Provisional Tolerable Weekly Intake Value Research Articles

Comparative Study on the Distribution of Essential, Non-Essential Toxic, and Other Elements across Trophic Levels in Various Edible Aquatic Organisms in Sri Lanka and Dietary Human Risk Assessment.

Thirty-six elements are categorized as essential but toxic in excess amount (EBTEs), non-essential toxic (NETs), and Other in 29 different edible aquatic species dwelling in offshore pelagic, and coastal and estuarine (CE) ecosystems were investigated in Sri Lanka. Elements were analyzed using an energy-dispersive X-ray fluorescence (EDXRF) spectrometer, and an NIC MA-3000 Mercury Analyzer. EBTEs showed a negative relationship, whereas NETs showed a positive relationship between the concentration (mg/kg wet weight) and trophic levels in both ecosystems. EBTEs showed trophic dilution, whereas NETs showed trophic magnification. Some elements in a few organisms exceeded the maximum allowable limit which is safe for human consumption. There was a positive relationship (R2 = 0.85) between the concentration of mercury and body weight of yellowfin tuna (YFT). For the widely consumed YFT, the calculated hazard index (HI) for the non-carcinogenic health and exposure daily intake of NETs for adults were 0.27 and 9.38 × 10−5 mg/kg bw/day, respectively. The estimated provisional tolerable weekly intake (PTWI) (μg/kg bw/w) was 0.47 for arsenic and 0.05 for antimony, cadmium, mercury, and lead. The HI and PTWI values were below the recommended limits; thus, consumption of YFT does not pose any health risk for Sri Lankan adults.

Heavy Metal Content in Sediment and Hora Shell (Cerithidea obtusa) in Panipahan Waters, Rokan Hilir, Riau

This research was carried out in March 2021 to analyze the heavy metal content of Pb and Cu in the sediment and flesh of the horn shell (Cerithidea obtusa). Sediment samples and horn shells were taken from the coastal waters of Panipahan, Panipahan Village, and Teluk Pulai Village, Rokan Hilir Regency, Riau Province. The method used in this research is a survey method. Sampling was determined by using purposive sampling at three different stations. The results of this study showed that the metal content of Pb and Cu was highest in sediments around residential areas (44.7150 g/g and 104.4200 g/g), while the horn shell was found in areas far from anthropogenic activities (2.4717 g/g and 8.6617 g/g). Differences in the metal content of Pb and Cu in the sediments were found between stations, while for horn shells there was no difference between stations. The metal content of Pb in the sediment did not show a significant effect (F < 0.05) Pb content in horn shells, as well as Cu. The results of the calculation of the PTWI (Provisional Tolerable Weekly Intake) value indicated that the horn shell in the waters is acceptable for consumption

Homa Dalyanı’nda sülüneslerde (Solen marginatus) Hg, Cd, Pb ve Cr birikimlerinin incelenmesi

In this study; the accumulation of Hg, Cd, Pb, and Cr were investigated seasonally in razor clams (Solen marginatus) from the Homa Lagoon. The highest heavy metal concentrations were found in summer which is spawning period. When detected Hg, Cd and Pb levels were compared with provisional tolerable weekly intake (PTWI), Turkish Food Codex and European Regulations values, no potential health risk was found. However, heavy metal pollution in razor clam from the Homa Lagoon should be monitored due to excessive Cr concentrations in respect to PTWI value.

Total Diet Study approach in estimating mercury and cadmium levels using selected fish: A case study from Sri Lanka

Total Diet Study (TDS) is a world-recognized approach in quantifying nutrients and contaminants in complete diets. In the present study, the TDS approach was used to determine the dietary exposure to mercury (Hg) and cadmium (Cd) by regular consumption of yellowfin tuna (YFT), swordfish (SWF) and sardinella (SAF) fish in Gampaha district, Sri Lanka. The study was based on the TDS method established by the World Health Organization (WHO). Hg and Cd were analyzed using Atomic Absorption Spectrophotometer after microwave digestion of samples. Survey results revealed that the weekly average fresh fish consumption was 301 g per person. Hg and Cd levels were calculated on the wet weight basis. The maximum allowable limits of Hg and Cd were compared with European Union/European Commission (EU/EC) regulation limits for each species. None of the samples exceeded the EU/EC maximum limit for Cd, but two samples of SWF exceeded the maximum limit for Hg, recommended by the EU/EC. The Provisional Tolerable Weekly Intake (PTWI) for Hg was calculated for risk assessment. The percentage contributions of SWF, YFT, and SAF for PTWI-Hg were 64.92 and 40.16 and 8.55 respectively. Accordingly, the SWF were close to exceed the PTWI value. YFT and SWF are considered as the top predators in the marine food web. Cooking did not significantly reduce the Hg and Cd contents in selected fish species. Further studies are recommended to evaluate the PTWI values for predatory fish species before consumption.

Occurrence and health risk assessment of aflatoxins and ochratoxin a in Sürk, a Turkish dairy food, as studied by HPLC

The concentration of aflatoxins (AFs) and ochratoxin A (OTA) in Sürk cheese samples was determined by high-performance liquid chromatography with fluorescence detection (HPLC-FD) system, for which the analytical method was validated according to the guidelines issued by European Commission (EC). Additionally, cancer related health risk via dietary intake of Sürk was assessed by calculating estimated daily intake (EDI) and hazard index (HI) for aflatoxin M1 (AFM1), and Margin of Exposure (MoE) for aflatoxin B1 (AFB1) and Provisional tolerable weekly intake (PTWI) for OTA. OTA was the most frequently detected toxin that was presented in 28 samples with concentration ranging from 0.058 to 5.04 μg kg−153.3% of samples contained AFM1 at levels > LOQ of 0.07 μg kg−1, of which none exceeded the permissible maximum limits (0.5 μg kg−1) established by Turkish legislation. Sürk samples were found to contain AFB1 at mean concentration of 0.610 μg kg−1. The range of concentrations of AFs and OTA in Sürk observed in the current study was found to be below the official Turkish standard determined for various foodstuffs. However, HI from consuming Sürk was found to be 1.02 ng kg−1 bw for AFM1, and MoE value for AFB1 was found to be 2982 which clearly indicates health risk AFM1 and AFB1 to Sürk consumers. However, OTA contamination level was found to be low to produce health hazards according to PTWI value. According to health risk assessment of this study presents the first data about occurrence of AFs and OTA in Sürk, yet data should be updated based on seasonal monitoring and consumption habits of both adults and infants.

Mercury, arsenic, cadmium and lead in two commercial shark species (Sphyrna lewini and Caraharinus porosus) in Trinidad and Tobago

Sharks are long-lived apex predators which can accumulate toxic metals such as mercury and arsenic. Samples of Sphyrna lewini and Carcharinus porosus were collected from two commercial fish landing sites in Trinidad. Heavy metal concentrations were determined in the muscle, dorsal fin, vertebrae and liver using atomic absorption spectrometric. The provisional tolerable weekly intake (PTWI) and target hazard quotient (THQ) were determined to assess the potential health risks to consumers. Mercury levels ranged between 74–1899μg/kg in S. lewini and 67–3268μg/kg in C. porosus. Arsenic levels ranged between 144–2309μg/kg in S. lewini and 762–6155μg/kg in C. porosus. Cadmium levels generally ranged between 0.27–27.29mg/kg in S. lewini and 0.6–29.89mg/kg in C. porosus. Lead levels generally ranged between 0.14 and 208.81mg/kg in S. lewini while C. porosus levels ranged between 0.30 and 459.94mg/kg. The PTWI and THQ values suggest that consumption of these shark species can therefore be a major source of exposure to lead, cadmium, arsenic and mercury in humans and is likely to have potential health risk over long term exposure.

Essential and toxic heavy metals in cereals and agricultural products marketed in Kermanshah, Iran, and human health risk assessment

ABSTRACTLevels of some essential and toxic heavy metals such as lead, cadmium, chromium, nickel, zinc and copper in cereals and agricultural products obtained from the markets in Kermanshah city, west Iran, were determined by inductively coupled plasma-optical emission spectrometry (ICP-OES). The average concentrations for lead and cadmium in some cereals were higher than the maximum levels set by the Codex Alimentarius. A potential human health risk assessment was conducted by calculating estimated weekly intake (EWI) of the metals from eating cereals and comparison of these values with provisional tolerable weekly intake (PTWI) values. In combination with recent cereal consumption data, the EWIs of heavy metals were calculated for the Kermanshah population. EWI data for the studied metals through cereal consumption were lower than the PTWI values. Cr, Ni, Zn and Cu levels in all samples analysed were within the ranges reported for similar cereals from various parts of the world.

Potential human health risk assessment of heavy metals via the consumption of tilapia Oreochromis mossambicus collected from contaminated and uncontaminated ponds.

Fish tilapia Oreochromis mossambicus were collected from a contaminated Seri Serdang (SS) pond potentially receiving domestic effluents and an uncontaminated pond from Universiti Putra Malaysia (UPM). The fish were dissected into four parts namely gills, muscles, intestines, and liver. All the fish parts were pooled and analyzed for the concentrations of Cd, Cu, Fe, Ni, Pb, and Zn. Generally, the concentrations of all metals were low in the edible muscle in comparison to the other parts of the fish. It was found that the levels of all the heavy metals in the different parts of fish collected from the SS were significantly (P<0.05) higher than those from UPM, indicating greater metal bioavailabilities in the SS pond. The sediment data also showed a similar pattern with significantly (P<0.05) higher metal concentrations in SS than in UPM, indicating higher metal contamination in SS. Potential health risk assessments based on provisional tolerable weekly intake (PTWI) and the amount of fish required to reach the PTWI values, estimated daily intake (EDI), and target hazard quotient (THQ) indicated that health risks associated with heavy metal exposure via consumption of the fish's muscles were insignificant to human. Therefore, the consumption of the edible muscles of tilapia from both ponds should pose no toxicological risk of heavy metals since their levels are also below the recommended safety guidelines. While it is advisable to discard the livers, gills, and intestines of the two tilapia fish populations before consumption, there were no potential human health risks of heavy metals to the consumers on the fish muscle part.

The risk of mercury exposure to the people consuming fish from Lake Phewa, Nepal.

The risk of mercury exposure through consumption of fish from Lake Phewa, Nepal was investigated. A total of 170 people were surveyed to know their fish consumption levels. The weekly mercury (Hg) intake in the form of methylmercury (MeHg) through fish was calculated by using the data on average MeHg concentrations in fish, the average consumption of fish per week, and an average body weight of the people. Hotel owners were consuming significantly high amounts of fish, followed by fishermen, in comparison to the government staff, army/police, locals and others (visitors). Some individuals exceeded the Provisional Tolerable Weekly Intake (PTWI) of 1.6 µg per kg body weight of MeHg (FAO/WHO). The minimum intake of MeHg (0.05 µg/kg/week) was found in the visitors (others) category, whereas the hotel owners had the maximum intake (3.71 µg/kg/week). In general, it was found that a person of 60 kg can consume at least 2 kg of fish per week without exceeding PTWI such that it does not pose any health risk associated with Hg poisoning at the present contamination level. Hg based PTWI values for Nepal has not been proposed yet in fishery resources so as to reduce health risk of the people.

Health concerns of consuming cockles (Cerastoderma edule L.) from a low contaminated coastal system

Commercial and recreational harvesting of shellfish within the coastal systems is usually very extensive. Since these ecosystems are frequently subjected to contamination, namely from agricultural, urban and industrial activities, and shellfish generally display a high capacity to bioaccumulate metals, populations may be at risk in terms of toxic metal exposure as a consequence of the harvesting and ingestion of near shore coastal marine organisms. Shellfish is regularly tested for concentrations of metals and other contaminants by legal authorities for commercial purposes, but although health officials use total metal as standards of food safety, only a part of the metal accumulated in shellfish is available to be assimilated and to cause toxic effect. In order to elucidate these issues an investigation on cockles inhabiting the Aveiro estuary was conducted. Element levels in sediments and wild Cerastoderma edule from sampling areas with different levels of contamination were measured; total element burden of cockles was related to accessible fraction for assimilation (TAM); element concentrations in wild C. edule were compared to EFSA (European Food Safe Authorities), USFDA (United States Food and Drug Administration) and FSANZ (Food Standards Australia and New Zealand) maximum levels (MLs); and the amount of cockle flesh needed to be consumed to exceed provisional tolerable weekly intake (PTWI) was determined. The present work showed that although sediment metal and metalloid contamination in Aveiro estuary is low the concentration of elements in C. edule does not reflect the contamination of the sediment. Aluminium (Al) and mercury (Hg) were the less and nickel (Ni), lead (Pb), zinc (Zn) and cadmium (Cd) were the most bioaccumulated metals by cockles. Comparison of MLs from international organisations with the concentration of elements in C. edule showed that arsenic (As) and Pb exceeded standard levels. The ingestion of less than 1kg for As and 1.5kg for Pb of cockles would result in exceeding the PTWI threshold (0.015 and 0.025mgkg−1week−1 respectively) in any of the areas considered in the study. Cd and Al also appear to be limiting elements for human consumption. Indeed, consumption of more than 3.1kg and 2.1kg of whole cockle soft part from one of the study areas during a single week would lead to exceedance of the recommended PTWI value for Cd (0.007mgkg−1week−1) and Al (7mgkg−1week−1) respectively. The health concerns to humans from cockle consumption from Aveiro estuary are discussed.

Nonessential Metals in Striped Marlin and Indo-Pacific Sailfish in the Southeast Gulf of California, Mexico: Concentration and Assessment of Human Health Risk

Seventeen sailfish (Istiophorus platypterus; 166-246 cm long) and 13 striped marlin (Tetrapturus audax; 159-254 cm long) specimens from the southern Gulf of California were analyzed for As, Cd, Hg, and Pb concentrations. More than 20% of the As and Cd levels exceeded the guideline levels of the World Health Organization (WHO), the U.S. Food and Drug Administration, and the European Union. About 65-90% of the specimens exceeded the limit value for Hg. Pb levels in billfish were significantly lower than guideline values. The intakes of As and Cd through billfish consumption by the population represented 20-40% of the provisional tolerable weekly intake (PTWI) values as recommended by the WHO. Levels of Hg exceeded the PTWI value. Pb intake represented <5% of the PTWI through these species in all age and gender groups. The target hazard quotients (THQs) for Cd and Pb were <1 in each group of interest. In contrast, THQ values based on As and Hg showed large variations, with the highest values for children, then pregnant women, and, finally, adults. Values of THQ >1 indicate risk for As and Hg; the risk from As was estimated assuming that 20% of the total As was inorganic. These metals can affect the nervous system and intellectual and physical development of unborn children and infants. A national moratorium on billfish consumption in México is recommended for children (0-6 years old), pregnant women, and women planning pregnancy.

Dietary Exposure and Risk Assessment of Mercury from the Korean Total Diet Study

As a national project, obtaining information on the amount of heavy metal exposure of individuals through food intake is an important basic parameter for risk assessment. This study was conducted to evaluate dietary exposure levels and various risks from mercury (Hg) in Korean foods. In total, 342 samples comprising 114 food items were collected and then cooked prior to analysis. As found by Hg analysis, the mean content of metal in the fish and shellfish group was highest among the 15 Korean food groups. The total daily amount of Hg intake from typical Korean foods was 2.40 μg/person/d. The daily amount (μg/person/d) of Hg intake from each food group was 0.155 in grains and cereals, 0.008 potatoes and starch, 0.005 sugars and sweets, 0.0093 pulses, 0.0018 nuts and seeds, 0.203 vegetables, 0.027 fruits, 0.021 meats and poultry, 0.004 eggs, 1.826 fish and shellfish, 0.022 seaweed, 0.043 milk and dairy products, 0.008 oils and fats, 0.042 beverages, and 0.023 seasonings. The fish and shellfish group contributed most to total dietary intake at 76%. For risk assessment, probable daily intake (PDI) was calculated and compared with provisional tolerable weekly intake (PTWI) of the Joint FAO/WHO Expert Committee on Food Additives (JECFA). The level of Hg intake through fish and shellfish of 0.001 mg/kg body weight bw/wk corresponded to 4.54% of the PTWI value of 0.005 mg/kg bw/wk, the safety standard for JECFA. The level of Hg intake through selected foods from the Food list for Koreans was 0.001 mg/kg bw/wk, corresponding to 5.95% of PTWI value. Therefore, overall intake was at levels below the recommended JECFA levels. The relative gender Hg hazard from Korean foods was 6.26% and 5.5% for males and females, respectively. The relative age Hg hazard from Korean foods was, 8.9% in those 3–6 yr old, 6.7% in those 7–12 yr old, 5.2% in those 13–19 yr old, 5.9% in those 20–29 yr old, 6.3% in those 30–49 yr old, 5.6% in those ages 50–64 yr, and 3.7% in the group of those over 65 yr of age. Relative regional Hg hazard from Korean foods was 6.3% in urban versus 5.5% in rural areas. Thus, the amount of Hg intake through consumption of Korean foods was found to be at a relatively safe level. These data may be thus used to establish safety standards for fish and shellfish consumption.

Intake of arsenic from water, food composites and excretion through urine, hair from a studied population in West Bengal, India

To evaluate the main intake source of arsenic by the villagers from arsenic-affected families in Jalangi and Domkol blocks in Mushidabad district, West Bengal—India, we determined the concentrations of arsenic in tubewell water and in food composites, mainly including vegetables and cereals collected from the surveyed families which were cultivated in that region. The daily dietary intakes of arsenic by the villagers were estimated and the excretions of arsenic through urine and hair were determined. The arsenic concentrations in hair and urine of the studied population living in mild (2.78 μg/L), moderate (30.7 μg/L) and high (118 μg/L) arsenic-affected families were 133, 1391 and 4713 μg/kg and 43.1, 244 and 336 μg/L, respectively. The linear regressions show good correlations between arsenic concentrations in water vs hair ( r 2 = 0.928, p < 0.001) and water vs urine ( r 2 = 0.464, p < 0.01). Approximately 29.4%, 58.1% and 62.1% of adult population from mild, moderate and high arsenic-affected families were suffering from arsenical skin manifestations. The mean arsenic concentrations of food composites (vegetables and cereals) in high arsenic-affected families are not significantly different from mild arsenic-affected families. The daily dietary intakes of arsenic from water and food composites of the studied population, living in high, moderate and mild arsenic-affected families were 568, 228 and 137 μg, respectively. The linear regressions show good correlations between arsenic concentrations in hair vs daily dietary intake ( r 2 = 0.452, p < 0.001) and urine vs daily dietary intake ( r 2 = 0.134, p < 0.001). The water for drinking contributed 6.07%, 26.7% and 58.1% of total arsenic in our study from mild, moderate and high arsenic-affected families. The result suggested that the contaminated water from high arsenic-affected families should be the main source for intake of arsenic. On contrary, the contribution of arsenic-contaminated food composites from mild and moderate arsenic-affected families might be the main source for intake of arsenic. The Food and Agriculture Organization/World Health Organization (FAO/WHO) provisional tolerable weekly intake (PTWI) values of arsenic in our study were 3.32, 5.75 and 12.9 μg/kg body weight/day from mild, moderate and high arsenic-affected families, respectively, which is higher than the recommended PTWI value of arsenic (2.1 μg/kg body weight/day).

Environmental exposure and preventive measures in Sweden and EU*

Environmental exposure to cadmium (Cd) gives rise to renal tubular dysfunction at low cumulative doses of Cd. A possible role of Cd in influencing the occurrence of diseases, e.g., bone, reproductive and cancer in the general population groups environmentally exposed to Cd has been reported from Japan, Belgium, Sweden and China. Authorities have to pay attention to this fact and to act in order to prevent serious outcomes and personal suffering in the population groups at risk. A general approach in setting recommended health based limits and to regulate the occurrence of a substance existing in food stuff is to keep low levels -better to be on the safer side than on the risk side. In the case of cadmium it should be most clear that since cadmium has a very long biological half-life of 20 years in humans, increased cadmium exposure due to human activities can never be accepted. In cases where cadmium exposure can not be avoided the approach should be to limit and decrease exposure. Presently FAO/WHO Expert Committee on Food Additives and Food has a PTWI (provisional tolerable weekly intake) value for adult persons of 7 microg/kg body weight for Cd (WHO 2003) a value corresponding to 1 microg/kg body weight for each day of a week. For children and pregnant or lactating women daily intakes should not exceed 1 microg/kg body weight.

Report of workshop on the significance of excursions of intake above the ADI.

The acceptable daily intake (ADI) for humans was originally developed by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) and defined as "an estimate of the amount of a food additive, expressed on a body weight basis, that can be ingested daily over a lifetime without appreciable health risk." JECFA has not provided any firm guidance on how to evaluate excursions of intake above the ADI, but WHO in 1987 stated that "because in most cases, data are extrapolated from life-time animal studies, the ADI relates to life-time use and provides a margin of safety large enough for toxicologists not to be particularly concerned about short-term use at exposure levels exceeding the ADI, providing the average intake over longer periods of time does not exceed it." In discussing short-term intakes in excess of recommended limits, JECFA in 1989 concluded that short-term exposures to levels exceeding the provisional tolerable weekly intake (PTWI) for a contaminant is not a cause of concern, provided the individual's intake averaged over longer periods of time does not exceed the level set. JECFA also stated that it was impossible to make a generalization concerning the length of time during which intakes in excess of the PTWI would be toxicologically detrimental. Any detrimental effect would depend upon the nature of the toxicity and the biological half-life of the chemical concerned. JECFA considered intakes of food additives in excess of the ADI less likely to occur and easier to control than in the case of contaminants which are allocated either a PTWI or a tolerable daily intake (TDI). The ILSI Europe Acceptable Daily Intake Task Force together with the Food Chemical Intake Task Force initiated a workshop which took place April 21-23, 1998, in Milan, Italy, in order to help identify what information would be needed, with what precision, and what is already available to evaluate the significance of excursions of intake above the ADI. The specific aims of the workshop were to address the following questions: By how much can the ADI be exceeded? For how long can excursions above the ADI be tolerated with respect to chronic toxicity, accumulation, and mechanisms of toxicity? What methods should be used to estimate intakes so that the estimates are relevant to the ADI? Do the same principles apply to contaminants that have TDI or PTWI values?