Pesticides, maximum allowable water

One of the most notorious cases of industrial disaster took place in 1984 in Bhopal, India. A plant with a license from the Union Carbide company was making methyl isocyanate (MIC), CH3NCO, which is an intermediate for the manufacture of pesticides. MIC boils at 39 °C, and the vapor density is heavier than air and very toxic by inhalation and skin absorption. The maximum allowable air concentration is 0.02 ppm by volume over 8 h. MIC also reacts with water and produces heat, which must be removed to prevent boiling over. On that day in 1984, the cooling system failed during... 

Polychlorinated biphenyls (PCB) - currently banned compounds - were formerly used in hydraulic fluids, plasticizers, adhesives, fire retardants, and pesticide extenders. These contaminants are persistent in the environment and are present in sediments at the bottom of lakes, rivers, and seas. As they exhibit carcinogenic and endocrine-disrupting activity, they are subject to regulation. For instance, in the United States, the maximum allowed concentration of PCBs in drinking water is 0.5 ng mL [21]. 

The rapid increase in the use of pesticides in agriculture after the Second World War led many governments to enforce regulations on their sale and use in order to protect users of pesticides, consumers of treated foodstuffs, domestic animals, and, at a later stage, the environment. Thus, the presence of pesticides in the environment has compelled official international institutions to establish maximum allowable concentration levels of pesticides in drinking water and foods. ... 

Environmental pollution by pesticides is a very serious problem. The appearance of herbicides in ground water and in agricultural products poses considerable problems in the control of drinking water and produa quality. Regulations governing herbicide concentration in drinking water are very strictly enforced by the European Community virith a maximum allowable at 0.1 pg/L level for each individual substances and 0.5 Pg/L for sum of photosynthesis inhibiting herbicides. ... 

In 1974, the Safe Drinking Water Act was passed by the US Congress and the Environmental Protection Agency (EPA) took responsibility for ensuring the safety of water supplies. The EPA proposed a list of materials that carry potential hazards when present in drinking water. Maximum allowable levels were set for more than a dozen inorganic species (As, Ba, B, Cd, Cr(VI), Cu, CN, F , Pb, NO3, NO2, Se, Ag) and for about the same number of organic pesticides. Turbidity and the amount of coli-form bacteria were also limited. Additionally, secondary... 

Regulation of permissible pesticide levels in food, water, air, and soil presents a special problem. A maximum permissible level (MPL) is set for each food that may contain a pesticide residue, according to the amount of that food consumed in daily nutrition. Pesticide concentrations that are less than the MPL will not change the food s palatability or nutritive value. Milk, berries (black currants, raspberries, and strawberries) and other products for children s and dietetic nutrition are forbidden to have pesticide residues. The acceptable daily intake (ADI) covers not only the foods that may contain residues but also allows for possible pesticide entry from water and air. For foods that under proper application methods will have residues that do not exceed the ADI, the MPL is set from actual conditions to permit a low level of pesticide content. The Instructions present examples of substantiated MPLs for foods, established on the basis of daily consumption rates and observed residues. 

Maximum allowable concentrations (MACs) for pesticides in water must take into account the effects on palatability and sanitary status. These data are compared with toxicological research to define an index of limits for use in establishing the MAC. If the organoleptic properties of water are affected by pesticide concentrations lower than those that produce threshold changes in tests on animals, palatability becomes the limiting index. If toxic alterations occur at concentrations that do not render the water unpalatable, the standard is set on the basis of toxicological criteria. Standards are established in a similar way for air. 

In Europe, a list of priority pollutants including pesticides was established to protect the environment from adverse ecological impact of these compounds [13,26]. The ECC Directive 80/778, which is concerned with ihe quality of water designated for human consumption, has set the maximum allowable concentration of each individual pesticide at 0.1 pg/L and the total amount of pesticides at 0.5 pg/L [27]. 

Initially, 50 c illary of 10 fxg mL mbbit anti-mouse IgG in 50 mM sodium carbonate buffer solution, pH 9.6 was incubated overnight at 4 °C. The capillaries were washed three times with PBS-Tl, and then twice with water. Thereafter, 50 pL of 10 pg mL anti-2,4-D IgG in PBS-T2 was added to each capillary, and incubated for 1 h at 37 °C. The capillaries were washed with washing b er and water. Thereafter, 50 pL mixture of 2,4D-TOP and standards or sanqrles were added to each capillary, and the competitive reaction was allowed to proceed by incubation for 2 h at RT. To determine nonspecific binding, four c illaiies received non specific IgG and no pesticide, while ten capillaries received specific IgG but no pesticide, in order to determine the maximum chemiluminescent intensity for the bound fraction. Finally, the capillaries were washed and 50 pL capillary of luminol substrate solution was added, and the maximum chemiluminescent intensity was measured with the modified Hamamatsu PMT. 

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