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Maximum residual limits (MRLs) for pesticides are based on science. This is true both for MRLs devised by national governments and multilaterally through the Codex. Science-based Codex MRLs are internationally harmonized to facilitate trade. Since the 1990s, an increasing number of countries have devised national MRLs and eschewed those of the Codex. These differing national standards are becoming important barriers to trade. The purpose of this paper is to explore the ramifications of these diverging MRLs for food security, investigate the reasons for the rise of national standards, and explore the role of science in regulatory processes.

The approach is an examination of the scientific basis for MRLs in the context of food safety outcomes.

It finds that there is no improvement in food safety from the move to national MRLs, only a loss of the benefits of trade. As all countries, along with the Codex, claim that their MRLs are based on science, suggesting that there is a need for an examination of the role of science in the making of public policy.

This study identifies a potential risk to food security for food policy makers. Given future food security challenges and that pesticides are used almost universally in conventional agriculture, trade barriers based on divergent interpretations of science need to be addressed by food policy makers.

The purpose of this paper is to analyze the impacts of differences in sanitary and phytosanitary measures as non-tariff measures (NTMs) in the tea trade between importing and exporting countries. With the progress of trade liberalization, there has been a shift of focus to NTMs as alternative or potential trade barriers.

In order to quantify an NTM on tea trade and implement its empirical application, this study designed an index of differences in maximum residue levels (MRLs) for the pesticide endosulfan and introduced it into a gravity trade model. The estimation challenges in the presence of heteroscedasticity and many zero-trade flows are resolved by taking the Heckman and Poisson pseudo-maximum likelihood estimators.

This study found that differences in MRLs, arising from the stricter standards in importing countries lead to a significant decrease in tea trade value. This negative impact of differences in MRLs is found to be slightly less than that of tariffs, implying that in this case, the NTM acts as a policy substitute for import tariffs in the global tea trade.

The main contribution of this study is to suggest and quantify the differences in MRLs across countries as a substantial NTM on the global tea trade and provide its empirical application.

Maximum residue limits (MRLs) on pesticides and veterinary drugs in plant and animal products are established to promote food safety and animal and plant health. In practice, however, they are often accused of creating unnecessary trade barriers. The controversy is more prominent when a given MRL is stricter than the corresponding international standard developed by Codex. Using the score indices constructed by Li and Beghin (2012), we empirically assess the implications of stringency in MRLs in plant and animal products, relative to Codex levels, for Canadian and US trade performance. We find little evidence that US imports are influenced by domestic stringency or those imposed by its trading partners. However, US exports are negatively affected by stringency in destination markets. Canada’s stringent MRLs facilitate its exports of plant and animal products and these exports do not seem to be impeded by MRL stringency in destination markets. Canada’s imports do not appear to be systematically influenced by either its own or its trading partners’ MRL stringency. We draw implications for the potential harmonization of MRLs between the two countries.

The purpose of this paper is to empirically examine how China's food safety standards affect agricultural trade in the case of dairy products.

A gravity model is applied to quantitatively address the impacts of changing food safety standards in China in the case of its dairy imports. The paper considers the trade impacts of not only a specific hazard substance but also overall strictness of safety standards.

The paper shows that changes in food safety standards of dairy products have no effect on China's dairy imports. The finding is not particularly surprising considering special characteristics of China's food safety standards. Given the fact that China's safety standards are relatively lower than that in its major exporters, the trade-impeding effect may not be substantial.

First, this study is unable to estimate the trade-enhancing and trade-impending effects separately. Second, the study does not account for a potential endogeneity issue associated with food safety standards.

This paper contributes to the debate on how food safety standards affect trade by demonstrating that safety standards in developing countries like China can affect international trade differently from that in developed countries. Although results are specific to China's dairy imports, the explanations are applicable to food safety standards in other developing countries.

The study assessed the levels of organochlorine pesticides (OCPs) and their potential non-carcinogenic and carcinogenic health risks in four regularly consumed fruit vegetables.

The OCPs’ residues were quantified using a gas chromatograph coupled with an electron capture detector (GC-ECD) and the dietary exposure of children, and adult consumers to the detected OCPs was evaluated using carcinogenic and systemic health risk estimations.

Aldrin, endrin, endrin aldehyde, a-endosulfan, β-endosulfan, endosulfan sulphate, heptachlor, heptachlor epoxide and dieldrin were detected in the four fruit vegetables. The predominant OCP residue in carrot, cucumber, tomatoes and watermelon was endosulfan sulphate with mean concentrations of 2.532 mg kg⁻¹, 1.729 mg kg⁻¹, 2.363 mg kg⁻¹ and 1.154 mg kg⁻¹, respectively. The residues levels in some of the fruit vegetables were higher than their respective maximum residue levels (MRLs) of 0.01–0.05 mg kg⁻¹ set by the European Commission with concentrations above MRLs ranging between 25.5% and 100%. The systemic health risk estimations showed that the hazard index (HI) values for carrot (3.20), cucumber (9.25), tomatoes (50.21) and watermelon (16.76) were >1 for children consumers and the respective HI values of 2.87, 15.57 and 5.20 for adult consumers of cucumber, tomatoes and watermelon were >1 which implies potential systemic health risks. Four carcinogens (aldrin, dieldrin, heptachlor and heptachlor epoxide) had cancer risk index values greater than the acceptable risk of 1 in 1 million for both adult and children consumers.

The paper shows that despite the ban on the use of OCPs in Nigeria, they are still being used for agricultural production especially on some locally produced and regularly consumed fruit vegetables as reported in the present study. The non-existence of surveillance programmes on pesticide usage and the lack of proper monitoring of pesticide residues in food products including fruit and vegetables must have contributed to the levels of the detected OCP in the samples analysed. The current daily intake of OCP via contaminated vegetables may pose potential health risks to both the children and adult consumers of the fruit vegetables.

The purposes of this study were to analyze fruits, vegetables, water and soil for organochlorine pesticide (OCP) residues and to assess the food exposure of these pesticides in Qatar.

Pesticides were quantified in dates, leafy vegetables, fruiting vegetables, water and soil samples using a gas chromatography-electron capture detector and gas chromatography-mass spectrometry. These pesticides were α-benzene hexachloride (BHC), ß-BHC, heptachlor, aldrin, g-chlordane, endosulfan I, α-chlordane, dieldrin, endrin and methoxychlor. Additionally, food exposure risk assessment was performed by estimating daily intakes of OCP.

Most analyzed samples contained at least one OCP residue. Endosulfan was the only pesticide that was not detected. The concentrations of OCP in samples were below the maximum residue level (MRL) except endosulfan. Among all the samples analyzed, ˜18% of those exceeded the MRL with respect to the concentrations of methoxychlor and heptachlor. Only intake of methoxychlor (0.018 mg/day) exceeded the MRL (0.01 mg/day). Dates and fruiting vegetables were likely to pose a higher risk than leafy vegetables because they contained heptachlor, endrin and methoxychlor. Leafy vegetables might pose a greater risk than dates and fruiting vegetables because of the presence of β-BHC and dieldrin.

Eight out of ten OCPs that were measured were found to be below the MRL. These pesticides should be eliminated from the food supply based on the Qatar National Implementation Plan of the Stockholm Convention in 2010. Based on the intake risk assessment, overall, the intake of OCP may not pose a major risk to human health as the concentrations of OCP were below MRL, except methoxychlor. Water and soil are the potential sources of contamination of OCP in foods that were tested in Qatar. To limit the health risks associated with OCPs, there is a need for close monitoring of food and agricultural practices and the types of pesticides imported into Qatar.

Effective rail surface defects detection method is the basic guarantee to manufacture high-quality rail. However, the existed visual inspection methods have disadvantages such as poor ability to locate the rail surface region and high sensitivity to uneven reflection. This study aims to propose a bionic rail surface defect detection method to obtain the high detection accuracy of rail surface defects under uneven reflection environments.

Through this bionic rail surface defect detection algorithm, the positioning and correction of the rail surface region can be computed from maximum run-length smearing (MRLS) and background difference. A saliency image can be generated to simulate the human visual system through some features including local grayscale, local contrast and edge corner effect. Finally, the meanshift algorithm and adaptive threshold are developed to cluster and segment the saliency image.

On the constructed rail defect data set, the bionic rail surface defect detection algorithm shows good recognition ability on the surface defects of the rail. Pixel- and defect-level index in the experimental results demonstrate that the detection algorithm is better than three advanced rail defect detection algorithms and five saliency models.

The bionic rail surface defect detection algorithm in the production process is proposed. Particularly, a method based on MRLS is introduced to extract the rail surface region and a multifeature saliency fusion model is presented to identify rail surface defects.

Nontariff Measures (NTMs) encompass all policy instruments other than tariffs, from labeling requirements to macro-policies affecting trade. These measures have been growing as tariffs have been greatly reduced and sometimes eliminated through numerous global and preferential trade agreements such as those of the World Trade Organization (WTO) and its predecessor, as well as regional trade agreements (RTAs). Among NTMs particularly, sanitary and phytosanitary (SPS) measures and technical barriers to trade (TBTs) have been proliferating. These measures have much in common as they act as standards affecting cost and potentially demand by addressing market imperfections (asymmetric information, external effects) (Bacchetta & Beverelli, 2012).

A similarity index of maximum residue level (MRL) regulations is introduced into a variable elasticity of substitution (VES) model to analyze the impacts of MRL regulation similarity on trade flows and social welfare. We specially consider the situation where the requirements set by the importing country are stricter than those of the exporting country. We find that the more similar the MRL regulation between trading partners is, the more substitutable their goods are, and for the consumers that have home preferences for domestic goods, they prefer the imported goods that are more similar to the domestic goods. Our results also show that if the developing countries upward harmonized their MRL standards to developed countries, their exports would expand.