum residue limits in five of 1080 samples of wheat grain and in 340 of 632 samples of wheat flour. The failure to meet the requirement of the γ-HCH maximum residue limit in large number of wheat flour samples was attributed to the fixation of practically unachievable zero limit. Comparing the previous studies and the present one, the levels of residues of DDT and HCH in wheat were significantly decreased.     

Arsenic and lead residues in carrots from foliar applications of monosodium methanearsonate (MSMA): A comparison between mineral and organic soils, or from soil residues

Carrot roots may absorb arsenic residues when grown in soil that has been treated previously with arsenical pesticides. Arsenic residues in crops also may result from the inappropriate application of post-emergence arsenical herbicides. To compare potential sources of arsenic residues, carrots were planted in mineral or organic soil and treated post-emergence with the herbicide monosodium methanearsonate (MSMA) at 0, 0.56, 1.12, 2.24, 4.48, or 8.96 kg ha^-1. Arsenic concentration in all plant parts declined between 30 days before harvest and harvest. Arsenic concentration in peeled carrot roots ranged from less than the limit of detection (LOD) for untreated carrots to 0.963 mg kg^-1 (fresh weight) at harvest for carrots treated with 8.96 kg ha^-1 MSMA. In another study, carrots were grown in a greenhouse in soil collected from an old orchard site that had been sprayed with lead arsenate for many years. The old orchard site soil had an arsenic level of 110 mg kg^-1, and similar non-orchard soil had an arsenic level of 1.97 mg kg^-1. All carrot plant segments from plants grown in old orchard soil had higher arsenic concentrations than those from non-orchard soil. Peeled carrot roots from non-orchard soil contained 0.034 mg kg^-1 arsenic, while the peeled roots from old orchard soil had 0.135 mg kg^-1. Old orchard soil had a lead level of 496 mg kg^-1, compared with 6.52 mg kg^-1 for non-orchard soil. Peeled carrot roots from old orchard soil contained 0.885 mg kg^-1 lead, and peeled roots from non-orchard soil contained 0.147 mg kg^-1 lead.     

A survey of nitrate and nitrite content of fruit and vegetables grown in Slovenia during 1996-2002

Monitoring of nitrate (NO₃^-) and nitrite (NO₂^-) content in agricultural products in Slovenia has been carried out since 1996. The results of monitoring over the period 1996-2002 are presented. During this time 924 samples of 14 different agricultural products (potato, lettuce, apples, carrot, silage maize, cabbage, grapes, peaches, string beans, cereals, pears, cucumbers, strawberries and tomato) were analysed. The samples were taken at the time of maturity directly from growing sites and they were analysed using segmented flow analysis. The average nitrate contents were the highest in lettuce (1074 mg kg^-1), cabbage (881 mg kg^-1), string beans (298 mg kg^-1) and carrot (264 mg kg^-1), and they were moderately high in potato (158 mg kg^-1), silage maize (122 mg kg^-1), strawberries (94 mg kg^-1), cucumbers (93 mg kg^-1) and cereals (49 mg kg^-1). Low nitrate contents (below 6 mg kg^-1) were found in fruit (grapes, peaches, apples and pears) and tomato. With the exception of cereals (8.9 mg kg^-1), apples (1.5 mg kg^-1), potato (1.2 mg kg^-1) and pears (1.0 mg kg^-1) the content of nitrites did not exceed 0.5 mg kg^-1. It may be concluded that the results of the monitoring were in most cases similar to the results of investigations obtained in other countries.     

An intercomparison study of the determination of glyphosate, chlormequat and mepiquat residues in wheat

An intercomparison study of the determinations of glyphosate, chlormequat and mepiquat residues in cereals was performed. Four samples comprising one blank, two incurred and one spiked sample were sent to six participating laboratories. For glyphosate, two laboratories reported considerably lower results than the other four. One of the two laboratories with low results also reported low recoveries. The results of a sample spiked with 0.80 mg kg^-1 glyphosate and an incurred sample, ranged from 0.23-0.87 mg kg^-1 and 0.11-0.25 mg kg^-1 respectively. The strong correlation between the two samples (r² = 0.95) indicates a systematic between-laboratory variation. Several different principles were used for the analysis of glyphosate using different clean-up techniques and GC/MS, HPLC-fluorescence or LC/MS for detection. The results of the chlormequat residues showed more consistency. All but one laboratory obtained comparable results. However the correlation between the results for the sample spiked with 0.38 mg kg^-1 (range: 0.26-0.65 mg kg^-1) and the incurred samples (range: 0.19-0.45 and 0.15-0.23 mg kg^-1, respectively) again showed a strong correlation (r² = 0.99 and 0.88) indicating a systematic component. For mepiquat, results above the limit of quantification were only reported for the spiked sample. The results ranged from 0.29-0.92 mg kg^-1 (spiked concentration = 0.38 mg kg^-1). Three laboratories had results that deviated less than 25% from the fortified concentration. Two laboratories reported results 38% and 141% above the fortified concentration, respectively.     

Toxic and essential metals in liver, kidney and muscle of pigs at slaughter in Galicia, north-west Spain

The aims of the study were to evaluate toxic and essential metal concentrations in meat and offal from pigs in north-west Spain to compare these with reported metal concentrations in pigs in other countries and in cattle in this region, and to relate the observed concentrations to maximum acceptable concentrations. Samples from 63 pigs aged 6 months were randomly collected at slaughter. After acid digestion, levels of metals were determined by ICP-OES and ICP-MS. As regards the toxic metals, mean concentrations in liver, kidney and muscle were 0.073, 0.308 and 0.009 mg kg^-1 fresh weight for cadmium, 0.004, 0.008 and 0.003 mg kg^-1 for lead, 0.013, 0.011 and 0.003 mg kg^-1 for arsenic, and 0.001, 0.002 and 0.001 mg kg^-1 for mercury. These concentrations can be considered low, and in general similar to those reported in similar studies in recent years. In addition, maximum admissible concentrations established by the European Union were not exceeded in any sample. As regards the essential metals, concentrations in liver, kidney and muscle were 14.9, 5.63 and 6.85 mg kg^-1 for copper, 81.3, 28.9 and 42.5 mg kg^-1 for zinc, 195, 51.6 and 26.5 mg kg^-1 for iron; 1.17, 2.51 and 0.656 mg kg^-1 for selenium, 3.32, 1.56 and 1.01 mg kg^-1 for manganese, 0.023, 0.027 and 0.003 mg kg^-1 for cobalt, 0.120, 0.077 and 0.131 mg kg^-1 for chromium, 0.009, 0.027 and 0.026 mg kg^-1 for nickel, and 1.62, 0.683 and 0.140 mg kg^-1 for molybdenum. These concentrations are all within the accepted adequate-safe ranges for this animal species, and in general are in line with those previously reported in the literature.     

Residues of azoxystrobin, fenhexamid and pyrimethanil in strawberry following field treatments and the effect of domestic washing

Residues of the pesticides azoxystrobin, fenhexamid and pyrimethanil were determined in strawberry after field treatment. The effect of 'home' washing with tap water and a commercially available vegetable detergent on residue levels was also studied. After treatment, azoxystrobin and pyrimethanil residues on strawberry were on average 0.55 and 2.98 mg kg^-1, respectively, values below the maximum residue level (MRL) fixed by the European Union (2.0 and 5 mg kg^-1, respectively), while fenhexamid residues were on average 2.99 mg kg^-1, which is very close to the MRL of 3.0 mg kg^-1, but some samples were over the MRL. Thereafter, all residues declined, with a half-life of about 8 days (azoxystrobin and fenhexamid) and 4.8 days (pyrimethanil). Washing the fruit with tap water reduced the residues of azoxystrobin and fenhexamid but did not affect pyrimethanil residues. Finally, when fruits were washed with a commercial detergent, greater amounts were removed (about 45% of azoxystrobin and pyrimethanil and 60% of fenhexamid).     

Monitoring of pesticide residues in apples, lettuce and potato of the Slovene origin, 2001-04

Apples, lettuce and potatoes (404 samples) produced in the Republic of Slovenia were analysed for pesticide residues at the Agricultural Institute of Slovenia, Ljubljana, in 2001-04. Sampling from eight agricultural production areas was performed at market producers at the harvesting of products or in storehouses after the pre-harvest interval of plant protection products used. Samples exceeding the maximum residue levels were the following: three apple samples (2.0%) containing 0.33-2.24 mg kg^-1 (phosalone and tolylfluanid), three lettuce samples (3.1%) containing 0.14-6.36 mg kg^-1 (dimethoate, dithiocarbamates and metalaxyl) and 36 potato samples (23.1%) containing 0.06-0.51 mg kg^-1 (dithiocarbamates). Residues of two or more active substances were found in 73 apple samples (48.3%), of which the maximum residue limit (MRL) was exceeded by three samples (2.0%) with the values ranging from 0.33 to 2.24 mg kg^-1, and nine lettuce samples (9.3%), for which the MRL was exceeded by three samples (3.1%) with values from 0.14 to 6.36 mg kg^-1. In potato samples, only residues of dithiocarbamates or no residues at all were found. Residues of the dithiocarbamate group were the most frequently found, i.e. in 66 apple samples (43.7%), 30 lettuce samples (30.9%) and 38 potato samples (24.4%).     

A sulfadimidine model to evaluate pharmacokinetics and residues at various concentrations in laying hen

Low level intake of drugs from the ingestion of contaminated feed may lead to residue problems in food animals. Sulfadimidine (SDD) was used as a model to determine the residue risk at various doses in laying hens. The drug was administered as a single intravenous injection (100 mg kg^-1 body weight, BW), as a single oral dose (100, 30, 10, 3, 1 mg kg^-1 BW) and via medicated feed for 7 consecutive days (30, 10, 3 mg kg^-1 BW). Drug levels were determined with HPLC-UV for plasma, yolk and albumen. Pharmacokinetic values, which were calculated using a first-order one-compartment model, residue levels and transfer rates into the eggs were found to be dose-dependent. Even low doses of 3 and 1 mg kg^-1 BW resulted in measurable residues in yolk and albumen 1 day after a single oral administration. After ingestion of medicated feed at 3 mg kg^-1 BW, mean drug levels at 0.14 ± 0.01 µg g^-1 were found in albumen and at 0.09 ± 0.01 µg ml^-1 in plasma. Generally, the residue levels in albumen and plasma were higher than in yolk. These findings demonstrate a residue risk for the consumer even after low level intake of drugs.     

Levels of eight trace elements in edible mushrooms from a rural area

Eight trace elements were determined using ICP-MS in 78 fruiting body samples of 22 edible mushroom species. The mushrooms were collected from four sites in a rural area, unpolluted by human activity. Median values (dry matter) were as follows: Arsenic (As) 1.45 mg kg^-1, barium (Ba) 1.41 mg kg^-1, cobalt (Co) 0.28 mg kg^-1, copper (Cu) 47.0 mg kg^-1, rubidium (Rb) 130 mg kg^-1, silver (Ag) 2.95 mg kg^-1, thallium (Tl) 0.02 mg kg^-1 and vanadium (V) 0.25 mg kg^-1. Higher trace element accumulation was observed in samples of Macrolepiota procera, Macrolepiota rhacodes, Lycoperdon perlatum, Lycoperdon gigantea and Xerocomus chrysenteron for As and Cu, and in samples of Cantharellus cibarius and of genera Boletus and Suillus for Rb.